Commit f8fe23ec authored Jan 21, 2014 by Victor Kamensky Committed by Russell King Jan 28, 2014

ARM: 7946/1: asm: __und_usr_thumb need byteswap instructions in BE case



__und_usr_thumb function deals with thumb2 opcodes. In case of BE
image, it needs to byteswap half word thumb2 encoded instructions
before further processing them.

Without this fix BE image user-land thread executing first VFP
instruction encoded in thumb2 fails with SIGILL, because kernel
does not recognize instruction and does not enable VFP.

Reported-by: Corey Melton <comelton@cisco.com>
Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent b25f3e1c

arch/arm/kernel/entry-armv.S

+2 −0

Original line number	Diff line number	Diff line
		@@ -451,9 +451,11 @@ __und_usr_thumb:
		.arch armv6t2
		#endif
		2: ldrht r5, [r4]
		ARM_BE8(rev16 r5, r5) @ little endian instruction
		cmp r5, #0xe800 @ 32bit instruction if xx != 0
		blo __und_usr_fault_16 @ 16bit undefined instruction
		3: ldrht r0, [r2]
		ARM_BE8(rev16 r0, r0) @ little endian instruction
		add r2, r2, #2 @ r2 is PC + 2, make it PC + 4
		str r2, [sp, #S_PC] @ it's a 2x16bit instr, update
		orr r0, r0, r5, lsl #16