forked from Minki/linux
crypto: crypto_xor - use helpers for unaligned accesses
Dereferencing a misaligned pointer is undefined behavior in C, and may result in codegen on architectures such as ARM that trigger alignments traps and expensive fixups in software. Instead, use the get_aligned()/put_aligned() accessors, which are cheap or even completely free when CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y. In the converse case, the prior alignment checks ensure that the casts are safe, and so no unaligned accessors are necessary. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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@ -1022,7 +1022,13 @@ void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int len)
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}
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while (IS_ENABLED(CONFIG_64BIT) && len >= 8 && !(relalign & 7)) {
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if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) {
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u64 l = get_unaligned((u64 *)src1) ^
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get_unaligned((u64 *)src2);
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put_unaligned(l, (u64 *)dst);
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} else {
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*(u64 *)dst = *(u64 *)src1 ^ *(u64 *)src2;
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}
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dst += 8;
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src1 += 8;
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src2 += 8;
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@ -1030,7 +1036,13 @@ void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int len)
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}
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while (len >= 4 && !(relalign & 3)) {
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if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) {
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u32 l = get_unaligned((u32 *)src1) ^
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get_unaligned((u32 *)src2);
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put_unaligned(l, (u32 *)dst);
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} else {
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*(u32 *)dst = *(u32 *)src1 ^ *(u32 *)src2;
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}
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dst += 4;
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src1 += 4;
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src2 += 4;
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@ -1038,7 +1050,13 @@ void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int len)
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}
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while (len >= 2 && !(relalign & 1)) {
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if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) {
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u16 l = get_unaligned((u16 *)src1) ^
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get_unaligned((u16 *)src2);
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put_unaligned(l, (u16 *)dst);
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} else {
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*(u16 *)dst = *(u16 *)src1 ^ *(u16 *)src2;
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}
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dst += 2;
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src1 += 2;
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src2 += 2;
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@ -13,6 +13,8 @@
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#include <linux/list.h>
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#include <linux/types.h>
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#include <asm/unaligned.h>
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/*
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* Maximum values for blocksize and alignmask, used to allocate
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* static buffers that are big enough for any combination of
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@ -154,9 +156,11 @@ static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
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(size % sizeof(unsigned long)) == 0) {
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unsigned long *d = (unsigned long *)dst;
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unsigned long *s = (unsigned long *)src;
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unsigned long l;
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while (size > 0) {
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*d++ ^= *s++;
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l = get_unaligned(d) ^ get_unaligned(s++);
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put_unaligned(l, d++);
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size -= sizeof(unsigned long);
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}
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} else {
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@ -173,9 +177,11 @@ static inline void crypto_xor_cpy(u8 *dst, const u8 *src1, const u8 *src2,
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unsigned long *d = (unsigned long *)dst;
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unsigned long *s1 = (unsigned long *)src1;
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unsigned long *s2 = (unsigned long *)src2;
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unsigned long l;
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while (size > 0) {
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*d++ = *s1++ ^ *s2++;
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l = get_unaligned(s1++) ^ get_unaligned(s2++);
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put_unaligned(l, d++);
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size -= sizeof(unsigned long);
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}
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} else {
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