4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Matt Redfearn <matt.redfearn@xxxxxxxxxx>
commit 5fdc66e046206306bf61ff2d626bfa52ca087f7b upstream.
Commit db8466c581cc ("MIPS: IRQ Stack: Unwind IRQ stack onto task
stack") erroneously set the initial stack pointer of the IRQ stack to a
value with a 4 byte alignment. The MIPS32 ABI requires that the minimum
stack alignment is 8 byte, and the MIPS64 ABIs(n32/n64) require 16 byte
minimum alignment. Fix IRQ_STACK_START such that it leaves space for the
dummy stack frame (containing interrupted task kernel stack pointer)
while also meeting minimum alignment requirements.
Fixes: db8466c581cc ("MIPS: IRQ Stack: Unwind IRQ stack onto task stack")
Reported-by: Darius Ivanauskas <dasilt@xxxxxxxxx>
Signed-off-by: Matt Redfearn <matt.redfearn@xxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Aaron Tomlin <atomlin@xxxxxxxxxx>
Cc: Jason A. Donenfeld <jason@xxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/16760/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/mips/include/asm/irq.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/mips/include/asm/irq.h
+++ b/arch/mips/include/asm/irq.h
@@ -18,7 +18,7 @@
#include <irq.h>
#define IRQ_STACK_SIZE THREAD_SIZE
-#define IRQ_STACK_START (IRQ_STACK_SIZE - sizeof(unsigned long))
+#define IRQ_STACK_START (IRQ_STACK_SIZE - 16)
extern void *irq_stack[NR_CPUS];