diff options
| 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/traps.c | |
| parent | 6657fe0a0281e06ff46eb42bc18ecb68d8b14b27 (diff) | |
[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/traps.c')
| -rw-r--r-- | arch/mips/kernel/traps.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 6bee29097a56..5fd0cd020af5 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -46,6 +46,9 @@ #include <asm/types.h> #include <asm/stacktrace.h> +extern void check_wait(void); +extern asmlinkage void r4k_wait(void); +extern asmlinkage void rollback_handle_int(void); extern asmlinkage void handle_int(void); extern asmlinkage void handle_tlbm(void); extern asmlinkage void handle_tlbl(void); @@ -1251,6 +1254,9 @@ static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs) extern char except_vec_vi, except_vec_vi_lui; extern char except_vec_vi_ori, except_vec_vi_end; + extern char rollback_except_vec_vi; + char *vec_start = (cpu_wait == r4k_wait) ? + &rollback_except_vec_vi : &except_vec_vi; #ifdef CONFIG_MIPS_MT_SMTC /* * We need to provide the SMTC vectored interrupt handler @@ -1258,11 +1264,11 @@ static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs) * Status.IM bit to be masked before going there. */ extern char except_vec_vi_mori; - const int mori_offset = &except_vec_vi_mori - &except_vec_vi; + const int mori_offset = &except_vec_vi_mori - vec_start; #endif /* CONFIG_MIPS_MT_SMTC */ - const int handler_len = &except_vec_vi_end - &except_vec_vi; - const int lui_offset = &except_vec_vi_lui - &except_vec_vi; - const int ori_offset = &except_vec_vi_ori - &except_vec_vi; + const int handler_len = &except_vec_vi_end - vec_start; + const int lui_offset = &except_vec_vi_lui - vec_start; + const int ori_offset = &except_vec_vi_ori - vec_start; if (handler_len > VECTORSPACING) { /* @@ -1272,7 +1278,7 @@ static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs) panic("VECTORSPACING too small"); } - memcpy(b, &except_vec_vi, handler_len); + memcpy(b, vec_start, handler_len); #ifdef CONFIG_MIPS_MT_SMTC BUG_ON(n > 7); /* Vector index %d exceeds SMTC maximum. */ @@ -1554,6 +1560,10 @@ void __init trap_init(void) extern char except_vec3_generic, except_vec3_r4000; extern char except_vec4; unsigned long i; + int rollback; + + check_wait(); + rollback = (cpu_wait == r4k_wait); #if defined(CONFIG_KGDB) if (kgdb_early_setup) @@ -1618,7 +1628,7 @@ void __init trap_init(void) if (board_be_init) board_be_init(); - set_except_vector(0, handle_int); + set_except_vector(0, rollback ? rollback_handle_int : handle_int); set_except_vector(1, handle_tlbm); set_except_vector(2, handle_tlbl); set_except_vector(3, handle_tlbs); |