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 mask, 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 mask = GEN_INT(sext_hwi(sp_mask, GET_MODE_PRECISION(Pmode))); 37 masked_sp = gen_reg_rtx(Pmode); 38 39 emit_insn_before(gen_rtx_SET(masked_sp, 40 gen_rtx_AND(Pmode, 41 stack_pointer_rtx, 42 mask)), 43 insn); 44 45 SET_SRC(body) = gen_rtx_PLUS(Pmode, masked_sp, 46 GEN_INT(canary_offset)); 47 } 48 return 0; 49 } 50 51 #define PASS_NAME arm_pertask_ssp_rtl 52 53 #define NO_GATE 54 #include "gcc-generate-rtl-pass.h" 55 56 #if BUILDING_GCC_VERSION >= 9000 57 static bool no(void) 58 { 59 return false; 60 } 61 62 static void arm_pertask_ssp_start_unit(void *gcc_data, void *user_data) 63 { 64 targetm.have_stack_protect_combined_set = no; 65 targetm.have_stack_protect_combined_test = no; 66 } 67 #endif 68 69 __visible int plugin_init(struct plugin_name_args *plugin_info, 70 struct plugin_gcc_version *version) 71 { 72 const char * const plugin_name = plugin_info->base_name; 73 const int argc = plugin_info->argc; 74 const struct plugin_argument *argv = plugin_info->argv; 75 int tso = 0; 76 int i; 77 78 if (!plugin_default_version_check(version, &gcc_version)) { 79 error(G_("incompatible gcc/plugin versions")); 80 return 1; 81 } 82 83 for (i = 0; i < argc; ++i) { 84 if (!strcmp(argv[i].key, "disable")) 85 return 0; 86 87 /* all remaining options require a value */ 88 if (!argv[i].value) { 89 error(G_("no value supplied for option '-fplugin-arg-%s-%s'"), 90 plugin_name, argv[i].key); 91 return 1; 92 } 93 94 if (!strcmp(argv[i].key, "tso")) { 95 tso = atoi(argv[i].value); 96 continue; 97 } 98 99 if (!strcmp(argv[i].key, "offset")) { 100 canary_offset = atoi(argv[i].value); 101 continue; 102 } 103 error(G_("unknown option '-fplugin-arg-%s-%s'"), 104 plugin_name, argv[i].key); 105 return 1; 106 } 107 108 /* create the mask that produces the base of the stack */ 109 sp_mask = ~((1U << (12 + tso)) - 1); 110 111 PASS_INFO(arm_pertask_ssp_rtl, "expand", 1, PASS_POS_INSERT_AFTER); 112 113 register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, 114 NULL, &arm_pertask_ssp_rtl_pass_info); 115 116 #if BUILDING_GCC_VERSION >= 9000 117 register_callback(plugin_info->base_name, PLUGIN_START_UNIT, 118 arm_pertask_ssp_start_unit, NULL); 119 #endif 120 121 return 0; 122 } 123