arch: fix has_transparent_hugepage()
I've just discovered that the useful-sounding has_transparent_hugepage()
is actually an architecture-dependent minefield: on some arches it only
builds if CONFIG_TRANSPARENT_HUGEPAGE=y, on others it's also there when
not, but on some of those (arm and arm64) it then gives the wrong
answer; and on mips alone it's marked __init, which would crash if
called later (but so far it has not been called later).
Straighten this out: make it available to all configs, with a sensible
default in asm-generic/pgtable.h, removing its definitions from those
arches (arc, arm, arm64, sparc, tile) which are served by the default,
adding #define has_transparent_hugepage has_transparent_hugepage to
those (mips, powerpc, s390, x86) which need to override the default at
runtime, and removing the __init from mips (but maybe that kind of code
should be avoided after init: set a static variable the first time it's
called).
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Yang Shi <yang.shi@linaro.org>
Cc: Ning Qu <quning@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Vineet Gupta <vgupta@synopsys.com> [arch/arc]
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [arch/s390]
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/arc/include/asm/hugepage.h b/arch/arc/include/asm/hugepage.h
index 7afe3356..317ff77 100644
--- a/arch/arc/include/asm/hugepage.h
+++ b/arch/arc/include/asm/hugepage.h
@@ -61,8 +61,6 @@
extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd);
-#define has_transparent_hugepage() 1
-
/* Generic variants assume pgtable_t is struct page *, hence need for these */
#define __HAVE_ARCH_PGTABLE_DEPOSIT
extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index dc46398..fa70db7 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -281,11 +281,6 @@
flush_pmd_entry(pmdp);
}
-static inline int has_transparent_hugepage(void)
-{
- return 1;
-}
-
#endif /* __ASSEMBLY__ */
#endif /* _ASM_PGTABLE_3LEVEL_H */
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 2da46ae..a7ac45a 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -314,11 +314,6 @@
#define set_pmd_at(mm, addr, pmdp, pmd) set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
-static inline int has_transparent_hugepage(void)
-{
- return 1;
-}
-
#define __pgprot_modify(prot,mask,bits) \
__pgprot((pgprot_val(prot) & ~(mask)) | (bits))
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 9a4fe01..f53a7e3a4 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -468,6 +468,7 @@
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define has_transparent_hugepage has_transparent_hugepage
extern int has_transparent_hugepage(void);
static inline int pmd_trans_huge(pmd_t pmd)
diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
index c17d762..2d93b63 100644
--- a/arch/mips/mm/tlb-r4k.c
+++ b/arch/mips/mm/tlb-r4k.c
@@ -400,19 +400,20 @@
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-int __init has_transparent_hugepage(void)
+int has_transparent_hugepage(void)
{
- unsigned int mask;
- unsigned long flags;
+ static unsigned int mask = -1;
- local_irq_save(flags);
- write_c0_pagemask(PM_HUGE_MASK);
- back_to_back_c0_hazard();
- mask = read_c0_pagemask();
- write_c0_pagemask(PM_DEFAULT_MASK);
+ if (mask == -1) { /* first call comes during __init */
+ unsigned long flags;
- local_irq_restore(flags);
-
+ local_irq_save(flags);
+ write_c0_pagemask(PM_HUGE_MASK);
+ back_to_back_c0_hazard();
+ mask = read_c0_pagemask();
+ write_c0_pagemask(PM_DEFAULT_MASK);
+ local_irq_restore(flags);
+ }
return mask == PM_HUGE_MASK;
}
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 77d3ce0..8fe6f6b4 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -219,6 +219,7 @@
pmd_t *pmdp, pmd_t pmd);
extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd);
+#define has_transparent_hugepage has_transparent_hugepage
extern int has_transparent_hugepage(void);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 47897a3..ee09e99 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -65,7 +65,6 @@
struct page **pages, int *nr);
#ifndef CONFIG_TRANSPARENT_HUGEPAGE
#define pmd_large(pmd) 0
-#define has_transparent_hugepage() 0
#endif
pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
bool *is_thp, unsigned *shift);
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 2f66645..18d2beb 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1223,6 +1223,7 @@
return pmd_val(pmd) & _SEGMENT_ENTRY_LARGE;
}
+#define has_transparent_hugepage has_transparent_hugepage
static inline int has_transparent_hugepage(void)
{
return MACHINE_HAS_HPAGE ? 1 : 0;
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index f089cfa..93ce0ad 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -681,8 +681,6 @@
return pte_val(pte) & _PAGE_PMD_HUGE;
}
-#define has_transparent_hugepage() 1
-
static inline pmd_t pmd_mkold(pmd_t pmd)
{
pte_t pte = __pte(pmd_val(pmd));
diff --git a/arch/tile/include/asm/pgtable.h b/arch/tile/include/asm/pgtable.h
index 96cecf5..2a26cc4 100644
--- a/arch/tile/include/asm/pgtable.h
+++ b/arch/tile/include/asm/pgtable.h
@@ -487,7 +487,6 @@
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-#define has_transparent_hugepage() 1
#define pmd_trans_huge pmd_huge_page
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index f86491a..1a27396 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -181,6 +181,7 @@
return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE;
}
+#define has_transparent_hugepage has_transparent_hugepage
static inline int has_transparent_hugepage(void)
{
return boot_cpu_has(X86_FEATURE_PSE);
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 9401f48..d4458b6 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -806,4 +806,12 @@
#define io_remap_pfn_range remap_pfn_range
#endif
+#ifndef has_transparent_hugepage
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define has_transparent_hugepage() 1
+#else
+#define has_transparent_hugepage() 0
+#endif
+#endif
+
#endif /* _ASM_GENERIC_PGTABLE_H */