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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/lib/iomem.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/lib/iomem.c')
-rw-r--r--arch/x86/lib/iomem.c123
1 files changed, 123 insertions, 0 deletions
diff --git a/arch/x86/lib/iomem.c b/arch/x86/lib/iomem.c
new file mode 100644
index 000000000..e0411a377
--- /dev/null
+++ b/arch/x86/lib/iomem.c
@@ -0,0 +1,123 @@
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/kmsan-checks.h>
+
+#define movs(type,to,from) \
+ asm volatile("movs" type:"=&D" (to), "=&S" (from):"0" (to), "1" (from):"memory")
+
+/* Originally from i386/string.h */
+static __always_inline void rep_movs(void *to, const void *from, size_t n)
+{
+ unsigned long d0, d1, d2;
+ asm volatile("rep ; movsl\n\t"
+ "testb $2,%b4\n\t"
+ "je 1f\n\t"
+ "movsw\n"
+ "1:\ttestb $1,%b4\n\t"
+ "je 2f\n\t"
+ "movsb\n"
+ "2:"
+ : "=&c" (d0), "=&D" (d1), "=&S" (d2)
+ : "0" (n / 4), "q" (n), "1" ((long)to), "2" ((long)from)
+ : "memory");
+}
+
+static void string_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
+{
+ if (unlikely(!n))
+ return;
+
+ /* Align any unaligned source IO */
+ if (unlikely(1 & (unsigned long)from)) {
+ movs("b", to, from);
+ n--;
+ }
+ if (n > 1 && unlikely(2 & (unsigned long)from)) {
+ movs("w", to, from);
+ n-=2;
+ }
+ rep_movs(to, (const void *)from, n);
+ /* KMSAN must treat values read from devices as initialized. */
+ kmsan_unpoison_memory(to, n);
+}
+
+static void string_memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
+{
+ if (unlikely(!n))
+ return;
+
+ /* Make sure uninitialized memory isn't copied to devices. */
+ kmsan_check_memory(from, n);
+ /* Align any unaligned destination IO */
+ if (unlikely(1 & (unsigned long)to)) {
+ movs("b", to, from);
+ n--;
+ }
+ if (n > 1 && unlikely(2 & (unsigned long)to)) {
+ movs("w", to, from);
+ n-=2;
+ }
+ rep_movs((void *)to, (const void *) from, n);
+}
+
+static void unrolled_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
+{
+ const volatile char __iomem *in = from;
+ char *out = to;
+ int i;
+
+ for (i = 0; i < n; ++i)
+ out[i] = readb(&in[i]);
+}
+
+static void unrolled_memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
+{
+ volatile char __iomem *out = to;
+ const char *in = from;
+ int i;
+
+ for (i = 0; i < n; ++i)
+ writeb(in[i], &out[i]);
+}
+
+static void unrolled_memset_io(volatile void __iomem *a, int b, size_t c)
+{
+ volatile char __iomem *mem = a;
+ int i;
+
+ for (i = 0; i < c; ++i)
+ writeb(b, &mem[i]);
+}
+
+void memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
+{
+ if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO))
+ unrolled_memcpy_fromio(to, from, n);
+ else
+ string_memcpy_fromio(to, from, n);
+}
+EXPORT_SYMBOL(memcpy_fromio);
+
+void memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
+{
+ if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO))
+ unrolled_memcpy_toio(to, from, n);
+ else
+ string_memcpy_toio(to, from, n);
+}
+EXPORT_SYMBOL(memcpy_toio);
+
+void memset_io(volatile void __iomem *a, int b, size_t c)
+{
+ if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) {
+ unrolled_memset_io(a, b, c);
+ } else {
+ /*
+ * TODO: memset can mangle the IO patterns quite a bit.
+ * perhaps it would be better to use a dumb one:
+ */
+ memset((void *)a, b, c);
+ }
+}
+EXPORT_SYMBOL(memset_io);