Messages in this thread Patch in this message | | | From | Qian Cai <> | Subject | [PATCH v2] arm64/prefetch: fix a -Wtype-limits warning | Date | Fri, 2 Aug 2019 20:33:58 -0400 |
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The commit d5370f754875 ("arm64: prefetch: add alternative pattern for CPUs without a prefetcher") introduced MIDR_IS_CPU_MODEL_RANGE() to be used in has_no_hw_prefetch() with rv_min=0 which generates a compilation warning from GCC,
In file included from ./arch/arm64/include/asm/cache.h:8, from ./include/linux/cache.h:6, from ./include/linux/printk.h:9, from ./include/linux/kernel.h:15, from ./include/linux/cpumask.h:10, from arch/arm64/kernel/cpufeature.c:11: arch/arm64/kernel/cpufeature.c: In function 'has_no_hw_prefetch': ./arch/arm64/include/asm/cputype.h:59:26: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] _model == (model) && rv >= (rv_min) && rv <= (rv_max); \ ^~ arch/arm64/kernel/cpufeature.c:889:9: note: in expansion of macro 'MIDR_IS_CPU_MODEL_RANGE' return MIDR_IS_CPU_MODEL_RANGE(midr, MIDR_THUNDERX, ^~~~~~~~~~~~~~~~~~~~~~~
Fix it by making "rv" a "s32".
Signed-off-by: Qian Cai <cai@lca.pw> ---
v2: Use "s32" for "rv", so "variant 0/revision 0" can be covered.
arch/arm64/include/asm/cputype.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h index e7d46631cc42..d52fe8651c2d 100644 --- a/arch/arm64/include/asm/cputype.h +++ b/arch/arm64/include/asm/cputype.h @@ -54,7 +54,7 @@ #define MIDR_IS_CPU_MODEL_RANGE(midr, model, rv_min, rv_max) \ ({ \ u32 _model = (midr) & MIDR_CPU_MODEL_MASK; \ - u32 rv = (midr) & (MIDR_REVISION_MASK | MIDR_VARIANT_MASK); \ + s32 rv = (midr) & (MIDR_REVISION_MASK | MIDR_VARIANT_MASK); \ \ _model == (model) && rv >= (rv_min) && rv <= (rv_max); \ }) -- 2.20.1 (Apple Git-117)
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