Merge tag 'objtool-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

 - Mark arch_cpu_idle_dead() __noreturn, make all architectures &
   drivers that did this inconsistently follow this new, common
   convention, and fix all the fallout that objtool can now detect
   statically

 - Fix/improve the ORC unwinder becoming unreliable due to
   UNWIND_HINT_EMPTY ambiguity, split it into UNWIND_HINT_END_OF_STACK
   and UNWIND_HINT_UNDEFINED to resolve it

 - Fix noinstr violations in the KCSAN code and the lkdtm/stackleak code

 - Generate ORC data for __pfx code

 - Add more __noreturn annotations to various kernel startup/shutdown
   and panic functions

 - Misc improvements & fixes

* tag 'objtool-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  x86/hyperv: Mark hv_ghcb_terminate() as noreturn
  scsi: message: fusion: Mark mpt_halt_firmware() __noreturn
  x86/cpu: Mark {hlt,resume}_play_dead() __noreturn
  btrfs: Mark btrfs_assertfail() __noreturn
  objtool: Include weak functions in global_noreturns check
  cpu: Mark nmi_panic_self_stop() __noreturn
  cpu: Mark panic_smp_self_stop() __noreturn
  arm64/cpu: Mark cpu_park_loop() and friends __noreturn
  x86/head: Mark *_start_kernel() __noreturn
  init: Mark start_kernel() __noreturn
  init: Mark [arch_call_]rest_init() __noreturn
  objtool: Generate ORC data for __pfx code
  x86/linkage: Fix padding for typed functions
  objtool: Separate prefix code from stack validation code
  objtool: Remove superfluous dead_end_function() check
  objtool: Add symbol iteration helpers
  objtool: Add WARN_INSN()
  scripts/objdump-func: Support multiple functions
  context_tracking: Fix KCSAN noinstr violation
  objtool: Add stackleak instrumentation to uaccess safe list
  ...

7 files changed, 92 insertions, 62 deletions

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index 3a7909ed5498..d3cbb6c16bab 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -98,7 +98,7 @@ static inline void exception_exit(enum ctx_state prev_ctx) { }
 static inline int ct_state(void) { return -1; }
 static inline int __ct_state(void) { return -1; }
 static __always_inline bool context_tracking_guest_enter(void) { return false; }
-static inline void context_tracking_guest_exit(void) { }
+static __always_inline void context_tracking_guest_exit(void) { }
 #define CT_WARN_ON(cond) do { } while (0)
 #endif /* !CONFIG_CONTEXT_TRACKING_USER */
 
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index f83e4519c5f0..8582a7142623 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -182,7 +182,7 @@ void arch_cpu_idle(void);
 void arch_cpu_idle_prepare(void);
 void arch_cpu_idle_enter(void);
 void arch_cpu_idle_exit(void);
-void arch_cpu_idle_dead(void);
+void __noreturn arch_cpu_idle_dead(void);
 
 int cpu_report_state(int cpu);
 int cpu_check_up_prepare(int cpu);
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 9ac3df3fccf0..03f82c2c2ebf 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -2,47 +2,7 @@
 #ifndef _LINUX_OBJTOOL_H
 #define _LINUX_OBJTOOL_H
 
-#ifndef __ASSEMBLY__
-
-#include <linux/types.h>
-
-/*
- * This struct is used by asm and inline asm code to manually annotate the
- * location of registers on the stack.
- */
-struct unwind_hint {
-	u32		ip;
-	s16		sp_offset;
-	u8		sp_reg;
-	u8		type;
-	u8		signal;
-	u8		end;
-};
-#endif
-
-/*
- * UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP
- * (the caller's SP right before it made the call).  Used for all callable
- * functions, i.e. all C code and all callable asm functions.
- *
- * UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset
- * points to a fully populated pt_regs from a syscall, interrupt, or exception.
- *
- * UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that
- * sp_reg+sp_offset points to the iret return frame.
- *
- * UNWIND_HINT_FUNC: Generate the unwind metadata of a callable function.
- * Useful for code which doesn't have an ELF function annotation.
- *
- * UNWIND_HINT_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc.
- */
-#define UNWIND_HINT_TYPE_CALL		0
-#define UNWIND_HINT_TYPE_REGS		1
-#define UNWIND_HINT_TYPE_REGS_PARTIAL	2
-#define UNWIND_HINT_TYPE_FUNC		3
-#define UNWIND_HINT_TYPE_ENTRY		4
-#define UNWIND_HINT_TYPE_SAVE		5
-#define UNWIND_HINT_TYPE_RESTORE	6
+#include <linux/objtool_types.h>
 
 #ifdef CONFIG_OBJTOOL
 
@@ -50,7 +10,7 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end)	\
+#define UNWIND_HINT(type, sp_reg, sp_offset, signal)	\
 	"987: \n\t"						\
 	".pushsection .discard.unwind_hints\n\t"		\
 	/* struct unwind_hint */				\
@@ -59,7 +19,6 @@ struct unwind_hint {
 	".byte " __stringify(sp_reg) "\n\t"			\
 	".byte " __stringify(type) "\n\t"			\
 	".byte " __stringify(signal) "\n\t"			\
-	".byte " __stringify(end) "\n\t"			\
 	".balign 4 \n\t"					\
 	".popsection\n\t"
 
@@ -89,7 +48,7 @@ struct unwind_hint {
 #define ANNOTATE_NOENDBR					\
 	"986: \n\t"						\
 	".pushsection .discard.noendbr\n\t"			\
-	_ASM_PTR " 986b\n\t"					\
+	".long 986b - .\n\t"					\
 	".popsection\n\t"
 
 #define ASM_REACHABLE							\
@@ -107,7 +66,7 @@ struct unwind_hint {
 #define ANNOTATE_INTRA_FUNCTION_CALL				\
 	999:							\
 	.pushsection .discard.intra_function_calls;		\
-	.long 999b;						\
+	.long 999b - .;						\
 	.popsection;
 
 /*
@@ -131,23 +90,22 @@ struct unwind_hint {
  * the debuginfo as necessary.  It will also warn if it sees any
  * inconsistencies.
  */
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
-.Lunwind_hint_ip_\@:
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
+.Lhere_\@:
 	.pushsection .discard.unwind_hints
 		/* struct unwind_hint */
-		.long .Lunwind_hint_ip_\@ - .
+		.long .Lhere_\@ - .
 		.short \sp_offset
 		.byte \sp_reg
 		.byte \type
 		.byte \signal
-		.byte \end
 		.balign 4
 	.popsection
 .endm
 
 .macro STACK_FRAME_NON_STANDARD func:req
 	.pushsection .discard.func_stack_frame_non_standard, "aw"
-	_ASM_PTR \func
+	.long \func - .
 	.popsection
 .endm
 
@@ -160,8 +118,24 @@ struct unwind_hint {
 .macro ANNOTATE_NOENDBR
 .Lhere_\@:
 	.pushsection .discard.noendbr
-	.quad	.Lhere_\@
+	.long	.Lhere_\@ - .
+	.popsection
+.endm
+
+/*
+ * Use objtool to validate the entry requirement that all code paths do
+ * VALIDATE_UNRET_END before RET.
+ *
+ * NOTE: The macro must be used at the beginning of a global symbol, otherwise
+ * it will be ignored.
+ */
+.macro VALIDATE_UNRET_BEGIN
+#if defined(CONFIG_NOINSTR_VALIDATION) && defined(CONFIG_CPU_UNRET_ENTRY)
+.Lhere_\@:
+	.pushsection .discard.validate_unret
+	.long	.Lhere_\@ - .
 	.popsection
+#endif
 .endm
 
 .macro REACHABLE
@@ -177,15 +151,14 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
-	"\n\t"
+#define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t"
 #define STACK_FRAME_NON_STANDARD(func)
 #define STACK_FRAME_NON_STANDARD_FP(func)
 #define ANNOTATE_NOENDBR
 #define ASM_REACHABLE
 #else
 #define ANNOTATE_INTRA_FUNCTION_CALL
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
 .endm
 .macro STACK_FRAME_NON_STANDARD func:req
 .endm
diff --git a/include/linux/objtool_types.h b/include/linux/objtool_types.h
new file mode 100644
index 000000000000..453a4f4ef39d
--- /dev/null
+++ b/include/linux/objtool_types.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_OBJTOOL_TYPES_H
+#define _LINUX_OBJTOOL_TYPES_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+
+/*
+ * This struct is used by asm and inline asm code to manually annotate the
+ * location of registers on the stack.
+ */
+struct unwind_hint {
+	u32		ip;
+	s16		sp_offset;
+	u8		sp_reg;
+	u8		type;
+	u8		signal;
+};
+
+#endif /* __ASSEMBLY__ */
+
+/*
+ * UNWIND_HINT_TYPE_UNDEFINED: A blind spot in ORC coverage which can result in
+ * a truncated and unreliable stack unwind.
+ *
+ * UNWIND_HINT_TYPE_END_OF_STACK: The end of the kernel stack unwind before
+ * hitting user entry, boot code, or fork entry (when there are no pt_regs
+ * available).
+ *
+ * UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP
+ * (the caller's SP right before it made the call).  Used for all callable
+ * functions, i.e. all C code and all callable asm functions.
+ *
+ * UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset
+ * points to a fully populated pt_regs from a syscall, interrupt, or exception.
+ *
+ * UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that
+ * sp_reg+sp_offset points to the iret return frame.
+ *
+ * UNWIND_HINT_TYPE_FUNC: Generate the unwind metadata of a callable function.
+ * Useful for code which doesn't have an ELF function annotation.
+ *
+ * UNWIND_HINT_TYPE_{SAVE,RESTORE}: Save the unwind metadata at a certain
+ * location so that it can be restored later.
+ */
+#define UNWIND_HINT_TYPE_UNDEFINED	0
+#define UNWIND_HINT_TYPE_END_OF_STACK	1
+#define UNWIND_HINT_TYPE_CALL		2
+#define UNWIND_HINT_TYPE_REGS		3
+#define UNWIND_HINT_TYPE_REGS_PARTIAL	4
+/* The below hint types don't have corresponding ORC types */
+#define UNWIND_HINT_TYPE_FUNC		5
+#define UNWIND_HINT_TYPE_SAVE		6
+#define UNWIND_HINT_TYPE_RESTORE	7
+
+#endif /* _LINUX_OBJTOOL_TYPES_H */
diff --git a/include/linux/sched/task_stack.h b/include/linux/sched/task_stack.h
index 5e799a47431e..f158b025c175 100644
--- a/include/linux/sched/task_stack.h
+++ b/include/linux/sched/task_stack.h
@@ -23,7 +23,7 @@ static __always_inline void *task_stack_page(const struct task_struct *task)
 
 #define setup_thread_stack(new,old)	do { } while(0)
 
-static inline unsigned long *end_of_stack(const struct task_struct *task)
+static __always_inline unsigned long *end_of_stack(const struct task_struct *task)
 {
 #ifdef CONFIG_STACK_GROWSUP
 	return (unsigned long *)((unsigned long)task->stack + THREAD_SIZE) - 1;
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a80ab58ae3f1..7b93504eed26 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -59,8 +59,8 @@ int smp_call_function_single_async(int cpu, struct __call_single_data *csd);
  * Cpus stopping functions in panic. All have default weak definitions.
  * Architecture-dependent code may override them.
  */
-void panic_smp_self_stop(void);
-void nmi_panic_self_stop(struct pt_regs *regs);
+void __noreturn panic_smp_self_stop(void);
+void __noreturn nmi_panic_self_stop(struct pt_regs *regs);
 void crash_smp_send_stop(void);
 
 /*
diff --git a/include/linux/start_kernel.h b/include/linux/start_kernel.h
index 8b369a41c03c..a9806a44a605 100644
--- a/include/linux/start_kernel.h
+++ b/include/linux/start_kernel.h
@@ -8,8 +8,8 @@
 /* Define the prototype for start_kernel here, rather than cluttering
    up something else. */
 
-extern asmlinkage void __init start_kernel(void);
-extern void __init arch_call_rest_init(void);
-extern void __ref rest_init(void);
+extern asmlinkage void __init __noreturn start_kernel(void);
+extern void __init __noreturn arch_call_rest_init(void);
+extern void __ref __noreturn rest_init(void);
 
 #endif /* _LINUX_START_KERNEL_H */