When I compile files with sparse, I get these sorts of warnings: arch/arm64/include/asm/lse.h:14:28: warning: Unknown escape 'l' arch/arm64/include/asm/lse.h:14:37: warning: Unknown escape 'l' arch/arm64/include/asm/alternative.h:172:28: warning: Unknown escape 'o'
This is because sparse is trying to tokenize these files and sees a line like this: alternative_insn "\llsc", "\lse", ARM64_HAS_LSE_ATOMICS It gets past alternative_insn part and then sees the start of a string with the double quote character. So sparse starts to parse the string (eat_string() in the sparse code) but the string has an escape character '\' in it. Sparse sees the escape character, so it checks to see if it's an escape sequence, but '\l' isn't. This causes sparse to spit out this warning of an unknown escape sequence 'l'. In reality, sparse isn't going to use these macros anyway because this whole thing is inside an __ASSEMBLER__ ifdef. One hacky solution is to make sparse think it actually is an escape sequence by starting the macro arguments with the 'n' character. Then sparse will see a \n inside a string, which keeps it silent and the assembler doesn't seem to mind either. Cc: <[email protected]> Signed-off-by: Stephen Boyd <[email protected]> --- arch/arm64/include/asm/alternative.h | 4 ++-- arch/arm64/include/asm/lse.h | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h index 6e1cb8c5af4d..dd393db554c8 100644 --- a/arch/arm64/include/asm/alternative.h +++ b/arch/arm64/include/asm/alternative.h @@ -168,8 +168,8 @@ alternative_endif #define _ALTERNATIVE_CFG(insn1, insn2, cap, cfg, ...) \ alternative_insn insn1, insn2, cap, IS_ENABLED(cfg) -.macro user_alt, label, oldinstr, newinstr, cond -9999: alternative_insn "\oldinstr", "\newinstr", \cond +.macro user_alt, label, noldinstr, newinstr, cond +9999: alternative_insn "\noldinstr", "\newinstr", \cond _ASM_EXTABLE 9999b, \label .endm diff --git a/arch/arm64/include/asm/lse.h b/arch/arm64/include/asm/lse.h index fc756e22c84c..36206d75943d 100644 --- a/arch/arm64/include/asm/lse.h +++ b/arch/arm64/include/asm/lse.h @@ -10,8 +10,8 @@ .arch_extension lse -.macro alt_lse, llsc, lse - alternative_insn "\llsc", "\lse", ARM64_HAS_LSE_ATOMICS +.macro alt_lse, nllsc, nlse + alternative_insn "\nllsc", "\nlse", ARM64_HAS_LSE_ATOMICS .endm #else /* __ASSEMBLER__ */ -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
