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| author | Chris Metcalf <cmetcalf@tilera.com> | 2011-02-28 15:30:16 -0500 |
|---|---|---|
| committer | Chris Metcalf <cmetcalf@tilera.com> | 2011-03-01 16:21:00 -0500 |
| commit | 3cebbafd28e6f91677f3becffcdf9150b74a4e0c (patch) | |
| tree | e744b9970878141fea0bd9e6f868cc5b6bae5d31 | |
| parent | 6c4d11268819d9c920c7befd8e8e9aad456bb067 (diff) | |
| download | talos-obmc-linux-3cebbafd28e6f91677f3becffcdf9150b74a4e0c.tar.gz talos-obmc-linux-3cebbafd28e6f91677f3becffcdf9150b74a4e0c.zip | |
arch/tile: fix two bugs in the backtracer code
The first is that we were using an incorrect hand-rolled variant
of __kernel_text_address() which didn't handle module PCs. We now
just use the standard API.
The second was that we weren't accounting for the three-level
page table when we were trying to pre-verify the addresses on
the 64-bit TILE-Gx processor; we now do that correctly.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
| -rw-r--r-- | arch/tile/kernel/stack.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c index 0d54106be3d6..dd81713a90dc 100644 --- a/arch/tile/kernel/stack.c +++ b/arch/tile/kernel/stack.c @@ -44,13 +44,6 @@ static int in_kernel_stack(struct KBacktraceIterator *kbt, VirtualAddress sp) return sp >= kstack_base && sp < kstack_base + THREAD_SIZE; } -/* Is address in the specified kernel code? */ -static int in_kernel_text(VirtualAddress address) -{ - return (address >= MEM_SV_INTRPT && - address < MEM_SV_INTRPT + HPAGE_SIZE); -} - /* Is address valid for reading? */ static int valid_address(struct KBacktraceIterator *kbt, VirtualAddress address) { @@ -63,6 +56,23 @@ static int valid_address(struct KBacktraceIterator *kbt, VirtualAddress address) if (l1_pgtable == NULL) return 0; /* can't read user space in other tasks */ +#ifdef CONFIG_64BIT + /* Find the real l1_pgtable by looking in the l0_pgtable. */ + pte = l1_pgtable[HV_L0_INDEX(address)]; + if (!hv_pte_get_present(pte)) + return 0; + pfn = hv_pte_get_pfn(pte); + if (pte_huge(pte)) { + if (!pfn_valid(pfn)) { + pr_err("L0 huge page has bad pfn %#lx\n", pfn); + return 0; + } + return hv_pte_get_present(pte) && hv_pte_get_readable(pte); + } + page = pfn_to_page(pfn); + BUG_ON(PageHighMem(page)); /* No HIGHMEM on 64-bit. */ + l1_pgtable = (HV_PTE *)pfn_to_kaddr(pfn); +#endif pte = l1_pgtable[HV_L1_INDEX(address)]; if (!hv_pte_get_present(pte)) return 0; @@ -92,7 +102,7 @@ static bool read_memory_func(void *result, VirtualAddress address, { int retval; struct KBacktraceIterator *kbt = (struct KBacktraceIterator *)vkbt; - if (in_kernel_text(address)) { + if (__kernel_text_address(address)) { /* OK to read kernel code. */ } else if (address >= PAGE_OFFSET) { /* We only tolerate kernel-space reads of this task's stack */ @@ -132,7 +142,7 @@ static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt) } } if (EX1_PL(p->ex1) == KERNEL_PL && - in_kernel_text(p->pc) && + __kernel_text_address(p->pc) && in_kernel_stack(kbt, p->sp) && p->sp >= sp) { if (kbt->verbose) |
