diff options
| author | Leonid Yegoshin <yegoshin@mips.com> | 2012-07-19 09:11:14 +0200 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2012-07-19 11:23:43 +0200 |
| commit | 2dd17030c940ef1199a07b095ec79c4660fa8734 (patch) | |
| tree | 34261c3c27f418a785ef127afe6a1f0109310a53 /arch/mips | |
| parent | dc34b05fea0cc9a869863b929f37f1e8ce30edf4 (diff) | |
MIPS: Fix race condition with FPU thread task flag during context switch.
[ralf@linux-mips.org: Cosmetic changes; also fixed up r2300_switch.S and
octeon_switch.S which needed similar modifications.]
Signed-off-by: Leonid Yegoshin <yegoshin@mips.com>
Signed-off-by: Steven J. Hill <sjhill@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3784/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/include/asm/switch_to.h | 6 | ||||
| -rw-r--r-- | arch/mips/kernel/octeon_switch.S | 2 | ||||
| -rw-r--r-- | arch/mips/kernel/r2300_switch.S | 15 | ||||
| -rw-r--r-- | arch/mips/kernel/r4k_switch.S | 12 |
4 files changed, 11 insertions, 24 deletions
diff --git a/arch/mips/include/asm/switch_to.h b/arch/mips/include/asm/switch_to.h index 5d33621b5658..4f8ddba8c360 100644 --- a/arch/mips/include/asm/switch_to.h +++ b/arch/mips/include/asm/switch_to.h @@ -22,7 +22,7 @@ struct task_struct; * switch_to(n) should switch tasks to task nr n, first * checking that n isn't the current task, in which case it does nothing. */ -extern asmlinkage void *resume(void *last, void *next, void *next_ti); +extern asmlinkage void *resume(void *last, void *next, void *next_ti, u32 __usedfpu); extern unsigned int ll_bit; extern struct task_struct *ll_task; @@ -66,11 +66,13 @@ do { \ #define switch_to(prev, next, last) \ do { \ + u32 __usedfpu; \ __mips_mt_fpaff_switch_to(prev); \ if (cpu_has_dsp) \ __save_dsp(prev); \ __clear_software_ll_bit(); \ - (last) = resume(prev, next, task_thread_info(next)); \ + __usedfpu = test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU); \ + (last) = resume(prev, next, task_thread_info(next), __usedfpu); \ } while (0) #define finish_arch_switch(prev) \ diff --git a/arch/mips/kernel/octeon_switch.S b/arch/mips/kernel/octeon_switch.S index ce89c8061708..0441f54b2a6a 100644 --- a/arch/mips/kernel/octeon_switch.S +++ b/arch/mips/kernel/octeon_switch.S @@ -31,7 +31,7 @@ /* * task_struct *resume(task_struct *prev, task_struct *next, - * struct thread_info *next_ti) + * struct thread_info *next_ti, int usedfpu) */ .align 7 LEAF(resume) diff --git a/arch/mips/kernel/r2300_switch.S b/arch/mips/kernel/r2300_switch.S index 293898391e67..9c51be5a163a 100644 --- a/arch/mips/kernel/r2300_switch.S +++ b/arch/mips/kernel/r2300_switch.S @@ -43,7 +43,7 @@ /* * task_struct *resume(task_struct *prev, task_struct *next, - * struct thread_info *next_ti) ) + * struct thread_info *next_ti, int usedfpu) */ LEAF(resume) mfc0 t1, CP0_STATUS @@ -51,18 +51,9 @@ LEAF(resume) cpu_save_nonscratch a0 sw ra, THREAD_REG31(a0) - /* - * check if we need to save FPU registers - */ - lw t3, TASK_THREAD_INFO(a0) - lw t0, TI_FLAGS(t3) - li t1, _TIF_USEDFPU - and t2, t0, t1 - beqz t2, 1f - nor t1, zero, t1 + beqz a3, 1f - and t0, t0, t1 - sw t0, TI_FLAGS(t3) + PTR_L t3, TASK_THREAD_INFO(a0) /* * clear saved user stack CU1 bit diff --git a/arch/mips/kernel/r4k_switch.S b/arch/mips/kernel/r4k_switch.S index 9414f9354469..42d2a3938420 100644 --- a/arch/mips/kernel/r4k_switch.S +++ b/arch/mips/kernel/r4k_switch.S @@ -41,7 +41,7 @@ /* * task_struct *resume(task_struct *prev, task_struct *next, - * struct thread_info *next_ti) + * struct thread_info *next_ti, int usedfpu) */ .align 5 LEAF(resume) @@ -53,16 +53,10 @@ /* * check if we need to save FPU registers */ - PTR_L t3, TASK_THREAD_INFO(a0) - LONG_L t0, TI_FLAGS(t3) - li t1, _TIF_USEDFPU - and t2, t0, t1 - beqz t2, 1f - nor t1, zero, t1 - and t0, t0, t1 - LONG_S t0, TI_FLAGS(t3) + beqz a3, 1f + PTR_L t3, TASK_THREAD_INFO(a0) /* * clear saved user stack CU1 bit */ |