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