Import iosubmit_cmds512() from arch/x86/include/asm/io.h into tools/ so it can be used by VFIO selftests to interact with Intel DSA devices.
Also pull in movdir64b() from arch/x86/include/asm/special_insns.h into tools/, which is the underlying instruction used by iosubmit_cmds512().
Changes made when importing: None
Acked-by: Vinicius Costa Gomes vinicius.gomes@intel.com Acked-by: Shuah Khan skhan@linuxfoundation.org Signed-off-by: David Matlack dmatlack@google.com --- tools/arch/x86/include/asm/io.h | 26 +++++++++++++++++++++ tools/arch/x86/include/asm/special_insns.h | 27 ++++++++++++++++++++++ 2 files changed, 53 insertions(+) create mode 100644 tools/arch/x86/include/asm/special_insns.h
diff --git a/tools/arch/x86/include/asm/io.h b/tools/arch/x86/include/asm/io.h index 4c787a2363de..ecad61a3ea52 100644 --- a/tools/arch/x86/include/asm/io.h +++ b/tools/arch/x86/include/asm/io.h @@ -4,6 +4,7 @@
#include <linux/compiler.h> #include <linux/types.h> +#include "special_insns.h"
#define build_mmio_read(name, size, type, reg, barrier) \ static inline type name(const volatile void __iomem *addr) \ @@ -72,4 +73,29 @@ build_mmio_write(__writeq, "q", u64, "r", )
#include <asm-generic/io.h>
+/** + * iosubmit_cmds512 - copy data to single MMIO location, in 512-bit units + * @dst: destination, in MMIO space (must be 512-bit aligned) + * @src: source + * @count: number of 512 bits quantities to submit + * + * Submit data from kernel space to MMIO space, in units of 512 bits at a + * time. Order of access is not guaranteed, nor is a memory barrier + * performed afterwards. + * + * 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, + size_t count) +{ + const u8 *from = src; + const u8 *end = from + count * 64; + + while (from < end) { + movdir64b(dst, from); + from += 64; + } +} + #endif /* _TOOLS_ASM_X86_IO_H */ diff --git a/tools/arch/x86/include/asm/special_insns.h b/tools/arch/x86/include/asm/special_insns.h new file mode 100644 index 000000000000..04af42a99c38 --- /dev/null +++ b/tools/arch/x86/include/asm/special_insns.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TOOLS_ASM_X86_SPECIAL_INSNS_H +#define _TOOLS_ASM_X86_SPECIAL_INSNS_H + +/* 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 to, thus the deref'ing '*'. + */ + asm volatile(".byte 0x66, 0x0f, 0x38, 0xf8, 0x02" + : "+m" (*__dst) + : "m" (*__src), "a" (__dst), "d" (__src)); +} + +#endif /* _TOOLS_ASM_X86_SPECIAL_INSNS_H */