On Thu, Oct 18, 2018 at 6:18 PM Borislav Petkov <b...@alien8.de> wrote: > > On Wed, Oct 17, 2018 at 09:40:53PM -0300, Leonardo Bras wrote: > > The idea was to put it as default and fix all the shadowing warnings. > > What do you think? I am open to suggestions. > > That's Masahiro's call. In the rest of the kernel, those warnings are behind > the W=2 switch - i.e., not enabled by default.
It is not realistic to enable this warning option by default. Even -Wshadow=local emits tons of warnings. (More with -Wshadow) The problem of this flag is, it is false positive in macro expansions. For example, I think the following is a legitimate case. In file included from ./arch/arm64/include/asm/cputype.h:126:0, from ./arch/arm64/include/asm/cache.h:19, from ./include/linux/cache.h:6, from ./include/linux/printk.h:9, from ./include/linux/kernel.h:14, from ./include/linux/bitmap.h:10, from arch/arm64/kernel/fpsimd.c:20: arch/arm64/kernel/fpsimd.c: In function ‘sve_kernel_enable’: ./arch/arm64/include/asm/sysreg.h:707:6: warning: declaration of ‘__val’ shadows a previous local [-Wshadow=compatible-local] u64 __val; \ ^ ./arch/arm64/include/asm/sysreg.h:717:20: note: in definition of macro ‘write_sysreg’ u64 __val = (u64)(v); \ ^ arch/arm64/kernel/fpsimd.c:713:15: note: in expansion of macro ‘read_sysreg’ write_sysreg(read_sysreg(CPACR_EL1) | CPACR_EL1_ZEN_EL1EN, CPACR_EL1); ^~~~~~~~~~~ ./arch/arm64/include/asm/sysreg.h:717:6: note: shadowed declaration is here u64 __val = (u64)(v); \ ^ arch/arm64/kernel/fpsimd.c:713:2: note: in expansion of macro ‘write_sysreg’ write_sysreg(read_sysreg(CPACR_EL1) | CPACR_EL1_ZEN_EL1EN, CPACR_EL1); ^~~~~~~~~~~~ -- Best Regards Masahiro Yamada