1 | /* Create new context. RISC-V version. |
2 | Copyright (C) 2001-2022 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library. If not, see |
17 | <https://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <sysdep.h> |
20 | #include <sys/asm.h> |
21 | #include <sys/ucontext.h> |
22 | #include <stdarg.h> |
23 | #include <assert.h> |
24 | |
25 | void |
26 | __makecontext (ucontext_t *ucp, void (*func) (void), int argc, |
27 | long int a0, long int a1, long int a2, long int a3, long int a4, |
28 | ...) |
29 | { |
30 | extern void __start_context (void) attribute_hidden; |
31 | long int i, sp; |
32 | |
33 | _Static_assert (REG_NARGS == 8, "__makecontext assumes 8 argument registers" ); |
34 | |
35 | /* Set up the stack. */ |
36 | sp = ((long int) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size) & ALMASK; |
37 | |
38 | /* Set up the register context. |
39 | ra = s0 = 0, terminating the stack for backtracing purposes. |
40 | s1 = the function we must call. |
41 | s2 = the subsequent context to run. */ |
42 | ucp->uc_mcontext.__gregs[REG_RA] = 0; |
43 | ucp->uc_mcontext.__gregs[REG_S0] = 0; |
44 | ucp->uc_mcontext.__gregs[REG_S1] = (long int) func; |
45 | ucp->uc_mcontext.__gregs[REG_S2] = (long int) ucp->uc_link; |
46 | ucp->uc_mcontext.__gregs[REG_SP] = sp; |
47 | ucp->uc_mcontext.__gregs[REG_PC] = (long int) &__start_context; |
48 | |
49 | /* Put args in a0-a7, then put any remaining args on the stack. */ |
50 | ucp->uc_mcontext.__gregs[REG_A0 + 0] = a0; |
51 | ucp->uc_mcontext.__gregs[REG_A0 + 1] = a1; |
52 | ucp->uc_mcontext.__gregs[REG_A0 + 2] = a2; |
53 | ucp->uc_mcontext.__gregs[REG_A0 + 3] = a3; |
54 | ucp->uc_mcontext.__gregs[REG_A0 + 4] = a4; |
55 | |
56 | if (__glibc_unlikely (argc > 5)) |
57 | { |
58 | va_list vl; |
59 | va_start (vl, a4); |
60 | |
61 | long reg_args = argc < REG_NARGS ? argc : REG_NARGS; |
62 | for (i = 5; i < reg_args; i++) |
63 | ucp->uc_mcontext.__gregs[REG_A0 + i] = va_arg (vl, long); |
64 | |
65 | long int stack_args = argc - reg_args; |
66 | if (stack_args > 0) |
67 | { |
68 | sp = (sp - stack_args * sizeof (long int)) & ALMASK; |
69 | ucp->uc_mcontext.__gregs[REG_SP] = sp; |
70 | for (i = 0; i < stack_args; i++) |
71 | ((long int *) sp)[i] = va_arg (vl, long int); |
72 | } |
73 | |
74 | va_end (vl); |
75 | } |
76 | } |
77 | |
78 | weak_alias (__makecontext, makecontext) |
79 | |