From: Jian Cai caij2003@gmail.com
commit a780e485b5768e78aef087502499714901b68cc4 upstream
ALT_UP_B macro sets symbol up_b_offset via .equ to an expression involving another symbol. The macro gets expanded twice when arch/arm/kernel/sleep.S is assembled, creating a scenario where up_b_offset is set to another expression involving symbols while its current value is based on symbols. LLVM integrated assembler does not allow such cases, and based on the documentation of binutils, "Values that are based on expressions involving other symbols are allowed, but some targets may restrict this to only being done once per assembly", so it may be better to avoid such cases as it is not clearly stated which targets should support or disallow them. The fix in this case is simple, as up_b_offset has only one use, so we can replace the use with the definition and get rid of up_b_offset.
Link:https://github.com/ClangBuiltLinux/linux/issues/920
Reviewed-by: Stefan Agner stefan@agner.ch
Reviewed-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Jian Cai caij2003@gmail.com Signed-off-by: Russell King rmk+kernel@armlinux.org.uk Signed-off-by: Florian Fainelli f.fainelli@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm/include/asm/assembler.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -279,10 +279,9 @@ .endif ;\ .popsection #define ALT_UP_B(label) \ - .equ up_b_offset, label - 9998b ;\ .pushsection ".alt.smp.init", "a" ;\ .long 9998b ;\ - W(b) . + up_b_offset ;\ + W(b) . + (label - 9998b) ;\ .popsection #else #define ALT_SMP(instr...)