119 lines
2.7 KiB
C
119 lines
2.7 KiB
C
#include <linux/string.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#define movs(type,to,from) \
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asm volatile("movs" type:"=&D" (to), "=&S" (from):"0" (to), "1" (from):"memory")
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/* Originally from i386/string.h */
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static __always_inline void rep_movs(void *to, const void *from, size_t n)
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{
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unsigned long d0, d1, d2;
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asm volatile("rep ; movsl\n\t"
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"testb $2,%b4\n\t"
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"je 1f\n\t"
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"movsw\n"
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"1:\ttestb $1,%b4\n\t"
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"je 2f\n\t"
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"movsb\n"
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"2:"
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: "=&c" (d0), "=&D" (d1), "=&S" (d2)
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: "0" (n / 4), "q" (n), "1" ((long)to), "2" ((long)from)
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: "memory");
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}
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static void string_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
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{
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if (unlikely(!n))
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return;
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/* Align any unaligned source IO */
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if (unlikely(1 & (unsigned long)from)) {
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movs("b", to, from);
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n--;
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}
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if (n > 1 && unlikely(2 & (unsigned long)from)) {
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movs("w", to, from);
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n-=2;
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}
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rep_movs(to, (const void *)from, n);
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}
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static void string_memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
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{
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if (unlikely(!n))
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return;
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/* Align any unaligned destination IO */
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if (unlikely(1 & (unsigned long)to)) {
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movs("b", to, from);
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n--;
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}
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if (n > 1 && unlikely(2 & (unsigned long)to)) {
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movs("w", to, from);
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n-=2;
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}
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rep_movs((void *)to, (const void *) from, n);
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}
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static void unrolled_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
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{
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const volatile char __iomem *in = from;
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char *out = to;
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int i;
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for (i = 0; i < n; ++i)
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out[i] = readb(&in[i]);
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}
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static void unrolled_memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
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{
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volatile char __iomem *out = to;
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const char *in = from;
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int i;
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for (i = 0; i < n; ++i)
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writeb(in[i], &out[i]);
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}
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static void unrolled_memset_io(volatile void __iomem *a, int b, size_t c)
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{
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volatile char __iomem *mem = a;
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int i;
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for (i = 0; i < c; ++i)
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writeb(b, &mem[i]);
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}
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void memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
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{
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if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO))
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unrolled_memcpy_fromio(to, from, n);
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else
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string_memcpy_fromio(to, from, n);
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}
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EXPORT_SYMBOL(memcpy_fromio);
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void memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
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{
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if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO))
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unrolled_memcpy_toio(to, from, n);
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else
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string_memcpy_toio(to, from, n);
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}
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EXPORT_SYMBOL(memcpy_toio);
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void memset_io(volatile void __iomem *a, int b, size_t c)
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{
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if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) {
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unrolled_memset_io(a, b, c);
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} else {
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/*
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* TODO: memset can mangle the IO patterns quite a bit.
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* perhaps it would be better to use a dumb one:
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*/
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memset((void *)a, b, c);
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}
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}
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EXPORT_SYMBOL(memset_io);
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