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#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)
{
const void *orig_to = to;
const size_t orig_n = 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(orig_to, orig_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);
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