| Message ID | 20240528153717.2439910-1-arnd@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] arm64/io: add constant-argument check | expand |
On Tue, May 28, 2024 at 05:37:11PM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > 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. > > Fixes: ead79118dae6 ("arm64/io: Provide a WC friendly __iowriteXX_copy()") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > v2: > - fix both 32-bit and 64-bit copies > - remove now-redundant macros > --- > arch/arm64/include/asm/io.h | 24 +++++++++--------------- > 1 file changed, 9 insertions(+), 15 deletions(-) I think this is superseded by Mark's diff in reply to v1, right? https://lore.kernel.org/r/ZlcODqVXTDh6n0h-@J2N7QTR9R3 If so, Mark, please can you post that as a proper patch so that we can get this fixed? Cheers, Will
On Tue, Jun 04, 2024 at 04:55:37PM +0100, Will Deacon wrote: > On Tue, May 28, 2024 at 05:37:11PM +0200, Arnd Bergmann wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > > > 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. > > > > Fixes: ead79118dae6 ("arm64/io: Provide a WC friendly __iowriteXX_copy()") > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > > --- > > v2: > > - fix both 32-bit and 64-bit copies > > - remove now-redundant macros > > --- > > arch/arm64/include/asm/io.h | 24 +++++++++--------------- > > 1 file changed, 9 insertions(+), 15 deletions(-) > > I think this is superseded by Mark's diff in reply to v1, right? > > https://lore.kernel.org/r/ZlcODqVXTDh6n0h-@J2N7QTR9R3 > > If so, Mark, please can you post that as a proper patch so that we can > get this fixed? I wouldn't say superseded, but I agree with Mark that we should have the __always_inline added to the __iowrite64_copy() and __const_memcpy_toio_aligned64() in addition to the stuff here. When I originally wrote this I copied the fairly common pattern of having the builtin_constant_p test inside a macro, but I see now it is quite common to put that into an inline. Putting it in the inline is definately much better, so I like Arnd's patch. Arnd can you just make that addition and repost this? Thanks, Jason
On Tue, Jun 4, 2024, at 22:12, Jason Gunthorpe wrote: > On Tue, Jun 04, 2024 at 04:55:37PM +0100, Will Deacon wrote: >> On Tue, May 28, 2024 at 05:37:11PM +0200, Arnd Bergmann wrote: >> >> I think this is superseded by Mark's diff in reply to v1, right? >> >> https://lore.kernel.org/r/ZlcODqVXTDh6n0h-@J2N7QTR9R3 >> >> If so, Mark, please can you post that as a proper patch so that we can >> get this fixed? > > I wouldn't say superseded, but I agree with Mark that we should have > the __always_inline added to the __iowrite64_copy() and > __const_memcpy_toio_aligned64() in addition to the stuff here. > > When I originally wrote this I copied the fairly common pattern of > having the builtin_constant_p test inside a macro, but I see now it is > quite common to put that into an inline. Putting it in the inline is > definately much better, so I like Arnd's patch. > > Arnd can you just make that addition and repost this? > Yes, sorry for failing to follow up earlier. I'm doing a little more build testing now, will send soon. Arnd
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h index 4ff0ae3f6d66..902026f81b97 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -196,21 +196,18 @@ 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 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(to, from, count) \ - (__builtin_constant_p(count) ? \ - __const_iowrite32_copy(to, from, count) : \ - __iowrite32_copy_full(to, from, count)) +#define __iowrite32_copy(to, from, count) __iowrite32_copy(to, from, count) static inline void __const_memcpy_toio_aligned64(volatile u64 __iomem *to, const u64 *from, size_t count) @@ -255,21 +252,18 @@ 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, +static 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(to, from, count) __iowrite64_copy(to, from, count) /* * I/O memory mapping functions.