On 02/06/2017 05:01 PM, Stephen Boyd wrote: > 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: <sparse@xxxxxxxxxxxxxxx> Sorry, supposed to be <linux-sparse@xxxxxxxxxxxxxxx> > Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> > --- > 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__ */ -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
