hardening updates for v6.18-rc1

- Clean up usage of TRAILING_OVERLAP() (Gustavo A. R. Silva)
 
 - lkdtm: fortify: Fix potential NULL dereference on kmalloc failure
   (Junjie Cao)
 
 - Add str_assert_deassert() helper (Lad Prabhakar)
 
 - gcc-plugins: Remove TODO_verify_il for GCC >= 16
 
 - kconfig: Fix BrokenPipeError warnings in selftests
 
 - kconfig: Add transitional symbol attribute for migration support
 
 - kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI
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Merge tag 'hardening-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:
 "One notable addition is the creation of the 'transitional' keyword for
  kconfig so CONFIG renaming can go more smoothly.

  This has been a long-standing deficiency, and with the renaming of
  CONFIG_CFI_CLANG to CONFIG_CFI (since GCC will soon have KCFI
  support), this came up again.

  The breadth of the diffstat is mainly this renaming.

   - Clean up usage of TRAILING_OVERLAP() (Gustavo A. R. Silva)

   - lkdtm: fortify: Fix potential NULL dereference on kmalloc failure
     (Junjie Cao)

   - Add str_assert_deassert() helper (Lad Prabhakar)

   - gcc-plugins: Remove TODO_verify_il for GCC >= 16

   - kconfig: Fix BrokenPipeError warnings in selftests

   - kconfig: Add transitional symbol attribute for migration support

   - kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI"

* tag 'hardening-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lib/string_choices: Add str_assert_deassert() helper
  kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI
  kconfig: Add transitional symbol attribute for migration support
  kconfig: Fix BrokenPipeError warnings in selftests
  gcc-plugins: Remove TODO_verify_il for GCC >= 16
  stddef: Introduce __TRAILING_OVERLAP()
  stddef: Remove token-pasting in TRAILING_OVERLAP()
  lkdtm: fortify: Fix potential NULL dereference on kmalloc failure

Documentation/kbuild/kconfig-language.rst

@@ -232,6 +232,38 @@ applicable everywhere (see syntax).
   enables the third modular state for all config symbols.
   At most one symbol may have the "modules" option set.
 
+- transitional attribute: "transitional"
+  This declares the symbol as transitional, meaning it should be processed
+  during configuration but omitted from newly written .config files.
+  Transitional symbols are useful for backward compatibility during config
+  option migrations - they allow olddefconfig to process existing .config
+  files while ensuring the old option doesn't appear in new configurations.
+
+  A transitional symbol:
+  - Has no prompt (is not visible to users in menus)
+  - Is processed normally during configuration (values are read and used)
+  - Can be referenced in default expressions of other symbols
+  - Is not written to new .config files
+  - Cannot have any other properties (it is a pass-through option)
+
+  Example migration from OLD_NAME to NEW_NAME::
+
+    config NEW_NAME
+	bool "New option name"
+	default OLD_NAME
+	help
+	  This replaces the old CONFIG_OLD_NAME option.
+
+    config OLD_NAME
+	bool
+	transitional
+	help
+	  Transitional config for OLD_NAME to NEW_NAME migration.
+
+  With this setup, existing .config files with "CONFIG_OLD_NAME=y" will
+  result in "CONFIG_NEW_NAME=y" being set, while CONFIG_OLD_NAME will be
+  omitted from newly written .config files.
+
 Menu dependencies
 -----------------
 

Makefile

@@ -1020,7 +1020,7 @@ KBUILD_AFLAGS	+= -fno-lto
 export CC_FLAGS_LTO
 endif
 
-ifdef CONFIG_CFI_CLANG
+ifdef CONFIG_CFI
 CC_FLAGS_CFI	:= -fsanitize=kcfi
 ifdef CONFIG_CFI_ICALL_NORMALIZE_INTEGERS
 	CC_FLAGS_CFI	+= -fsanitize-cfi-icall-experimental-normalize-integers

arch/Kconfig

@@ -867,22 +867,26 @@ config PROPELLER_CLANG
 
 	  If unsure, say N.
 
-config ARCH_SUPPORTS_CFI_CLANG
+config ARCH_SUPPORTS_CFI
 	bool
 	help
-	  An architecture should select this option if it can support Clang's
+	  An architecture should select this option if it can support Kernel
-	  Control-Flow Integrity (CFI) checking.
+	  Control-Flow Integrity (CFI) checking (-fsanitize=kcfi).
 
 config ARCH_USES_CFI_TRAPS
 	bool
+	help
+	  An architecture should select this option if it requires the
+	  .kcfi_traps section for KCFI trap handling.
 
-config CFI_CLANG
+config CFI
-	bool "Use Clang's Control Flow Integrity (CFI)"
+	bool "Use Kernel Control Flow Integrity (kCFI)"
-	depends on ARCH_SUPPORTS_CFI_CLANG
+	default CFI_CLANG
+	depends on ARCH_SUPPORTS_CFI
 	depends on $(cc-option,-fsanitize=kcfi)
 	help
-	  This option enables Clang's forward-edge Control Flow Integrity
+	  This option enables forward-edge Control Flow Integrity (CFI)
-	  (CFI) checking, where the compiler injects a runtime check to each
+	  checking, where the compiler injects a runtime check to each
 	  indirect function call to ensure the target is a valid function with
 	  the correct static type. This restricts possible call targets and
 	  makes it more difficult for an attacker to exploit bugs that allow
@@ -891,10 +895,16 @@ config CFI_CLANG
 
 	    https://clang.llvm.org/docs/ControlFlowIntegrity.html
 
+config CFI_CLANG
+	bool
+	transitional
+	help
+	  Transitional config for CFI_CLANG to CFI migration.
+
 config CFI_ICALL_NORMALIZE_INTEGERS
 	bool "Normalize CFI tags for integers"
-	depends on CFI_CLANG
+	depends on CFI
-	depends on HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG
+	depends on HAVE_CFI_ICALL_NORMALIZE_INTEGERS
 	help
 	  This option normalizes the CFI tags for integer types so that all
 	  integer types of the same size and signedness receive the same CFI
@@ -907,7 +917,7 @@ config CFI_ICALL_NORMALIZE_INTEGERS
 
 	  This option is necessary for using CFI with Rust. If unsure, say N.
 
-config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG
+config HAVE_CFI_ICALL_NORMALIZE_INTEGERS
 	def_bool y
 	depends on $(cc-option,-fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers)
 	# With GCOV/KASAN we need this fix: https://github.com/llvm/llvm-project/pull/104826
@@ -915,7 +925,7 @@ config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG
 
 config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
 	def_bool y
-	depends on HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG
+	depends on HAVE_CFI_ICALL_NORMALIZE_INTEGERS
 	depends on RUSTC_VERSION >= 107900
 	# With GCOV/KASAN we need this fix: https://github.com/rust-lang/rust/pull/129373
 	depends on (RUSTC_LLVM_VERSION >= 190103 && RUSTC_VERSION >= 108200) || \
@@ -923,7 +933,7 @@ config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
 
 config CFI_PERMISSIVE
 	bool "Use CFI in permissive mode"
-	depends on CFI_CLANG
+	depends on CFI
 	help
 	  When selected, Control Flow Integrity (CFI) violations result in a
 	  warning instead of a kernel panic. This option should only be used

arch/arm/Kconfig

@@ -38,7 +38,7 @@ config ARM
 	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
 	select ARCH_NEED_CMPXCHG_1_EMU if CPU_V6
 	select ARCH_SUPPORTS_ATOMIC_RMW
-	select ARCH_SUPPORTS_CFI_CLANG
+	select ARCH_SUPPORTS_CFI
 	select ARCH_SUPPORTS_HUGETLBFS if ARM_LPAE
 	select ARCH_SUPPORTS_PER_VMA_LOCK
 	select ARCH_USE_BUILTIN_BSWAP

arch/arm/kernel/hw_breakpoint.c

@@ -904,7 +904,7 @@ unlock:
 	watchpoint_single_step_handler(addr);
 }
 
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 static void hw_breakpoint_cfi_handler(struct pt_regs *regs)
 {
 	/*

arch/arm/mm/Makefile

@@ -89,7 +89,7 @@ obj-$(CONFIG_CPU_V6)		+= proc-v6.o
 obj-$(CONFIG_CPU_V6K)		+= proc-v6.o
 obj-$(CONFIG_CPU_V7)		+= proc-v7.o proc-v7-bugs.o
 obj-$(CONFIG_CPU_V7M)		+= proc-v7m.o
-obj-$(CONFIG_CFI_CLANG)		+= proc.o
+obj-$(CONFIG_CFI)		+= proc.o
 
 obj-$(CONFIG_OUTER_CACHE)	+= l2c-common.o
 obj-$(CONFIG_CACHE_B15_RAC)	+= cache-b15-rac.o

arch/arm/mm/cache-fa.S

@@ -112,7 +112,7 @@ SYM_FUNC_END(fa_flush_user_cache_range)
  *	- end	 - virtual end address
  */
 SYM_TYPED_FUNC_START(fa_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	fa_coherent_user_range
 #endif
 SYM_FUNC_END(fa_coherent_kern_range)

arch/arm/mm/cache-v4.S

@@ -104,7 +104,7 @@ SYM_FUNC_END(v4_coherent_user_range)
  *	- size	- region size
  */
 SYM_TYPED_FUNC_START(v4_flush_kern_dcache_area)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	v4_dma_flush_range
 #endif
 SYM_FUNC_END(v4_flush_kern_dcache_area)

arch/arm/mm/cache-v4wb.S

@@ -136,7 +136,7 @@ SYM_FUNC_END(v4wb_flush_user_cache_range)
  */
 SYM_TYPED_FUNC_START(v4wb_flush_kern_dcache_area)
 	add	r1, r0, r1
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	v4wb_coherent_user_range
 #endif
 SYM_FUNC_END(v4wb_flush_kern_dcache_area)
@@ -152,7 +152,7 @@ SYM_FUNC_END(v4wb_flush_kern_dcache_area)
  *	- end	 - virtual end address
  */
 SYM_TYPED_FUNC_START(v4wb_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	v4wb_coherent_user_range
 #endif
 SYM_FUNC_END(v4wb_coherent_kern_range)

arch/arm/mm/cache-v4wt.S

@@ -108,7 +108,7 @@ SYM_FUNC_END(v4wt_flush_user_cache_range)
  *	- end	 - virtual end address
  */
 SYM_TYPED_FUNC_START(v4wt_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	v4wt_coherent_user_range
 #endif
 SYM_FUNC_END(v4wt_coherent_kern_range)

arch/arm/mm/cache-v6.S

@@ -117,7 +117,7 @@ SYM_FUNC_END(v6_flush_user_cache_range)
  *	- the Icache does not read data from the write buffer
  */
 SYM_TYPED_FUNC_START(v6_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	v6_coherent_user_range
 #endif
 SYM_FUNC_END(v6_coherent_kern_range)

arch/arm/mm/cache-v7.S

@@ -261,7 +261,7 @@ SYM_FUNC_END(v7_flush_user_cache_range)
  *	- the Icache does not read data from the write buffer
  */
 SYM_TYPED_FUNC_START(v7_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	v7_coherent_user_range
 #endif
 SYM_FUNC_END(v7_coherent_kern_range)

arch/arm/mm/cache-v7m.S

@@ -286,7 +286,7 @@ SYM_FUNC_END(v7m_flush_user_cache_range)
  *	- the Icache does not read data from the write buffer
  */
 SYM_TYPED_FUNC_START(v7m_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	v7m_coherent_user_range
 #endif
 SYM_FUNC_END(v7m_coherent_kern_range)

arch/arm/mm/proc-arm1020.S

@@ -203,7 +203,7 @@ SYM_FUNC_END(arm1020_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm1020_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm1020_coherent_user_range
 #endif
 SYM_FUNC_END(arm1020_coherent_kern_range)

arch/arm/mm/proc-arm1020e.S

@@ -200,7 +200,7 @@ SYM_FUNC_END(arm1020e_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm1020e_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm1020e_coherent_user_range
 #endif
 SYM_FUNC_END(arm1020e_coherent_kern_range)

arch/arm/mm/proc-arm1022.S

@@ -199,7 +199,7 @@ SYM_FUNC_END(arm1022_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm1022_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm1022_coherent_user_range
 #endif
 SYM_FUNC_END(arm1022_coherent_kern_range)

arch/arm/mm/proc-arm1026.S

@@ -194,7 +194,7 @@ SYM_FUNC_END(arm1026_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm1026_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm1026_coherent_user_range
 #endif
 SYM_FUNC_END(arm1026_coherent_kern_range)

arch/arm/mm/proc-arm920.S

@@ -180,7 +180,7 @@ SYM_FUNC_END(arm920_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm920_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm920_coherent_user_range
 #endif
 SYM_FUNC_END(arm920_coherent_kern_range)

arch/arm/mm/proc-arm922.S

@@ -182,7 +182,7 @@ SYM_FUNC_END(arm922_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm922_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm922_coherent_user_range
 #endif
 SYM_FUNC_END(arm922_coherent_kern_range)

arch/arm/mm/proc-arm925.S

@@ -229,7 +229,7 @@ SYM_FUNC_END(arm925_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm925_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm925_coherent_user_range
 #endif
 SYM_FUNC_END(arm925_coherent_kern_range)

arch/arm/mm/proc-arm926.S

@@ -192,7 +192,7 @@ SYM_FUNC_END(arm926_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm926_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm926_coherent_user_range
 #endif
 SYM_FUNC_END(arm926_coherent_kern_range)

arch/arm/mm/proc-arm940.S

@@ -153,7 +153,7 @@ SYM_FUNC_END(arm940_coherent_kern_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm940_coherent_user_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm940_flush_kern_dcache_area
 #endif
 SYM_FUNC_END(arm940_coherent_user_range)

arch/arm/mm/proc-arm946.S

@@ -173,7 +173,7 @@ SYM_FUNC_END(arm946_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(arm946_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	arm946_coherent_user_range
 #endif
 SYM_FUNC_END(arm946_coherent_kern_range)

arch/arm/mm/proc-feroceon.S

@@ -208,7 +208,7 @@ SYM_FUNC_END(feroceon_flush_user_cache_range)
  */
 	.align	5
 SYM_TYPED_FUNC_START(feroceon_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	feroceon_coherent_user_range
 #endif
 SYM_FUNC_END(feroceon_coherent_kern_range)

arch/arm/mm/proc-mohawk.S

@@ -163,7 +163,7 @@ SYM_FUNC_END(mohawk_flush_user_cache_range)
  *	- end	- virtual end address
  */
 SYM_TYPED_FUNC_START(mohawk_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	mohawk_coherent_user_range
 #endif
 SYM_FUNC_END(mohawk_coherent_kern_range)

arch/arm/mm/proc-xsc3.S

@@ -223,7 +223,7 @@ SYM_FUNC_END(xsc3_flush_user_cache_range)
  *	it also trashes the mini I-cache used by JTAG debuggers.
  */
 SYM_TYPED_FUNC_START(xsc3_coherent_kern_range)
-#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
+#ifdef CONFIG_CFI /* Fallthrough if !CFI */
 	b	xsc3_coherent_user_range
 #endif
 SYM_FUNC_END(xsc3_coherent_kern_range)

arch/arm/mm/tlb-v4.S

@@ -52,7 +52,7 @@ SYM_FUNC_END(v4_flush_user_tlb_range)
  *	- start - virtual address (may not be aligned)
  *	- end   - virtual address (may not be aligned)
  */
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 SYM_TYPED_FUNC_START(v4_flush_kern_tlb_range)
 	b	.v4_flush_kern_tlb_range
 SYM_FUNC_END(v4_flush_kern_tlb_range)

arch/arm64/Kconfig

@@ -100,7 +100,7 @@ config ARM64
 	select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
 	select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
 	select ARCH_SUPPORTS_LTO_CLANG_THIN
-	select ARCH_SUPPORTS_CFI_CLANG
+	select ARCH_SUPPORTS_CFI
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
 	select ARCH_SUPPORTS_NUMA_BALANCING
@@ -212,7 +212,7 @@ config ARM64
 	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \
 		if DYNAMIC_FTRACE_WITH_ARGS && DYNAMIC_FTRACE_WITH_CALL_OPS
 	select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \
-		if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG && \
+		if (DYNAMIC_FTRACE_WITH_ARGS && !CFI && \
 		    (CC_IS_CLANG || !CC_OPTIMIZE_FOR_SIZE))
 	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
 		if DYNAMIC_FTRACE_WITH_ARGS

arch/arm64/kernel/debug-monitors.c

@@ -212,7 +212,7 @@ static int call_el1_break_hook(struct pt_regs *regs, unsigned long esr)
 	if (esr_brk_comment(esr) == BUG_BRK_IMM)
 		return bug_brk_handler(regs, esr);
 
-	if (IS_ENABLED(CONFIG_CFI_CLANG) && esr_is_cfi_brk(esr))
+	if (IS_ENABLED(CONFIG_CFI) && esr_is_cfi_brk(esr))
 		return cfi_brk_handler(regs, esr);
 
 	if (esr_brk_comment(esr) == FAULT_BRK_IMM)

arch/arm64/kernel/traps.c

@@ -1015,7 +1015,7 @@ int bug_brk_handler(struct pt_regs *regs, unsigned long esr)
 	return DBG_HOOK_HANDLED;
 }
 
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 int cfi_brk_handler(struct pt_regs *regs, unsigned long esr)
 {
 	unsigned long target;
@@ -1039,7 +1039,7 @@ int cfi_brk_handler(struct pt_regs *regs, unsigned long esr)
 	arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
 	return DBG_HOOK_HANDLED;
 }
-#endif /* CONFIG_CFI_CLANG */
+#endif /* CONFIG_CFI */
 
 int reserved_fault_brk_handler(struct pt_regs *regs, unsigned long esr)
 {

arch/arm64/kvm/handle_exit.c

@@ -545,7 +545,7 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
 			kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line);
 		else
 			print_nvhe_hyp_panic("BUG", panic_addr);
-	} else if (IS_ENABLED(CONFIG_CFI_CLANG) && esr_is_cfi_brk(esr)) {
+	} else if (IS_ENABLED(CONFIG_CFI) && esr_is_cfi_brk(esr)) {
 		kvm_nvhe_report_cfi_failure(panic_addr);
 	} else if (IS_ENABLED(CONFIG_UBSAN_KVM_EL2) &&
 		   ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 &&

arch/arm64/net/bpf_jit_comp.c

@@ -185,7 +185,7 @@ static inline void emit_bti(u32 insn, struct jit_ctx *ctx)
 
 static inline void emit_kcfi(u32 hash, struct jit_ctx *ctx)
 {
-	if (IS_ENABLED(CONFIG_CFI_CLANG))
+	if (IS_ENABLED(CONFIG_CFI))
 		emit_u32_data(hash, ctx);
 }
 

arch/riscv/Kconfig

@@ -61,7 +61,7 @@ config RISCV
 	select ARCH_STACKWALK
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	# clang >= 17: https://github.com/llvm/llvm-project/commit/62fa708ceb027713b386c7e0efda994f8bdc27e2
-	select ARCH_SUPPORTS_CFI_CLANG if CLANG_VERSION >= 170000
+	select ARCH_SUPPORTS_CFI if (!CC_IS_CLANG || CLANG_VERSION >= 170000)
 	select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
 	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
 	select ARCH_SUPPORTS_HUGETLBFS if MMU
@@ -77,7 +77,7 @@ config RISCV
 	select ARCH_USE_MEMTEST
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_SYM_ANNOTATIONS
-	select ARCH_USES_CFI_TRAPS if CFI_CLANG
+	select ARCH_USES_CFI_TRAPS if CFI
 	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if MMU
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
 	select ARCH_WANT_FRAME_POINTERS
@@ -155,7 +155,7 @@ config RISCV
 	select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
 	select FUNCTION_ALIGNMENT_4B if HAVE_DYNAMIC_FTRACE && RISCV_ISA_C
 	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS if HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
-	select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG)
+	select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS if (DYNAMIC_FTRACE_WITH_ARGS && !CFI)
 	select HAVE_DYNAMIC_FTRACE_WITH_ARGS if HAVE_DYNAMIC_FTRACE
 	select HAVE_FTRACE_GRAPH_FUNC
 	select HAVE_FUNCTION_GRAPH_TRACER if HAVE_DYNAMIC_FTRACE_WITH_ARGS

arch/riscv/include/asm/cfi.h

@@ -11,7 +11,7 @@
 
 struct pt_regs;
 
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 enum bug_trap_type handle_cfi_failure(struct pt_regs *regs);
 #define __bpfcall
 #else
@@ -19,6 +19,6 @@ static inline enum bug_trap_type handle_cfi_failure(struct pt_regs *regs)
 {
 	return BUG_TRAP_TYPE_NONE;
 }
-#endif /* CONFIG_CFI_CLANG */
+#endif /* CONFIG_CFI */
 
 #endif /* _ASM_RISCV_CFI_H */

arch/riscv/kernel/Makefile

@@ -113,7 +113,7 @@ obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o
 
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 
-obj-$(CONFIG_CFI_CLANG)		+= cfi.o
+obj-$(CONFIG_CFI)		+= cfi.o
 
 obj-$(CONFIG_EFI)		+= efi.o
 obj-$(CONFIG_COMPAT)		+= compat_syscall_table.o

arch/riscv/net/bpf_jit_comp64.c

@@ -18,7 +18,7 @@
 #define RV_MAX_REG_ARGS 8
 #define RV_FENTRY_NINSNS 2
 #define RV_FENTRY_NBYTES (RV_FENTRY_NINSNS * 4)
-#define RV_KCFI_NINSNS (IS_ENABLED(CONFIG_CFI_CLANG) ? 1 : 0)
+#define RV_KCFI_NINSNS (IS_ENABLED(CONFIG_CFI) ? 1 : 0)
 /* imm that allows emit_imm to emit max count insns */
 #define RV_MAX_COUNT_IMM 0x7FFF7FF7FF7FF7FF
 
@@ -469,7 +469,7 @@ static int emit_call(u64 addr, bool fixed_addr, struct rv_jit_context *ctx)
 
 static inline void emit_kcfi(u32 hash, struct rv_jit_context *ctx)
 {
-	if (IS_ENABLED(CONFIG_CFI_CLANG))
+	if (IS_ENABLED(CONFIG_CFI))
 		emit(hash, ctx);
 }
 

arch/riscv/purgatory/Makefile

@@ -71,7 +71,7 @@ ifdef CONFIG_STACKPROTECTOR_STRONG
 PURGATORY_CFLAGS_REMOVE		+= -fstack-protector-strong
 endif
 
-ifdef CONFIG_CFI_CLANG
+ifdef CONFIG_CFI
 PURGATORY_CFLAGS_REMOVE		+= $(CC_FLAGS_CFI)
 endif
 

arch/x86/Kconfig

@@ -127,8 +127,8 @@ config X86
 	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
 	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
 	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
-	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
+	select ARCH_SUPPORTS_CFI		if X86_64
-	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
+	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI
 	select ARCH_SUPPORTS_LTO_CLANG
 	select ARCH_SUPPORTS_LTO_CLANG_THIN
 	select ARCH_SUPPORTS_RT
@@ -2396,11 +2396,11 @@ config FUNCTION_PADDING_CFI
 	default  3 if FUNCTION_ALIGNMENT_8B
 	default  0
 
-# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
+# Basically: FUNCTION_ALIGNMENT - 5*CFI
 # except Kconfig can't do arithmetic :/
 config FUNCTION_PADDING_BYTES
 	int
-	default FUNCTION_PADDING_CFI if CFI_CLANG
+	default FUNCTION_PADDING_CFI if CFI
 	default FUNCTION_ALIGNMENT
 
 config CALL_PADDING
@@ -2410,7 +2410,7 @@ config CALL_PADDING
 
 config FINEIBT
 	def_bool y
-	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
+	depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE
 	select CALL_PADDING
 
 config FINEIBT_BHI
@@ -2427,7 +2427,7 @@ config CALL_THUNKS
 
 config PREFIX_SYMBOLS
 	def_bool y
-	depends on CALL_PADDING && !CFI_CLANG
+	depends on CALL_PADDING && !CFI
 
 menuconfig CPU_MITIGATIONS
 	bool "Mitigations for CPU vulnerabilities"

arch/x86/include/asm/cfi.h

@@ -113,7 +113,7 @@ extern bhi_thunk __bhi_args_end[];
 
 struct pt_regs;
 
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 enum bug_trap_type handle_cfi_failure(struct pt_regs *regs);
 #define __bpfcall
 
@@ -157,7 +157,7 @@ static inline int cfi_get_func_arity(void *func)
 {
 	return 0;
 }
-#endif /* CONFIG_CFI_CLANG */
+#endif /* CONFIG_CFI */
 
 #if HAS_KERNEL_IBT == 1
 #define CFI_NOSEAL(x)	asm(IBT_NOSEAL(__stringify(x)))

arch/x86/kernel/Makefile

@@ -148,7 +148,7 @@ obj-$(CONFIG_UNWINDER_ORC)		+= unwind_orc.o
 obj-$(CONFIG_UNWINDER_FRAME_POINTER)	+= unwind_frame.o
 obj-$(CONFIG_UNWINDER_GUESS)		+= unwind_guess.o
 
-obj-$(CONFIG_CFI_CLANG)			+= cfi.o
+obj-$(CONFIG_CFI)			+= cfi.o
 
 obj-$(CONFIG_CALL_THUNKS)		+= callthunks.o
 

arch/x86/kernel/alternative.c

@@ -1170,7 +1170,7 @@ void __init_or_module apply_seal_endbr(s32 *start, s32 *end) { }
 
 #ifdef CONFIG_CFI_AUTO_DEFAULT
 # define __CFI_DEFAULT CFI_AUTO
-#elif defined(CONFIG_CFI_CLANG)
+#elif defined(CONFIG_CFI)
 # define __CFI_DEFAULT CFI_KCFI
 #else
 # define __CFI_DEFAULT CFI_OFF
@@ -1182,7 +1182,7 @@ enum cfi_mode cfi_mode __ro_after_init = __CFI_DEFAULT;
 bool cfi_bhi __ro_after_init = false;
 #endif
 
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 u32 cfi_get_func_hash(void *func)
 {
 	u32 hash;

arch/x86/kernel/kprobes/core.c

@@ -339,7 +339,7 @@ static bool can_probe(unsigned long paddr)
 	if (is_exception_insn(&insn))
 		return false;
 
-	if (IS_ENABLED(CONFIG_CFI_CLANG)) {
+	if (IS_ENABLED(CONFIG_CFI)) {
 		/*
 		 * The compiler generates the following instruction sequence
 		 * for indirect call checks and cfi.c decodes this;

arch/x86/purgatory/Makefile

@@ -57,7 +57,7 @@ ifdef CONFIG_MITIGATION_RETPOLINE
 PURGATORY_CFLAGS_REMOVE		+= $(RETPOLINE_CFLAGS)
 endif
 
-ifdef CONFIG_CFI_CLANG
+ifdef CONFIG_CFI
 PURGATORY_CFLAGS_REMOVE		+= $(CC_FLAGS_CFI)
 endif
 

drivers/misc/lkdtm/cfi.c

@@ -43,7 +43,7 @@ static void lkdtm_CFI_FORWARD_PROTO(void)
 	lkdtm_indirect_call((void *)lkdtm_increment_int);
 
 	pr_err("FAIL: survived mismatched prototype function call!\n");
-	pr_expected_config(CONFIG_CFI_CLANG);
+	pr_expected_config(CONFIG_CFI);
 }
 
 /*

drivers/misc/lkdtm/fortify.c

@@ -44,6 +44,9 @@ static void lkdtm_FORTIFY_STR_MEMBER(void)
 	char *src;
 
 	src = kmalloc(size, GFP_KERNEL);
+	if (!src)
+		return;
+
 	strscpy(src, "over ten bytes", size);
 	size = strlen(src) + 1;
 
@@ -109,6 +112,9 @@ static void lkdtm_FORTIFY_MEM_MEMBER(void)
 	char *src;
 
 	src = kmalloc(size, GFP_KERNEL);
+	if (!src)
+		return;
+
 	strscpy(src, "over ten bytes", size);
 	size = strlen(src) + 1;
 

include/asm-generic/vmlinux.lds.h

@@ -157,7 +157,7 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG)
 #define PATCHABLE_DISCARDS	*(__patchable_function_entries)
 #endif
 
-#ifndef CONFIG_ARCH_SUPPORTS_CFI_CLANG
+#ifndef CONFIG_ARCH_SUPPORTS_CFI
 /*
  * Simply points to ftrace_stub, but with the proper protocol.
  * Defined by the linker script in linux/vmlinux.lds.h

include/linux/cfi.h

@@ -11,7 +11,7 @@
 #include <linux/module.h>
 #include <asm/cfi.h>
 
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 extern bool cfi_warn;
 
 enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr,
@@ -52,7 +52,7 @@ static inline u32 cfi_get_func_hash(void *func)
 extern u32 cfi_bpf_hash;
 extern u32 cfi_bpf_subprog_hash;
 
-#else /* CONFIG_CFI_CLANG */
+#else /* CONFIG_CFI */
 
 static inline int cfi_get_offset(void) { return 0; }
 static inline u32 cfi_get_func_hash(void *func) { return 0; }
@@ -60,7 +60,7 @@ static inline u32 cfi_get_func_hash(void *func) { return 0; }
 #define cfi_bpf_hash 0U
 #define cfi_bpf_subprog_hash 0U
 
-#endif /* CONFIG_CFI_CLANG */
+#endif /* CONFIG_CFI */
 
 #ifdef CONFIG_ARCH_USES_CFI_TRAPS
 bool is_cfi_trap(unsigned long addr);

include/linux/cfi_types.h

@@ -8,7 +8,7 @@
 #ifdef __ASSEMBLY__
 #include <linux/linkage.h>
 
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 /*
  * Use the __kcfi_typeid_<function> type identifier symbol to
  * annotate indirectly called assembly functions. The compiler emits
@@ -29,12 +29,12 @@
 #define SYM_TYPED_START(name, linkage, align...)	\
 	SYM_TYPED_ENTRY(name, linkage, align)
 
-#else /* CONFIG_CFI_CLANG */
+#else /* CONFIG_CFI */
 
 #define SYM_TYPED_START(name, linkage, align...)	\
 	SYM_START(name, linkage, align)
 
-#endif /* CONFIG_CFI_CLANG */
+#endif /* CONFIG_CFI */
 
 #ifndef SYM_TYPED_FUNC_START
 #define SYM_TYPED_FUNC_START(name) 			\
@@ -43,7 +43,7 @@
 
 #else /* __ASSEMBLY__ */
 
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 #define DEFINE_CFI_TYPE(name, func)						\
 	/*									\
 	 * Force a reference to the function so the compiler generates		\

include/linux/compiler.h

@@ -248,7 +248,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 
 #endif /* __KERNEL__ */
 
-#if defined(CONFIG_CFI_CLANG) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
+#if defined(CONFIG_CFI) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
 /*
  * Force a reference to the external symbol so the compiler generates
  * __kcfi_typid.

include/linux/stddef.h

@@ -93,6 +93,28 @@ enum {
 #define DECLARE_FLEX_ARRAY(TYPE, NAME) \
 	__DECLARE_FLEX_ARRAY(TYPE, NAME)
 
+/**
+ * __TRAILING_OVERLAP() - Overlap a flexible-array member with trailing
+ *			  members.
+ *
+ * Creates a union between a flexible-array member (FAM) in a struct and a set
+ * of additional members that would otherwise follow it.
+ *
+ * @TYPE: Flexible structure type name, including "struct" keyword.
+ * @NAME: Name for a variable to define.
+ * @FAM: The flexible-array member within @TYPE
+ * @ATTRS: Any struct attributes (usually empty)
+ * @MEMBERS: Trailing overlapping members.
+ */
+#define __TRAILING_OVERLAP(TYPE, NAME, FAM, ATTRS, MEMBERS)			\
+	union {									\
+		TYPE NAME;							\
+		struct {							\
+			unsigned char __offset_to_FAM[offsetof(TYPE, FAM)];	\
+			MEMBERS							\
+		} ATTRS;							\
+	}
+
 /**
  * TRAILING_OVERLAP() - Overlap a flexible-array member with trailing members.
  *
@@ -105,12 +127,6 @@ enum {
  * @MEMBERS: Trailing overlapping members.
  */
 #define TRAILING_OVERLAP(TYPE, NAME, FAM, MEMBERS)				\
-	union {									\
+	__TRAILING_OVERLAP(TYPE, NAME, FAM, /* no attrs */, MEMBERS)
-		TYPE NAME;							\
-		struct {							\
-			unsigned char __offset_to_##FAM[offsetof(TYPE, FAM)];	\
-			MEMBERS							\
-		};								\
-	}
 
 #endif

include/linux/string_choices.h

@@ -17,6 +17,12 @@
 
 #include <linux/types.h>
 
+static inline const char *str_assert_deassert(bool v)
+{
+	return v ? "assert" : "deassert";
+}
+#define str_deassert_assert(v)		str_assert_deassert(!(v))
+
 static inline const char *str_enable_disable(bool v)
 {
 	return v ? "enable" : "disable";

init/Kconfig

@@ -2071,8 +2071,8 @@ config RUST
 	depends on !GCC_PLUGIN_RANDSTRUCT
 	depends on !RANDSTRUCT
 	depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO)
-	depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
+	depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
-	select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG
+	select CFI_ICALL_NORMALIZE_INTEGERS if CFI
 	depends on !CALL_PADDING || RUSTC_VERSION >= 108100
 	depends on !KASAN_SW_TAGS
 	depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300

kernel/Makefile

@@ -122,7 +122,7 @@ obj-$(CONFIG_KCSAN) += kcsan/
 obj-$(CONFIG_SHADOW_CALL_STACK) += scs.o
 obj-$(CONFIG_HAVE_STATIC_CALL) += static_call.o
 obj-$(CONFIG_HAVE_STATIC_CALL_INLINE) += static_call_inline.o
-obj-$(CONFIG_CFI_CLANG) += cfi.o
+obj-$(CONFIG_CFI) += cfi.o
 
 obj-$(CONFIG_PERF_EVENTS) += events/
 

kernel/configs/hardening.config

@@ -93,8 +93,8 @@ CONFIG_SECCOMP_FILTER=y
 # Provides some protections against SYN flooding.
 CONFIG_SYN_COOKIES=y
 
-# Enable Kernel Control Flow Integrity (currently Clang only).
+# Enable Kernel Control Flow Integrity.
-CONFIG_CFI_CLANG=y
+CONFIG_CFI=y
 # CONFIG_CFI_PERMISSIVE is not set
 
 # Attack surface reduction: do not autoload TTY line disciplines.

kernel/module/Kconfig

@@ -460,6 +460,6 @@ config UNUSED_KSYMS_WHITELIST
 
 config MODULES_TREE_LOOKUP
 	def_bool y
-	depends on PERF_EVENTS || TRACING || CFI_CLANG
+	depends on PERF_EVENTS || TRACING || CFI
 
 endif # MODULES

kernel/module/tree_lookup.c

@@ -14,7 +14,7 @@
  * Use a latched RB-tree for __module_address(); this allows us to use
  * RCU lookups of the address from any context.
  *
- * This is conditional on PERF_EVENTS || TRACING || CFI_CLANG because those can
+ * This is conditional on PERF_EVENTS || TRACING || CFI because those can
  * really hit __module_address() hard by doing a lot of stack unwinding;
  * potentially from NMI context.
  */

lib/Kconfig.debug

@@ -2908,7 +2908,7 @@ config FORTIFY_KUNIT_TEST
 config LONGEST_SYM_KUNIT_TEST
 	tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
 	depends on KUNIT && KPROBES
-	depends on !PREFIX_SYMBOLS && !CFI_CLANG && !GCOV_KERNEL
+	depends on !PREFIX_SYMBOLS && !CFI && !GCOV_KERNEL
 	default KUNIT_ALL_TESTS
 	help
 	  Tests the longest symbol possible

scripts/gcc-plugins/gcc-common.h

@@ -173,10 +173,17 @@ static inline opt_pass *get_pass_for_id(int id)
 	return g->get_passes()->get_pass_for_id(id);
 }
 
+#if BUILDING_GCC_VERSION < 16000
 #define TODO_verify_ssa TODO_verify_il
 #define TODO_verify_flow TODO_verify_il
 #define TODO_verify_stmts TODO_verify_il
 #define TODO_verify_rtl_sharing TODO_verify_il
+#else
+#define TODO_verify_ssa 0
+#define TODO_verify_flow 0
+#define TODO_verify_stmts 0
+#define TODO_verify_rtl_sharing 0
+#endif
 
 #define INSN_DELETED_P(insn) (insn)->deleted()
 

scripts/kconfig/expr.h

@@ -145,6 +145,7 @@ struct symbol {
 #define SYMBOL_CONST      0x0001  /* symbol is const */
 #define SYMBOL_CHECK      0x0008  /* used during dependency checking */
 #define SYMBOL_VALID      0x0080  /* set when symbol.curr is calculated */
+#define SYMBOL_TRANS      0x0100  /* symbol is transitional only (not visible)*/
 #define SYMBOL_WRITE      0x0200  /* write symbol to file (KCONFIG_CONFIG) */
 #define SYMBOL_WRITTEN    0x0800  /* track info to avoid double-write to .config */
 #define SYMBOL_CHECKED    0x2000  /* used during dependency checking */

scripts/kconfig/lexer.l

@@ -126,6 +126,7 @@ n	[A-Za-z0-9_-]
 "select"		return T_SELECT;
 "source"		return T_SOURCE;
 "string"		return T_STRING;
+"transitional"		return T_TRANSITIONAL;
 "tristate"		return T_TRISTATE;
 "visible"		return T_VISIBLE;
 "||"			return T_OR;

scripts/kconfig/parser.y

@@ -75,6 +75,7 @@ struct menu *current_menu, *current_entry, *current_choice;
 %token T_SELECT
 %token T_SOURCE
 %token T_STRING
+%token T_TRANSITIONAL
 %token T_TRISTATE
 %token T_VISIBLE
 %token T_EOL
@@ -205,6 +206,12 @@ config_option: T_PROMPT T_WORD_QUOTE if_expr T_EOL
 	printd(DEBUG_PARSE, "%s:%d:prompt\n", cur_filename, cur_lineno);
 };
 
+config_option: T_TRANSITIONAL T_EOL
+{
+	current_entry->sym->flags |= SYMBOL_TRANS;
+	printd(DEBUG_PARSE, "%s:%d:transitional\n", cur_filename, cur_lineno);
+};
+
 config_option: default expr if_expr T_EOL
 {
 	menu_add_expr(P_DEFAULT, $2, $3);
@@ -482,6 +489,43 @@ assign_val:
 
 %%
 
+/**
+ * transitional_check_sanity - check transitional symbols have no other
+ *			       properties
+ *
+ * @menu: menu of the potentially transitional symbol
+ *
+ * Return: -1 if an error is found, 0 otherwise.
+ */
+static int transitional_check_sanity(const struct menu *menu)
+{
+	struct property *prop;
+
+	if (!menu->sym || !(menu->sym->flags & SYMBOL_TRANS))
+		return 0;
+
+	/* Check for depends and visible conditions. */
+	if ((menu->dep && !expr_is_yes(menu->dep)) ||
+	    (menu->visibility && !expr_is_yes(menu->visibility))) {
+		fprintf(stderr, "%s:%d: error: %s",
+			menu->filename, menu->lineno,
+			"transitional symbols can only have help sections\n");
+		return -1;
+	}
+
+	/* Check for any property other than "help". */
+	for (prop = menu->sym->prop; prop; prop = prop->next) {
+		if (prop->type != P_COMMENT) {
+			fprintf(stderr, "%s:%d: error: %s",
+				prop->filename, prop->lineno,
+				"transitional symbols can only have help sections\n");
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
 /**
  * choice_check_sanity - check sanity of a choice member
  *
@@ -558,6 +602,9 @@ void conf_parse(const char *name)
 		if (menu->sym && sym_check_deps(menu->sym))
 			yynerrs++;
 
+		if (transitional_check_sanity(menu))
+			yynerrs++;
+
 		if (menu->sym && sym_is_choice(menu->sym)) {
 			menu_for_each_sub_entry(child, menu)
 				if (child->sym && choice_check_sanity(child))

scripts/kconfig/symbol.c

@@ -214,6 +214,11 @@ static void sym_calc_visibility(struct symbol *sym)
 	struct property *prop;
 	tristate tri;
 
+	if (sym->flags & SYMBOL_TRANS) {
+		sym->visible = yes;
+		return;
+	}
+
 	/* any prompt visible? */
 	tri = no;
 	for_all_prompts(sym, prop) {
@@ -526,7 +531,7 @@ void sym_calc_value(struct symbol *sym)
 		}
 	}
 
-	if (sym_is_choice(sym))
+	if (sym_is_choice(sym) || sym->flags & SYMBOL_TRANS)
 		sym->flags &= ~SYMBOL_WRITE;
 }
 

scripts/kconfig/tests/conftest.py

@@ -81,7 +81,22 @@ class Conf:
                 # For interactive modes such as oldaskconfig, oldconfig,
                 # send 'Enter' key until the program finishes.
                 if interactive:
-                    ps.stdin.write(b'\n')
+                    try:
+                        ps.stdin.write(b'\n')
+                        ps.stdin.flush()
+                    except (BrokenPipeError, OSError):
+                        # Process has exited, stop sending input
+                        break
+
+            # Close stdin gracefully
+            try:
+                ps.stdin.close()
+            except (BrokenPipeError, OSError):
+                # Ignore broken pipe on close
+                pass
+
+            # Wait for process to complete
+            ps.wait()
 
             self.retcode = ps.returncode
             self.stdout = ps.stdout.read().decode()

scripts/kconfig/tests/err_transitional/Kconfig

@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: GPL-2.0
+# Test that transitional symbols cannot have properties other than help
+
+config BAD_DEFAULT
+	bool
+	transitional
+	default y
+	help
+	  This transitional symbol illegally has a default property.
+
+config BAD_PROMPT
+	bool
+	transitional
+	prompt "Bad prompt"
+	help
+	  This transitional symbol illegally has a prompt.
+
+config BAD_SELECT
+	bool
+	transitional
+	select OTHER_SYMBOL
+	help
+	  This transitional symbol illegally has a select.
+
+config BAD_IMPLY
+	bool
+	transitional
+	imply OTHER_SYMBOL
+	help
+	  This transitional symbol illegally has an imply.
+
+config BAD_DEPENDS
+	bool
+	transitional
+	depends on OTHER_SYMBOL
+	help
+	  This transitional symbol illegally has a depends.
+
+config BAD_RANGE
+	int
+	transitional
+	range 1 10
+	help
+	  This transitional symbol illegally has a range.
+
+config BAD_NO_TYPE
+	transitional
+	help
+	  This transitional symbol illegally has no type specified.
+
+config OTHER_SYMBOL
+	bool

scripts/kconfig/tests/err_transitional/__init__.py

@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0
+"""
+Test that transitional symbols with invalid properties are rejected.
+
+Transitional symbols can only have help sections. Any other properties
+(default, select, depends, etc.) should cause a parser error.
+"""
+
+def test(conf):
+    # This should fail with exit code 1 due to invalid transitional symbol
+    assert conf.olddefconfig() == 1
+
+    # Check that the error message is about transitional symbols
+    assert conf.stderr_contains('expected_stderr')

scripts/kconfig/tests/err_transitional/expected_stderr

@@ -0,0 +1,7 @@
+Kconfig:46:warning: config symbol defined without type
+Kconfig:7: error: transitional symbols can only have help sections
+Kconfig:14: error: transitional symbols can only have help sections
+Kconfig:21: error: transitional symbols can only have help sections
+Kconfig:28: error: transitional symbols can only have help sections
+Kconfig:32: error: transitional symbols can only have help sections
+Kconfig:42: error: transitional symbols can only have help sections

scripts/kconfig/tests/transitional/Kconfig

@@ -0,0 +1,100 @@
+# SPDX-License-Identifier: GPL-2.0
+# Test transitional symbols for config migration with all Kconfig types
+
+# Enable module support for tristate testing
+config MODULES
+	bool "Enable loadable module support"
+	modules
+	default y
+
+# Basic migration tests for all types
+config NEW_BOOL
+	bool "New bool option"
+	default OLD_BOOL
+
+config OLD_BOOL
+	bool
+	transitional
+
+config NEW_TRISTATE
+	tristate "New tristate option"
+	default OLD_TRISTATE
+
+config OLD_TRISTATE
+	tristate
+	transitional
+
+config NEW_STRING
+	string "New string option"
+	default OLD_STRING
+
+config OLD_STRING
+	string
+	transitional
+
+config NEW_HEX
+	hex "New hex option"
+	default OLD_HEX
+
+config OLD_HEX
+	hex
+	transitional
+
+config NEW_INT
+	int "New int option"
+	default OLD_INT
+
+config OLD_INT
+	int
+	transitional
+
+# Precedence tests for all types
+config NEW_BOOL_PRECEDENCE
+	bool "New bool option with precedence"
+	default OLD_BOOL_PRECEDENCE
+
+config OLD_BOOL_PRECEDENCE
+	bool
+	transitional
+
+config NEW_STRING_PRECEDENCE
+	string "New string option with precedence"
+	default OLD_STRING_PRECEDENCE
+
+config OLD_STRING_PRECEDENCE
+	string
+	transitional
+
+config NEW_TRISTATE_PRECEDENCE
+	tristate "New tristate option with precedence"
+	default OLD_TRISTATE_PRECEDENCE
+
+config OLD_TRISTATE_PRECEDENCE
+	tristate
+	transitional
+
+config NEW_HEX_PRECEDENCE
+	hex "New hex option with precedence"
+	default OLD_HEX_PRECEDENCE
+
+config OLD_HEX_PRECEDENCE
+	hex
+	transitional
+
+config NEW_INT_PRECEDENCE
+	int "New int option with precedence"
+	default OLD_INT_PRECEDENCE
+
+config OLD_INT_PRECEDENCE
+	int
+	transitional
+
+# Test that help sections are allowed for transitional symbols
+config OLD_WITH_HELP
+	bool
+	transitional
+	help
+	  This transitional symbol has a help section to validate that help is allowed.
+
+config REGULAR_OPTION
+	bool "Regular option"

scripts/kconfig/tests/transitional/__init__.py

@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0
+"""
+Test transitional symbol migration functionality for all Kconfig types.
+
+This tests that:
+- OLD_* options in existing .config cause NEW_* options to be set
+- OLD_* options are not written to the new .config file
+- NEW_* options appear in the new .config file with correct values
+- All Kconfig types work correctly: bool, tristate, string, hex, int
+- User-set NEW values take precedence over conflicting OLD transitional values
+"""
+
+def test(conf):
+    # Run olddefconfig to process the migration with the initial config
+    assert conf.olddefconfig(dot_config='initial_config') == 0
+
+    # Check that the configuration matches expected output
+    assert conf.config_contains('expected_config')

scripts/kconfig/tests/transitional/expected_config

@@ -0,0 +1,12 @@
+CONFIG_MODULES=y
+CONFIG_NEW_BOOL=y
+CONFIG_NEW_TRISTATE=m
+CONFIG_NEW_STRING="test string"
+CONFIG_NEW_HEX=0x1234
+CONFIG_NEW_INT=42
+# CONFIG_NEW_BOOL_PRECEDENCE is not set
+CONFIG_NEW_STRING_PRECEDENCE="user value"
+CONFIG_NEW_TRISTATE_PRECEDENCE=y
+CONFIG_NEW_HEX_PRECEDENCE=0xABCD
+CONFIG_NEW_INT_PRECEDENCE=100
+# CONFIG_REGULAR_OPTION is not set

scripts/kconfig/tests/transitional/initial_config

@@ -0,0 +1,16 @@
+CONFIG_MODULES=y
+CONFIG_OLD_BOOL=y
+CONFIG_OLD_TRISTATE=m
+CONFIG_OLD_STRING="test string"
+CONFIG_OLD_HEX=0x1234
+CONFIG_OLD_INT=42
+# CONFIG_NEW_BOOL_PRECEDENCE is not set
+CONFIG_OLD_BOOL_PRECEDENCE=y
+CONFIG_NEW_STRING_PRECEDENCE="user value"
+CONFIG_OLD_STRING_PRECEDENCE="old value"
+CONFIG_NEW_TRISTATE_PRECEDENCE=y
+CONFIG_OLD_TRISTATE_PRECEDENCE=m
+CONFIG_NEW_HEX_PRECEDENCE=0xABCD
+CONFIG_OLD_HEX_PRECEDENCE=0x5678
+CONFIG_NEW_INT_PRECEDENCE=100
+CONFIG_OLD_INT_PRECEDENCE=200

tools/include/linux/cfi_types.h

@@ -8,7 +8,7 @@
 #ifdef __ASSEMBLY__
 #include <linux/linkage.h>
 
-#ifdef CONFIG_CFI_CLANG
+#ifdef CONFIG_CFI
 /*
  * Use the __kcfi_typeid_<function> type identifier symbol to
  * annotate indirectly called assembly functions. The compiler emits
@@ -29,12 +29,12 @@
 #define SYM_TYPED_START(name, linkage, align...)	\
 	SYM_TYPED_ENTRY(name, linkage, align)
 
-#else /* CONFIG_CFI_CLANG */
+#else /* CONFIG_CFI */
 
 #define SYM_TYPED_START(name, linkage, align...)	\
 	SYM_START(name, linkage, align)
 
-#endif /* CONFIG_CFI_CLANG */
+#endif /* CONFIG_CFI */
 
 #ifndef SYM_TYPED_FUNC_START
 #define SYM_TYPED_FUNC_START(name) 			\

tools/perf/util/include/linux/linkage.h

@@ -120,7 +120,7 @@
 #endif
 
 // In the kernel sources (include/linux/cfi_types.h), this has a different
-// definition when CONFIG_CFI_CLANG is used, for tools/ just use the !clang
+// definition when CONFIG_CFI is used, for tools/ just use the !cfi
 // definition:
 #ifndef SYM_TYPED_START
 #define SYM_TYPED_START(name, linkage, align...)        \