1 // SPDX-License-Identifier: GPL-2.0
2
3 #include "gcc-common.h"
4
5 __visible int plugin_is_GPL_compatible;
6
7 static unsigned int canary_offset;
8
9 static unsigned int arm_pertask_ssp_rtl_execute(void)
10 {
11 rtx_insn *insn;
12
13 for (insn = get_insns(); insn; insn = NEXT_INSN(insn)) {
14 const char *sym;
15 rtx body;
16 rtx current;
17
18 /*
19 * Find a SET insn involving a SYMBOL_REF to __stack_chk_guard
20 */
21 if (!INSN_P(insn))
22 continue;
23 body = PATTERN(insn);
24 if (GET_CODE(body) != SET ||
25 GET_CODE(SET_SRC(body)) != SYMBOL_REF)
26 continue;
27 sym = XSTR(SET_SRC(body), 0);
28 if (strcmp(sym, "__stack_chk_guard"))
29 continue;
30
31 /*
32 * Replace the source of the SET insn with an expression that
33 * produces the address of the current task's stack canary value
34 */
35 current = gen_reg_rtx(Pmode);
36
37 emit_insn_before(gen_load_tp_hard(current), insn);
38
39 SET_SRC(body) = gen_rtx_PLUS(Pmode, current,
40 GEN_INT(canary_offset));
41 }
42 return 0;
43 }
44
45 #define PASS_NAME arm_pertask_ssp_rtl
46
47 #define NO_GATE
48 #include "gcc-generate-rtl-pass.h"
49
50 #if BUILDING_GCC_VERSION >= 9000
51 static bool no(void)
52 {
53 return false;
54 }
55
56 static void arm_pertask_ssp_start_unit(void *gcc_data, void *user_data)
57 {
58 targetm.have_stack_protect_combined_set = no;
59 targetm.have_stack_protect_combined_test = no;
60 }
61 #endif
62
63 __visible int plugin_init(struct plugin_name_args *plugin_info,
64 struct plugin_gcc_version *version)
65 {
66 const char * const plugin_name = plugin_info->base_name;
67 const int argc = plugin_info->argc;
68 const struct plugin_argument *argv = plugin_info->argv;
69 int i;
70
71 if (!plugin_default_version_check(version, &gcc_version)) {
72 error(G_("incompatible gcc/plugin versions"));
73 return 1;
74 }
75
76 for (i = 0; i < argc; ++i) {
77 if (!strcmp(argv[i].key, "disable"))
78 return 0;
79
80 /* all remaining options require a value */
81 if (!argv[i].value) {
82 error(G_("no value supplied for option '-fplugin-arg-%s-%s'"),
83 plugin_name, argv[i].key);
84 return 1;
85 }
86
87 if (!strcmp(argv[i].key, "offset")) {
88 canary_offset = atoi(argv[i].value);
89 continue;
90 }
91 error(G_("unknown option '-fplugin-arg-%s-%s'"),
92 plugin_name, argv[i].key);
93 return 1;
94 }
95
96 PASS_INFO(arm_pertask_ssp_rtl, "expand", 1, PASS_POS_INSERT_AFTER);
97
98 register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP,
99 NULL, &arm_pertask_ssp_rtl_pass_info);
100
101 #if BUILDING_GCC_VERSION >= 9000
102 register_callback(plugin_info->base_name, PLUGIN_START_UNIT,
103 arm_pertask_ssp_start_unit, NULL);
104 #endif
105
106 return 0;
107 }
108
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