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| author | Atsushi Nemoto <anemo@mba.ocn.ne.jp> | 2007-11-12 02:05:18 +0900 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2008-09-21 14:52:57 +0200 |
| commit | c65a5480ff29198c241f11d39d9e34ab22c72c69 (patch) | |
| tree | bb6fadfbb27c607b4c99745844339f9f1e740940 /arch/mips/kernel/genex.S | |
| parent | 6657fe0a0281e06ff46eb42bc18ecb68d8b14b27 (diff) | |
| download | linux-c65a5480ff29198c241f11d39d9e34ab22c72c69.tar.gz linux-c65a5480ff29198c241f11d39d9e34ab22c72c69.tar.bz2 linux-c65a5480ff29198c241f11d39d9e34ab22c72c69.zip | |
[MIPS] Fix potential latency problem due to non-atomic cpu_wait.
If an interrupt happened between checking of NEED_RESCHED and WAIT
instruction, adjust EPC to restart from checking of NEED_RESCHED.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/genex.S')
| -rw-r--r-- | arch/mips/kernel/genex.S | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S index c6ada98ee042..f886dd7f708e 100644 --- a/arch/mips/kernel/genex.S +++ b/arch/mips/kernel/genex.S @@ -20,6 +20,7 @@ #include <asm/stackframe.h> #include <asm/war.h> #include <asm/page.h> +#include <asm/thread_info.h> #define PANIC_PIC(msg) \ .set push; \ @@ -126,7 +127,42 @@ handle_vcei: __FINIT + .align 5 /* 32 byte rollback region */ +LEAF(r4k_wait) + .set push + .set noreorder + /* start of rollback region */ + LONG_L t0, TI_FLAGS($28) + nop + andi t0, _TIF_NEED_RESCHED + bnez t0, 1f + nop + nop + nop + .set mips3 + wait + /* end of rollback region (the region size must be power of two) */ + .set pop +1: + jr ra + END(r4k_wait) + + .macro BUILD_ROLLBACK_PROLOGUE handler + FEXPORT(rollback_\handler) + .set push + .set noat + MFC0 k0, CP0_EPC + PTR_LA k1, r4k_wait + ori k0, 0x1f /* 32 byte rollback region */ + xori k0, 0x1f + bne k0, k1, 9f + MTC0 k0, CP0_EPC +9: + .set pop + .endm + .align 5 +BUILD_ROLLBACK_PROLOGUE handle_int NESTED(handle_int, PT_SIZE, sp) #ifdef CONFIG_TRACE_IRQFLAGS /* @@ -201,6 +237,7 @@ NESTED(except_vec_ejtag_debug, 0, sp) * This prototype is copied to ebase + n*IntCtl.VS and patched * to invoke the handler */ +BUILD_ROLLBACK_PROLOGUE except_vec_vi NESTED(except_vec_vi, 0, sp) SAVE_SOME SAVE_AT |