From f8829caee311207afbc882794bdc5aa0db5caf33 Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Sat, 21 Oct 2006 23:17:35 +0100 Subject: [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 Signed-off-by: Ralf Baechle --- arch/mips/mm/pgtable-32.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'arch/mips/mm/pgtable-32.c') diff --git a/arch/mips/mm/pgtable-32.c b/arch/mips/mm/pgtable-32.c index 4bdaa05f485..4a61e624b0e 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: */ -- cgit v1.2.3