Merge tag 'hardening-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull compiler hardening updates from Kees Cook:
 "These are various compiler-related hardening feature updates. Notable
  is the addition of an explicit limited rationale for, and deprecation
  schedule of, gcc-plugins.

  gcc-plugins:
   - remove support for GCC 4.9 and older (Ard Biesheuvel)
   - remove duplicate include in gcc-common.h (Ye Guojin)
   - Explicitly document purpose and deprecation schedule (Kees Cook)
   - Remove cyc_complexity (Kees Cook)

  instrumentation:
   - Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO (Kees Cook)

  Clang LTO:
   - kallsyms: strip LTO suffixes from static functions (Nick Desaulniers)"

* tag 'hardening-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-plugins: remove duplicate include in gcc-common.h
  gcc-plugins: Remove cyc_complexity
  gcc-plugins: Explicitly document purpose and deprecation schedule
  kallsyms: strip LTO suffixes from static functions
  gcc-plugins: remove support for GCC 4.9 and older
  hardening: Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO

13 files changed, 75 insertions, 320 deletions

diff --git a/Documentation/kbuild/gcc-plugins.rst b/Documentation/kbuild/gcc-plugins.rst
index 3349966f213dcf..0ba76719f1b936 100644
--- a/Documentation/kbuild/gcc-plugins.rst
+++ b/Documentation/kbuild/gcc-plugins.rst
@@ -32,6 +32,32 @@ This infrastructure was ported from grsecurity [6]_ and PaX [7]_.
 .. [7] https://pax.grsecurity.net/
 
 
+Purpose
+=======
+
+GCC plugins are designed to provide a place to experiment with potential
+compiler features that are neither in GCC nor Clang upstream. Once
+their utility is proven, the goal is to upstream the feature into GCC
+(and Clang), and then to finally remove them from the kernel once the
+feature is available in all supported versions of GCC.
+
+Specifically, new plugins should implement only features that have no
+upstream compiler support (in either GCC or Clang).
+
+When a feature exists in Clang but not GCC, effort should be made to
+bring the feature to upstream GCC (rather than just as a kernel-specific
+GCC plugin), so the entire ecosystem can benefit from it.
+
+Similarly, even if a feature provided by a GCC plugin does *not* exist
+in Clang, but the feature is proven to be useful, effort should be spent
+to upstream the feature to GCC (and Clang).
+
+After a feature is available in upstream GCC, the plugin will be made
+unbuildable for the corresponding GCC version (and later). Once all
+kernel-supported versions of GCC provide the feature, the plugin will
+be removed from the kernel.
+
+
 Files
 =====
 
@@ -70,7 +96,6 @@ Enable the GCC plugin infrastructure and some plugin(s) you want to use
 in the kernel config::
 
 	CONFIG_GCC_PLUGINS=y
-	CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=y
 	CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y
 	...
 
@@ -89,4 +114,3 @@ The GCC plugins are in scripts/gcc-plugins/. You need to put plugin source files
 right under scripts/gcc-plugins/. Creating subdirectories is not supported.
 It must be added to scripts/gcc-plugins/Makefile, scripts/Makefile.gcc-plugins
 and a relevant Kconfig file.
-See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin.
diff --git a/Makefile b/Makefile
index a5231635ed43e4..d6520b79776888 100644
--- a/Makefile
+++ b/Makefile
@@ -831,12 +831,12 @@ endif
 
 # Initialize all stack variables with a zero value.
 ifdef CONFIG_INIT_STACK_ALL_ZERO
-# Future support for zero initialization is still being debated, see
-# https://bugs.llvm.org/show_bug.cgi?id=45497. These flags are subject to being
-# renamed or dropped.
 KBUILD_CFLAGS	+= -ftrivial-auto-var-init=zero
+ifdef CONFIG_CC_IS_CLANG
+# https://bugs.llvm.org/show_bug.cgi?id=45497
 KBUILD_CFLAGS	+= -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
 endif
+endif
 
 # While VLAs have been removed, GCC produces unreachable stack probes
 # for the randomize_kstack_offset feature. Disable it for all compilers.
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 0ba87982d017fc..3011bc33a5bac0 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -164,26 +164,46 @@ static unsigned long kallsyms_sym_address(int idx)
 	return kallsyms_relative_base - 1 - kallsyms_offsets[idx];
 }
 
-#if defined(CONFIG_CFI_CLANG) && defined(CONFIG_LTO_CLANG_THIN)
-/*
- * LLVM appends a hash to static function names when ThinLTO and CFI are
- * both enabled, i.e. foo() becomes foo$707af9a22804d33c81801f27dcfe489b.
- * This causes confusion and potentially breaks user space tools, so we
- * strip the suffix from expanded symbol names.
- */
-static inline bool cleanup_symbol_name(char *s)
+static bool cleanup_symbol_name(char *s)
 {
 	char *res;
 
+	if (!IS_ENABLED(CONFIG_LTO_CLANG))
+		return false;
+
+	/*
+	 * LLVM appends various suffixes for local functions and variables that
+	 * must be promoted to global scope as part of LTO.  This can break
+	 * hooking of static functions with kprobes. '.' is not a valid
+	 * character in an identifier in C. Suffixes observed:
+	 * - foo.llvm.[0-9a-f]+
+	 * - foo.[0-9a-f]+
+	 * - foo.[0-9a-f]+.cfi_jt
+	 */
+	res = strchr(s, '.');
+	if (res) {
+		*res = '\0';
+		return true;
+	}
+
+	if (!IS_ENABLED(CONFIG_CFI_CLANG) ||
+	    !IS_ENABLED(CONFIG_LTO_CLANG_THIN) ||
+	    CONFIG_CLANG_VERSION >= 130000)
+		return false;
+
+	/*
+	 * Prior to LLVM 13, the following suffixes were observed when thinLTO
+	 * and CFI are both enabled:
+	 * - foo$[0-9]+
+	 */
 	res = strrchr(s, '$');
-	if (res)
+	if (res) {
 		*res = '\0';
+		return true;
+	}
 
-	return res != NULL;
+	return false;
 }
-#else
-static inline bool cleanup_symbol_name(char *s) { return false; }
-#endif
 
 /* Lookup the address for this symbol. Returns 0 if not found. */
 unsigned long kallsyms_lookup_name(const char *name)
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index 4aad2848003558..1d16ca1b78c91e 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -1,7 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 
-gcc-plugin-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY)	+= cyc_complexity_plugin.so
-
 gcc-plugin-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY)	+= latent_entropy_plugin.so
 gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY)		\
 		+= -DLATENT_ENTROPY_PLUGIN
diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index ab9eb4cbe33a66..51d81c3f03d6b4 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -19,24 +19,10 @@ menuconfig GCC_PLUGINS
 
 if GCC_PLUGINS
 
-config GCC_PLUGIN_CYC_COMPLEXITY
-	bool "Compute the cyclomatic complexity of a function" if EXPERT
-	depends on !COMPILE_TEST	# too noisy
-	help
-	  The complexity M of a function's control flow graph is defined as:
-	   M = E - N + 2P
-	  where
-
-	  E = the number of edges
-	  N = the number of nodes
-	  P = the number of connected components (exit nodes).
-
-	  Enabling this plugin reports the complexity to stderr during the
-	  build. It mainly serves as a simple example of how to create a
-	  gcc plugin for the kernel.
-
 config GCC_PLUGIN_SANCOV
 	bool
+	# Plugin can be removed once the kernel only supports GCC 6+
+	depends on !CC_HAS_SANCOV_TRACE_PC
 	help
 	  This plugin inserts a __sanitizer_cov_trace_pc() call at the start of
 	  basic blocks. It supports all gcc versions with plugin support (from
@@ -83,8 +69,6 @@ config GCC_PLUGIN_RANDSTRUCT
 	  the existing seed and will be removed by a make mrproper or
 	  make distclean.
 
-	  Note that the implementation requires gcc 4.7 or newer.
-
 	  This plugin was ported from grsecurity/PaX. More information at:
 	   * https://grsecurity.net/
 	   * https://pax.grsecurity.net/
diff --git a/scripts/gcc-plugins/cyc_complexity_plugin.c b/scripts/gcc-plugins/cyc_complexity_plugin.c
deleted file mode 100644
index 73124c2b3eddab..00000000000000
--- a/scripts/gcc-plugins/cyc_complexity_plugin.c
+++ /dev/null
@@ -1,69 +0,0 @@
-/*
- * Copyright 2011-2016 by Emese Revfy <re.emese@gmail.com>
- * Licensed under the GPL v2, or (at your option) v3
- *
- * Homepage:
- * https://github.com/ephox-gcc-plugins/cyclomatic_complexity
- *
- * https://en.wikipedia.org/wiki/Cyclomatic_complexity
- * The complexity M is then defined as:
- * M = E - N + 2P
- * where
- *
- *  E = the number of edges of the graph
- *  N = the number of nodes of the graph
- *  P = the number of connected components (exit nodes).
- *
- * Usage (4.5 - 5):
- * $ make clean; make run
- */
-
-#include "gcc-common.h"
-
-__visible int plugin_is_GPL_compatible;
-
-static struct plugin_info cyc_complexity_plugin_info = {
-	.version	= "20160225",
-	.help		= "Cyclomatic Complexity\n",
-};
-
-static unsigned int cyc_complexity_execute(void)
-{
-	int complexity;
-	expanded_location xloc;
-
-	/* M = E - N + 2P */
-	complexity = n_edges_for_fn(cfun) - n_basic_blocks_for_fn(cfun) + 2;
-
-	xloc = expand_location(DECL_SOURCE_LOCATION(current_function_decl));
-	fprintf(stderr, "Cyclomatic Complexity %d %s:%s\n", complexity,
-		xloc.file, DECL_NAME_POINTER(current_function_decl));
-
-	return 0;
-}
-
-#define PASS_NAME cyc_complexity
-
-#define NO_GATE
-#define TODO_FLAGS_FINISH TODO_dump_func
-
-#include "gcc-generate-gimple-pass.h"
-
-__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
-{
-	const char * const plugin_name = plugin_info->base_name;
-
-	PASS_INFO(cyc_complexity, "ssa", 1, PASS_POS_INSERT_AFTER);
-
-	if (!plugin_default_version_check(version, &gcc_version)) {
-		error(G_("incompatible gcc/plugin versions"));
-		return 1;
-	}
-
-	register_callback(plugin_name, PLUGIN_INFO, NULL,
-				&cyc_complexity_plugin_info);
-	register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL,
-				&cyc_complexity_pass_info);
-
-	return 0;
-}
diff --git a/scripts/gcc-plugins/gcc-common.h b/scripts/gcc-plugins/gcc-common.h
index 0c087614fc3e41..9a1895747b1536 100644
--- a/scripts/gcc-plugins/gcc-common.h
+++ b/scripts/gcc-plugins/gcc-common.h
@@ -27,9 +27,7 @@
 #include "except.h"
 #include "function.h"
 #include "toplev.h"
-#if BUILDING_GCC_VERSION >= 5000
 #include "expr.h"
-#endif
 #include "basic-block.h"
 #include "intl.h"
 #include "ggc.h"
@@ -39,11 +37,7 @@
 #include "params.h"
 #endif
 
-#if BUILDING_GCC_VERSION <= 4009
-#include "pointer-set.h"
-#else
 #include "hash-map.h"
-#endif
 
 #if BUILDING_GCC_VERSION >= 7000
 #include "memmodel.h"
@@ -92,16 +86,13 @@
 #include "stmt.h"
 #include "gimplify.h"
 #include "gimple.h"
-#include "tree-ssa-operands.h"
 #include "tree-phinodes.h"
 #include "tree-cfg.h"
 #include "gimple-iterator.h"
 #include "gimple-ssa.h"
 #include "ssa-iterators.h"
 
-#if BUILDING_GCC_VERSION >= 5000
 #include "builtins.h"
-#endif
 
 /* missing from basic_block.h... */
 void debug_dominance_info(enum cdi_direction dir);
@@ -152,125 +143,6 @@ struct register_pass_info NAME##_pass_info = {	\
 #define TODO_dump_func 0
 #define TODO_dump_cgraph 0
 
-#if BUILDING_GCC_VERSION <= 4009
-#define TODO_verify_il 0
-#define AVAIL_INTERPOSABLE AVAIL_OVERWRITABLE
-
-#define section_name_prefix LTO_SECTION_NAME_PREFIX
-#define fatal_error(loc, gmsgid, ...) fatal_error((gmsgid), __VA_ARGS__)
-
-rtx emit_move_insn(rtx x, rtx y);
-
-typedef struct rtx_def rtx_insn;
-
-static inline const char *get_decl_section_name(const_tree decl)
-{
-	if (DECL_SECTION_NAME(decl) == NULL_TREE)
-		return NULL;
-
-	return TREE_STRING_POINTER(DECL_SECTION_NAME(decl));
-}
-
-static inline void set_decl_section_name(tree node, const char *value)
-{
-	if (value)
-		DECL_SECTION_NAME(node) = build_string(strlen(value) + 1, value);
-	else
-		DECL_SECTION_NAME(node) = NULL;
-}
-#endif
-
-#if BUILDING_GCC_VERSION == 4009
-typedef struct gimple_statement_asm gasm;
-typedef struct gimple_statement_base gassign;
-typedef struct gimple_statement_call gcall;
-typedef struct gimple_statement_base gcond;
-typedef struct gimple_statement_base gdebug;
-typedef struct gimple_statement_base ggoto;
-typedef struct gimple_statement_phi gphi;
-typedef struct gimple_statement_base greturn;
-
-static inline gasm *as_a_gasm(gimple stmt)
-{
-	return as_a<gasm>(stmt);
-}
-
-static inline const gasm *as_a_const_gasm(const_gimple stmt)
-{
-	return as_a<const gasm>(stmt);
-}
-
-static inline gassign *as_a_gassign(gimple stmt)
-{
-	return stmt;
-}
-
-static inline const gassign *as_a_const_gassign(const_gimple stmt)
-{
-	return stmt;
-}
-
-static inline gcall *as_a_gcall(gimple stmt)
-{
-	return as_a<gcall>(stmt);
-}
-
-static inline const gcall *as_a_const_gcall(const_gimple stmt)
-{
-	return as_a<const gcall>(stmt);
-}
-
-static inline gcond *as_a_gcond(gimple stmt)
-{
-	return stmt;
-}
-
-static inline const gcond *as_a_const_gcond(const_gimple stmt)
-{
-	return stmt;
-}
-
-static inline gdebug *as_a_gdebug(gimple stmt)
-{
-	return stmt;
-}
-
-static inline const gdebug *as_a_const_gdebug(const_gimple stmt)
-{
-	return stmt;
-}
-
-static inline ggoto *as_a_ggoto(gimple stmt)
-{
-	return stmt;
-}
-
-static inline const ggoto *as_a_const_ggoto(const_gimple stmt)
-{
-	return stmt;
-}
-
-static inline gphi *as_a_gphi(gimple stmt)
-{
-	return as_a<gphi>(stmt);
-}
-
-static inline const gphi *as_a_const_gphi(const_gimple stmt)
-{
-	return as_a<const gphi>(stmt);
-}
-
-static inline greturn *as_a_greturn(gimple stmt)
-{
-	return stmt;
-}
-
-static inline const greturn *as_a_const_greturn(const_gimple stmt)
-{
-	return stmt;
-}
-#endif
-
 #define TODO_ggc_collect 0
 #define NODE_SYMBOL(node) (node)
 #define NODE_DECL(node) (node)->decl
@@ -282,7 +154,7 @@ static inline opt_pass *get_pass_for_id(int id)
 	return g->get_passes()->get_pass_for_id(id);
 }
 
-#if BUILDING_GCC_VERSION >= 5000 && BUILDING_GCC_VERSION < 6000
+#if BUILDING_GCC_VERSION < 6000
 /* gimple related */
 template <>
 template <>
@@ -292,7 +164,6 @@ inline bool is_a_helper<const gassign *>::test(const_gimple gs)
 }
 #endif
 
-#if BUILDING_GCC_VERSION >= 5000
 #define TODO_verify_ssa TODO_verify_il
 #define TODO_verify_flow TODO_verify_il
 #define TODO_verify_stmts TODO_verify_il
@@ -533,7 +404,6 @@ static inline void ipa_remove_stmt_references(symtab_node *referring_node, gimpl
 {
 	referring_node->remove_stmt_references(stmt);
 }
-#endif
 
 #if BUILDING_GCC_VERSION < 6000
 #define get_inner_reference(exp, pbitsize, pbitpos, poffset, pmode, punsignedp, preversep, pvolatilep, keep_aligning)	\
diff --git a/scripts/gcc-plugins/gcc-generate-gimple-pass.h b/scripts/gcc-plugins/gcc-generate-gimple-pass.h
index 51780828734e42..503c0749639637 100644
--- a/scripts/gcc-plugins/gcc-generate-gimple-pass.h
+++ b/scripts/gcc-plugins/gcc-generate-gimple-pass.h
@@ -78,17 +78,6 @@ static const pass_data _PASS_NAME_PASS_DATA = {
 		.type			= GIMPLE_PASS,
 		.name			= _PASS_NAME_NAME,
 		.optinfo_flags		= OPTGROUP_NONE,
-#if BUILDING_GCC_VERSION >= 5000
-#elif BUILDING_GCC_VERSION == 4009
-		.has_gate		= _HAS_GATE,
-		.has_execute		= _HAS_EXECUTE,
-#else
-		.gate			= _GATE,
-		.execute		= _EXECUTE,
-		.sub			= NULL,
-		.next			= NULL,
-		.static_pass_number	= 0,
-#endif
 		.tv_id			= TV_NONE,
 		.properties_required	= PROPERTIES_REQUIRED,
 		.properties_provided	= PROPERTIES_PROVIDED,
@@ -102,21 +91,13 @@ public:
 	_PASS_NAME_PASS() : gimple_opt_pass(_PASS_NAME_PASS_DATA, g) {}
 
 #ifndef NO_GATE
-#if BUILDING_GCC_VERSION >= 5000
 	virtual bool gate(function *) { return _GATE(); }
-#else
-	virtual bool gate(void) { return _GATE(); }
-#endif
 #endif
 
 	virtual opt_pass * clone () { return new _PASS_NAME_PASS(); }
 
 #ifndef NO_EXECUTE
-#if BUILDING_GCC_VERSION >= 5000
 	virtual unsigned int execute(function *) { return _EXECUTE(); }
-#else
-	virtual unsigned int execute(void) { return _EXECUTE(); }
-#endif
 };
 }
 
diff --git a/scripts/gcc-plugins/gcc-generate-ipa-pass.h b/scripts/gcc-plugins/gcc-generate-ipa-pass.h
index c34ffec035bfa7..1e7f064e8f6e6d 100644
--- a/scripts/gcc-plugins/gcc-generate-ipa-pass.h
+++ b/scripts/gcc-plugins/gcc-generate-ipa-pass.h
@@ -146,17 +146,6 @@ static const pass_data _PASS_NAME_PASS_DATA = {
 		.type			= IPA_PASS,
 		.name			= _PASS_NAME_NAME,
 		.optinfo_flags		= OPTGROUP_NONE,
-#if BUILDING_GCC_VERSION >= 5000
-#elif BUILDING_GCC_VERSION == 4009
-		.has_gate		= _HAS_GATE,
-		.has_execute		= _HAS_EXECUTE,
-#else
-		.gate			= _GATE,
-		.execute		= _EXECUTE,
-		.sub			= NULL,
-		.next			= NULL,
-		.static_pass_number	= 0,
-#endif
 		.tv_id			= TV_NONE,
 		.properties_required	= PROPERTIES_REQUIRED,
 		.properties_provided	= PROPERTIES_PROVIDED,
@@ -180,20 +169,12 @@ public:
 			 _VARIABLE_TRANSFORM) {}
 
 #ifndef NO_GATE
-#if BUILDING_GCC_VERSION >= 5000
 	virtual bool gate(function *) { return _GATE(); }
-#else
-	virtual bool gate(void) { return _GATE(); }
-#endif
 
 	virtual opt_pass *clone() { return new _PASS_NAME_PASS(); }
 
 #ifndef NO_EXECUTE
-#if BUILDING_GCC_VERSION >= 5000
 	virtual unsigned int execute(function *) { return _EXECUTE(); }
-#else
-	virtual unsigned int execute(void) { return _EXECUTE(); }
-#endif
 #endif
 };
 }
diff --git a/scripts/gcc-plugins/gcc-generate-rtl-pass.h b/scripts/gcc-plugins/gcc-generate-rtl-pass.h
index d14614f4b13934..7cd46e8d5049a4 100644
--- a/scripts/gcc-plugins/gcc-generate-rtl-pass.h
+++ b/scripts/gcc-plugins/gcc-generate-rtl-pass.h
@@ -78,17 +78,6 @@ static const pass_data _PASS_NAME_PASS_DATA = {
 		.type			= RTL_PASS,
 		.name			= _PASS_NAME_NAME,
 		.optinfo_flags		= OPTGROUP_NONE,
-#if BUILDING_GCC_VERSION >= 5000
-#elif BUILDING_GCC_VERSION == 4009
-		.has_gate		= _HAS_GATE,
-		.has_execute		= _HAS_EXECUTE,
-#else
-		.gate			= _GATE,
-		.execute		= _EXECUTE,
-		.sub			= NULL,
-		.next			= NULL,
-		.static_pass_number	= 0,
-#endif
 		.tv_id			= TV_NONE,
 		.properties_required	= PROPERTIES_REQUIRED,
 		.properties_provided	= PROPERTIES_PROVIDED,
@@ -102,21 +91,13 @@ public:
 	_PASS_NAME_PASS() : rtl_opt_pass(_PASS_NAME_PASS_DATA, g) {}
 
 #ifndef NO_GATE
-#if BUILDING_GCC_VERSION >= 5000
 	virtual bool gate(function *) { return _GATE(); }
-#else
-	virtual bool gate(void) { return _GATE(); }
-#endif
 #endif
 
 	virtual opt_pass *clone() { return new _PASS_NAME_PASS(); }
 
 #ifndef NO_EXECUTE
-#if BUILDING_GCC_VERSION >= 5000
 	virtual unsigned int execute(function *) { return _EXECUTE(); }
-#else
-	virtual unsigned int execute(void) { return _EXECUTE(); }
-#endif
 #endif
 };
 }
diff --git a/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h b/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h
index ef6f4c2cb6fa8c..33093ccc947a55 100644
--- a/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h
+++ b/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h
@@ -78,17 +78,6 @@ static const pass_data _PASS_NAME_PASS_DATA = {
 		.type			= SIMPLE_IPA_PASS,
 		.name			= _PASS_NAME_NAME,
 		.optinfo_flags		= OPTGROUP_NONE,
-#if BUILDING_GCC_VERSION >= 5000
-#elif BUILDING_GCC_VERSION == 4009
-		.has_gate		= _HAS_GATE,
-		.has_execute		= _HAS_EXECUTE,
-#else
-		.gate			= _GATE,
-		.execute		= _EXECUTE,
-		.sub			= NULL,
-		.next			= NULL,
-		.static_pass_number	= 0,
-#endif
 		.tv_id			= TV_NONE,
 		.properties_required	= PROPERTIES_REQUIRED,
 		.properties_provided	= PROPERTIES_PROVIDED,
@@ -102,21 +91,13 @@ public:
 	_PASS_NAME_PASS() : simple_ipa_opt_pass(_PASS_NAME_PASS_DATA, g) {}
 
 #ifndef NO_GATE
-#if BUILDING_GCC_VERSION >= 5000
 	virtual bool gate(function *) { return _GATE(); }
-#else
-	virtual bool gate(void) { return _GATE(); }
-#endif
 #endif
 
 	virtual opt_pass *clone() { return new _PASS_NAME_PASS(); }
 
 #ifndef NO_EXECUTE
-#if BUILDING_GCC_VERSION >= 5000
 	virtual unsigned int execute(function *) { return _EXECUTE(); }
-#else
-	virtual unsigned int execute(void) { return _EXECUTE(); }
-#endif
 #endif
 };
 }
diff --git a/scripts/gcc-plugins/structleak_plugin.c b/scripts/gcc-plugins/structleak_plugin.c
index d7190e443a14eb..74e319288389d3 100644
--- a/scripts/gcc-plugins/structleak_plugin.c
+++ b/scripts/gcc-plugins/structleak_plugin.c
@@ -103,10 +103,8 @@ static void finish_type(void *event_data, void *data)
 	if (type == NULL_TREE || type == error_mark_node)
 		return;
 
-#if BUILDING_GCC_VERSION >= 5000
 	if (TREE_CODE(type) == ENUMERAL_TYPE)
 		return;
-#endif
 
 	if (TYPE_USERSPACE(type))
 		return;
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index 90cbaff86e13a4..d051f8ceefddd1 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -23,13 +23,16 @@ config CC_HAS_AUTO_VAR_INIT_PATTERN
 	def_bool $(cc-option,-ftrivial-auto-var-init=pattern)
 
 config CC_HAS_AUTO_VAR_INIT_ZERO
+	# GCC ignores the -enable flag, so we can test for the feature with
+	# a single invocation using the flag, but drop it as appropriate in
+	# the Makefile, depending on the presence of Clang.
 	def_bool $(cc-option,-ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang)
 
 choice
 	prompt "Initialize kernel stack variables at function entry"
 	default GCC_PLUGIN_STRUCTLEAK_BYREF_ALL if COMPILE_TEST && GCC_PLUGINS
 	default INIT_STACK_ALL_PATTERN if COMPILE_TEST && CC_HAS_AUTO_VAR_INIT_PATTERN
-	default INIT_STACK_ALL_ZERO if CC_HAS_AUTO_VAR_INIT_PATTERN
+	default INIT_STACK_ALL_ZERO if CC_HAS_AUTO_VAR_INIT_ZERO
 	default INIT_STACK_NONE
 	help
 	  This option enables initialization of stack variables at
@@ -53,7 +56,8 @@ choice
 
 	config GCC_PLUGIN_STRUCTLEAK_USER
 		bool "zero-init structs marked for userspace (weak)"
-		depends on GCC_PLUGINS
+		# Plugin can be removed once the kernel only supports GCC 12+
+		depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO
 		select GCC_PLUGIN_STRUCTLEAK
 		help
 		  Zero-initialize any structures on the stack containing
@@ -64,7 +68,8 @@ choice
 
 	config GCC_PLUGIN_STRUCTLEAK_BYREF
 		bool "zero-init structs passed by reference (strong)"
-		depends on GCC_PLUGINS
+		# Plugin can be removed once the kernel only supports GCC 12+
+		depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO
 		depends on !(KASAN && KASAN_STACK)
 		select GCC_PLUGIN_STRUCTLEAK
 		help
@@ -82,7 +87,8 @@ choice
 
 	config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
 		bool "zero-init everything passed by reference (very strong)"
-		depends on GCC_PLUGINS
+		# Plugin can be removed once the kernel only supports GCC 12+
+		depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO
 		depends on !(KASAN && KASAN_STACK)
 		select GCC_PLUGIN_STRUCTLEAK
 		help