ARM: entry: avoid clobbering R9 in IRQ handler

Avoid using R9 in the IRQ handler code, as the entry code uses it for
tsk, and expects it to remain untouched between the IRQ entry and exit
code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index b58bda5..038aabb 100644 (file)
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -38,11 +38,10 @@
 #ifdef CONFIG_UNWINDER_ARM
        mov     fpreg, sp               @ Preserve original SP
 #else
-       mov     r8, fp                  @ Preserve original FP
-       mov     r9, sp                  @ Preserve original SP
+       mov     r7, fp                  @ Preserve original FP
+       mov     r8, sp                  @ Preserve original SP
 #endif
        ldr_this_cpu sp, irq_stack_ptr, r2, r3
-
        .if     \from_user == 0
 UNWIND(        .setfp  fpreg, sp               )
        @
@@ -82,8 +81,8 @@ UNWIND(       .setfp  fpreg, sp               )
 #ifdef CONFIG_UNWINDER_ARM
        mov     sp, fpreg               @ Restore original SP
 #else
-       mov     fp, r8                  @ Restore original FP
-       mov     sp, r9                  @ Restore original SP
+       mov     fp, r7                  @ Restore original FP
+       mov     sp, r8                  @ Restore original SP
 #endif // CONFIG_UNWINDER_ARM
 #endif // CONFIG_IRQSTACKS
        .endm