The following commit has been merged in the linux branch: commit a771fe6e4e3e58f2056823ef9c30a554ec48f453 Author: Catalin Marinas catalin.marinas@arm.com Date: Mon Oct 12 17:31:20 2009 +0100
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-armv.S b/arch/arm/kernel/entry-armv.S index 322410b..0022b4d 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -608,33 +608,33 @@ call_fpe: THUMB( add pc, r8 ) nop
- W(mov) pc, lr @ CP#0 + movw_pc lr @ CP#0 W(b) do_fpe @ CP#1 (FPE) W(b) do_fpe @ CP#2 (FPE) - W(mov) pc, lr @ CP#3 + movw_pc lr @ CP#3 #ifdef CONFIG_CRUNCH b crunch_task_enable @ CP#4 (MaverickCrunch) b crunch_task_enable @ CP#5 (MaverickCrunch) b crunch_task_enable @ CP#6 (MaverickCrunch) #else - W(mov) pc, lr @ CP#4 - W(mov) pc, lr @ CP#5 - W(mov) pc, lr @ CP#6 + movw_pc lr @ CP#4 + movw_pc lr @ CP#5 + movw_pc lr @ CP#6 #endif - W(mov) pc, lr @ CP#7 - W(mov) pc, lr @ CP#8 - W(mov) pc, lr @ CP#9 + movw_pc lr @ CP#7 + movw_pc lr @ CP#8 + movw_pc lr @ CP#9 #ifdef CONFIG_VFP W(b) do_vfp @ CP#10 (VFP) W(b) do_vfp @ CP#11 (VFP) #else - W(mov) pc, lr @ CP#10 (VFP) - W(mov) pc, lr @ CP#11 (VFP) + movw_pc lr @ CP#10 (VFP) + movw_pc lr @ CP#11 (VFP) #endif - W(mov) pc, lr @ CP#12 - W(mov) pc, lr @ CP#13 - W(mov) pc, lr @ CP#14 (Debug) - W(mov) pc, lr @ CP#15 (Control) + movw_pc lr @ CP#12 + movw_pc lr @ CP#13 + movw_pc lr @ CP#14 (Debug) + movw_pc lr @ CP#15 (Control)
#ifdef CONFIG_NEON .align 6 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 */
/*