aboutsummaryrefslogtreecommitdiff
path: root/arch/xtensa
diff options
context:
space:
mode:
authorMax Filippov <jcmvbkbc@gmail.com>2015-07-16 10:41:02 +0300
committerMax Filippov <jcmvbkbc@gmail.com>2015-08-17 07:33:35 +0300
commit77d6273e79e3a86552fcf10cdd31a69b46ed2ce6 (patch)
tree4cf6368299b9d521c93a9d2327b7e00e98b80ede /arch/xtensa
parent7d5f6a9a2496c6e4f2a3b5db7743ff4e3a99738e (diff)
downloadlinux-linaro-stable-77d6273e79e3a86552fcf10cdd31a69b46ed2ce6.tar.gz
xtensa: fix kernel register spilling
call12 can't be safely used as the first call in the inline function, because the compiler does not extend the stack frame of the bounding function accordingly, which may result in corruption of local variables. If a call needs to be done, do call8 first followed by call12. For pure assembly code in _switch_to increase stack frame size of the bounding function. Cc: stable@vger.kernel.org Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa')
-rw-r--r--arch/xtensa/include/asm/traps.h29
-rw-r--r--arch/xtensa/kernel/entry.S4
2 files changed, 21 insertions, 12 deletions
diff --git a/arch/xtensa/include/asm/traps.h b/arch/xtensa/include/asm/traps.h
index 677bfcf4ee5d..28f33a8b7f5f 100644
--- a/arch/xtensa/include/asm/traps.h
+++ b/arch/xtensa/include/asm/traps.h
@@ -25,30 +25,39 @@ static inline void spill_registers(void)
{
#if XCHAL_NUM_AREGS > 16
__asm__ __volatile__ (
- " call12 1f\n"
+ " call8 1f\n"
" _j 2f\n"
" retw\n"
" .align 4\n"
"1:\n"
+#if XCHAL_NUM_AREGS == 32
+ " _entry a1, 32\n"
+ " addi a8, a0, 3\n"
+ " _entry a1, 16\n"
+ " mov a12, a12\n"
+ " retw\n"
+#else
" _entry a1, 48\n"
- " addi a12, a0, 3\n"
-#if XCHAL_NUM_AREGS > 32
- " .rept (" __stringify(XCHAL_NUM_AREGS) " - 32) / 12\n"
+ " call12 1f\n"
+ " retw\n"
+ " .align 4\n"
+ "1:\n"
+ " .rept (" __stringify(XCHAL_NUM_AREGS) " - 16) / 12\n"
" _entry a1, 48\n"
" mov a12, a0\n"
" .endr\n"
-#endif
- " _entry a1, 48\n"
+ " _entry a1, 16\n"
#if XCHAL_NUM_AREGS % 12 == 0
- " mov a8, a8\n"
-#elif XCHAL_NUM_AREGS % 12 == 4
" mov a12, a12\n"
-#elif XCHAL_NUM_AREGS % 12 == 8
+#elif XCHAL_NUM_AREGS % 12 == 4
" mov a4, a4\n"
+#elif XCHAL_NUM_AREGS % 12 == 8
+ " mov a8, a8\n"
#endif
" retw\n"
+#endif
"2:\n"
- : : : "a12", "a13", "memory");
+ : : : "a8", "a9", "memory");
#else
__asm__ __volatile__ (
" mov a12, a12\n"
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 5e492aec7b47..3d9d221d2f0f 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -1823,7 +1823,7 @@ ENDPROC(system_call)
mov a12, a0
.endr
#endif
- _entry a1, 48
+ _entry a1, 16
#if XCHAL_NUM_AREGS % 12 == 0
mov a8, a8
#elif XCHAL_NUM_AREGS % 12 == 4
@@ -1847,7 +1847,7 @@ ENDPROC(system_call)
ENTRY(_switch_to)
- entry a1, 16
+ entry a1, 48
mov a11, a3 # and 'next' (a3)