diff options
| -rw-r--r-- | arch/arm/Kconfig | 2 | ||||
| -rw-r--r-- | arch/arm/include/asm/assembler.h | 22 | ||||
| -rw-r--r-- | arch/arm/kernel/entry-armv.S | 4 | ||||
| -rw-r--r-- | arch/arm/kernel/head.S | 13 |
4 files changed, 32 insertions, 9 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index db524e75c4a..290a4b57617 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1229,7 +1229,7 @@ config SMP config SMP_ON_UP bool "Allow booting SMP kernel on uniprocessor systems (EXPERIMENTAL)" depends on EXPERIMENTAL - depends on SMP && !XIP && !THUMB2_KERNEL + depends on SMP && !XIP default y help SMP kernels contain instructions which fail on non-SMP processors. diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 749bb662240..72d3389e9c1 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -157,16 +157,24 @@ #ifdef CONFIG_SMP #define ALT_SMP(instr...) \ 9998: instr +/* + * Note: if you get assembler errors from ALT_UP() when building with + * CONFIG_THUMB2_KERNEL, you almost certainly need to use + * ALT_SMP( W(instr) ... ) + */ #define ALT_UP(instr...) \ .pushsection ".alt.smp.init", "a" ;\ .long 9998b ;\ - instr ;\ +9997: instr ;\ + .if . - 9997b != 4 ;\ + .error "ALT_UP() content must assemble to exactly 4 bytes";\ + .endif ;\ .popsection #define ALT_UP_B(label) \ .equ up_b_offset, label - 9998b ;\ .pushsection ".alt.smp.init", "a" ;\ .long 9998b ;\ - b . + up_b_offset ;\ + W(b) . + up_b_offset ;\ .popsection #else #define ALT_SMP(instr...) @@ -177,16 +185,24 @@ /* * SMP data memory barrier */ - .macro smp_dmb + .macro smp_dmb mode #ifdef CONFIG_SMP #if __LINUX_ARM_ARCH__ >= 7 + .ifeqs "\mode","arm" ALT_SMP(dmb) + .else + ALT_SMP(W(dmb)) + .endif #elif __LINUX_ARM_ARCH__ == 6 ALT_SMP(mcr p15, 0, r0, c7, c10, 5) @ dmb #else #error Incompatible SMP platform #endif + .ifeqs "\mode","arm" ALT_UP(nop) + .else + ALT_UP(W(nop)) + .endif #endif .endm diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 955cf5f539e..7f22a11a510 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -842,7 +842,7 @@ __kuser_helper_start: */ __kuser_memory_barrier: @ 0xffff0fa0 - smp_dmb + smp_dmb arm usr_ret lr .align 5 @@ -959,7 +959,7 @@ kuser_cmpxchg_fixup: #else - smp_dmb + smp_dmb arm 1: ldrex r3, [r2] subs r3, r3, r0 strexeq r3, r1, [r2] diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index fd94e4e82fc..359e54e83bd 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -412,10 +412,17 @@ __fixup_smp_on_up: add r4, r4, r3 add r5, r5, r3 2: cmp r4, r5 + movhs pc, lr ldmia r4!, {r0, r6} - strlo r6, [r0, r3] - blo 2b - mov pc, lr + ARM( str r6, [r0, r3] ) + THUMB( add r0, r0, r3 ) +#ifdef __ARMEB__ + THUMB( mov r6, r6, ror #16 ) @ Convert word order for big-endian. +#endif + THUMB( strh r6, [r0], #2 ) @ For Thumb-2, store as two halfwords + THUMB( mov r6, r6, lsr #16 ) @ to be robust against misaligned r3. + THUMB( strh r6, [r0] ) + b 2b ENDPROC(__fixup_smp) 1: .word . |