[PATCH -V3 21/25] powerpc: Handle hugepage in perf callchain
From: Aneesh Kumar K.V <hidden>
Date: 2013-03-15 09:40:37
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
From: "Aneesh Kumar K.V" <redacted> Signed-off-by: Aneesh Kumar K.V <redacted> --- arch/powerpc/perf/callchain.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index 578cac7..99262ce 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c@@ -115,7 +115,7 @@ static int read_user_stack_slow(void __user *ptr, void *ret, int nb) { pgd_t *pgdir; pte_t *ptep, pte; - unsigned shift; + unsigned shift, hugepage; unsigned long addr = (unsigned long) ptr; unsigned long offset; unsigned long pfn;
@@ -125,20 +125,30 @@ static int read_user_stack_slow(void __user *ptr, void *ret, int nb) if (!pgdir) return -EFAULT; - ptep = find_linux_pte_or_hugepte(pgdir, addr, &shift, NULL); + ptep = find_linux_pte_or_hugepte(pgdir, addr, &shift, &hugepage); if (!shift) shift = PAGE_SHIFT; - /* align address to page boundary */ - offset = addr & ((1UL << shift) - 1); - addr -= offset; - - if (ptep == NULL) - return -EFAULT; - pte = *ptep; - if (!pte_present(pte) || !(pte_val(pte) & _PAGE_USER)) + if (!ptep) return -EFAULT; - pfn = pte_pfn(pte); + + if (hugepage) { + pmd_t pmd = *(pmd_t *)ptep; + shift = mmu_psize_defs[MMU_PAGE_16M].shift; + offset = addr & ((1UL << shift) - 1); + + if (!pmd_large(pmd) || !(pmd_val(pmd) & PMD_HUGE_USER)) + return -EFAULT; + pfn = pmd_pfn(pmd); + } else { + offset = addr & ((1UL << shift) - 1); + + pte = *ptep; + if (!pte_present(pte) || !(pte_val(pte) & _PAGE_USER)) + return -EFAULT; + pfn = pte_pfn(pte); + } + if (!page_is_ram(pfn)) return -EFAULT;
--
1.7.10