1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 2024 Christophe Leroy <[email protected]>, CS GROUP France
4 */
5 #ifndef _ASM_POWERPC_VDSO_GETRANDOM_H
6 #define _ASM_POWERPC_VDSO_GETRANDOM_H
7
8 #ifndef __ASSEMBLY__
9
10 #include <asm/vdso_datapage.h>
11
do_syscall_3(const unsigned long _r0,const unsigned long _r3,const unsigned long _r4,const unsigned long _r5)12 static __always_inline int do_syscall_3(const unsigned long _r0, const unsigned long _r3,
13 const unsigned long _r4, const unsigned long _r5)
14 {
15 register long r0 asm("r0") = _r0;
16 register unsigned long r3 asm("r3") = _r3;
17 register unsigned long r4 asm("r4") = _r4;
18 register unsigned long r5 asm("r5") = _r5;
19 register int ret asm ("r3");
20
21 asm volatile(
22 " sc\n"
23 " bns+ 1f\n"
24 " neg %0, %0\n"
25 "1:\n"
26 : "=r" (ret), "+r" (r4), "+r" (r5), "+r" (r0)
27 : "r" (r3)
28 : "memory", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "cr0", "ctr");
29
30 return ret;
31 }
32
33 /**
34 * getrandom_syscall - Invoke the getrandom() syscall.
35 * @buffer: Destination buffer to fill with random bytes.
36 * @len: Size of @buffer in bytes.
37 * @flags: Zero or more GRND_* flags.
38 * Returns: The number of bytes written to @buffer, or a negative value indicating an error.
39 */
getrandom_syscall(void * buffer,size_t len,unsigned int flags)40 static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
41 {
42 return do_syscall_3(__NR_getrandom, (unsigned long)buffer,
43 (unsigned long)len, (unsigned long)flags);
44 }
45
__arch_get_vdso_rng_data(void)46 static __always_inline struct vdso_rng_data *__arch_get_vdso_rng_data(void)
47 {
48 struct vdso_arch_data *data;
49
50 asm (
51 " bcl 20, 31, .+4 ;"
52 "0: mflr %0 ;"
53 " addis %0, %0, (_vdso_datapage - 0b)@ha ;"
54 " addi %0, %0, (_vdso_datapage - 0b)@l ;"
55 : "=r" (data) : : "lr"
56 );
57
58 return &data->rng_data;
59 }
60
61 ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state,
62 size_t opaque_len);
63
64 #endif /* !__ASSEMBLY__ */
65
66 #endif /* _ASM_POWERPC_VDSO_GETRANDOM_H */
67