/** * \file alignment.h * * \brief Utility code for dealing with unaligned memory accesses */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ #ifndef MBEDTLS_LIBRARY_ALIGNMENT_H #define MBEDTLS_LIBRARY_ALIGNMENT_H #include <stdint.h> #include <string.h> #include <stdlib.h> /* * Define MBEDTLS_EFFICIENT_UNALIGNED_ACCESS for architectures where unaligned memory * accesses are known to be efficient. * * All functions defined here will behave correctly regardless, but might be less * efficient when this is not defined. */ #if defined(__ARM_FEATURE_UNALIGNED) \ || defined(MBEDTLS_ARCH_IS_X86) || defined(MBEDTLS_ARCH_IS_X64) \ || defined(MBEDTLS_PLATFORM_IS_WINDOWS_ON_ARM64) /* * __ARM_FEATURE_UNALIGNED is defined where appropriate by armcc, gcc 7, clang 9 * (and later versions) for Arm v7 and later; all x86 platforms should have * efficient unaligned access. * * https://learn.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=msvc-170#alignment * specifies that on Windows-on-Arm64, unaligned access is safe (except for uncached * device memory). */ #define MBEDTLS_EFFICIENT_UNALIGNED_ACCESS #endif #if defined(__IAR_SYSTEMS_ICC__) && \ (defined(MBEDTLS_ARCH_IS_ARM64) || defined(MBEDTLS_ARCH_IS_ARM32) \ || defined(__ICCRX__) || defined(__ICCRL78__) || defined(__ICCRISCV__)) #pragma language=save #pragma language=extended #define MBEDTLS_POP_IAR_LANGUAGE_PRAGMA /* IAR recommend this technique for accessing unaligned data in * https://www.iar.com/knowledge/support/technical-notes/compiler/accessing-unaligned-data * This results in a single load / store instruction (if unaligned access is supported). * According to that document, this is only supported on certain architectures. */ #define UINT_UNALIGNED typedef uint16_t __packed mbedtls_uint16_unaligned_t; typedef uint32_t __packed mbedtls_uint32_unaligned_t; typedef uint64_t __packed mbedtls_uint64_unaligned_t; #elif defined(MBEDTLS_COMPILER_IS_GCC) && (MBEDTLS_GCC_VERSION >= 40504) && \ ((MBEDTLS_GCC_VERSION < 60300) || (!defined(MBEDTLS_EFFICIENT_UNALIGNED_ACCESS))) /* * gcc may generate a branch to memcpy for calls like `memcpy(dest, src, 4)` rather than * generating some LDR or LDRB instructions (similar for stores). * * This is architecture dependent: x86-64 seems fine even with old gcc; 32-bit Arm * is affected. To keep it simple, we enable for all architectures. * * For versions of gcc < 5.4.0 this issue always happens. * For gcc < 6.3.0, this issue happens at -O0 * For all versions, this issue happens iff unaligned access is not supported. * * For gcc 4.x, this implementation will generate byte-by-byte loads even if unaligned access is * supported, which is correct but not optimal. * * For performance (and code size, in some cases), we want to avoid the branch and just generate * some inline load/store instructions since the access is small and constant-size. * * The manual states: * "The packed attribute specifies that a variable or structure field should have the smallest * possible alignment—one byte for a variable" * https://gcc.gnu.org/onlinedocs/gcc-4.5.4/gcc/Variable-Attributes.html * * Previous implementations used __attribute__((__aligned__(1)), but had issues with a gcc bug: * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94662 * * Tested with several versions of GCC from 4.5.0 up to 13.2.0 * We don't enable for older than 4.5.0 as this has not been tested. */ #define UINT_UNALIGNED_STRUCT typedef struct { uint16_t x; } __attribute__((packed)) mbedtls_uint16_unaligned_t; typedef struct { uint32_t x; } __attribute__((packed)) mbedtls_uint32_unaligned_t; typedef struct { uint64_t x; } __attribute__((packed)) mbedtls_uint64_unaligned_t; #endif /* * We try to force mbedtls_(get|put)_unaligned_uintXX to be always inline, because this results * in code that is both smaller and faster. IAR and gcc both benefit from this when optimising * for size. */ /** * Read the unsigned 16 bits integer from the given address, which need not * be aligned. * * \param p pointer to 2 bytes of data * \return Data at the given address */ #if defined(__IAR_SYSTEMS_ICC__) #pragma inline = forced #elif defined(__GNUC__) __attribute__((always_inline)) #endif static inline uint16_t mbedtls_get_unaligned_uint16(const void *p) { … } /** * Write the unsigned 16 bits integer to the given address, which need not * be aligned. * * \param p pointer to 2 bytes of data * \param x data to write */ #if defined(__IAR_SYSTEMS_ICC__) #pragma inline = forced #elif defined(__GNUC__) __attribute__((always_inline)) #endif static inline void mbedtls_put_unaligned_uint16(void *p, uint16_t x) { … } /** * Read the unsigned 32 bits integer from the given address, which need not * be aligned. * * \param p pointer to 4 bytes of data * \return Data at the given address */ #if defined(__IAR_SYSTEMS_ICC__) #pragma inline = forced #elif defined(__GNUC__) __attribute__((always_inline)) #endif static inline uint32_t mbedtls_get_unaligned_uint32(const void *p) { … } /** * 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 */ #if defined(__IAR_SYSTEMS_ICC__) #pragma inline = forced #elif defined(__GNUC__) __attribute__((always_inline)) #endif static inline void mbedtls_put_unaligned_uint32(void *p, uint32_t x) { … } /** * Read the unsigned 64 bits integer from the given address, which need not * be aligned. * * \param p pointer to 8 bytes of data * \return Data at the given address */ #if defined(__IAR_SYSTEMS_ICC__) #pragma inline = forced #elif defined(__GNUC__) __attribute__((always_inline)) #endif static inline uint64_t mbedtls_get_unaligned_uint64(const void *p) { … } /** * Write the unsigned 64 bits integer to the given address, which need not * be aligned. * * \param p pointer to 8 bytes of data * \param x data to write */ #if defined(__IAR_SYSTEMS_ICC__) #pragma inline = forced #elif defined(__GNUC__) __attribute__((always_inline)) #endif static inline void mbedtls_put_unaligned_uint64(void *p, uint64_t x) { … } #if defined(MBEDTLS_POP_IAR_LANGUAGE_PRAGMA) #pragma language=restore #endif /** Byte Reading Macros * * Given a multi-byte integer \p x, MBEDTLS_BYTE_n retrieves the n-th * byte from x, where byte 0 is the least significant byte. */ #define MBEDTLS_BYTE_0(x) … #define MBEDTLS_BYTE_1(x) … #define MBEDTLS_BYTE_2(x) … #define MBEDTLS_BYTE_3(x) … #define MBEDTLS_BYTE_4(x) … #define MBEDTLS_BYTE_5(x) … #define MBEDTLS_BYTE_6(x) … #define MBEDTLS_BYTE_7(x) … /* * Detect GCC built-in byteswap routines */ #if defined(__GNUC__) && defined(__GNUC_PREREQ) #if __GNUC_PREREQ(4, 8) #define MBEDTLS_BSWAP16 … #endif /* __GNUC_PREREQ(4,8) */ #if __GNUC_PREREQ(4, 3) #define MBEDTLS_BSWAP32 … #define MBEDTLS_BSWAP64 … #endif /* __GNUC_PREREQ(4,3) */ #endif /* defined(__GNUC__) && defined(__GNUC_PREREQ) */ /* * Detect Clang built-in byteswap routines */ #if defined(__clang__) && defined(__has_builtin) #if __has_builtin(__builtin_bswap16) && !defined(MBEDTLS_BSWAP16) #define MBEDTLS_BSWAP16 … #endif /* __has_builtin(__builtin_bswap16) */ #if __has_builtin(__builtin_bswap32) && !defined(MBEDTLS_BSWAP32) #define MBEDTLS_BSWAP32 … #endif /* __has_builtin(__builtin_bswap32) */ #if __has_builtin(__builtin_bswap64) && !defined(MBEDTLS_BSWAP64) #define MBEDTLS_BSWAP64 … #endif /* __has_builtin(__builtin_bswap64) */ #endif /* defined(__clang__) && defined(__has_builtin) */ /* * Detect MSVC built-in byteswap routines */ #if defined(_MSC_VER) #if !defined(MBEDTLS_BSWAP16) #define MBEDTLS_BSWAP16 … #endif #if !defined(MBEDTLS_BSWAP32) #define MBEDTLS_BSWAP32 … #endif #if !defined(MBEDTLS_BSWAP64) #define MBEDTLS_BSWAP64 … #endif #endif /* defined(_MSC_VER) */ /* Detect armcc built-in byteswap routine */ #if defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 410000) && !defined(MBEDTLS_BSWAP32) #if defined(__ARM_ACLE) /* ARM Compiler 6 - earlier versions don't need a header */ #include <arm_acle.h> #endif #define MBEDTLS_BSWAP32 … #endif /* Detect IAR built-in byteswap routine */ #if defined(__IAR_SYSTEMS_ICC__) #if defined(__ARM_ACLE) #include <arm_acle.h> #define MBEDTLS_BSWAP16 … #define MBEDTLS_BSWAP32 … #define MBEDTLS_BSWAP64 … #endif #endif /* * Where compiler built-ins are not present, fall back to C code that the * compiler may be able to detect and transform into the relevant bswap or * similar instruction. */ #if !defined(MBEDTLS_BSWAP16) static inline uint16_t mbedtls_bswap16(uint16_t x) { return (x & 0x00ff) << 8 | (x & 0xff00) >> 8; } #define MBEDTLS_BSWAP16 … #endif /* !defined(MBEDTLS_BSWAP16) */ #if !defined(MBEDTLS_BSWAP32) static inline uint32_t mbedtls_bswap32(uint32_t x) { return (x & 0x000000ff) << 24 | (x & 0x0000ff00) << 8 | (x & 0x00ff0000) >> 8 | (x & 0xff000000) >> 24; } #define MBEDTLS_BSWAP32 … #endif /* !defined(MBEDTLS_BSWAP32) */ #if !defined(MBEDTLS_BSWAP64) static inline uint64_t mbedtls_bswap64(uint64_t x) { return (x & 0x00000000000000ffULL) << 56 | (x & 0x000000000000ff00ULL) << 40 | (x & 0x0000000000ff0000ULL) << 24 | (x & 0x00000000ff000000ULL) << 8 | (x & 0x000000ff00000000ULL) >> 8 | (x & 0x0000ff0000000000ULL) >> 24 | (x & 0x00ff000000000000ULL) >> 40 | (x & 0xff00000000000000ULL) >> 56; } #define MBEDTLS_BSWAP64 … #endif /* !defined(MBEDTLS_BSWAP64) */ #if !defined(__BYTE_ORDER__) #if defined(__LITTLE_ENDIAN__) /* IAR defines __xxx_ENDIAN__, but not __BYTE_ORDER__ */ #define MBEDTLS_IS_BIG_ENDIAN … #elif defined(__BIG_ENDIAN__) #define MBEDTLS_IS_BIG_ENDIAN … #else static const uint16_t mbedtls_byte_order_detector = { 0x100 }; #define MBEDTLS_IS_BIG_ENDIAN … #endif #else #if (__BYTE_ORDER__) == (__ORDER_BIG_ENDIAN__) #define MBEDTLS_IS_BIG_ENDIAN … #else #define MBEDTLS_IS_BIG_ENDIAN … #endif #endif /* !defined(__BYTE_ORDER__) */ /** * Get the unsigned 32 bits integer corresponding to four bytes in * big-endian order (MSB first). * * \param data Base address of the memory to get the four bytes from. * \param offset Offset from \p data of the first and most significant * byte of the four bytes to build the 32 bits unsigned * integer from. */ #define MBEDTLS_GET_UINT32_BE(data, offset) … /** * Put in memory a 32 bits unsigned integer in big-endian order. * * \param n 32 bits unsigned integer to put in memory. * \param data Base address of the memory where to put the 32 * bits unsigned integer in. * \param offset Offset from \p data where to put the most significant * byte of the 32 bits unsigned integer \p n. */ #define MBEDTLS_PUT_UINT32_BE(n, data, offset) … /** * Get the unsigned 32 bits integer corresponding to four bytes in * little-endian order (LSB first). * * \param data Base address of the memory to get the four bytes from. * \param offset Offset from \p data of the first and least significant * byte of the four bytes to build the 32 bits unsigned * integer from. */ #define MBEDTLS_GET_UINT32_LE(data, offset) … /** * Put in memory a 32 bits unsigned integer in little-endian order. * * \param n 32 bits unsigned integer to put in memory. * \param data Base address of the memory where to put the 32 * bits unsigned integer in. * \param offset Offset from \p data where to put the least significant * byte of the 32 bits unsigned integer \p n. */ #define MBEDTLS_PUT_UINT32_LE(n, data, offset) … /** * Get the unsigned 16 bits integer corresponding to two bytes in * little-endian order (LSB first). * * \param data Base address of the memory to get the two bytes from. * \param offset Offset from \p data of the first and least significant * byte of the two bytes to build the 16 bits unsigned * integer from. */ #define MBEDTLS_GET_UINT16_LE(data, offset) … /** * Put in memory a 16 bits unsigned integer in little-endian order. * * \param n 16 bits unsigned integer to put in memory. * \param data Base address of the memory where to put the 16 * bits unsigned integer in. * \param offset Offset from \p data where to put the least significant * byte of the 16 bits unsigned integer \p n. */ #define MBEDTLS_PUT_UINT16_LE(n, data, offset) … /** * Get the unsigned 16 bits integer corresponding to two bytes in * big-endian order (MSB first). * * \param data Base address of the memory to get the two bytes from. * \param offset Offset from \p data of the first and most significant * byte of the two bytes to build the 16 bits unsigned * integer from. */ #define MBEDTLS_GET_UINT16_BE(data, offset) … /** * Put in memory a 16 bits unsigned integer in big-endian order. * * \param n 16 bits unsigned integer to put in memory. * \param data Base address of the memory where to put the 16 * bits unsigned integer in. * \param offset Offset from \p data where to put the most significant * byte of the 16 bits unsigned integer \p n. */ #define MBEDTLS_PUT_UINT16_BE(n, data, offset) … /** * Get the unsigned 24 bits integer corresponding to three bytes in * big-endian order (MSB first). * * \param data Base address of the memory to get the three bytes from. * \param offset Offset from \p data of the first and most significant * byte of the three bytes to build the 24 bits unsigned * integer from. */ #define MBEDTLS_GET_UINT24_BE(data, offset) … /** * Put in memory a 24 bits unsigned integer in big-endian order. * * \param n 24 bits unsigned integer to put in memory. * \param data Base address of the memory where to put the 24 * bits unsigned integer in. * \param offset Offset from \p data where to put the most significant * byte of the 24 bits unsigned integer \p n. */ #define MBEDTLS_PUT_UINT24_BE(n, data, offset) … /** * Get the unsigned 24 bits integer corresponding to three bytes in * little-endian order (LSB first). * * \param data Base address of the memory to get the three bytes from. * \param offset Offset from \p data of the first and least significant * byte of the three bytes to build the 24 bits unsigned * integer from. */ #define MBEDTLS_GET_UINT24_LE(data, offset) … /** * Put in memory a 24 bits unsigned integer in little-endian order. * * \param n 24 bits unsigned integer to put in memory. * \param data Base address of the memory where to put the 24 * bits unsigned integer in. * \param offset Offset from \p data where to put the least significant * byte of the 24 bits unsigned integer \p n. */ #define MBEDTLS_PUT_UINT24_LE(n, data, offset) … /** * Get the unsigned 64 bits integer corresponding to eight bytes in * big-endian order (MSB first). * * \param data Base address of the memory to get the eight bytes from. * \param offset Offset from \p data of the first and most significant * byte of the eight bytes to build the 64 bits unsigned * integer from. */ #define MBEDTLS_GET_UINT64_BE(data, offset) … /** * Put in memory a 64 bits unsigned integer in big-endian order. * * \param n 64 bits unsigned integer to put in memory. * \param data Base address of the memory where to put the 64 * bits unsigned integer in. * \param offset Offset from \p data where to put the most significant * byte of the 64 bits unsigned integer \p n. */ #define MBEDTLS_PUT_UINT64_BE(n, data, offset) … /** * Get the unsigned 64 bits integer corresponding to eight bytes in * little-endian order (LSB first). * * \param data Base address of the memory to get the eight bytes from. * \param offset Offset from \p data of the first and least significant * byte of the eight bytes to build the 64 bits unsigned * integer from. */ #define MBEDTLS_GET_UINT64_LE(data, offset) … /** * Put in memory a 64 bits unsigned integer in little-endian order. * * \param n 64 bits unsigned integer to put in memory. * \param data Base address of the memory where to put the 64 * bits unsigned integer in. * \param offset Offset from \p data where to put the least significant * byte of the 64 bits unsigned integer \p n. */ #define MBEDTLS_PUT_UINT64_LE(n, data, offset) … #endif /* MBEDTLS_LIBRARY_ALIGNMENT_H */
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