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 sp_mask, 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 masked_sp; 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 copy of the stack canary value 34 * stored in struct thread_info 35 */ 36 masked_sp = gen_reg_rtx(Pmode); 37 38 emit_insn_before(gen_rtx_SET(masked_sp, 39 gen_rtx_AND(Pmode, 40 stack_pointer_rtx, 41 GEN_INT(sp_mask))), 42 insn); 43 44 SET_SRC(body) = gen_rtx_PLUS(Pmode, masked_sp, 45 GEN_INT(canary_offset)); 46 } 47 return 0; 48 } 49 50 #define PASS_NAME arm_pertask_ssp_rtl 51 52 #define NO_GATE 53 #include "gcc-generate-rtl-pass.h" 54 55 __visible int plugin_init(struct plugin_name_args *plugin_info, 56 struct plugin_gcc_version *version) 57 { 58 const char * const plugin_name = plugin_info->base_name; 59 const int argc = plugin_info->argc; 60 const struct plugin_argument *argv = plugin_info->argv; 61 int tso = 0; 62 int i; 63 64 if (!plugin_default_version_check(version, &gcc_version)) { 65 error(G_("incompatible gcc/plugin versions")); 66 return 1; 67 } 68 69 for (i = 0; i < argc; ++i) { 70 if (!strcmp(argv[i].key, "disable")) 71 return 0; 72 73 /* all remaining options require a value */ 74 if (!argv[i].value) { 75 error(G_("no value supplied for option '-fplugin-arg-%s-%s'"), 76 plugin_name, argv[i].key); 77 return 1; 78 } 79 80 if (!strcmp(argv[i].key, "tso")) { 81 tso = atoi(argv[i].value); 82 continue; 83 } 84 85 if (!strcmp(argv[i].key, "offset")) { 86 canary_offset = atoi(argv[i].value); 87 continue; 88 } 89 error(G_("unknown option '-fplugin-arg-%s-%s'"), 90 plugin_name, argv[i].key); 91 return 1; 92 } 93 94 /* create the mask that produces the base of the stack */ 95 sp_mask = ~((1U << (12 + tso)) - 1); 96 97 PASS_INFO(arm_pertask_ssp_rtl, "expand", 1, PASS_POS_INSERT_AFTER); 98 99 register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, 100 NULL, &arm_pertask_ssp_rtl_pass_info); 101 102 return 0; 103 } 104