1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Calculate a CRC T10-DIF with vpmsum acceleration 4 * 5 * Copyright 2017, Daniel Axtens, IBM Corporation. 6 * [based on crc32c-vpmsum_glue.c] 7 */ 8 9 #include <asm/switch_to.h> 10 #include <crypto/internal/simd.h> 11 #include <linux/cpufeature.h> 12 #include <linux/jump_label.h> 13 #include <linux/preempt.h> 14 #include <linux/uaccess.h> 15 16 #define VMX_ALIGN 16 17 #define VMX_ALIGN_MASK (VMX_ALIGN-1) 18 19 #define VECTOR_BREAKPOINT 64 20 21 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_vec_crypto); 22 23 u32 __crct10dif_vpmsum(u32 crc, unsigned char const *p, size_t len); 24 25 static inline u16 crc_t10dif_arch(u16 crci, const u8 *p, size_t len) 26 { 27 unsigned int prealign; 28 unsigned int tail; 29 u32 crc = crci; 30 31 if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || 32 !static_branch_likely(&have_vec_crypto) || !crypto_simd_usable()) 33 return crc_t10dif_generic(crc, p, len); 34 35 if ((unsigned long)p & VMX_ALIGN_MASK) { 36 prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK); 37 crc = crc_t10dif_generic(crc, p, prealign); 38 len -= prealign; 39 p += prealign; 40 } 41 42 if (len & ~VMX_ALIGN_MASK) { 43 crc <<= 16; 44 preempt_disable(); 45 pagefault_disable(); 46 enable_kernel_altivec(); 47 crc = __crct10dif_vpmsum(crc, p, len & ~VMX_ALIGN_MASK); 48 disable_kernel_altivec(); 49 pagefault_enable(); 50 preempt_enable(); 51 crc >>= 16; 52 } 53 54 tail = len & VMX_ALIGN_MASK; 55 if (tail) { 56 p += len & ~VMX_ALIGN_MASK; 57 crc = crc_t10dif_generic(crc, p, tail); 58 } 59 60 return crc & 0xffff; 61 } 62 63 #define crc_t10dif_mod_init_arch crc_t10dif_mod_init_arch 64 static inline void crc_t10dif_mod_init_arch(void) 65 { 66 if (cpu_has_feature(CPU_FTR_ARCH_207S) && 67 (cur_cpu_spec->cpu_user_features2 & PPC_FEATURE2_VEC_CRYPTO)) 68 static_branch_enable(&have_vec_crypto); 69 } 70