TWxSoftware/twx-linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[MIPS] Fix potential latency problem due to non-atomic cpu_wait.

Browse Source 
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>
This commit is contained in:
Atsushi Nemoto
2007-11-12 02:05:18 +09:00
committed by Ralf Baechle
parent 6657fe0a02
commit c65a5480ff
3 changed files with 55 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/mips/kernel/traps.c
+16 -6
View File
@@ -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);