From patchwork Tue Feb 26 08:05:11 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [-V1,21/24] powerpc: Handle huge page in perf callchain From: "Aneesh Kumar K.V" X-Patchwork-Id: 223140 Message-Id: <1361865914-13911-22-git-send-email-aneesh.kumar@linux.vnet.ibm.com> To: benh@kernel.crashing.org, paulus@samba.org Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, "Aneesh Kumar K.V" Date: Tue, 26 Feb 2013 13:35:11 +0530 From: "Aneesh Kumar K.V" Signed-off-by: Aneesh Kumar K.V --- 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;