aboutsummaryrefslogtreecommitdiff
path: root/arch/mips/kernel/traps.c
diff options
context:
space:
mode:
authorAtsushi Nemoto <anemo@mba.ocn.ne.jp>2007-11-12 02:05:18 +0900
committerRalf Baechle <ralf@linux-mips.org>2008-09-21 14:52:57 +0200
commitc65a5480ff29198c241f11d39d9e34ab22c72c69 (patch)
treebb6fadfbb27c607b4c99745844339f9f1e740940 /arch/mips/kernel/traps.c
parent6657fe0a0281e06ff46eb42bc18ecb68d8b14b27 (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.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 6bee29097a5..5fd0cd020af 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);