diff options
| author | Dave Martin <dave.martin@linaro.org> | 2011-08-19 18:00:08 +0100 |
|---|---|---|
| committer | Nicolas Pitre <nicolas.pitre@linaro.org> | 2011-08-22 12:29:12 -0400 |
| commit | ee49866febeac921a878088c58da1fdc0c0073f6 (patch) | |
| tree | 745dd6fc4a2610162349fb1b85009c1af330f36f | |
| parent | 9b45bd9beb2bc6ab6aade3f1fac4885c2c16839e (diff) | |
ARM: 7031/1: entry: Fix Thumb-2 undef handling for multi-CPU kernels
When v6 and >=v7 boards are supported in the same kernel, the
__und_usr code currently makes a build-time assumption that Thumb-2
instructions occurring in userspace don't need to be supported.
Strictly speaking this is incorrect.
This patch fixes the above case by doing a run-time check on the
CPU architecture in these cases. This only affects kernels which
support v6 and >=v7 CPUs together: plain v6 and plain v7 kernels
are unaffected.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Reviewed-by: Jon Medhurst <tixy@yxit.co.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
(cherry picked from commit 07ed43553f9ceefe5e3cbd25da0f6ff912b4fedb)
| -rw-r--r-- | arch/arm/kernel/entry-armv.S | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index b7236d400ae..9ad50c4208a 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -24,6 +24,7 @@ #include <asm/unwind.h> #include <asm/unistd.h> #include <asm/tls.h> +#include <asm/system.h> #include "entry-header.S" #include <asm/entry-macro-multi.S> @@ -439,7 +440,27 @@ __und_usr: #endif beq call_fpe @ Thumb instruction -#if __LINUX_ARM_ARCH__ >= 7 +#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 +/* + * Thumb-2 instruction handling. Note that because pre-v6 and >= v6 platforms + * can never be supported in a single kernel, this code is not applicable at + * all when __LINUX_ARM_ARCH__ < 6. This allows simplifying assumptions to be + * made about .arch directives. + */ +#if __LINUX_ARM_ARCH__ < 7 +/* If the target CPU may not be Thumb-2-capable, a run-time check is needed: */ +#define NEED_CPU_ARCHITECTURE + ldr r5, .LCcpu_architecture + ldr r5, [r5] + cmp r5, #CPU_ARCH_ARMv7 + blo __und_usr_unknown +/* + * The following code won't get run unless the running CPU really is v7, so + * coding round the lack of ldrht on older arches is pointless. Temporarily + * override the assembler target arch with the minimum required instead: + */ + .arch armv6t2 +#endif 2: ARM( ldrht r5, [r4], #2 ) THUMB( ldrht r5, [r4] ) @@ -449,7 +470,16 @@ __und_usr: 3: ldrht r0, [r4] add r2, r2, #2 @ r2 is PC + 2, make it PC + 4 orr r0, r0, r5, lsl #16 + +#if __LINUX_ARM_ARCH__ < 7 +/* If the target arch was overridden, change it back: */ +#ifdef CONFIG_CPU_32v6K + .arch armv6k #else + .arch armv6 +#endif +#endif /* __LINUX_ARM_ARCH__ < 7 */ +#else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */ b __und_usr_unknown #endif UNWIND(.fnend ) @@ -576,6 +606,12 @@ call_fpe: movw_pc lr @ CP#14 (Debug) movw_pc lr @ CP#15 (Control) +#ifdef NEED_CPU_ARCHITECTURE + .align 2 +.LCcpu_architecture: + .word __cpu_architecture +#endif + #ifdef CONFIG_NEON .align 6 |