ARM: 5757/1: Thumb-2: Correct "mov.w pc, lr" instruction which is unpredictable
The 32-bit wide variant of "mov pc, reg" in Thumb-2 is unpredictable
causing improper handling of the undefined instructions not caught by
the kernel. This patch adds a movw_pc macro for such situations
(currently only used in call_fpe).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index ac34c0d..7e9ed1e 100644
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -110,6 +110,13 @@
mov \rd, sp, lsr #13
mov \rd, \rd, lsl #13
.endm
+
+ @
+ @ 32-bit wide "mov pc, reg"
+ @
+ .macro movw_pc, reg
+ mov pc, \reg
+ .endm
#else /* CONFIG_THUMB2_KERNEL */
.macro svc_exit, rpsr
clrex @ clear the exclusive monitor
@@ -146,6 +153,14 @@
lsr \rd, \rd, #13
mov \rd, \rd, lsl #13
.endm
+
+ @
+ @ 32-bit wide "mov pc, reg"
+ @
+ .macro movw_pc, reg
+ mov pc, \reg
+ nop
+ .endm
#endif /* !CONFIG_THUMB2_KERNEL */
/*