crc32.h

 1// SPDX-License-Identifier: GPL-2.0-only
 2#include <asm/simd.h>
 3#include <asm/switch_to.h>
 4#include <linux/cpufeature.h>
 5#include <linux/jump_label.h>
 6#include <linux/preempt.h>
 7#include <linux/uaccess.h>
 8
 9#define VMX_ALIGN		16
10#define VMX_ALIGN_MASK		(VMX_ALIGN-1)
11
12#define VECTOR_BREAKPOINT	512
13
14static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_vec_crypto);
15
16#define crc32_le_arch crc32_le_base /* not implemented on this arch */
17#define crc32_be_arch crc32_be_base /* not implemented on this arch */
18
19u32 __crc32c_vpmsum(u32 crc, const u8 *p, size_t len);
20
21static inline u32 crc32c_arch(u32 crc, const u8 *p, size_t len)
22{
23	unsigned int prealign;
24	unsigned int tail;
25
26	if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) ||
27	    !static_branch_likely(&have_vec_crypto) ||
28	    unlikely(!may_use_simd()))
29		return crc32c_base(crc, p, len);
30
31	if ((unsigned long)p & VMX_ALIGN_MASK) {
32		prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
33		crc = crc32c_base(crc, p, prealign);
34		len -= prealign;
35		p += prealign;
36	}
37
38	if (len & ~VMX_ALIGN_MASK) {
39		preempt_disable();
40		pagefault_disable();
41		enable_kernel_altivec();
42		crc = __crc32c_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
43		disable_kernel_altivec();
44		pagefault_enable();
45		preempt_enable();
46	}
47
48	tail = len & VMX_ALIGN_MASK;
49	if (tail) {
50		p += len & ~VMX_ALIGN_MASK;
51		crc = crc32c_base(crc, p, tail);
52	}
53
54	return crc;
55}
56
57#define crc32_mod_init_arch crc32_mod_init_arch
58static void crc32_mod_init_arch(void)
59{
60	if (cpu_has_feature(CPU_FTR_ARCH_207S) &&
61	    (cur_cpu_spec->cpu_user_features2 & PPC_FEATURE2_VEC_CRYPTO))
62		static_branch_enable(&have_vec_crypto);
63}
64
65static inline u32 crc32_optimizations_arch(void)
66{
67	if (static_key_enabled(&have_vec_crypto))
68		return CRC32C_OPTIMIZATION;
69	return 0;
70}