[PATCH AUTOSEL 5.2 041/185] arm64/prefetch: fix a -Wtype-limits warning

Sasha Levin
2019-09-22T19:28:05Z

From: Qian Cai <cai@lca.pw>

[ Upstream commit b99286b088ea843b935dcfb29f187697359fe5cd ]

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 converting MIDR_IS_CPU_MODEL_RANGE to a static inline
function.

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/include/asm/cputype.h | 21 +++++++++++----------
arch/arm64/kernel/cpufeature.c | 2 +-
2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
index e7d46631cc42b..b1454d117cd2c 100644
--- a/arch/arm64/include/asm/cputype.h
+++ b/arch/arm64/include/asm/cputype.h
@@ -51,14 +51,6 @@
#define MIDR_CPU_MODEL_MASK (MIDR_IMPLEMENTOR_MASK | MIDR_PARTNUM_MASK | \
MIDR_ARCHITECTURE_MASK)

-#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); \
- \
- _model == (model) && rv >= (rv_min) && rv <= (rv_max); \
- })
-
#define ARM_CPU_IMP_ARM 0x41
#define ARM_CPU_IMP_APM 0x50
#define ARM_CPU_IMP_CAVIUM 0x43
@@ -159,10 +151,19 @@ struct midr_range {
#define MIDR_REV(m, v, r) MIDR_RANGE(m, v, r, v, r)
#define MIDR_ALL_VERSIONS(m) MIDR_RANGE(m, 0, 0, 0xf, 0xf)

+static inline bool midr_is_cpu_model_range(u32 midr, u32 model, u32 rv_min,
+ u32 rv_max)
+{
+ u32 _model = midr & MIDR_CPU_MODEL_MASK;
+ u32 rv = midr & (MIDR_REVISION_MASK | MIDR_VARIANT_MASK);
+
+ return _model == model && rv >= rv_min && rv <= rv_max;
+}
+
static inline bool is_midr_in_range(u32 midr, struct midr_range const *range)
{
- return MIDR_IS_CPU_MODEL_RANGE(midr, range->model,
- range->rv_min, range->rv_max);
+ return midr_is_cpu_model_range(midr, range->model,
+ range->rv_min, range->rv_max);
}

static inline bool
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 68faf535f40a3..d3fbb89a31e57 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -894,7 +894,7 @@ static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry, int _
u32 midr = read_cpuid_id();

/* Cavium ThunderX pass 1.x and 2.x */
- return MIDR_IS_CPU_MODEL_RANGE(midr, MIDR_THUNDERX,
+ return midr_is_cpu_model_range(midr, MIDR_THUNDERX,
MIDR_CPU_VAR_REV(0, 0),
MIDR_CPU_VAR_REV(1, MIDR_REVISION_MASK));
}
--
2.20.1