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| author | Vineet Gupta <vgupta@synopsys.com> | 2013-05-27 18:13:41 +0200 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2013-06-22 15:53:22 +0200 |
| commit | 16f9afe651e8197fb7ce6df0990d8e2ad779e1af (patch) | |
| tree | c6482028a0ceced44e7e4819f7741c2fd8084e3e /arch/arc/kernel/ctx_sw.c | |
| parent | ARC: pt_regs update #2: Remove unused gutter at start of pt_regs (diff) | |
| download | linux-16f9afe651e8197fb7ce6df0990d8e2ad779e1af.tar.xz linux-16f9afe651e8197fb7ce6df0990d8e2ad779e1af.zip | |
ARC: pt_regs update #3: Remove unused gutter at start of callee_regs
This is trickier than prev two:
* context switching code saves kernel mode callee regs in the format of
struct callee_regs thus needs adjustment. This also reduces the height
of topmost kernel stack frame by 1 word.
* Since kernel stack unwinder is sensitive to height of topmost kernel
stack frame, that needs a word of adjustment too.
ptrace needs a bit of updating since pt_regs now diverges from
user_regs_struct.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/kernel/ctx_sw.c')
| -rw-r--r-- | arch/arc/kernel/ctx_sw.c | 14 |
1 files changed, 5 insertions, 9 deletions
diff --git a/arch/arc/kernel/ctx_sw.c b/arch/arc/kernel/ctx_sw.c index 60844dac6132..34410eb1a308 100644 --- a/arch/arc/kernel/ctx_sw.c +++ b/arch/arc/kernel/ctx_sw.c @@ -23,10 +23,6 @@ __switch_to(struct task_struct *prev_task, struct task_struct *next_task) unsigned int tmp; unsigned int prev = (unsigned int)prev_task; unsigned int next = (unsigned int)next_task; - int num_words_to_skip = 1; -#ifdef CONFIG_ARC_CURR_IN_REG - num_words_to_skip++; -#endif __asm__ __volatile__( /* FP/BLINK save generated by gcc (standard function prologue */ @@ -44,8 +40,9 @@ __switch_to(struct task_struct *prev_task, struct task_struct *next_task) "st.a r24, [sp, -4] \n\t" #ifndef CONFIG_ARC_CURR_IN_REG "st.a r25, [sp, -4] \n\t" +#else + "sub sp, sp, 4 \n\t" /* usual r25 placeholder */ #endif - "sub sp, sp, %4 \n\t" /* create gutter at top */ /* set ksp of outgoing task in tsk->thread.ksp */ "st.as sp, [%3, %1] \n\t" @@ -76,10 +73,10 @@ __switch_to(struct task_struct *prev_task, struct task_struct *next_task) /* start loading it's CALLEE reg file */ - "add sp, sp, %4 \n\t" /* skip gutter at top */ - #ifndef CONFIG_ARC_CURR_IN_REG "ld.ab r25, [sp, 4] \n\t" +#else + "add sp, sp, 4 \n\t" #endif "ld.ab r24, [sp, 4] \n\t" "ld.ab r23, [sp, 4] \n\t" @@ -100,8 +97,7 @@ __switch_to(struct task_struct *prev_task, struct task_struct *next_task) /* FP/BLINK restore generated by gcc (standard func epilogue */ : "=r"(tmp) - : "n"((TASK_THREAD + THREAD_KSP) / 4), "r"(next), "r"(prev), - "n"(num_words_to_skip * 4) + : "n"((TASK_THREAD + THREAD_KSP) / 4), "r"(next), "r"(prev) : "blink" ); |