1 /* SPDX-License-Identifier: GPL-2.0-or-later *
2 /*
3 * Userland implementation of getrandom() for
4 * for use in the vDSO
5 *
6 * Copyright (C) 2024 Christophe Leroy <christo
7 */
8 #include <asm/processor.h>
9 #include <asm/ppc_asm.h>
10 #include <asm/vdso.h>
11 #include <asm/vdso_datapage.h>
12 #include <asm/asm-offsets.h>
13 #include <asm/unistd.h>
14
15 /*
16 * The macro sets two stack frames, one for th
17 * because there are no requirement for the ca
18 * calling VDSO so it may have omitted to set
19 */
20
21 .macro cvdso_call funct
22 .cfi_startproc
23 PPC_STLU r1, -PPC_MIN_STKFRM(r1
24 .cfi_adjust_cfa_offset PPC_MIN_STKFRM
25 mflr r0
26 PPC_STLU r1, -PPC_MIN_STKFRM(r1
27 .cfi_adjust_cfa_offset PPC_MIN_STKFRM
28 PPC_STL r0, PPC_MIN_STKFRM + P
29 .cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_
30 #ifdef __powerpc64__
31 PPC_STL r2, PPC_MIN_STKFRM + S
32 .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT
33 #endif
34 get_realdatapage r8, r11
35 addi r8, r8, VDSO_RNG_DATA_
36 bl CFUNC(DOTSYM(\funct))
37 PPC_LL r0, PPC_MIN_STKFRM + P
38 #ifdef __powerpc64__
39 PPC_LL r2, PPC_MIN_STKFRM + S
40 .cfi_restore r2
41 #endif
42 cmpwi r3, 0
43 mtlr r0
44 addi r1, r1, 2 * PPC_MIN_ST
45 .cfi_restore lr
46 .cfi_def_cfa_offset 0
47 crclr so
48 bgelr+
49 crset so
50 neg r3, r3
51 blr
52 .cfi_endproc
53 .endm
54
55 .text
56 V_FUNCTION_BEGIN(__kernel_getrandom)
57 cvdso_call __c_kernel_getrandom
58 V_FUNCTION_END(__kernel_getrandom)
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