The MOVDIR64B instruction can be used by other wrapper instructions. Move the asm code to special_insns.h and have iosubmit_cmds512() call the asm function.
Reviewed-by: Tony Luck <[email protected]> Suggested-by: Michael Matz <[email protected]> Reviewed-by: Borislav Petkov <[email protected]> Signed-off-by: Dave Jiang <[email protected]> --- arch/x86/include/asm/io.h | 17 +++-------------- arch/x86/include/asm/special_insns.h | 22 ++++++++++++++++++++++ 2 files changed, 25 insertions(+), 14 deletions(-) diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index e1aa17a468a8..d726459d08e5 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -401,7 +401,7 @@ extern bool phys_mem_access_encrypted(unsigned long phys_addr, /** * iosubmit_cmds512 - copy data to single MMIO location, in 512-bit units - * @__dst: destination, in MMIO space (must be 512-bit aligned) + * @dst: destination, in MMIO space (must be 512-bit aligned) * @src: source * @count: number of 512 bits quantities to submit * @@ -412,25 +412,14 @@ extern bool phys_mem_access_encrypted(unsigned long phys_addr, * Warning: Do not use this helper unless your driver has checked that the CPU * instruction is supported on the platform. */ -static inline void iosubmit_cmds512(void __iomem *__dst, const void *src, +static inline void iosubmit_cmds512(void __iomem *dst, const void *src, size_t count) { - /* - * Note that this isn't an "on-stack copy", just definition of "dst" - * as a pointer to 64-bytes of stuff that is going to be overwritten. - * In the MOVDIR64B case that may be needed as you can use the - * MOVDIR64B instruction to copy arbitrary memory around. This trick - * lets the compiler know how much gets clobbered. - */ - volatile struct { char _[64]; } *dst = __dst; const u8 *from = src; const u8 *end = from + count * 64; while (from < end) { - /* MOVDIR64B [rdx], rax */ - asm volatile(".byte 0x66, 0x0f, 0x38, 0xf8, 0x02" - : "=m" (dst) - : "d" (from), "a" (dst)); + movdir64b(dst, from); from += 64; } } diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index 59a3e13204c3..2258c7d6e281 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -234,6 +234,28 @@ static inline void clwb(volatile void *__p) #define nop() asm volatile ("nop") +/* The dst parameter must be 64-bytes aligned */ +static inline void movdir64b(void *dst, const void *src) +{ + const struct { char _[64]; } *__src = src; + struct { char _[64]; } *__dst = dst; + + /* + * MOVDIR64B %(rdx), rax. + * + * Both __src and __dst must be memory constraints in order to tell the + * compiler that no other memory accesses should be reordered around + * this one. + * + * Also, both must be supplied as lvalues because this tells + * the compiler what the object is (its size) the instruction accesses. + * I.e., not the pointers but what they point, thus the deref'ing '*'. + */ + asm volatile(".byte 0x66, 0x0f, 0x38, 0xf8, 0x02" + : "+m" (*__dst) + : "m" (*__src), "a" (__dst), "d" (__src)); +} + #endif /* __KERNEL__ */ #endif /* _ASM_X86_SPECIAL_INSNS_H */ -- 2.26.2
