aboutsummaryrefslogtreecommitdiff
path: root/arch/mips/include
diff options
context:
space:
mode:
authorKevin Cernekee <cernekee@gmail.com>2009-09-07 11:11:31 -0700
committerRalf Baechle <ralf@linux-mips.org>2009-11-02 12:00:04 +0100
commit0f334a3e8c3586f81286345eb077ed32b375e8d6 (patch)
tree02278a0f6ef99b43c56af12ba44d964f099c70c3 /arch/mips/include
parent39d2211d20518677511043d7ee16bbca6d0c5070 (diff)
MIPS: Fix machine check exception in kmap_coherent()
On an SMP system with cache aliases, the following sequence of events may happen: 1) copy_user_highpage() runs on CPU0, invoking kmap_coherent() to create a temporary mapping in the fixmap region 2) copy_page() starts on CPU0 3) CPU1 sends CPU0 an IPI asking CPU0 to run local_r4k_flush_cache_page() 4) CPU0 takes the interrupt, interrupting copy_page() 5) local_r4k_flush_cache_page() on CPU0 calls kmap_coherent() again 6) The second invocation of kmap_coherent() on CPU0 tries to use the same fixmap virtual address that was being used by copy_user_highpage() 7) CPU0 throws a machine check exception for the TLB address conflict Fixed by creating an extra set of fixmap entries for use in interrupt handlers. This prevents fixmap VA conflicts between copy_user_highpage() running in user context, and local_r4k_flush_cache_page() invoked from an SMP IPI. Signed-off-by: Kevin Cernekee <cernekee@gmail.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/include')
-rw-r--r--arch/mips/include/asm/fixmap.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/mips/include/asm/fixmap.h b/arch/mips/include/asm/fixmap.h
index efeddc8db8b..0b89b83e205 100644
--- a/arch/mips/include/asm/fixmap.h
+++ b/arch/mips/include/asm/fixmap.h
@@ -48,9 +48,9 @@ enum fixed_addresses {
#define FIX_N_COLOURS 8
FIX_CMAP_BEGIN,
#ifdef CONFIG_MIPS_MT_SMTC
- FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS),
+ FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS * 2),
#else
- FIX_CMAP_END = FIX_CMAP_BEGIN + FIX_N_COLOURS,
+ FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2),
#endif
#ifdef CONFIG_HIGHMEM
/* reserved pte's for temporary kernel mappings */