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authorArnd Bergmann <arnd@arndb.de>2024-06-04 22:59:57 +0200
committerWill Deacon <will@kernel.org>2024-06-05 13:30:58 +0100
commit5c40e428aea644c9d924e491b1bc22fa9f272bcc (patch)
tree51d3db96223a9db4f1e2e957e8c209b2b89ba53d /arch
parent14951beaec93696b092a906baa0f29322cf34004 (diff)
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arm64/io: add constant-argument check
In some configurations __const_iowrite32_copy() does not get inlined and gcc runs into the BUILD_BUG(): In file included from <command-line>: In function '__const_memcpy_toio_aligned32', inlined from '__const_iowrite32_copy' at arch/arm64/include/asm/io.h:203:3, inlined from '__const_iowrite32_copy' at arch/arm64/include/asm/io.h:199:20: include/linux/compiler_types.h:487:45: error: call to '__compiletime_assert_538' declared with attribute error: BUILD_BUG failed 487 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^ include/linux/compiler_types.h:468:25: note: in definition of macro '__compiletime_assert' 468 | prefix ## suffix(); \ | ^~~~~~ include/linux/compiler_types.h:487:9: note: in expansion of macro '_compiletime_assert' 487 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^~~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' 39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) | ^~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG' 59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") | ^~~~~~~~~~~~~~~~ arch/arm64/include/asm/io.h:193:17: note: in expansion of macro 'BUILD_BUG' 193 | BUILD_BUG(); | ^~~~~~~~~ Move the check for constant arguments into the inline function to ensure it is still constant if the compiler decides against inlining it, and mark them as __always_inline to override the logic that sometimes leads to the compiler not producing the simplified output. Note that either the __always_inline annotation or the check for a constant value are sufficient here, but combining the two looks cleaner as it also avoids the macro. With clang-8 and older, the macro was still needed, but all versions of gcc and clang can reliably perform constant folding here. Fixes: ead79118dae6 ("arm64/io: Provide a WC friendly __iowriteXX_copy()") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20240604210006.668912-1-arnd@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/io.h36
1 files changed, 16 insertions, 20 deletions
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 4ff0ae3f6d66..41fd90895dfc 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -153,8 +153,9 @@ extern void __memset_io(volatile void __iomem *, int, size_t);
* emit the large TLP from the CPU.
*/
-static inline void __const_memcpy_toio_aligned32(volatile u32 __iomem *to,
- const u32 *from, size_t count)
+static __always_inline void
+__const_memcpy_toio_aligned32(volatile u32 __iomem *to, const u32 *from,
+ size_t count)
{
switch (count) {
case 8:
@@ -196,24 +197,22 @@ static inline void __const_memcpy_toio_aligned32(volatile u32 __iomem *to,
void __iowrite32_copy_full(void __iomem *to, const void *from, size_t count);
-static inline void __const_iowrite32_copy(void __iomem *to, const void *from,
- size_t count)
+static __always_inline void
+__iowrite32_copy(void __iomem *to, const void *from, size_t count)
{
- if (count == 8 || count == 4 || count == 2 || count == 1) {
+ if (__builtin_constant_p(count) &&
+ (count == 8 || count == 4 || count == 2 || count == 1)) {
__const_memcpy_toio_aligned32(to, from, count);
dgh();
} else {
__iowrite32_copy_full(to, from, count);
}
}
+#define __iowrite32_copy __iowrite32_copy
-#define __iowrite32_copy(to, from, count) \
- (__builtin_constant_p(count) ? \
- __const_iowrite32_copy(to, from, count) : \
- __iowrite32_copy_full(to, from, count))
-
-static inline void __const_memcpy_toio_aligned64(volatile u64 __iomem *to,
- const u64 *from, size_t count)
+static __always_inline void
+__const_memcpy_toio_aligned64(volatile u64 __iomem *to, const u64 *from,
+ size_t count)
{
switch (count) {
case 8:
@@ -255,21 +254,18 @@ static inline void __const_memcpy_toio_aligned64(volatile u64 __iomem *to,
void __iowrite64_copy_full(void __iomem *to, const void *from, size_t count);
-static inline void __const_iowrite64_copy(void __iomem *to, const void *from,
- size_t count)
+static __always_inline void
+__iowrite64_copy(void __iomem *to, const void *from, size_t count)
{
- if (count == 8 || count == 4 || count == 2 || count == 1) {
+ if (__builtin_constant_p(count) &&
+ (count == 8 || count == 4 || count == 2 || count == 1)) {
__const_memcpy_toio_aligned64(to, from, count);
dgh();
} else {
__iowrite64_copy_full(to, from, count);
}
}
-
-#define __iowrite64_copy(to, from, count) \
- (__builtin_constant_p(count) ? \
- __const_iowrite64_copy(to, from, count) : \
- __iowrite64_copy_full(to, from, count))
+#define __iowrite64_copy __iowrite64_copy
/*
* I/O memory mapping functions.