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| author | Ralf Baechle <ralf@linux-mips.org> | 2006-10-21 23:17:35 +0100 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2006-10-21 23:17:35 +0100 |
| commit | f8829caee311207afbc882794bdc5aa0db5caf33 (patch) | |
| tree | dbadd9fa746a1a4f091bc7e240ca8d787188a913 /arch/mips/mm/pgtable-32.c | |
| parent | 224dc50ece1b40f8cff5ecadd42a6b2691e231de (diff) | |
| download | linux-stable-f8829caee311207afbc882794bdc5aa0db5caf33.tar.gz linux-stable-f8829caee311207afbc882794bdc5aa0db5caf33.tar.bz2 linux-stable-f8829caee311207afbc882794bdc5aa0db5caf33.zip | |
[MIPS] Fix aliasing bug in copy_to_user_page / copy_from_user_page
The current implementation uses a sequence of a cacheflush and a copy.
This is racy in case of a multithreaded debuggee and renders GDB
virtually unusable.
Aside this fixes a performance hog rendering access to /proc/cmdline very
slow and resulting in a enough cache stalls for the 34K AP/SP programming
model to make the bare metal code on the non-Linux VPE miss RT deadlines.
The main part of this patch was originally written by Ralf Baechle;
Atushi Nemoto did the the debugging.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/mm/pgtable-32.c')
| -rw-r--r-- | arch/mips/mm/pgtable-32.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/mips/mm/pgtable-32.c b/arch/mips/mm/pgtable-32.c index 4bdaa05f485b..4a61e624b0ec 100644 --- a/arch/mips/mm/pgtable-32.c +++ b/arch/mips/mm/pgtable-32.c @@ -31,9 +31,10 @@ void pgd_init(unsigned long page) void __init pagetable_init(void) { -#ifdef CONFIG_HIGHMEM unsigned long vaddr; - pgd_t *pgd, *pgd_base; + pgd_t *pgd_base; +#ifdef CONFIG_HIGHMEM + pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -44,7 +45,6 @@ void __init pagetable_init(void) pgd_init((unsigned long)swapper_pg_dir + sizeof(pgd_t) * USER_PTRS_PER_PGD); -#ifdef CONFIG_HIGHMEM pgd_base = swapper_pg_dir; /* @@ -53,6 +53,7 @@ void __init pagetable_init(void) vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; fixrange_init(vaddr, 0, pgd_base); +#ifdef CONFIG_HIGHMEM /* * Permanent kmaps: */ |