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* powerpc/boot: Request no dynamic linker for boot wrapperNicholas Piggin2017-07-181-1/+24
| | | | | | | | | | | | | | | | | | | | | | | | The boot wrapper performs its own relocations and does not require PT_INTERP segment. However currently we don't tell the linker that. Prior to binutils 2.28 that works OK. But since binutils commit 1a9ccd70f9a7 ("Fix the linker so that it will not silently generate ELF binaries with invalid program headers. Fix readelf to report such invalid binaries.") binutils tries to create a program header segment due to PT_INTERP, and the link fails because there is no space for it: ld: arch/powerpc/boot/zImage.pseries: Not enough room for program headers, try linking with -N ld: final link failed: Bad value So tell the linker not to do that, by passing --no-dynamic-linker. Cc: stable@vger.kernel.org Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Drop dependency on ld-version.sh and massage change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> (cherry picked from commit ff45000fcb56b5b0f1a14a865d3541746d838a0a) Signed-off-by: Joel Stanley <joel@jms.id.au>
* powerpc/boot: Add OPAL console to epapr wrappersOliver O'Halloran2017-07-187-2/+174
| | | | | | | | | | | | | | | | | | | This patch adds an OPAL console backend to the powerpc boot wrapper so that decompression failures inside the wrapper can be reported to the user. This is important since it typically indicates data corruption in the firmware and other nasty things. Currently this only works when building a little endian kernel. When compiling a 64 bit BE kernel the wrapper is always build 32 bit to be compatible with some 32 bit firmwares. BE support will be added at a later date. Another limitation of this is that only the "raw" type of OPAL console is supported, however machines that provide a hvsi console also provide a raw console so this is not an issue in practice. Actually-written-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Cc: Stewart Smith <stewart@linux.vnet.ibm.com> Signed-off-by: Joel Stanley <joel@jms.id.au>
* powerpc/eeh: Enable IO path on permanent errorGavin Shan2017-07-051-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 387bbc974f6adf91aa635090f73434ed10edd915 ] We give up recovery on permanent error, simply shutdown the affected devices and remove them. If the devices can't be put into quiet state, they spew more traffic that is likely to cause another unexpected EEH error. This was observed on "p8dtu2u" machine: 0002:00:00.0 PCI bridge: IBM Device 03dc 0002:01:00.0 Ethernet controller: Intel Corporation \ Ethernet Controller X710/X557-AT 10GBASE-T (rev 02) 0002:01:00.1 Ethernet controller: Intel Corporation \ Ethernet Controller X710/X557-AT 10GBASE-T (rev 02) 0002:01:00.2 Ethernet controller: Intel Corporation \ Ethernet Controller X710/X557-AT 10GBASE-T (rev 02) 0002:01:00.3 Ethernet controller: Intel Corporation \ Ethernet Controller X710/X557-AT 10GBASE-T (rev 02) On P8 PowerNV platform, the IO path is frozen when shutdowning the devices, meaning the memory registers are inaccessible. It is why the devices can't be put into quiet state before removing them. This fixes the issue by enabling IO path prior to putting the devices into quiet state. Reported-by: Pridhiviraj Paidipeddi <ppaidipe@linux.vnet.ibm.com> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Acked-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/slb: Force a full SLB flush when we insert for a bad EAMichael Ellerman2017-06-291-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [Note this patch is not upstream. The bug fix was fixed differently in upstream prior to the bug being identified.] The SLB miss handler calls slb_allocate_realmode() in order to create an SLB entry for the faulting address. At the very start of that function we check that the faulting Effective Address (EA) is less than PGTABLE_RANGE (ignoring the region), ie. is it an address which could possibly fit in the virtual address space. For an EA which fails that test, we branch out of line (to label 8), but we still go on to create an SLB entry for the address. The SLB entry we create has a VSID of 0, which means it will never match anything in the hash table and so can't actually translate to a physical address. However that SLB entry will be inserted in the SLB, and so needs to be managed properly like any other SLB entry. In particular we need to insert the SLB entry in the SLB cache, so that it will be flushed when the process is descheduled. And that is where the bugs begin. The first bug is that slb_finish_load() uses cr7 to decide if it should insert the SLB entry into the SLB cache. When we come from the invalid EA case we don't set cr7, it just has some junk value from userspace. So we may or may not insert the SLB entry in the SLB cache. If we fail to insert it, we may then incorrectly leave it in the SLB when the process is descheduled. The second bug is that even if we do happen to add the entry to the SLB cache, we do not have enough bits in the SLB cache to remember the full ESID value for very large EAs. For example if a process branches to 0x788c545a18000000, that results in a 256MB SLB entry with an ESID of 0x788c545a1. But each entry in the SLB cache is only 32-bits, meaning we truncate the ESID to 0x88c545a1. This has the same effect as the first bug, we incorrectly leave the SLB entry in the SLB when the process is descheduled. When a process accesses an invalid EA it results in a SEGV signal being sent to the process, which typically results in the process being killed. Process death isn't instantaneous however, the process may catch the SEGV signal and continue somehow, or the kernel may start writing a core dump for the process, either of which means it's possible for the process to be preempted while its processing the SEGV but before it's been killed. If that happens, when the process is scheduled back onto the CPU we will allocate a new SLB entry for the NIP, which will insert a second entry into the SLB for the bad EA. Because we never flushed the original entry, due to either bug one or two, we now have two SLB entries that match the same EA. If another access is made to that EA, either by the process continuing after catching the SEGV, or by a second process accessing the same bad EA on the same CPU, we will trigger an SLB multi-hit machine check exception. This has been observed happening in the wild. The fix is when we hit the invalid EA case, we mark the SLB cache as being full. This causes us to not insert the truncated ESID into the SLB cache, and means when the process is switched out we will flush the entire SLB. Note that this works both for the original fault and for a subsequent call to slb_allocate_realmode() from switch_slb(). Because we mark the SLB cache as full, it doesn't really matter what value is in cr7, but rather than leaving it as something random we set it to indicate the address was a kernel address. That also skips the attempt to insert it in the SLB cache which is a nice side effect. Another way to fix the bug would be to make the entries in the SLB cache wider, so that we don't truncate the ESID. However this would be a more intrusive change as it alters the size and layout of the paca. This bug was fixed in upstream by commit f0f558b131db ("powerpc/mm: Preserve CFAR value on SLB miss caused by access to bogus address"), which changed the way we handle a bad EA entirely removing this bug in the process. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/kprobes: Pause function_graph tracing during jprobes handlingNaveen N. Rao2017-06-291-0/+11
| | | | | | | | | | | | | | | | | | | | | | commit a9f8553e935f26cb5447f67e280946b0923cd2dc upstream. This fixes a crash when function_graph and jprobes are used together. This is essentially commit 237d28db036e ("ftrace/jprobes/x86: Fix conflict between jprobes and function graph tracing"), but for powerpc. Jprobes breaks function_graph tracing since the jprobe hook needs to use jprobe_return(), which never returns back to the hook, but instead to the original jprobe'd function. The solution is to momentarily pause function_graph tracing before invoking the jprobe hook and re-enable it when returning back to the original jprobe'd function. Fixes: 6794c78243bf ("powerpc64: port of the function graph tracer") Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: PPC: Book3S HV: Preserve userspace HTM state properlyPaul Mackerras2017-06-291-0/+21
| | | | | | | | | | | | | | | | | | | | | | | | | commit 46a704f8409f79fd66567ad3f8a7304830a84293 upstream. If userspace attempts to call the KVM_RUN ioctl when it has hardware transactional memory (HTM) enabled, the values that it has put in the HTM-related SPRs TFHAR, TFIAR and TEXASR will get overwritten by guest values. To fix this, we detect this condition and save those SPR values in the thread struct, and disable HTM for the task. If userspace goes to access those SPRs or the HTM facility in future, a TM-unavailable interrupt will occur and the handler will reload those SPRs and re-enable HTM. If userspace has started a transaction and suspended it, we would currently lose the transactional state in the guest entry path and would almost certainly get a "TM Bad Thing" interrupt, which would cause the host to crash. To avoid this, we detect this case and return from the KVM_RUN ioctl with an EINVAL error, with the KVM exit reason set to KVM_EXIT_FAIL_ENTRY. Fixes: b005255e12a3 ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs", 2014-01-08) Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* mm: larger stack guard gap, between vmasHugh Dickins2017-06-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream. Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [wt: backport to 4.11: adjust context] [wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide] [wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes] Signed-off-by: Willy Tarreau <w@1wt.eu> [gkh: minor build fixes for 4.4] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/hotplug-mem: Fix missing endian conversion of aa_indexMichael Bringmann2017-06-141-0/+2
| | | | | | | | | | | | | | | | commit dc421b200f91930c9c6a9586810ff8c232cf10fc upstream. When adding or removing memory, the aa_index (affinity value) for the memblock must also be converted to match the endianness of the rest of the 'ibm,dynamic-memory' property. Otherwise, subsequent retrieval of the attribute will likely lead to non-existent nodes, followed by using the default node in the code inappropriately. Fixes: 5f97b2a0d176 ("powerpc/pseries: Implement memory hotplug add in the kernel") Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/numa: Fix percpu allocations to be NUMA awareMichael Ellerman2017-06-142-2/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit ba4a648f12f4cd0a8003dd229b6ca8a53348ee4b upstream. In commit 8c272261194d ("powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID"), we switched to the generic implementation of cpu_to_node(), which uses a percpu variable to hold the NUMA node for each CPU. Unfortunately we neglected to notice that we use cpu_to_node() in the allocation of our percpu areas, leading to a chicken and egg problem. In practice what happens is when we are setting up the percpu areas, cpu_to_node() reports that all CPUs are on node 0, so we allocate all percpu areas on node 0. This is visible in the dmesg output, as all pcpu allocs being in group 0: pcpu-alloc: [0] 00 01 02 03 [0] 04 05 06 07 pcpu-alloc: [0] 08 09 10 11 [0] 12 13 14 15 pcpu-alloc: [0] 16 17 18 19 [0] 20 21 22 23 pcpu-alloc: [0] 24 25 26 27 [0] 28 29 30 31 pcpu-alloc: [0] 32 33 34 35 [0] 36 37 38 39 pcpu-alloc: [0] 40 41 42 43 [0] 44 45 46 47 To fix it we need an early_cpu_to_node() which can run prior to percpu being setup. We already have the numa_cpu_lookup_table we can use, so just plumb it in. With the patch dmesg output shows two groups, 0 and 1: pcpu-alloc: [0] 00 01 02 03 [0] 04 05 06 07 pcpu-alloc: [0] 08 09 10 11 [0] 12 13 14 15 pcpu-alloc: [0] 16 17 18 19 [0] 20 21 22 23 pcpu-alloc: [1] 24 25 26 27 [1] 28 29 30 31 pcpu-alloc: [1] 32 33 34 35 [1] 36 37 38 39 pcpu-alloc: [1] 40 41 42 43 [1] 44 45 46 47 We can also check the data_offset in the paca of various CPUs, with the fix we see: CPU 0: data_offset = 0x0ffe8b0000 CPU 24: data_offset = 0x1ffe5b0000 And we can see from dmesg that CPU 24 has an allocation on node 1: node 0: [mem 0x0000000000000000-0x0000000fffffffff] node 1: [mem 0x0000001000000000-0x0000001fffffffff] Fixes: 8c272261194d ("powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/eeh: Avoid use after free in eeh_handle_special_event()Russell Currey2017-06-141-4/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | commit daeba2956f32f91f3493788ff6ee02fb1b2f02fa upstream. eeh_handle_special_event() is called when an EEH event is detected but can't be narrowed down to a specific PE. This function looks through every PE to find one in an erroneous state, then calls the regular event handler eeh_handle_normal_event() once it knows which PE has an error. However, if eeh_handle_normal_event() found that the PE cannot possibly be recovered, it will free it, rendering the passed PE stale. This leads to a use after free in eeh_handle_special_event() as it attempts to clear the "recovering" state on the PE after eeh_handle_normal_event() returns. Thus, make sure the PE is valid when attempting to clear state in eeh_handle_special_event(). Fixes: 8a6b1bc70dbb ("powerpc/eeh: EEH core to handle special event") Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Russell Currey <ruscur@russell.cc> Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64e: Fix hang when debugging programs with relocated kernelLiuHailong2017-05-251-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit fd615f69a18a9d4aa5ef02a1dc83f319f75da8e7 upstream. Debug interrupts can be taken during interrupt entry, since interrupt entry does not automatically turn them off. The kernel will check whether the faulting instruction is between [interrupt_base_book3e, __end_interrupts], and if so clear MSR[DE] and return. However, when the kernel is built with CONFIG_RELOCATABLE, it can't use LOAD_REG_IMMEDIATE(r14,interrupt_base_book3e) and LOAD_REG_IMMEDIATE(r15,__end_interrupts), as they ignore relocation. Thus, if the kernel is actually running at a different address than it was built at, the address comparison will fail, and the exception entry code will hang at kernel_dbg_exc. r2(toc) is also not usable here, as r2 still holds data from the interrupted context, so LOAD_REG_ADDR() doesn't work either. So we use the *name@got* to get the EV of two labels directly. Test programs test.c shows as follows: int main(int argc, char *argv[]) { if (access("/proc/sys/kernel/perf_event_paranoid", F_OK) == -1) printf("Kernel doesn't have perf_event support\n"); } Steps to reproduce the bug, for example: 1) ./gdb ./test 2) (gdb) b access 3) (gdb) r 4) (gdb) s Signed-off-by: Liu Hailong <liu.hailong6@zte.com.cn> Signed-off-by: Jiang Xuexin <jiang.xuexin@zte.com.cn> Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn> Reviewed-by: Liu Song <liu.song11@zte.com.cn> Reviewed-by: Huang Jian <huang.jian@zte.com.cn> [scottwood: cleaned up commit message, and specified bad behavior as a hang rather than an oops to correspond to mainline kernel behavior] Fixes: 1cb6e0649248 ("powerpc/book3e: support CONFIG_RELOCATABLE") Signed-off-by: Scott Wood <oss@buserror.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/pseries: Fix of_node_put() underflow during DLPAR removeTyrel Datwyler2017-05-251-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 68baf692c435339e6295cb470ea5545cbc28160e upstream. Historically struct device_node references were tracked using a kref embedded as a struct field. Commit 75b57ecf9d1d ("of: Make device nodes kobjects so they show up in sysfs") (Mar 2014) refactored device_nodes to be kobjects such that the device tree could by more simply exposed to userspace using sysfs. Commit 0829f6d1f69e ("of: device_node kobject lifecycle fixes") (Mar 2014) followed up these changes to better control the kobject lifecycle and in particular the referecne counting via of_node_get(), of_node_put(), and of_node_init(). A result of this second commit was that it introduced an of_node_put() call when a dynamic node is detached, in of_node_remove(), that removes the initial kobj reference created by of_node_init(). Traditionally as the original dynamic device node user the pseries code had assumed responsibilty for releasing this final reference in its platform specific DLPAR detach code. This patch fixes a refcount underflow introduced by commit 0829f6d1f6, and recently exposed by the upstreaming of the recount API. Messages like the following are no longer seen in the kernel log with this patch following DLPAR remove operations of cpus and pci devices. rpadlpar_io: slot PHB 72 removed refcount_t: underflow; use-after-free. ------------[ cut here ]------------ WARNING: CPU: 5 PID: 3335 at lib/refcount.c:128 refcount_sub_and_test+0xf4/0x110 Fixes: 0829f6d1f69e ("of: device_node kobject lifecycle fixes") Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> [mpe: Make change log commit references more verbose] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/book3s/mce: Move add_taint() later in virtual modeMahesh Salgaonkar2017-05-252-2/+4
| | | | | | | | | | | | | | | | | | | | | | | commit d93b0ac01a9ce276ec39644be47001873d3d183c upstream. machine_check_early() gets called in real mode. The very first time when add_taint() is called, it prints a warning which ends up calling opal call (that uses OPAL_CALL wrapper) for writing it to console. If we get a very first machine check while we are in opal we are doomed. OPAL_CALL overwrites the PACASAVEDMSR in r13 and in this case when we are done with MCE handling the original opal call will use this new MSR on it's way back to opal_return. This usually leads to unexpected behaviour or the kernel to panic. Instead move the add_taint() call later in the virtual mode where it is safe to call. This is broken with current FW level. We got lucky so far for not getting very first MCE hit while in OPAL. But easily reproducible on Mambo. Fixes: 27ea2c420cad ("powerpc: Set the correct kernel taint on machine check errors.") Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/powernv: Fix opal_exit tracepoint opcodeMichael Ellerman2017-05-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | commit a7e0fb6c2029a780444d09560f739e020d54fe4d upstream. Currently the opal_exit tracepoint usually shows the opcode as 0: <idle>-0 [047] d.h. 635.654292: opal_entry: opcode=63 <idle>-0 [047] d.h. 635.654296: opal_exit: opcode=0 retval=0 kopald-1209 [019] d... 636.420943: opal_entry: opcode=10 kopald-1209 [019] d... 636.420959: opal_exit: opcode=0 retval=0 This is because we incorrectly load the opcode into r0 before calling __trace_opal_exit(), whereas it expects the opcode in r3 (first function parameter). In fact we are leaving the retval in r3, so opcode and retval will always show the same value. Instead load the opcode into r3, resulting in: <idle>-0 [040] d.h. 636.618625: opal_entry: opcode=63 <idle>-0 [040] d.h. 636.618627: opal_exit: opcode=63 retval=0 Fixes: c49f63530bb6 ("powernv: Add OPAL tracepoints") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/kprobe: Fix oops when kprobed on 'stdu' instructionRavi Bangoria2017-04-271-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 9e1ba4f27f018742a1aa95d11e35106feba08ec1 upstream. If we set a kprobe on a 'stdu' instruction on powerpc64, we see a kernel OOPS: Bad kernel stack pointer cd93c840 at c000000000009868 Oops: Bad kernel stack pointer, sig: 6 [#1] ... GPR00: c000001fcd93cb30 00000000cd93c840 c0000000015c5e00 00000000cd93c840 ... NIP [c000000000009868] resume_kernel+0x2c/0x58 LR [c000000000006208] program_check_common+0x108/0x180 On a 64-bit system when the user probes on a 'stdu' instruction, the kernel does not emulate actual store in emulate_step() because it may corrupt the exception frame. So the kernel does the actual store operation in exception return code i.e. resume_kernel(). resume_kernel() loads the saved stack pointer from memory using lwz, which only loads the low 32-bits of the address, causing the kernel crash. Fix this by loading the 64-bit value instead. Fixes: be96f63375a1 ("powerpc: Split out instruction analysis part of emulate_step()") Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> [mpe: Change log massage, add stable tag] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc: Disable HFSCR[TM] if TM is not supportedBenjamin Herrenschmidt2017-04-211-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 7ed23e1bae8bf7e37fd555066550a00b95a3a98b upstream. On Power8 & Power9 the early CPU inititialisation in __init_HFSCR() turns on HFSCR[TM] (Hypervisor Facility Status and Control Register [Transactional Memory]), but that doesn't take into account that TM might be disabled by CPU features, or disabled by the kernel being built with CONFIG_PPC_TRANSACTIONAL_MEM=n. So later in boot, when we have setup the CPU features, clear HSCR[TM] if the TM CPU feature has been disabled. We use CPU_FTR_TM_COMP to account for the CONFIG_PPC_TRANSACTIONAL_MEM=n case. Without this a KVM guest might try use TM, even if told not to, and cause an oops in the host kernel. Typically the oops is seen in __kvmppc_vcore_entry() and may or may not be fatal to the host, but is always bad news. In practice all shipping CPU revisions do support TM, and all host kernels we are aware of build with TM support enabled, so no one should actually be able to hit this in the wild. Fixes: 2a3563b023e5 ("powerpc: Setup in HFSCR for POWER8") Cc: stable@vger.kernel.org # v3.10+ Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by: Sam Bobroff <sam.bobroff@au1.ibm.com> [mpe: Rewrite change log with input from Sam, add Fixes/stable] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> [sb: Backported to linux-4.4.y: adjusted context] Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc: Don't try to fix up misaligned load-with-reservation instructionsPaul Mackerras2017-04-121-8/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | commit 48fe9e9488743eec9b7c1addd3c93f12f2123d54 upstream. In the past, there was only one load-with-reservation instruction, lwarx, and if a program attempted a lwarx on a misaligned address, it would take an alignment interrupt and the kernel handler would emulate it as though it was lwzx, which was not really correct, but benign since it is loading the right amount of data, and the lwarx should be paired with a stwcx. to the same address, which would also cause an alignment interrupt which would result in a SIGBUS being delivered to the process. We now have 5 different sizes of load-with-reservation instruction. Of those, lharx and ldarx cause an immediate SIGBUS by luck since their entries in aligninfo[] overlap instructions which were not fixed up, but lqarx overlaps with lhz and will be emulated as such. lbarx can never generate an alignment interrupt since it only operates on 1 byte. To straighten this out and fix the lqarx case, this adds code to detect the l[hwdq]arx instructions and return without fixing them up, resulting in a SIGBUS being delivered to the process. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/mm: Add missing global TLB invalidate if cxl is activeFrederic Barrat2017-04-121-2/+5
| | | | | | | | | | | | | | | | | | | | | commit 88b1bf7268f56887ca88eb09c6fb0f4fc970121a upstream. Commit 4c6d9acce1f4 ("powerpc/mm: Add hooks for cxl") converted local TLB invalidates to global if the cxl driver is active. This is necessary because the CAPP snoops invalidations to forward them to the PSL on the cxl adapter. However one path was forgotten. native_flush_hash_range() still does local TLB invalidates, as found out the hard way recently. This patch fixes it by following the same logic as previously: if the cxl driver is active, the local TLB invalidates are 'upgraded' to global. Fixes: 4c6d9acce1f4 ("powerpc/mm: Add hooks for cxl") Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/boot: Fix zImage TOC alignmentMichael Ellerman2017-03-261-0/+1
| | | | | | | | | | | | | | | commit 97ee351b50a49717543533cfb85b4bf9d88c9680 upstream. Recent toolchains force the TOC to be 256 byte aligned. We need to enforce this alignment in the zImage linker script, otherwise pointers to our TOC variables (__toc_start) could be incorrect. If the actual start of the TOC and __toc_start don't have the same value we crash early in the zImage wrapper. Suggested-by: Alan Modra <amodra@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: PPC: Book3S PR: Fix illegal opcode emulationThomas Huth2017-03-261-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 708e75a3ee750dce1072134e630d66c4e6eaf63c upstream. If kvmppc_handle_exit_pr() calls kvmppc_emulate_instruction() to emulate one instruction (in the BOOK3S_INTERRUPT_H_EMUL_ASSIST case), it calls kvmppc_core_queue_program() afterwards if kvmppc_emulate_instruction() returned EMULATE_FAIL, so the guest gets an program interrupt for the illegal opcode. However, the kvmppc_emulate_instruction() also tried to inject a program exception for this already, so the program interrupt gets injected twice and the return address in srr0 gets destroyed. All other callers of kvmppc_emulate_instruction() are also injecting a program interrupt, and since the callers have the right knowledge about the srr1 flags that should be used, it is the function kvmppc_emulate_instruction() that should _not_ inject program interrupts, so remove the kvmppc_core_queue_program() here. This fixes the issue discovered by Laurent Vivier with kvm-unit-tests where the logs are filled with these messages when the test tries to execute an illegal instruction: Couldn't emulate instruction 0x00000000 (op 0 xop 0) kvmppc_handle_exit_pr: emulation at 700 failed (00000000) Signed-off-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Alexander Graf <agraf@suse.de> Tested-by: Laurent Vivier <lvivier@redhat.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Cc: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc: Emulation support for load/store instructions on LERavi Bangoria2017-03-181-20/+0
| | | | | | | | | | | | | | commit e148bd17f48bd17fca2f4f089ec879fa6e47e34c upstream. emulate_step() uses a number of underlying kernel functions that were initially not enabled for LE. This has been rectified since. So, fix emulate_step() for LE for the corresponding instructions. Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/xmon: Fix data-breakpointRavi Bangoria2017-03-121-1/+3
| | | | | | | | | | | | | | | | | | | | | | commit c21a493a2b44650707d06741601894329486f2ad upstream. Currently xmon data-breakpoint feature is broken. Whenever there is a watchpoint match occurs, hw_breakpoint_handler will be called by do_break via notifier chains mechanism. If watchpoint is registered by xmon, hw_breakpoint_handler won't find any associated perf_event and returns immediately with NOTIFY_STOP. Similarly, do_break also returns without notifying to xmon. Solve this by returning NOTIFY_DONE when hw_breakpoint_handler does not find any perf_event associated with matched watchpoint, rather than NOTIFY_STOP, which tells the core code to continue calling the other breakpoint handlers including the xmon one. Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc: Add missing error check to prom_find_boot_cpu()Darren Stevens2017-02-091-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit af2b7fa17eb92e52b65f96604448ff7a2a89ee99 upstream. prom_init.c calls 'instance-to-package' twice, but the return is not checked during prom_find_boot_cpu(). The result is then passed to prom_getprop(), which could be PROM_ERROR. Add a return check to prevent this. This was found on a pasemi system, where CFE doesn't have a working 'instance-to package' prom call. Before Commit 5c0484e25ec0 ('powerpc: Endian safe trampoline') the area around addr 0 was mostly 0's and this doesn't cause a problem. Once the macro 'FIXUP_ENDIAN' has been added to head_64.S, the low memory area now has non-zero values, which cause the prom_getprop() call to hang. mpe: Also confirmed that under SLOF if 'instance-to-package' did fail with PROM_ERROR we would crash in SLOF. So the bug is not specific to CFE, it's just that other open firmwares don't trigger it because they have a working 'instance-to-package'. Fixes: 5c0484e25ec0 ("powerpc: Endian safe trampoline") Signed-off-by: Darren Stevens <darren@stevens-zone.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/eeh: Fix wrong flag passed to eeh_unfreeze_pe()Gavin Shan2017-02-091-1/+1
| | | | | | | | | | | | | | | | | | | commit f05fea5b3574a5926c53865eea27139bb40b2f2b upstream. In __eeh_clear_pe_frozen_state(), we should pass the flag's value instead of its address to eeh_unfreeze_pe(). The isolated flag is cleared if no error returned from __eeh_clear_pe_frozen_state(). We never observed the error from the function. So the isolated flag should have been always cleared, no real issue is caused because of the misused @flag. This fixes the code by passing the value of @flag to eeh_unfreeze_pe(). Fixes: 5cfb20b96f6 ("powerpc/eeh: Emulate EEH recovery for VFIO devices") Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/ibmebus: Fix device reference leaks in sysfs interfaceJohan Hovold2017-01-191-2/+6
| | | | | | | | | | | | | | commit fe0f3168169f7c34c29b0cf0c489f126a7f29643 upstream. Make sure to drop any reference taken by bus_find_device() in the sysfs callbacks that are used to create and destroy devices based on device-tree entries. Fixes: 6bccf755ff53 ("[POWERPC] ibmebus: dynamic addition/removal of adapters, some code cleanup") Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/ibmebus: Fix further device reference leaksJohan Hovold2017-01-191-2/+6
| | | | | | | | | | | | | commit 815a7141c4d1b11610dccb7fcbb38633759824f2 upstream. Make sure to drop any reference taken by bus_find_device() when creating devices during init and driver registration. Fixes: 55347cc9962f ("[POWERPC] ibmebus: Add device creation and bus probing based on of_device") Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc: Fix build warning on 32-bit PPCLarry Finger2017-01-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 8ae679c4bc2ea2d16d92620da8e3e9332fa4039f upstream. I am getting the following warning when I build kernel 4.9-git on my PowerBook G4 with a 32-bit PPC processor: AS arch/powerpc/kernel/misc_32.o arch/powerpc/kernel/misc_32.S:299:7: warning: "CONFIG_FSL_BOOKE" is not defined [-Wundef] This problem is evident after commit 989cea5c14be ("kbuild: prevent lib-ksyms.o rebuilds"); however, this change in kbuild only exposes an error that has been in the code since 2005 when this source file was created. That was with commit 9994a33865f4 ("powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S"). The offending line does not make a lot of sense. This error does not seem to cause any errors in the executable, thus I am not recommending that it be applied to any stable versions. Thanks to Nicholas Piggin for suggesting this solution. Fixes: 9994a33865f4 ("powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S") Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc: Convert cmp to cmpd in idle enter sequenceSegher Boessenkool2017-01-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | commit 80f23935cadb1c654e81951f5a8b7ceae0acc1b4 upstream. PowerPC's "cmp" instruction has four operands. Normally people write "cmpw" or "cmpd" for the second cmp operand 0 or 1. But, frequently people forget, and write "cmp" with just three operands. With older binutils this is silently accepted as if this was "cmpw", while often "cmpd" is wanted. With newer binutils GAS will complain about this for 64-bit code. For 32-bit code it still silently assumes "cmpw" is what is meant. In this instance the code comes directly from ISA v2.07, including the cmp, but cmpd is correct. Backport to stable so that new toolchains can build old kernels. Fixes: 948cf67c4726 ("powerpc: Add NAP mode support on Power7 in HV mode") Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/ps3: Fix system hang with GCC 5 buildsGeoff Levand2017-01-092-12/+1
| | | | | | | | | | | | | commit 6dff5b67054e17c91bd630bcdda17cfca5aa4215 upstream. GCC 5 generates different code for this bootwrapper null check that causes the PS3 to hang very early in its bootup. This check is of limited value, so just get rid of it. Signed-off-by: Geoff Levand <geoff@infradead.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: PPC: Book3S HV: Don't lose hardware R/C bit updates in H_PROTECTPaul Mackerras2017-01-091-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | commit f064a0de1579fabded8990bed93971e30deb9ecb upstream. The hashed page table MMU in POWER processors can update the R (reference) and C (change) bits in a HPTE at any time until the HPTE has been invalidated and the TLB invalidation sequence has completed. In kvmppc_h_protect, which implements the H_PROTECT hypercall, we read the HPTE, modify the second doubleword, invalidate the HPTE in memory, do the TLB invalidation sequence, and then write the modified value of the second doubleword back to memory. In doing so we could overwrite an R/C bit update done by hardware between when we read the HPTE and when the TLB invalidation completed. To fix this we re-read the second doubleword after the TLB invalidation and OR in the (possibly) new values of R and C. We can use an OR since hardware only ever sets R and C, never clears them. This race was found by code inspection. In principle this bug could cause occasional guest memory corruption under host memory pressure. Fixes: a8606e20e41a ("KVM: PPC: Handle some PAPR hcalls in the kernel", 2011-06-29) Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: PPC: Book3S HV: Save/restore XER in checkpointed register statePaul Mackerras2017-01-095-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | commit 0d808df06a44200f52262b6eb72bcb6042f5a7c5 upstream. When switching from/to a guest that has a transaction in progress, we need to save/restore the checkpointed register state. Although XER is part of the CPU state that gets checkpointed, the code that does this saving and restoring doesn't save/restore XER. This fixes it by saving and restoring the XER. To allow userspace to read/write the checkpointed XER value, we also add a new ONE_REG specifier. The visible effect of this bug is that the guest may see its XER value being corrupted when it uses transactions. Fixes: e4e38121507a ("KVM: PPC: Book3S HV: Add transactional memory support") Fixes: 0a8eccefcb34 ("KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit") Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/eeh: Fix deadlock when PE frozen state can't be clearedAndrew Donnellan2016-12-151-1/+3
| | | | | | | | | | | | | | | | | | | | commit 409bf7f8a02ef88db5a0f2cdcf9489914f4b8508 upstream. In eeh_reset_device(), we take the pci_rescan_remove_lock immediately after after we call eeh_reset_pe() to reset the PCI controller. We then call eeh_clear_pe_frozen_state(), which can return an error. In this case, we bail out of eeh_reset_device() without calling pci_unlock_rescan_remove(). Add a call to pci_unlock_rescan_remove() in the eeh_clear_pe_frozen_state() error path so that we don't cause a deadlock later on. Reported-by: Pradipta Ghosh <pradghos@in.ibm.com> Fixes: 78954700631f ("powerpc/eeh: Avoid I/O access during PE reset") Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Acked-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/ptrace: Fix out of bounds array access warningKhem Raj2016-11-101-2/+2
| | | | | | | | | | | | | | | | | | | | | | | commit 1e407ee3b21f981140491d5b8a36422979ca246f upstream. gcc-6 correctly warns about a out of bounds access arch/powerpc/kernel/ptrace.c:407:24: warning: index 32 denotes an offset greater than size of 'u64[32][1] {aka long long unsigned int[32][1]}' [-Warray-bounds] offsetof(struct thread_fp_state, fpr[32][0])); ^ check the end of array instead of beginning of next element to fix this Signed-off-by: Khem Raj <raj.khem@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Segher Boessenkool <segher@kernel.crashing.org> Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi> Acked-by: Olof Johansson <olof@lixom.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/nvram: Fix an incorrect partition mergePan Xinhui2016-10-311-3/+3
| | | | | | | | | | | | | | | | | commit 11b7e154b132232535befe51c55db048069c8461 upstream. When we merge two contiguous partitions whose signatures are marked NVRAM_SIG_FREE, We need update prev's length and checksum, then write it to nvram, not cur's. So lets fix this mistake now. Also use memset instead of strncpy to set the partition's name. It's more readable if we want to fill up with duplicate chars . Fixes: fa2b4e54d41f ("powerpc/nvram: Improve partition removal") Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/eeh: Null check uses of eeh_pe_bus_getRussell Currey2016-10-312-0/+13
| | | | | | | | | | | | | | | | | | commit 04fec21c06e35b169a83e75a84a015ab4606bf5e upstream. eeh_pe_bus_get() can return NULL if a PCI bus isn't found for a given PE. Some callers don't check this, and can cause a null pointer dereference under certain circumstances. Fix this by checking NULL everywhere eeh_pe_bus_get() is called. Fixes: 8a6b1bc70dbb ("powerpc/eeh: EEH core to handle special event") Cc: stable@vger.kernel.org # v3.11+ Signed-off-by: Russell Currey <ruscur@russell.cc> Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/mm: Prevent unlikely crash in copro_calculate_slb()Frederic Barrat2016-10-281-0/+2
| | | | | | | | | | | | | | | | | | commit d2cf909cda5f8c5609cb7ed6cda816c3e15528c7 upstream. If a cxl adapter faults on an invalid address for a kernel context, we may enter copro_calculate_slb() with a NULL mm pointer (kernel context) and an effective address which looks like a user address. Which will cause a crash when dereferencing mm. It is clearly an AFU bug, but there's no reason to crash either. So return an error, so that cxl can ack the interrupt with an address error. Fixes: 73d16a6e0e51 ("powerpc/cell: Move data segment faulting code out of cell platform") Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/pseries: Fix stack corruption in htpe codeLaurent Dufour2016-10-281-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 05af40e885955065aee8bb7425058eb3e1adca08 upstream. This commit fixes a stack corruption in the pseries specific code dealing with the huge pages. In __pSeries_lpar_hugepage_invalidate() the buffer used to pass arguments to the hypervisor is not large enough. This leads to a stack corruption where a previously saved register could be corrupted leading to unexpected result in the caller, like the following panic: Oops: Kernel access of bad area, sig: 11 [#1] SMP NR_CPUS=2048 NUMA pSeries Modules linked in: virtio_balloon ip_tables x_tables autofs4 virtio_blk 8139too virtio_pci virtio_ring 8139cp virtio CPU: 11 PID: 1916 Comm: mmstress Not tainted 4.8.0 #76 task: c000000005394880 task.stack: c000000005570000 NIP: c00000000027bf6c LR: c00000000027bf64 CTR: 0000000000000000 REGS: c000000005573820 TRAP: 0300 Not tainted (4.8.0) MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 84822884 XER: 20000000 CFAR: c00000000010a924 DAR: 420000000014e5e0 DSISR: 40000000 SOFTE: 1 GPR00: c00000000027bf64 c000000005573aa0 c000000000e02800 c000000004447964 GPR04: c00000000404de18 c000000004d38810 00000000042100f5 00000000f5002104 GPR08: e0000000f5002104 0000000000000001 042100f5000000e0 00000000042100f5 GPR12: 0000000000002200 c00000000fe02c00 c00000000404de18 0000000000000000 GPR16: c1ffffffffffe7ff 00003fff62000000 420000000014e5e0 00003fff63000000 GPR20: 0008000000000000 c0000000f7014800 0405e600000000e0 0000000000010000 GPR24: c000000004d38810 c000000004447c10 c00000000404de18 c000000004447964 GPR28: c000000005573b10 c000000004d38810 00003fff62000000 420000000014e5e0 NIP [c00000000027bf6c] zap_huge_pmd+0x4c/0x470 LR [c00000000027bf64] zap_huge_pmd+0x44/0x470 Call Trace: [c000000005573aa0] [c00000000027bf64] zap_huge_pmd+0x44/0x470 (unreliable) [c000000005573af0] [c00000000022bbd8] unmap_page_range+0xcf8/0xed0 [c000000005573c30] [c00000000022c2d4] unmap_vmas+0x84/0x120 [c000000005573c80] [c000000000235448] unmap_region+0xd8/0x1b0 [c000000005573d80] [c0000000002378f0] do_munmap+0x2d0/0x4c0 [c000000005573df0] [c000000000237be4] SyS_munmap+0x64/0xb0 [c000000005573e30] [c000000000009560] system_call+0x38/0x108 Instruction dump: fbe1fff8 fb81ffe0 7c7f1b78 7ca32b78 7cbd2b78 f8010010 7c9a2378 f821ffb1 7cde3378 4bfffea9 7c7b1b79 41820298 <e87f0000> 48000130 7fa5eb78 7fc4f378 Most of the time, the bug is surfacing in a caller up in the stack from __pSeries_lpar_hugepage_invalidate() which is quite confusing. This bug is pending since v3.11 but was hidden if a caller of the caller of __pSeries_lpar_hugepage_invalidate() has pushed the corruped register (r18 in this case) in the stack and is not using it until restoring it. GCC 6.2.0 seems to raise it more frequently. This commit also change the definition of the parameter buffer in pSeries_lpar_flush_hash_range() to rely on the global define PLPAR_HCALL9_BUFSIZE (no functional change here). Fixes: 1a5272866f87 ("powerpc: Optimize hugepage invalidate") Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/64: Fix incorrect return value from __copy_tofrom_userPaul Mackerras2016-10-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 1a34439e5a0b2235e43f96816dbb15ee1154f656 upstream. Debugging a data corruption issue with virtio-net/vhost-net led to the observation that __copy_tofrom_user was occasionally returning a value 16 larger than it should. Since the return value from __copy_tofrom_user is the number of bytes not copied, this means that __copy_tofrom_user can occasionally return a value larger than the number of bytes it was asked to copy. In turn this can cause higher-level copy functions such as copy_page_to_iter_iovec to corrupt memory by copying data into the wrong memory locations. It turns out that the failing case involves a fault on the store at label 79, and at that point the first unmodified byte of the destination is at R3 + 16. Consequently the exception handler for that store needs to add 16 to R3 before using it to work out how many bytes were not copied, but in this one case it was not adding the offset to R3. To fix it, this moves the label 179 to the point where we add 16 to R3. I have checked manually all the exception handlers for the loads and stores in this code and the rest of them are correct (it would be excellent to have an automated test of all the exception cases). This bug has been present since this code was initially committed in May 2002 to Linux version 2.5.20. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/powernv: Use CPU-endian PEST in pnv_pci_dump_p7ioc_diag_data()Gavin Shan2016-10-281-2/+2
| | | | | | | | | | | | | | | commit 5adaf8629b193f185ca5a1665b9e777a0579f518 upstream. This fixes the warnings reported from sparse: pci.c:312:33: warning: restricted __be64 degrades to integer pci.c:313:33: warning: restricted __be64 degrades to integer Fixes: cee72d5bb489 ("powerpc/powernv: Display diag data on p7ioc EEH errors") Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/powernv: Use CPU-endian hub diag-data type in ↵Gavin Shan2016-10-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | pnv_eeh_get_and_dump_hub_diag() commit a7032132d7560a8434e1f54b71efd7fa20f073bd upstream. The hub diag-data type is filled with big-endian data by OPAL call opal_pci_get_hub_diag_data(). We need convert it to CPU-endian value before using it. The issue is reported by sparse as pointed by Michael Ellerman: eeh-powernv.c:1309:21: warning: restricted __be16 degrades to integer This converts hub diag-data type to CPU-endian before using it in pnv_eeh_get_and_dump_hub_diag(). Fixes: 2a485ad7c88d ("powerpc/powernv: Drop PHB operation next_error()") Suggested-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Reviewed-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/powernv: Pass CPU-endian PE number to opal_pci_eeh_freeze_clear()Gavin Shan2016-10-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | commit d63e51b31e0b655ed0f581b8a8fd4c4b4f8d1919 upstream. The PE number (@frozen_pe_no), filled by opal_pci_next_error() is in big-endian format. It should be converted to CPU-endian before it is passed to opal_pci_eeh_freeze_clear() when clearing the frozen state if the PE is invalid one. As Michael Ellerman pointed out, the issue is also detected by sparse: eeh-powernv.c:1541:41: warning: incorrect type in argument 2 (different base types) This passes CPU-endian PE number to opal_pci_eeh_freeze_clear() and it should be part of commit <0f36db77643b> ("powerpc/eeh: Fix wrong printed PE number"), which was merged to 4.3 kernel. Fixes: 71b540adffd9 ("powerpc/powernv: Don't escalate non-existing frozen PE") Suggested-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Reviewed-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/vdso64: Use double word compare on pointersAnton Blanchard2016-10-282-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 5045ea37377ce8cca6890d32b127ad6770e6dce5 upstream. __kernel_get_syscall_map() and __kernel_clock_getres() use cmpli to check if the passed in pointer is non zero. cmpli maps to a 32 bit compare on binutils, so we ignore the top 32 bits. A simple test case can be created by passing in a bogus pointer with the bottom 32 bits clear. Using a clk_id that is handled by the VDSO, then one that is handled by the kernel shows the problem: printf("%d\n", clock_getres(CLOCK_REALTIME, (void *)0x100000000)); printf("%d\n", clock_getres(CLOCK_BOOTTIME, (void *)0x100000000)); And we get: 0 -1 The bigger issue is if we pass a valid pointer with the bottom 32 bits clear, in this case we will return success but won't write any data to the pointer. I stumbled across this issue because the LLVM integrated assembler doesn't accept cmpli with 3 arguments. Fix this by converting them to cmpldi. Fixes: a7f290dad32e ("[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel") Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: PPC: BookE: Fix a sanity checkDan Carpenter2016-10-161-1/+1
| | | | | | | | | | | | | | commit ac0e89bb4744d3882ccd275f2416d9ce22f4e1e7 upstream. We use logical negate where bitwise negate was intended. It means that we never return -EINVAL here. Fixes: ce11e48b7fdd ('KVM: PPC: E500: Add userspace debug stub support') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Alexander Graf <agraf@suse.de> Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: PPC: Book3s PR: Allow access to unprivileged MMCR2 registerThomas Huth2016-10-162-0/+3
| | | | | | | | | | | | | | | | | | | | | commit fa73c3b25bd8d0d393dc6109a1dba3c2aef0451e upstream. The MMCR2 register is available twice, one time with number 785 (privileged access), and one time with number 769 (unprivileged, but it can be disabled completely). In former times, the Linux kernel was using the unprivileged register 769 only, but since commit 8dd75ccb571f3c92c ("powerpc: Use privileged SPR number for MMCR2"), it uses the privileged register 785 instead. The KVM-PR code then of course also switched to use the SPR 785, but this is causing older guest kernels to crash, since these kernels still access 769 instead. So to support older kernels with KVM-PR again, we have to support register 769 in KVM-PR, too. Fixes: 8dd75ccb571f3c92c48014b3dabd3d51a115ab41 Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/prom: Fix sub-processor option passed to ibm, ↵Michael Ellerman2016-10-071-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | client-architecture-support commit 66443efa83dc73775100b7442962ce2cb0d4472e upstream. When booting from an OpenFirmware which supports it, we use the "ibm,client-architecture-support" firmware call to communicate our capabilities to firmware. The format of the structure we pass to firmware is specified in PAPR (Power Architecture Platform Requirements), or the public version LoPAPR (Linux on Power Architecture Platform Reference). Referring to table 244 in LoPAPR v1.1, option vector 5 contains a 4 byte field at bytes 17-20 for the "Platform Facilities Enable". This is followed by a 1 byte field at byte 21 for "Sub-Processor Represenation Level". Comparing to the code, there we have the Platform Facilities options (OV5_PFO_*) at byte 17, but we fail to pad that field out to its full width of 4 bytes. This means the OV5_SUB_PROCESSORS option is incorrectly placed at byte 18. Fix it by adding zero bytes for bytes 18, 19, 20, and comment the bytes to hopefully make it clearer in future. As far as I'm aware nothing actually consumes this value at this time, so the effect of this bug is nil in practice. It does mean we've been incorrectly setting bit 15 of the "Platform Facilities Enable" option for the past ~3 1/2 years, so we should avoid allocating that bit to anything else in future. Fixes: df77c7992029 ("powerpc/pseries: Update ibm,architecture.vec for PAPR 2.7/POWER8") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ppc32: fix copy_from_user()Al Viro2016-09-241-19/+2
| | | | | | | | | | | commit 224264657b8b228f949b42346e09ed8c90136a8e upstream. should clear on access_ok() failures. Also remove the useless range truncation logics. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/mm: Don't alias user region to other regions below PAGE_OFFSETPaul Mackerras2016-09-241-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit f077aaf0754bcba0fffdbd925bc12f09cd1e38aa upstream. In commit c60ac5693c47 ("powerpc: Update kernel VSID range", 2013-03-13) we lost a check on the region number (the top four bits of the effective address) for addresses below PAGE_OFFSET. That commit replaced a check that the top 18 bits were all zero with a check that bits 46 - 59 were zero (performed for all addresses, not just user addresses). This means that userspace can access an address like 0x1000_0xxx_xxxx_xxxx and we will insert a valid SLB entry for it. The VSID used will be the same as if the top 4 bits were 0, but the page size will be some random value obtained by indexing beyond the end of the mm_ctx_high_slices_psize array in the paca. If that page size is the same as would be used for region 0, then userspace just has an alias of the region 0 space. If the page size is different, then no HPTE will be found for the access, and the process will get a SIGSEGV (since hash_page_mm() will refuse to create a HPTE for the bogus address). The access beyond the end of the mm_ctx_high_slices_psize can be at most 5.5MB past the array, and so will be in RAM somewhere. Since the access is a load performed in real mode, it won't fault or crash the kernel. At most this bug could perhaps leak a little bit of information about blocks of 32 bytes of memory located at offsets of i * 512kB past the paca->mm_ctx_high_slices_psize array, for 1 <= i <= 11. Fixes: c60ac5693c47 ("powerpc: Update kernel VSID range") Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/powernv : Drop reference added by kset_find_obj()Mukesh Ojha2016-09-242-2/+12
| | | | | | | | | | | | | | | | | | | | | | commit a9cbf0b2195b695cbeeeecaa4e2770948c212e9a upstream. In a situation, where Linux kernel gets notified about duplicate error log from OPAL, it is been observed that kernel fails to remove sysfs entries (/sys/firmware/opal/elog/0xXXXXXXXX) of such error logs. This is because, we currently search the error log/dump kobject in the kset list via 'kset_find_obj()' routine. Which eventually increment the reference count by one, once it founds the kobject. So, unless we decrement the reference count by one after it found the kobject, we would not be able to release the kobject properly later. This patch adds the 'kobject_put()' which was missing earlier. Signed-off-by: Mukesh Ojha <mukesh02@linux.vnet.ibm.com> Reviewed-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/tm: do not use r13 for tabort_syscallNicholas Piggin2016-09-241-6/+6
| | | | | | | | | | | | | | | commit cc7786d3ee7e3c979799db834b528db2c0834c2e upstream. tabort_syscall runs with RI=1, so a nested recoverable machine check will load the paca into r13 and overwrite what we loaded it with, because exceptions returning to privileged mode do not restore r13. Fixes: b4b56f9ecab4 (powerpc/tm: Abort syscalls in active transactions) Signed-off-by: Nick Piggin <npiggin@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/tm: Avoid SLB faults in treclaim/trecheckpoint when RI=0Michael Neuling2016-09-151-17/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 190ce8693c23eae09ba5f303a83bf2fbeb6478b1 upstream. Currently we have 2 segments that are bolted for the kernel linear mapping (ie 0xc000... addresses). This is 0 to 1TB and also the kernel stacks. Anything accessed outside of these regions may need to be faulted in. (In practice machines with TM always have 1T segments) If a machine has < 2TB of memory we never fault on the kernel linear mapping as these two segments cover all physical memory. If a machine has > 2TB of memory, there may be structures outside of these two segments that need to be faulted in. This faulting can occur when running as a guest as the hypervisor may remove any SLB that's not bolted. When we treclaim and trecheckpoint we have a window where we need to run with the userspace GPRs. This means that we no longer have a valid stack pointer in r1. For this window we therefore clear MSR RI to indicate that any exceptions taken at this point won't be able to be handled. This means that we can't take segment misses in this RI=0 window. In this RI=0 region, we currently access the thread_struct for the process being context switched to or from. This thread_struct access may cause a segment fault since it's not guaranteed to be covered by the two bolted segment entries described above. We've seen this with a crash when running as a guest with > 2TB of memory on PowerVM: Unrecoverable exception 4100 at c00000000004f138 Oops: Unrecoverable exception, sig: 6 [#1] SMP NR_CPUS=2048 NUMA pSeries CPU: 1280 PID: 7755 Comm: kworker/1280:1 Tainted: G X 4.4.13-46-default #1 task: c000189001df4210 ti: c000189001d5c000 task.ti: c000189001d5c000 NIP: c00000000004f138 LR: 0000000010003a24 CTR: 0000000010001b20 REGS: c000189001d5f730 TRAP: 4100 Tainted: G X (4.4.13-46-default) MSR: 8000000100001031 <SF,ME,IR,DR,LE> CR: 24000048 XER: 00000000 CFAR: c00000000004ed18 SOFTE: 0 GPR00: ffffffffc58d7b60 c000189001d5f9b0 00000000100d7d00 000000003a738288 GPR04: 0000000000002781 0000000000000006 0000000000000000 c0000d1f4d889620 GPR08: 000000000000c350 00000000000008ab 00000000000008ab 00000000100d7af0 GPR12: 00000000100d7ae8 00003ffe787e67a0 0000000000000000 0000000000000211 GPR16: 0000000010001b20 0000000000000000 0000000000800000 00003ffe787df110 GPR20: 0000000000000001 00000000100d1e10 0000000000000000 00003ffe787df050 GPR24: 0000000000000003 0000000000010000 0000000000000000 00003fffe79e2e30 GPR28: 00003fffe79e2e68 00000000003d0f00 00003ffe787e67a0 00003ffe787de680 NIP [c00000000004f138] restore_gprs+0xd0/0x16c LR [0000000010003a24] 0x10003a24 Call Trace: [c000189001d5f9b0] [c000189001d5f9f0] 0xc000189001d5f9f0 (unreliable) [c000189001d5fb90] [c00000000001583c] tm_recheckpoint+0x6c/0xa0 [c000189001d5fbd0] [c000000000015c40] __switch_to+0x2c0/0x350 [c000189001d5fc30] [c0000000007e647c] __schedule+0x32c/0x9c0 [c000189001d5fcb0] [c0000000007e6b58] schedule+0x48/0xc0 [c000189001d5fce0] [c0000000000deabc] worker_thread+0x22c/0x5b0 [c000189001d5fd80] [c0000000000e7000] kthread+0x110/0x130 [c000189001d5fe30] [c000000000009538] ret_from_kernel_thread+0x5c/0xa4 Instruction dump: 7cb103a6 7cc0e3a6 7ca222a6 78a58402 38c00800 7cc62838 08860000 7cc000a6 38a00006 78c60022 7cc62838 0b060000 <e8c701a0> 7ccff120 e8270078 e8a70098 ---[ end trace 602126d0a1dedd54 ]--- This fixes this by copying the required data from the thread_struct to the stack before we clear MSR RI. Then once we clear RI, we only access the stack, guaranteeing there's no segment miss. We also tighten the region over which we set RI=0 on the treclaim() path. This may have a slight performance impact since we're adding an mtmsr instruction. Fixes: 090b9284d725 ("powerpc/tm: Clear MSR RI in non-recoverable TM code") Signed-off-by: Michael Neuling <mikey@neuling.org> Reviewed-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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