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author | Paul Mundt <lethal@linux-sh.org> | 2008-11-10 20:00:45 +0900 |
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committer | Paul Mundt <lethal@linux-sh.org> | 2008-11-10 20:00:45 +0900 |
commit | acca4f4d9bd657e8bc7e1665ba5077465138f133 (patch) | |
tree | 39b107c67d9dc59e6064e528457ca97ba4396ba2 /arch/sh/mm/pg-sh4.c | |
parent | f7160c7573615ec82c691e294cf80d920b5d588d (diff) | |
download | linux-stable-acca4f4d9bd657e8bc7e1665ba5077465138f133.tar.gz linux-stable-acca4f4d9bd657e8bc7e1665ba5077465138f133.tar.bz2 linux-stable-acca4f4d9bd657e8bc7e1665ba5077465138f133.zip |
sh: Handle fixmap TLB eviction more coherently.
There was a race in the kmap_coherent() implementation. While we
guarded against preemption, there was nothing preventing eviction of
the pre-faulted fixmap entry from the UTLB. Under certain workloads
this would result in the fixmap entries used for cache colouring being
evicted from the UTLB in the midst of a copy_page().
In addition to pre-faulting, we also make sure to preserve the PTEs
in the kernel page table and introduce a cached PTE for kmap_coherent()
usage. This follows a similar change on MIPS ("[MIPS] Fix aliasing bug
in copy_to_user_page / copy_from_user_page").
Reported-by: Hideo Saito <saito@densan.co.jp>
Reported-by: CHIKAMA Masaki <masaki.chikama@gmail.com>
Tested-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/mm/pg-sh4.c')
-rw-r--r-- | arch/sh/mm/pg-sh4.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/sh/mm/pg-sh4.c b/arch/sh/mm/pg-sh4.c index 38870e0fc182..2fe14da1f839 100644 --- a/arch/sh/mm/pg-sh4.c +++ b/arch/sh/mm/pg-sh4.c @@ -7,6 +7,7 @@ * Released under the terms of the GNU GPL v2.0. */ #include <linux/mm.h> +#include <linux/init.h> #include <linux/mutex.h> #include <linux/fs.h> #include <linux/highmem.h> @@ -16,6 +17,20 @@ #define CACHE_ALIAS (current_cpu_data.dcache.alias_mask) +#define kmap_get_fixmap_pte(vaddr) \ + pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr)) + +static pte_t *kmap_coherent_pte; + +void __init kmap_coherent_init(void) +{ + unsigned long vaddr; + + /* cache the first coherent kmap pte */ + vaddr = __fix_to_virt(FIX_CMAP_BEGIN); + kmap_coherent_pte = kmap_get_fixmap_pte(vaddr); +} + static inline void *kmap_coherent(struct page *page, unsigned long addr) { enum fixed_addresses idx; @@ -34,6 +49,8 @@ static inline void *kmap_coherent(struct page *page, unsigned long addr) update_mmu_cache(NULL, vaddr, pte); + set_pte(kmap_coherent_pte - (FIX_CMAP_END - idx), pte); + return (void *)vaddr; } |