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authorMax Filippov <jcmvbkbc@gmail.com>2015-07-16 10:41:02 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-09-21 10:00:09 -0700
commit0bd183de611348459ef08b1e893dad005d8880f6 (patch)
tree252f105bc02ff01f851d12c09105dba6520ab7b0
parent8db5a692d7f860645a4f2a2c3b822637ecdfa3bf (diff)
xtensa: fix kernel register spilling
commit 77d6273e79e3a86552fcf10cdd31a69b46ed2ce6 upstream. 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. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 f2faa58f9a43..03d02df47b9a 100644
--- a/arch/xtensa/include/asm/traps.h
+++ b/arch/xtensa/include/asm/traps.h
@@ -24,30 +24,39 @@ 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 d29bac601be5..b268d3cc01d1 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -1934,7 +1934,7 @@ 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
@@ -1958,7 +1958,7 @@ ENDPROC(system_call)
ENTRY(_switch_to)
- entry a1, 16
+ entry a1, 48
mov a11, a3 # and 'next' (a3)