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authorChris Metcalf <cmetcalf@tilera.com>2011-02-28 15:30:16 -0500
committerChris Metcalf <cmetcalf@tilera.com>2011-03-01 16:21:00 -0500
commit3cebbafd28e6f91677f3becffcdf9150b74a4e0c (patch)
treee744b9970878141fea0bd9e6f868cc5b6bae5d31
parent6c4d11268819d9c920c7befd8e8e9aad456bb067 (diff)
downloadblackbird-op-linux-3cebbafd28e6f91677f3becffcdf9150b74a4e0c.tar.gz
blackbird-op-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.c28
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)
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