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>
diff --git a/arch/arc/include/asm/entry.h b/arch/arc/include/asm/entry.h
index 5ff7b8d..820202a 100644
--- a/arch/arc/include/asm/entry.h
+++ b/arch/arc/include/asm/entry.h
@@ -124,8 +124,6 @@
st.a r25, [sp, -4]
#endif
- /* move up by 1 word to "create" callee_regs->"stack_place_holder" */
- sub sp, sp, 4
.endm
/*--------------------------------------------------------------
@@ -148,10 +146,9 @@
st.a r23, [sp, -4]
st.a r24, [sp, -4]
#ifdef CONFIG_ARC_CURR_IN_REG
- sub sp, sp, 8
+ sub sp, sp, 4
#else
st.a r25, [sp, -4]
- sub sp, sp, 4
#endif
.endm
@@ -168,14 +165,11 @@
*-------------------------------------------------------------*/
.macro RESTORE_CALLEE_SAVED_KERNEL
-
#ifdef CONFIG_ARC_CURR_IN_REG
- add sp, sp, 8 /* skip callee_reg gutter and user r25 placeholder */
+ add sp, sp, 4 /* skip usual r25 placeholder */
#else
- add sp, sp, 4 /* skip "callee_regs->stack_place_holder" */
ld.ab r25, [sp, 4]
#endif
-
ld.ab r24, [sp, 4]
ld.ab r23, [sp, 4]
ld.ab r22, [sp, 4]
@@ -203,8 +197,6 @@
*-------------------------------------------------------------*/
.macro RESTORE_CALLEE_SAVED_USER
- add sp, sp, 4 /* skip "callee_regs->stack_place_holder" */
-
#ifdef CONFIG_ARC_CURR_IN_REG
ld.ab r12, [sp, 4]
st r12, [r25, TASK_THREAD + THREAD_USER_R25]
@@ -230,7 +222,7 @@
* Super FAST Restore callee saved regs by simply re-adjusting SP
*-------------------------------------------------------------*/
.macro DISCARD_CALLEE_SAVED_USER
- add sp, sp, 14 * 4
+ add sp, sp, SZ_CALLEE_REGS
.endm
/*--------------------------------------------------------------