Unverified Commit 4bfa185f authored by Leonardo Bras's avatar Leonardo Bras Committed by Palmer Dabbelt
Browse files

riscv/cmpxchg: Deduplicate xchg() asm functions 



In this header every xchg define (_relaxed, _acquire, _release, vanilla)
contain it's own asm file, both for 4-byte variables an 8-byte variables,
on a total of 8 versions of mostly the same asm.

This is usually bad, as it means any change may be done in up to 8
different places.

Unify those versions by creating a new define with enough parameters to
generate any version of the previous 8.

Then unify the result under a more general define, and simplify
arch_xchg* generation.

(This did not cause any change in generated asm)

Signed-off-by: default avatarLeonardo Bras <leobras@redhat.com>
Reviewed-by: default avatarGuo Ren <guoren@kernel.org>
Reviewed-by: default avatarAndrea Parri <parri.andrea@gmail.com>
Tested-by: default avatarGuo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20240103163203.72768-3-leobras@redhat.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 6613476e

arch/riscv/include/asm/cmpxchg.h

+23 −115
Original line number Diff line number Diff line
@@ -11,140 +11,48 @@ 
#include <asm/barrier.h>

#include <asm/fence.h>



#define __xchg_relaxed(ptr, new, size)					\

#define __arch_xchg(sfx, prepend, append, r, p, n)			\

({									\

	__typeof__(ptr) __ptr = (ptr);					\

	__typeof__(new) __new = (new);					\

	__typeof__(*(ptr)) __ret;					\

	switch (size) {							\

	case 4:								\

	__asm__ __volatile__ (						\

			"	amoswap.w %0, %2, %1\n"			\

			: "=r" (__ret), "+A" (*__ptr)			\

			: "r" (__new)					\

		prepend							\

		"	amoswap" sfx " %0, %2, %1\n"			\

		append							\

		: "=r" (r), "+A" (*(p))					\

		: "r" (n)						\

		: "memory");						\

		break;							\

	case 8:								\

		__asm__ __volatile__ (					\

			"	amoswap.d %0, %2, %1\n"			\

			: "=r" (__ret), "+A" (*__ptr)			\

			: "r" (__new)					\

			: "memory");					\

		break;							\

	default:							\

		BUILD_BUG();						\

	}								\

	__ret;								\

})



#define arch_xchg_relaxed(ptr, x)					\

({									\

	__typeof__(*(ptr)) _x_ = (x);					\

	(__typeof__(*(ptr))) __xchg_relaxed((ptr),			\

					    _x_, sizeof(*(ptr)));	\

})



#define __xchg_acquire(ptr, new, size)					\

#define _arch_xchg(ptr, new, sfx, prepend, append)			\

({									\

	__typeof__(ptr) __ptr = (ptr);					\

	__typeof__(new) __new = (new);					\

	__typeof__(*(ptr)) __ret;					\

	switch (size) {							\

	__typeof__(*(__ptr)) __new = (new);				\

	__typeof__(*(__ptr)) __ret;					\

	switch (sizeof(*__ptr)) {					\

	case 4:								\

		__asm__ __volatile__ (					\

			"	amoswap.w %0, %2, %1\n"			\

			RISCV_ACQUIRE_BARRIER				\

			: "=r" (__ret), "+A" (*__ptr)			\

			: "r" (__new)					\

			: "memory");					\

		__arch_xchg(".w" sfx, prepend, append,			\

			      __ret, __ptr, __new);			\

		break;							\

	case 8:								\

		__asm__ __volatile__ (					\

			"	amoswap.d %0, %2, %1\n"			\

			RISCV_ACQUIRE_BARRIER				\

			: "=r" (__ret), "+A" (*__ptr)			\

			: "r" (__new)					\

			: "memory");					\

		__arch_xchg(".d" sfx, prepend, append,			\

			      __ret, __ptr, __new);			\

		break;							\

	default:							\

		BUILD_BUG();						\

	}								\

	__ret;								\

	(__typeof__(*(__ptr)))__ret;					\

})



#define arch_xchg_acquire(ptr, x)					\

({									\

	__typeof__(*(ptr)) _x_ = (x);					\

	(__typeof__(*(ptr))) __xchg_acquire((ptr),			\

					    _x_, sizeof(*(ptr)));	\

})

#define arch_xchg_relaxed(ptr, x)					\

	_arch_xchg(ptr, x, "", "", "")



#define __xchg_release(ptr, new, size)					\

({									\

	__typeof__(ptr) __ptr = (ptr);					\

	__typeof__(new) __new = (new);					\

	__typeof__(*(ptr)) __ret;					\

	switch (size) {							\

	case 4:								\

		__asm__ __volatile__ (					\

			RISCV_RELEASE_BARRIER				\

			"	amoswap.w %0, %2, %1\n"			\

			: "=r" (__ret), "+A" (*__ptr)			\

			: "r" (__new)					\

			: "memory");					\

		break;							\

	case 8:								\

		__asm__ __volatile__ (					\

			RISCV_RELEASE_BARRIER				\

			"	amoswap.d %0, %2, %1\n"			\

			: "=r" (__ret), "+A" (*__ptr)			\

			: "r" (__new)					\

			: "memory");					\

		break;							\

	default:							\

		BUILD_BUG();						\

	}								\

	__ret;								\

})

#define arch_xchg_acquire(ptr, x)					\

	_arch_xchg(ptr, x, "", "", RISCV_ACQUIRE_BARRIER)



#define arch_xchg_release(ptr, x)					\

({									\

	__typeof__(*(ptr)) _x_ = (x);					\

	(__typeof__(*(ptr))) __xchg_release((ptr),			\

					    _x_, sizeof(*(ptr)));	\

})



#define __arch_xchg(ptr, new, size)					\

({									\

	__typeof__(ptr) __ptr = (ptr);					\

	__typeof__(new) __new = (new);					\

	__typeof__(*(ptr)) __ret;					\

	switch (size) {							\

	case 4:								\

		__asm__ __volatile__ (					\

			"	amoswap.w.aqrl %0, %2, %1\n"		\

			: "=r" (__ret), "+A" (*__ptr)			\

			: "r" (__new)					\

			: "memory");					\

		break;							\

	case 8:								\

		__asm__ __volatile__ (					\

			"	amoswap.d.aqrl %0, %2, %1\n"		\

			: "=r" (__ret), "+A" (*__ptr)			\

			: "r" (__new)					\

			: "memory");					\

		break;							\

	default:							\

		BUILD_BUG();						\

	}								\

	__ret;								\

})

	_arch_xchg(ptr, x, "", RISCV_RELEASE_BARRIER, "")



#define arch_xchg(ptr, x)						\

({									\

	__typeof__(*(ptr)) _x_ = (x);					\

	(__typeof__(*(ptr))) __arch_xchg((ptr), _x_, sizeof(*(ptr)));	\

})

	_arch_xchg(ptr, x, ".aqrl", "", "")



#define xchg32(ptr, x)							\

({									\