From: Ard Biesheuvel ardb@kernel.org
commit 9f80ccda53b9417236945bc7ece4b519037df74d upstream.
When building for Thumb2, the .alt.smp.init sections that are emitted by the ALT_UP() patching code may not be 32-bit aligned, even though the fixup_smp_on_up() routine expects that. This results in alignment faults at module load time, which need to be fixed up by the fault handler.
So let's align those sections explicitly, and prevent this from occurring.
Cc: stable@vger.kernel.org Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Russell King (Oracle) rmk+kernel@armlinux.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm/include/asm/assembler.h | 2 ++ arch/arm/include/asm/processor.h | 1 + 2 files changed, 3 insertions(+)
--- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -288,6 +288,7 @@ */ #define ALT_UP(instr...) \ .pushsection ".alt.smp.init", "a" ;\ + .align 2 ;\ .long 9998b - . ;\ 9997: instr ;\ .if . - 9997b == 2 ;\ @@ -299,6 +300,7 @@ .popsection #define ALT_UP_B(label) \ .pushsection ".alt.smp.init", "a" ;\ + .align 2 ;\ .long 9998b - . ;\ W(b) . + (label - 9998b) ;\ .popsection --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -96,6 +96,7 @@ unsigned long __get_wchan(struct task_st #define __ALT_SMP_ASM(smp, up) \ "9998: " smp "\n" \ " .pushsection ".alt.smp.init", "a"\n" \ + " .align 2\n" \ " .long 9998b - .\n" \ " " up "\n" \ " .popsection\n"