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-64.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch/mips/mm/pgtable-64.c') diff --git a/arch/mips/mm/pgtable-64.c b/arch/mips/mm/pgtable-64.c index 44b5e97fff6..8d600d307d5 100644 --- a/arch/mips/mm/pgtable-64.c +++ b/arch/mips/mm/pgtable-64.c @@ -8,6 +8,7 @@ */ #include #include +#include #include void pgd_init(unsigned long page) @@ -52,7 +53,17 @@ void pmd_init(unsigned long addr, unsigned long pagetable) void __init pagetable_init(void) { + unsigned long vaddr; + pgd_t *pgd_base; + /* Initialize the entire pgd. */ pgd_init((unsigned long)swapper_pg_dir); pmd_init((unsigned long)invalid_pmd_table, (unsigned long)invalid_pte_table); + + pgd_base = swapper_pg_dir; + /* + * Fixed mappings: + */ + vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; + fixrange_init(vaddr, 0, pgd_base); } -- cgit v1.2.3