[PATCH -V10 14/15] powerpc: use smp_rmb when looking at deposisted pgtable to store hash index
flat view
STALE4859d
From: Aneesh Kumar K.V <hidden>
Date: 2013-06-05 15:28:54
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
From: "Aneesh Kumar K.V" <redacted> We need to use smb_rmb when looking at hpte slot array. Otherwise we could reorder the hpte_slot array load bfore even we marked the pmd trans huge. Related smb_wmb()s is done in pgtable_trans_huge_deposit when we deposit a pgtable. Signed-off-by: Aneesh Kumar K.V <redacted> --- arch/powerpc/include/asm/pgtable-ppc64.h | 15 +++++++++++++++ arch/powerpc/mm/hugepage-hash64.c | 6 +----- arch/powerpc/mm/pgtable_64.c | 6 +----- 3 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index d046289..46db094 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h@@ -10,6 +10,7 @@ #else #include <asm/pgtable-ppc64-4k.h> #endif +#include <asm/barrier.h> #define FIRST_USER_ADDRESS 0
@@ -393,6 +394,20 @@ static inline void mark_hpte_slot_valid(unsigned char *hpte_slot_array, hpte_slot_array[index] = hidx << 4 | 0x1 << 3; } +static inline char *get_hpte_slot_array(pmd_t *pmdp) +{ + /* + * The hpte hindex is stored in the pgtable whose address is in the + * second half of the PMD + * + * Order this load with the test for pmd_trans_huge in the caller + */ + smp_rmb(); + return *(char **)(pmdp + PTRS_PER_PMD); + + +} + extern void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp); #ifdef CONFIG_TRANSPARENT_HUGEPAGE
diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c
index 5241784..34de9e0 100644
--- a/arch/powerpc/mm/hugepage-hash64.c
+++ b/arch/powerpc/mm/hugepage-hash64.c@@ -84,11 +84,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid, vpn = hpt_vpn(ea, vsid, ssize); hash = hpt_hash(vpn, shift, ssize); - /* - * The hpte hindex are stored in the pgtable whose address is in the - * second half of the PMD - */ - hpte_slot_array = *(char **)(pmdp + PTRS_PER_PMD); + hpte_slot_array = get_hpte_slot_array(pmdp); valid = hpte_valid(hpte_slot_array, index); if (valid) {
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 8501aa3..bbecac4 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c@@ -701,11 +701,7 @@ void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr, * Flush all the hptes mapping this hugepage */ s_addr = addr & HPAGE_PMD_MASK; - /* - * The hpte hindex are stored in the pgtable whose address is in the - * second half of the PMD - */ - hpte_slot_array = *(char **)(pmdp + PTRS_PER_PMD); + hpte_slot_array = get_hpte_slot_array(pmdp); /* * IF we try to do a HUGE PTE update after a withdraw is done. * we will find the below NULL. This happens when we do
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1.8.1.2