ARM: save and reset the address limit when entering an exception
When we enter an exception, the current address limit should not apply
to the exception context: if the exception context wishes to access
kernel space via the user accessors (eg, perf code), it must explicitly
request such access.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 0d6f541..bc5f507 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -185,6 +185,12 @@
@
stmia r7, {r2 - r6}
+ get_thread_info tsk
+ ldr r0, [tsk, #TI_ADDR_LIMIT]
+ mov r1, #TASK_SIZE
+ str r1, [tsk, #TI_ADDR_LIMIT]
+ str r0, [sp, #SVC_ADDR_LIMIT]
+
uaccess_save r0
.if \uaccess
uaccess_disable r0
@@ -213,7 +219,6 @@
irq_handler
#ifdef CONFIG_PREEMPT
- get_thread_info tsk
ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
ldr r0, [tsk, #TI_FLAGS] @ get flags
teq r8, #0 @ if preempt count != 0