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* i386: move kernelThomas Gleixner2007-10-111-5/+0
| | | | | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* i386: prepare shared kernel/vmlinux.lds.SThomas Gleixner2007-10-111-212/+4
| | | | | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* i386: Put allocated ELF notes in read-only data segmentRoland McGrath2007-07-191-3/+3
| | | | | | | | | | | | | | | | | | | | This changes the i386 linker script and the asm-generic macro it uses so that ELF note sections with SHF_ALLOC set are linked into the kernel image along with other read-only data. The PT_NOTE also points to their location. This paves the way for putting useful build-time information into ELF notes that can be found easily later in a kernel memory dump. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Andi Kleen <ak@suse.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* define new percpu interface for shared dataFenghua Yu2007-07-191-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | per cpu data section contains two types of data. One set which is exclusively accessed by the local cpu and the other set which is per cpu, but also shared by remote cpus. In the current kernel, these two sets are not clearely separated out. This can potentially cause the same data cacheline shared between the two sets of data, which will result in unnecessary bouncing of the cacheline between cpus. One way to fix the problem is to cacheline align the remotely accessed per cpu data, both at the beginning and at the end. Because of the padding at both ends, this will likely cause some memory wastage and also the interface to achieve this is not clean. This patch: Moves the remotely accessed per cpu data (which is currently marked as ____cacheline_aligned_in_smp) into a different section, where all the data elements are cacheline aligned. And as such, this differentiates the local only data and remotely accessed data cleanly. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Christoph Lameter <clameter@sgi.com> Cc: <linux-arch@vger.kernel.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* xen: Core Xen implementationJeremy Fitzhardinge2007-07-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a rollup of all the core pieces of the Xen implementation, including: - booting and setup - pagetable setup - privileged instructions - segmentation - interrupt flags - upcalls - multicall batching BOOTING AND SETUP The vmlinux image is decorated with ELF notes which tell the Xen domain builder what the kernel's requirements are; the domain builder then constructs the address space accordingly and starts the kernel. Xen has its own entrypoint for the kernel (contained in an ELF note). The ELF notes are set up by xen-head.S, which is included into head.S. In principle it could be linked separately, but it seems to provoke lots of binutils bugs. Because the domain builder starts the kernel in a fairly sane state (32-bit protected mode, paging enabled, flat segments set up), there's not a lot of setup needed before starting the kernel proper. The main steps are: 1. Install the Xen paravirt_ops, which is simply a matter of a structure assignment. 2. Set init_mm to use the Xen-supplied pagetables (analogous to the head.S generated pagetables in a native boot). 3. Reserve address space for Xen, since it takes a chunk at the top of the address space for its own use. 4. Call start_kernel() PAGETABLE SETUP Once we hit the main kernel boot sequence, it will end up calling back via paravirt_ops to set up various pieces of Xen specific state. One of the critical things which requires a bit of extra care is the construction of the initial init_mm pagetable. Because Xen places tight constraints on pagetables (an active pagetable must always be valid, and must always be mapped read-only to the guest domain), we need to be careful when constructing the new pagetable to keep these constraints in mind. It turns out that the easiest way to do this is use the initial Xen-provided pagetable as a template, and then just insert new mappings for memory where a mapping doesn't already exist. This means that during pagetable setup, it uses a special version of xen_set_pte which ignores any attempt to remap a read-only page as read-write (since Xen will map its own initial pagetable as RO), but lets other changes to the ptes happen, so that things like NX are set properly. PRIVILEGED INSTRUCTIONS AND SEGMENTATION When the kernel runs under Xen, it runs in ring 1 rather than ring 0. This means that it is more privileged than user-mode in ring 3, but it still can't run privileged instructions directly. Non-performance critical instructions are dealt with by taking a privilege exception and trapping into the hypervisor and emulating the instruction, but more performance-critical instructions have their own specific paravirt_ops. In many cases we can avoid having to do any hypercalls for these instructions, or the Xen implementation is quite different from the normal native version. The privileged instructions fall into the broad classes of: Segmentation: setting up the GDT and the GDT entries, LDT, TLS and so on. Xen doesn't allow the GDT to be directly modified; all GDT updates are done via hypercalls where the new entries can be validated. This is important because Xen uses segment limits to prevent the guest kernel from damaging the hypervisor itself. Traps and exceptions: Xen uses a special format for trap entrypoints, so when the kernel wants to set an IDT entry, it needs to be converted to the form Xen expects. Xen sets int 0x80 up specially so that the trap goes straight from userspace into the guest kernel without going via the hypervisor. sysenter isn't supported. Kernel stack: The esp0 entry is extracted from the tss and provided to Xen. TLB operations: the various TLB calls are mapped into corresponding Xen hypercalls. Control registers: all the control registers are privileged. The most important is cr3, which points to the base of the current pagetable, and we handle it specially. Another instruction we treat specially is CPUID, even though its not privileged. We want to control what CPU features are visible to the rest of the kernel, and so CPUID ends up going into a paravirt_op. Xen implements this mainly to disable the ACPI and APIC subsystems. INTERRUPT FLAGS Xen maintains its own separate flag for masking events, which is contained within the per-cpu vcpu_info structure. Because the guest kernel runs in ring 1 and not 0, the IF flag in EFLAGS is completely ignored (and must be, because even if a guest domain disables interrupts for itself, it can't disable them overall). (A note on terminology: "events" and interrupts are effectively synonymous. However, rather than using an "enable flag", Xen uses a "mask flag", which blocks event delivery when it is non-zero.) There are paravirt_ops for each of cli/sti/save_fl/restore_fl, which are implemented to manage the Xen event mask state. The only thing worth noting is that when events are unmasked, we need to explicitly see if there's a pending event and call into the hypervisor to make sure it gets delivered. UPCALLS Xen needs a couple of upcall (or callback) functions to be implemented by each guest. One is the event upcalls, which is how events (interrupts, effectively) are delivered to the guests. The other is the failsafe callback, which is used to report errors in either reloading a segment register, or caused by iret. These are implemented in i386/kernel/entry.S so they can jump into the normal iret_exc path when necessary. MULTICALL BATCHING Xen provides a multicall mechanism, which allows multiple hypercalls to be issued at once in order to mitigate the cost of trapping into the hypervisor. This is particularly useful for context switches, since the 4-5 hypercalls they would normally need (reload cr3, update TLS, maybe update LDT) can be reduced to one. This patch implements a generic batching mechanism for hypercalls, which gets used in many places in the Xen code. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Ian Pratt <ian.pratt@xensource.com> Cc: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Cc: Adrian Bunk <bunk@stusta.de>
* all-archs: consolidate .data section definition in asm-genericSam Ravnborg2007-05-191-1/+1
| | | | | | | With this consolidation we can now modify the .data section definition in one spot for all archs. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* all-archs: consolidate .text section definition in asm-genericSam Ravnborg2007-05-191-1/+1
| | | | | | Move definition of .text section to asm-generic. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* Revert "[PATCH] paravirt: Add startup infrastructure for paravirtualization"Eric W. Biederman2007-05-101-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit c9ccf30d77f04064fe5436027ab9d2230c7cdd94. Entering the kernel at startup_32 without passing our real mode data in %esi, and without guaranteeing that physical and virtual addresses are identity mapped makes head.S impossible to maintain. The only user of this infrastructure is lguest which is not merged so nothing we currently support will break by removing this over designed nightmare, and only the pending lguest patches will be affected. The pending Xen patches have a different entry point that they use. We are currently discussing what Xen and lguest need to do to boot the kernel in a more normal fashion so using startup_32 in this weird manner is clearly not their long term direction. So let's remove this code in head.S before it causes brain damage to people trying to maintain head.S Cc: Chris Wright <chrisw@sous-sol.org> Cc: Andi Kleen <ak@suse.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Zachary Amsden <zach@vmware.com> CC: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] i386: Clean up ELF note generationJeremy Fitzhardinge2007-05-021-1/+1
| | | | | | | | | | | | | | | | | Three cleanups: 1: ELF notes are never mapped, so there's no need to have any access flags in their phdr. 2: When generating them from asm, tell the assembler to use a SHT_NOTE section type. There doesn't seem to be a way to do this from C. 3: Use ANSI rather than traditional cpp behaviour to stringify the macro argument. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Eric W. Biederman <ebiederm@xmission.com>
* [PATCH] x86: PARAVIRT: Jeremy Fitzhardinge <jeremy@goop.org>Jeremy Fitzhardinge2007-05-021-2/+2
| | | | | | | | | | | The other symbols used to delineate the alt-instructions sections have the form __foo/__foo_end. Rename parainstructions to match. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* [PATCH] i386: Convert PDA into the percpu sectionJeremy Fitzhardinge2007-05-021-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Currently x86 (similar to x84-64) has a special per-cpu structure called "i386_pda" which can be easily and efficiently referenced via the %fs register. An ELF section is more flexible than a structure, allowing any piece of code to use this area. Indeed, such a section already exists: the per-cpu area. So this patch: (1) Removes the PDA and uses per-cpu variables for each current member. (2) Replaces the __KERNEL_PDA segment with __KERNEL_PERCPU. (3) Creates a per-cpu mirror of __per_cpu_offset called this_cpu_off, which can be used to calculate addresses for this CPU's variables. (4) Simplifies startup, because %fs doesn't need to be loaded with a special segment at early boot; it can be deferred until the first percpu area is allocated (or never for UP). The result is less code and one less x86-specific concept. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de>
* [PATCH] i386: Remove smp_alt_instructionsJeremy Fitzhardinge2007-05-021-11/+0
| | | | | | | | | | | The .smp_altinstructions section and its corresponding symbols are completely unused, so remove them. Also, remove stray #ifdef __KENREL__ in asm-i386/alternative.h Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de>
* [PATCH] x86: Allow percpu variables to be page-alignedJeremy Fitzhardinge2007-05-021-1/+1
| | | | | | | | | | | | | | | Let's allow page-alignment in general for per-cpu data (wanted by Xen, and Ingo suggested KVM as well). Because larger alignments can use more room, we increase the max per-cpu memory to 64k rather than 32k: it's getting a little tight. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* [PATCH] x86: tighten kernel image page access rightsJan Beulich2007-05-021-2/+2
| | | | | | | | | | | | | | | | | | | | | | | On x86-64, kernel memory freed after init can be entirely unmapped instead of just getting 'poisoned' by overwriting with a debug pattern. On i386 and x86-64 (under CONFIG_DEBUG_RODATA), kernel text and bug table can also be write-protected. Compared to the first version, this one prevents re-creating deleted mappings in the kernel image range on x86-64, if those got removed previously. This, together with the original changes, prevents temporarily having inconsistent mappings when cacheability attributes are being changed on such pages (e.g. from AGP code). While on i386 such duplicate mappings don't exist, the same change is done there, too, both for consistency and because checking pte_present() before using various other pte_XXX functions is a requirement anyway. At once, i386 code gets adjusted to use pte_huge() instead of open coding this. AK: split out cpa() changes Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] x86: Fix gcc 4.2 _proxy_pda workaroundAndi Kleen2007-04-161-1/+1
| | | | | | | | | | | | | Due to an over aggressive optimizer gcc 4.2 cannot optimize away _proxy_pda in all cases (counter intuitive, but true). This breaks loading of some modules. The earlier workaround to just export a dummy symbol didn't work unfortunately because the module code ignores exports with 0 value. Make it 1 instead. Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: move startup_32() in text.head sectionVivek Goyal2007-02-131-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | o Entry startup_32 was in .text section but it was accessing some init data too and it prompts MODPOST to generate compilation warnings. WARNING: vmlinux - Section mismatch: reference to .init.data:boot_params from .text between '_text' (at offset 0xc0100029) and 'startup_32_smp' WARNING: vmlinux - Section mismatch: reference to .init.data:boot_params from .text between '_text' (at offset 0xc0100037) and 'startup_32_smp' WARNING: vmlinux - Section mismatch: reference to .init.data:init_pg_tables_end from .text between '_text' (at offset 0xc0100099) and 'startup_32_smp' o Can't move startup_32 to .init.text as this entry point has to be at the start of bzImage. Hence moved startup_32 to a new section .text.head and instructed MODPOST to not to generate warnings if init data is being accessed from .text.head section. This code has been audited. o SMP boot up code (startup_32_smp) can go into .init.text if CPU hotplug is not supported. Otherwise it generates more warnings WARNING: vmlinux - Section mismatch: reference to .init.data:new_cpu_data from .text between 'checkCPUtype' (at offset 0xc0100126) and 'is486' WARNING: vmlinux - Section mismatch: reference to .init.data:new_cpu_data from .text between 'checkCPUtype' (at offset 0xc0100130) and 'is486' Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] disable init/initramfs.c: architecturesJean-Paul Saman2007-02-111-0/+2
| | | | | | | | | | | | Update all arch/*/kernel/vmlinux.lds.S to not include space for initramfs when CONFIG_BLK_DEV_INITRAMFS is not selected. This saves another 4 kbytes on most platfoms (some reserve PAGE_SIZE for initramfs). Signed-off-by: Jean-Paul Saman <jean-paul.saman@nxp.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] x86: Work around gcc 4.2 over aggressive optimizerAndi Kleen2006-12-091-0/+1
| | | | | | | | | | The new PDA code uses a dummy _proxy_pda variable to describe memory references to the PDA. It is never referenced in inline assembly, but exists as input/output arguments. gcc 4.2 in some cases can CSE references to this which causes unresolved symbols. Define it to zero to avoid this. Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] Generic BUG for i386Jeremy Fitzhardinge2006-12-081-0/+2
| | | | | | | | | | | | | | | | | | | | This makes i386 use the generic BUG machinery. There are no functional changes from the old i386 implementation. The main advantage in using the generic BUG machinery for i386 is that the inlined overhead of BUG is just the ud2a instruction; the file+line(+function) information are no longer inlined into the instruction stream. This reduces cache pollution, and makes disassembly work properly. Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Andi Kleen <ak@muc.de> Cc: Hugh Dickens <hugh@veritas.com> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unwinder: move .eh_frame to RODATAJan Beulich2006-12-071-9/+0
| | | | | | | | | | The .eh_frame section contents is never written to, so it can as well benefit from CONFIG_DEBUG_RODATA. Diff-ed against firstfloor tree. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: Convert more absolute symbols to section relativeVivek Goyal2006-12-071-4/+10
| | | | | | | | | | | | | o Convert more absolute symbols to section relative to keep the theme in vmlinux.lds.S file and to avoid problem if kernel is relocated. o Also put a message so that in future people can be aware of it and avoid introducing absolute symbols. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] paravirt: Add startup infrastructure for paravirtualizationRusty Russell2006-12-071-0/+6
| | | | | | | | | | | | | | | | | 1) Each hypervisor writes a probe function to detect whether we are running under that hypervisor. paravirt_probe() registers this function. 2) If vmlinux is booted with ring != 0, we call all the probe functions (with registers except %esp intact) in link order: the winner will not return. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Zachary Amsden <zach@vmware.com> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] paravirt: Patch inline replacements for paravirt interceptsRusty Russell2006-12-071-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It turns out that the most called ops, by several orders of magnitude, are the interrupt manipulation ops. These are obvious candidates for patching, so mark them up and create infrastructure for it. The method used is that the ops structure has a patch function, which is called for each place which needs to be patched: this returns a number of instructions (the rest are NOP-padded). Usually we can spare a register (%eax) for the binary patched code to use, but in a couple of critical places in entry.S we can't: we make the clobbers explicit at the call site, and manually clobber the allowed registers in debug mode as an extra check. And: Don't abuse CONFIG_DEBUG_KERNEL, add CONFIG_DEBUG_PARAVIRT. And: AK: Fix warnings in x86-64 alternative.c build And: AK: Fix compilation with defconfig And: ^From: Andrew Morton <akpm@osdl.org> Some binutlises still like to emit references to __stop_parainstructions and __start_parainstructions. And: AK: Fix warnings about unused variables when PARAVIRT is disabled. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] i386: Implement CONFIG_PHYSICAL_ALIGNVivek Goyal2006-12-071-1/+2
| | | | | | | | | | | | | | | | | | | | o Now CONFIG_PHYSICAL_START is being replaced with CONFIG_PHYSICAL_ALIGN. Hardcoding the kernel physical start value creates a problem in relocatable kernel context due to boot loader limitations. For ex, if somebody compiles a relocatable kernel to be run from address 4MB, but this kernel will run from location 1MB as grub loads the kernel at physical address 1MB. Kernel thinks that I am a relocatable kernel and I should run from the address I have been loaded at. So somebody wanting to run kernel from 4MB alignment location (for improved performance regions) can't do that. o Hence, Eric proposed that probably CONFIG_PHYSICAL_ALIGN will make more sense in relocatable kernel context. At run time kernel will move itself to a physical addr location which meets user specified alignment restrictions. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: CONFIG_PHYSICAL_START cleanupEric W. Biederman2006-12-071-1/+1
| | | | | | | | | | | | Defining __PHYSICAL_START and __KERNEL_START in asm-i386/page.h works but it triggers a full kernel rebuild for the silliest of reasons. This modifies the users to directly use CONFIG_PHYSICAL_START and linux/config.h which prevents the full rebuild problem, which makes the code much more maintainer and hopefully user friendly. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: Add comment for align to vmlinux.ldsVivek Goyal2006-12-071-0/+6
| | | | | Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: Distinguish absolute symbolsVivek Goyal2006-12-071-50/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ld knows about 2 kinds of symbols, absolute and section relative. Section relative symbols symbols change value when a section is moved and absolute symbols do not. Currently in the linker script we have several labels marking the beginning and ending of sections that are outside of sections, making them absolute symbols. Having a mixture of absolute and section relative symbols refereing to the same data is currently harmless but it is confusing. This must be done carefully as newer revs of ld do not place symbols that appear in sections without data and instead ld makes those symbols global :( My ultimate goal is to build a relocatable kernel. The safest and least intrusive technique is to generate relocation entries so the kernel can be relocated at load time. The only penalty would be an increase in the size of the kernel binary. The problem is that if absolute and relocatable symbols are not properly specified absolute symbols will be relocated or section relative symbols won't be, which is fatal. The practical motivation is that when generating kernels that will run from a reserved area for analyzing what caused a kernel panic, it is simpler if you don't need to hard code the physical memory location they will run at, especially for the distributions. [AK: and merged:] o Also put a message so that in future people can be aware of it and avoid introducing absolute symbols. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: Force data segment to be 4K alignedVivek Goyal2006-11-081-0/+1
| | | | | | | | | | | | | o Currently there is no specific alignment restriction in linker script and in some cases it can be placed non 4K aligned addresses. This fails kexec which checks that segment to be loaded is page aligned. o I guess, it does not harm data segment to be 4K aligned. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] vmlinux.lds: consolidate initcall sectionsAndrew Morton2006-10-271-7/+1
| | | | | | | | | | | | | | Add a vmlinux.lds.h helper macro for defining the eight-level initcall table, teach all the architectures to use it. This is a prerequisite for a patch which performs initcall synchronisation for multithreaded-probing. Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> [ Added AVR32 as well ] Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] x86: put .note.* sections into a PT_NOTE segment in vmlinuxJeremy Fitzhardinge2006-09-261-2/+10
| | | | | | | | | | | | | | | | | | | | | | | This patch will pack any .note.* section into a PT_NOTE segment in the output file. To do this, we tell ld that we need a PT_NOTE segment. This requires us to start explicitly mapping sections to segments, so we also need to explicitly create PT_LOAD segments for text and data, and map the sections to them appropriately. Fortunately, each section will default to its previous section's segment, so it doesn't take many changes to vmlinux.lds.S. This only changes i386 for now, but I presume the corresponding changes for other architectures will be as simple. This change also adds <linux/elfnote.h>, which defines C and Assembler macros for actually creating ELF notes. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Hollis Blanchard <hollisb@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] i386: reliable stack trace support (i386)Jan Beulich2006-06-261-0/+9
| | | | | | | | | | These are the i386-specific pieces to enable reliable stack traces. This is going to be even more useful once CFI annotations get added to he assembly code, namely to entry.S. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Add some basic resume trace facilitiesLinus Torvalds2006-06-241-0/+7
| | | | | | | | | | Considering that there isn't a lot of hw we can depend on during resume, this is about as good as it gets. This is x86-only for now, although the basic concept (and most of the code) will certainly work on almost any platform. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge master.kernel.org:/pub/scm/linux/kernel/git/sam/kbuildLinus Torvalds2006-03-251-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * master.kernel.org:/pub/scm/linux/kernel/git/sam/kbuild: (46 commits) kbuild: remove obsoleted scripts/reference_* files kbuild: fix make help & make *pkg kconfig: fix time ordering of writes to .kconfig.d and include/linux/autoconf.h Kconfig: remove the CONFIG_CC_ALIGN_* options kbuild: add -fverbose-asm to i386 Makefile kbuild: clean-up genksyms kbuild: Lindent genksyms.c kbuild: fix genksyms build error kbuild: in makefile.txt note that Makefile is preferred name for kbuild files kbuild: replace PHONY with FORCE kbuild: Fix bug in crc symbol generating of kernel and modules kbuild: change kbuild to not rely on incorrect GNU make behavior kbuild: when warning symbols exported twice now tell user this is the problem kbuild: fix make dir/file.xx when asm symlink is missing kbuild: in the section mismatch check try harder to find symbols kbuild: fix section mismatch check for unwind on IA64 kbuild: kill false positives from section mismatch warnings for powerpc kbuild: kill trailing whitespace in modpost & friends kbuild: small update of allnoconfig description kbuild: make namespace.pl CROSS_COMPILE happy ... Trivial conflict in arch/ppc/boot/Makefile manually fixed up
| * x86: align per-cpu section to configured cache bytesZach Brown2006-02-191-1/+2
| | | | | | | | | | | | | | | | This matches the fix for a bug seen on x86-64. Test booted on old hardware that had 32 byte cachelines to begin with. Signed-off-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* | [PATCH] x86: SMP alternativesGerd Hoffmann2006-03-231-0/+20
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement SMP alternatives, i.e. switching at runtime between different code versions for UP and SMP. The code can patch both SMP->UP and UP->SMP. The UP->SMP case is useful for CPU hotplug. With CONFIG_CPU_HOTPLUG enabled the code switches to UP at boot time and when the number of CPUs goes down to 1, and switches to SMP when the number of CPUs goes up to 2. Without CONFIG_CPU_HOTPLUG or on non-SMP-capable systems the code is patched once at boot time (if needed) and the tables are released afterwards. The changes in detail: * The current alternatives bits are moved to a separate file, the SMP alternatives code is added there. * The patch adds some new elf sections to the kernel: .smp_altinstructions like .altinstructions, also contains a list of alt_instr structs. .smp_altinstr_replacement like .altinstr_replacement, but also has some space to save original instruction before replaving it. .smp_locks list of pointers to lock prefixes which can be nop'ed out on UP. The first two are used to replace more complex instruction sequences such as spinlocks and semaphores. It would be possible to deal with the lock prefixes with that as well, but by handling them as special case the table sizes become much smaller. * The sections are page-aligned and padded up to page size, so they can be free if they are not needed. * Splitted the code to release init pages to a separate function and use it to release the elf sections if they are unused. Signed-off-by: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] i386 / uml: add dwarf sections to static link scriptPaolo 'Blaisorblade' Giarrusso2005-09-101-8/+3
| | | | | | | | | | | | | | | | | | | | | | | Inside the linker script, insert the code for DWARF debug info sections. This may help GDB'ing a Uml binary. Actually, it seems that ld is able to guess what I added correctly, but normal linker scripts include this section so it should be correct anyway adding it. On request by Sam Ravnborg <sam@ravnborg.org>, I've added it to asm-generic/vmlinux.lds.s. I've also moved there the stabs debug section, used the new macro in i386 linker script and added DWARF debug section to that. In the truth, I've not been able to verify the difference in GDB behaviour after this change (I've seen large improvements with another patch). This may depend on my binutils version, older one may have worse defaults. However, this section is present in normal linker script, so add it at least for the sake of cleanness. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kprobes: prevent possible race conditions i386 changesPrasanna S Panchamukhi2005-09-071-0/+1
| | | | | | | | | This patch contains the i386 architecture specific changes to prevent the possible race conditions. Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mostly_read data sectionChristoph Lameter2005-07-071-0/+3
| | | | | | | | | | | | | | | | | | | | | Add a new section called ".data.read_mostly" for data items that are read frequently and rarely written to like cpumaps etc. If these maps are placed in the .data section then these frequenly read items may end up in cachelines with data is is frequently updated. In that case all processors in an SMP system must needlessly reload the cachelines again and again containing elements of those frequently used variables. The ability to share these cachelines will allow each cpu in an SMP system to keep local copies of those shared cachelines thereby optimizing performance. Signed-off-by: Alok N Kataria <alokk@calsoftinc.com> Signed-off-by: Shobhit Dayal <shobhit@calsoftinc.com> Signed-off-by: Christoph Lameter <christoph@scalex86.org> Signed-off-by: Shai Fultheim <shai@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kexec: x86: add CONFIG_PYSICAL_STARTEric W. Biederman2005-06-251-1/+1
| | | | | | | | | | | | | | | | | | | For one kernel to report a crash another kernel has created we need to have 2 kernels loaded simultaneously in memory. To accomplish this the two kernels need to built to run at different physical addresses. This patch adds the CONFIG_PHYSICAL_START option to the x86 kernel so we can do just that. You need to know what you are doing and the ramifications are before changing this value, and most users won't care so I have made it depend on CONFIG_EMBEDDED bzImage kernels will work and run at a different address when compiled with this option but they will still load at 1MB. If you need a kernel loaded at a different address as well you need to boot a vmlinux. Signed-off-by: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kexec: x86: vmlinux: fix physical addressesEric W. Biederman2005-06-251-21/+38
| | | | | | | | | | | | | | | | | | | The vmlinux on i386 does not report the correct physical address of the kernel. Instead in the physical address field it currently reports the virtual address of the kernel. This is patch is a bug fix that corrects vmlinux to report the proper physical addresses. This is potentially a help for crash dump analysis tools. This definitiely allows bootloaders that load vmlinux as a standard ELF executable. Bootloaders directly loading vmlinux become of practical importance when we consider the kexec on panic case. Signed-off-by: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+134
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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