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Use memcpy for unaligned accesses

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Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
This commit is contained in:
Dave Rodgman 2022-11-24 19:33:22 +00:00
parent fbc23225d6
commit 96d61d14d8
2 changed files with 27 additions and 41 deletions
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50
library/alignment.h
View File

@ -24,38 +24,32 @@
#define MBEDTLS_LIBRARY_ALIGNMENT_H
#include <stdint.h>
#include <string.h>
/** MBEDTLS_ALLOW_UNALIGNED_ACCESS is defined for architectures where unaligned
* memory accesses are safe and performant.
/**
* Read the unsigned 32 bits integer from the given address, which need not
* be aligned.
*
* Unaligned accesses must be made via the UNALIGNED_UINT32_T type
* defined here.
*
* This list is incomplete.
* \param p pointer to 4 bytes of data
*/
#if defined(__i386__) || defined(__amd64__) || defined( __x86_64__) \
|| defined(__ARM_FEATURE_UNALIGNED) \
|| defined(__aarch64__) \
|| defined(__ARM_ARCH_8__) || defined(__ARM_ARCH_8A__) || defined(__ARM_ARCH_8M__) \
|| defined(__ARM_ARCH_7A__)
#if (defined(__GNUC__) && __GNUC__ >= 4) \
|| (defined(__clang__) && __has_attribute(aligned)) \
|| (defined(__ARMCC_VERSION) && __ARMCC_VERSION >= 5000000 )
/* GCC, Clang and armcc */
#define MBEDTLS_ALLOW_UNALIGNED_ACCESS
__attribute__((aligned(1))) typedef uint32_t mbedtls_unaligned_uint32_t;
#define UNALIGNED_UINT32_T mbedtls_unaligned_uint32_t
#elif defined(_MSC_VER)
/* MSVC */
#define MBEDTLS_ALLOW_UNALIGNED_ACCESS
#define UNALIGNED_UINT32_T __declspec(align(1)) uint32_t
#elif (defined __ICCARM__)
/* IAR - this is disabled until we have the opportunity to test it */
#undef MBEDTLS_ALLOW_UNALIGNED_ACCESS
#define UNALIGNED_UINT32_T _Pragma("data_alignment = 1") uint32_t
#endif
#endif
static inline uint32_t mbedtls_get_unaligned_uint32( void const *p )
{
uint32_t r;
memcpy( &r, p, 4 );
return r;
}
/**
* Write the unsigned 32 bits integer to the given address, which need not
* be aligned.
*
* \param p pointer to 4 bytes of data
* \param x data to write
*/
static inline void mbedtls_put_unaligned_uint32( void *p, uint32_t x )
{
memcpy(p, &x, 4);
}
/** Byte Reading Macros
*

18
library/common.h
View File

@ -88,24 +88,16 @@ extern void (*mbedtls_test_hook_test_fail)( const char * test, int line, const c
*/
inline void mbedtls_xor( unsigned char *r, unsigned char const *a, unsigned char const *b, size_t n )
{
#if defined(MBEDTLS_ALLOW_UNALIGNED_ACCESS)
UNALIGNED_UINT32_T *a32 = (uint32_t *)a;
UNALIGNED_UINT32_T *b32 = (uint32_t *)b;
UNALIGNED_UINT32_T *r32 = (uint32_t *)r;
for ( size_t i = 0; i < ( n >> 2 ); i++ )
size_t i;
for ( i = 0; (i + 4) < n; i+= 4 )
{
r32[i] = a32[i] ^ b32[i];
uint32_t x = mbedtls_get_unaligned_uint32(a + i) ^ mbedtls_get_unaligned_uint32(b + i);
mbedtls_put_unaligned_uint32(r + i, x);
}
for ( size_t i = n - ( n % 4 ) ; i < n; i++ )
for ( ; i < n; i++ )
{
r[i] = a[i] ^ b[i];
}
#else
for ( size_t i = 0; i < n; i++ )
{
r[i] = a[i] ^ b[i];
}
#endif
}
/* Fix MSVC C99 compatible issue