cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sancov_plugin.c (3805B)

      1/*
      2 * Copyright 2011-2016 by Emese Revfy <re.emese@gmail.com>
      3 * Licensed under the GPL v2, or (at your option) v3
      4 *
      5 * Homepage:
      6 * https://github.com/ephox-gcc-plugins/sancov
      7 *
      8 * This plugin inserts a __sanitizer_cov_trace_pc() call at the start of basic blocks.
      9 * It supports all gcc versions with plugin support (from gcc-4.5 on).
     10 * It is based on the commit "Add fuzzing coverage support" by Dmitry Vyukov <dvyukov@google.com>.
     11 *
     12 * You can read about it more here:
     13 *  https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=231296
     14 *  https://lwn.net/Articles/674854/
     15 *  https://github.com/google/syzkaller
     16 *  https://lwn.net/Articles/677764/
     17 *
     18 * Usage:
     19 * make run
     20 */
     21
     22#include "gcc-common.h"
     23
     24__visible int plugin_is_GPL_compatible;
     25
     26tree sancov_fndecl;
     27
     28static struct plugin_info sancov_plugin_info = {
     29	.version	= PLUGIN_VERSION,
     30	.help		= "sancov plugin\n",
     31};
     32
     33static unsigned int sancov_execute(void)
     34{
     35	basic_block bb;
     36
     37	/* Remove this line when this plugin and kcov will be in the kernel.
     38	if (!strcmp(DECL_NAME_POINTER(current_function_decl), DECL_NAME_POINTER(sancov_fndecl)))
     39		return 0;
     40	*/
     41
     42	FOR_EACH_BB_FN(bb, cfun) {
     43		const_gimple stmt;
     44		gcall *gcall;
     45		gimple_stmt_iterator gsi = gsi_after_labels(bb);
     46
     47		if (gsi_end_p(gsi))
     48			continue;
     49
     50		stmt = gsi_stmt(gsi);
     51		gcall = as_a_gcall(gimple_build_call(sancov_fndecl, 0));
     52		gimple_set_location(gcall, gimple_location(stmt));
     53		gsi_insert_before(&gsi, gcall, GSI_SAME_STMT);
     54	}
     55	return 0;
     56}
     57
     58#define PASS_NAME sancov
     59
     60#define NO_GATE
     61#define TODO_FLAGS_FINISH TODO_dump_func | TODO_verify_stmts | TODO_update_ssa_no_phi | TODO_verify_flow
     62
     63#include "gcc-generate-gimple-pass.h"
     64
     65static void sancov_start_unit(void __unused *gcc_data, void __unused *user_data)
     66{
     67	tree leaf_attr, nothrow_attr;
     68	tree BT_FN_VOID = build_function_type_list(void_type_node, NULL_TREE);
     69
     70	sancov_fndecl = build_fn_decl("__sanitizer_cov_trace_pc", BT_FN_VOID);
     71
     72	DECL_ASSEMBLER_NAME(sancov_fndecl);
     73	TREE_PUBLIC(sancov_fndecl) = 1;
     74	DECL_EXTERNAL(sancov_fndecl) = 1;
     75	DECL_ARTIFICIAL(sancov_fndecl) = 1;
     76	DECL_PRESERVE_P(sancov_fndecl) = 1;
     77	DECL_UNINLINABLE(sancov_fndecl) = 1;
     78	TREE_USED(sancov_fndecl) = 1;
     79
     80	nothrow_attr = tree_cons(get_identifier("nothrow"), NULL, NULL);
     81	decl_attributes(&sancov_fndecl, nothrow_attr, 0);
     82	gcc_assert(TREE_NOTHROW(sancov_fndecl));
     83	leaf_attr = tree_cons(get_identifier("leaf"), NULL, NULL);
     84	decl_attributes(&sancov_fndecl, leaf_attr, 0);
     85}
     86
     87__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
     88{
     89	int i;
     90	const char * const plugin_name = plugin_info->base_name;
     91	const int argc = plugin_info->argc;
     92	const struct plugin_argument * const argv = plugin_info->argv;
     93	bool enable = true;
     94
     95	static const struct ggc_root_tab gt_ggc_r_gt_sancov[] = {
     96		{
     97			.base = &sancov_fndecl,
     98			.nelt = 1,
     99			.stride = sizeof(sancov_fndecl),
    100			.cb = &gt_ggc_mx_tree_node,
    101			.pchw = &gt_pch_nx_tree_node
    102		},
    103		LAST_GGC_ROOT_TAB
    104	};
    105
    106	/* BBs can be split afterwards?? */
    107	PASS_INFO(sancov, "asan", 0, PASS_POS_INSERT_BEFORE);
    108
    109	if (!plugin_default_version_check(version, &gcc_version)) {
    110		error(G_("incompatible gcc/plugin versions"));
    111		return 1;
    112	}
    113
    114	for (i = 0; i < argc; ++i) {
    115		if (!strcmp(argv[i].key, "no-sancov")) {
    116			enable = false;
    117			continue;
    118		}
    119		error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key);
    120	}
    121
    122	register_callback(plugin_name, PLUGIN_INFO, NULL, &sancov_plugin_info);
    123
    124	if (!enable)
    125		return 0;
    126
    127#if BUILDING_GCC_VERSION < 6000
    128	register_callback(plugin_name, PLUGIN_START_UNIT, &sancov_start_unit, NULL);
    129	register_callback(plugin_name, PLUGIN_REGISTER_GGC_ROOTS, NULL, (void *)&gt_ggc_r_gt_sancov);
    130	register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &sancov_pass_info);
    131#endif
    132
    133	return 0;
    134}