tools headers: Import x86 MMIO helper overrides

Import the x86-specific overrides for <asm-generic/io.h> from the kernel
headers into tools/include/.

Changes made when importing:
 - Replace CONFIG_X86_64 with __x86_64__.

Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20250822212518.4156428-17-dmatlack@google.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

tools/arch/x86/include/asm/io.h

@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TOOLS_ASM_X86_IO_H
+#define _TOOLS_ASM_X86_IO_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+#define build_mmio_read(name, size, type, reg, barrier) \
+static inline type name(const volatile void __iomem *addr) \
+{ type ret; asm volatile("mov" size " %1,%0":reg (ret) \
+:"m" (*(volatile type __force *)addr) barrier); return ret; }
+
+#define build_mmio_write(name, size, type, reg, barrier) \
+static inline void name(type val, volatile void __iomem *addr) \
+{ asm volatile("mov" size " %0,%1": :reg (val), \
+"m" (*(volatile type __force *)addr) barrier); }
+
+build_mmio_read(readb, "b", unsigned char, "=q", :"memory")
+build_mmio_read(readw, "w", unsigned short, "=r", :"memory")
+build_mmio_read(readl, "l", unsigned int, "=r", :"memory")
+
+build_mmio_read(__readb, "b", unsigned char, "=q", )
+build_mmio_read(__readw, "w", unsigned short, "=r", )
+build_mmio_read(__readl, "l", unsigned int, "=r", )
+
+build_mmio_write(writeb, "b", unsigned char, "q", :"memory")
+build_mmio_write(writew, "w", unsigned short, "r", :"memory")
+build_mmio_write(writel, "l", unsigned int, "r", :"memory")
+
+build_mmio_write(__writeb, "b", unsigned char, "q", )
+build_mmio_write(__writew, "w", unsigned short, "r", )
+build_mmio_write(__writel, "l", unsigned int, "r", )
+
+#define readb readb
+#define readw readw
+#define readl readl
+#define readb_relaxed(a) __readb(a)
+#define readw_relaxed(a) __readw(a)
+#define readl_relaxed(a) __readl(a)
+#define __raw_readb __readb
+#define __raw_readw __readw
+#define __raw_readl __readl
+
+#define writeb writeb
+#define writew writew
+#define writel writel
+#define writeb_relaxed(v, a) __writeb(v, a)
+#define writew_relaxed(v, a) __writew(v, a)
+#define writel_relaxed(v, a) __writel(v, a)
+#define __raw_writeb __writeb
+#define __raw_writew __writew
+#define __raw_writel __writel
+
+#ifdef __x86_64__
+
+build_mmio_read(readq, "q", u64, "=r", :"memory")
+build_mmio_read(__readq, "q", u64, "=r", )
+build_mmio_write(writeq, "q", u64, "r", :"memory")
+build_mmio_write(__writeq, "q", u64, "r", )
+
+#define readq_relaxed(a)	__readq(a)
+#define writeq_relaxed(v, a)	__writeq(v, a)
+
+#define __raw_readq		__readq
+#define __raw_writeq		__writeq
+
+/* Let people know that we have them */
+#define readq			readq
+#define writeq			writeq
+
+#endif /* __x86_64__ */
+
+#include <asm-generic/io.h>
+
+#endif /* _TOOLS_ASM_X86_IO_H */

tools/include/asm/io.h

@@ -2,6 +2,10 @@
 #ifndef _TOOLS_ASM_IO_H
 #define _TOOLS_ASM_IO_H
 
+#if defined(__i386__) || defined(__x86_64__)
+#include "../../arch/x86/include/asm/io.h"
+#else
 #include <asm-generic/io.h>
+#endif
 
 #endif /* _TOOLS_ASM_IO_H */