20 files changed, 116 insertions, 95 deletions

diff --git a/Documentation/livepatch/reliable-stacktrace.rst b/Documentation/livepatch/reliable-stacktrace.rst
index 67459d2ca2af..d56bb706172f 100644
--- a/Documentation/livepatch/reliable-stacktrace.rst
+++ b/Documentation/livepatch/reliable-stacktrace.rst
@@ -183,7 +183,7 @@ trampoline or return trampoline. For example, considering the x86_64
 .. code-block:: none
 
    SYM_CODE_START(return_to_handler)
-           UNWIND_HINT_EMPTY
+           UNWIND_HINT_UNDEFINED
            subq  $24, %rsp
 
            /* Save the return values */
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 5b93eb7db0ab..45e135be2a9f 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -205,7 +205,7 @@ syscall_return_via_sysret:
 	 */
 	movq	%rsp, %rdi
 	movq	PER_CPU_VAR(cpu_tss_rw + TSS_sp0), %rsp
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 
 	pushq	RSP-RDI(%rdi)	/* RSP */
 	pushq	(%rdi)		/* RDI */
@@ -286,7 +286,7 @@ SYM_FUNC_END(__switch_to_asm)
 .pushsection .text, "ax"
 	__FUNC_ALIGN
 SYM_CODE_START_NOALIGN(ret_from_fork)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	ANNOTATE_NOENDBR // copy_thread
 	CALL_DEPTH_ACCOUNT
 	movq	%rax, %rdi
@@ -303,7 +303,7 @@ SYM_CODE_START_NOALIGN(ret_from_fork)
 
 1:
 	/* kernel thread */
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	movq	%r12, %rdi
 	CALL_NOSPEC rbx
 	/*
@@ -643,7 +643,7 @@ SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL)
 	 */
 	movq	%rsp, %rdi
 	movq	PER_CPU_VAR(cpu_tss_rw + TSS_sp0), %rsp
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 
 	/* Copy the IRET frame to the trampoline stack. */
 	pushq	6*8(%rdi)	/* SS */
@@ -869,7 +869,7 @@ SYM_CODE_END(exc_xen_hypervisor_callback)
  */
 	__FUNC_ALIGN
 SYM_CODE_START_NOALIGN(xen_failsafe_callback)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_UNDEFINED
 	ENDBR
 	movl	%ds, %ecx
 	cmpw	%cx, 0x10(%rsp)
@@ -1520,7 +1520,7 @@ SYM_CODE_END(asm_exc_nmi)
  * MSRs to fully disable 32-bit SYSCALL.
  */
 SYM_CODE_START(ignore_sysret)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	ENDBR
 	mov	$-ENOSYS, %eax
 	sysretl
diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h
index b4d4ec78589e..46d7e06763c9 100644
--- a/arch/x86/include/asm/orc_types.h
+++ b/arch/x86/include/asm/orc_types.h
@@ -39,9 +39,11 @@
 #define ORC_REG_SP_INDIRECT		9
 #define ORC_REG_MAX			15
 
-#define ORC_TYPE_CALL			0
-#define ORC_TYPE_REGS			1
-#define ORC_TYPE_REGS_PARTIAL		2
+#define ORC_TYPE_UNDEFINED		0
+#define ORC_TYPE_END_OF_STACK		1
+#define ORC_TYPE_CALL			2
+#define ORC_TYPE_REGS			3
+#define ORC_TYPE_REGS_PARTIAL		4
 
 #ifndef __ASSEMBLY__
 #include <asm/byteorder.h>
@@ -60,16 +62,14 @@ struct orc_entry {
 #if defined(__LITTLE_ENDIAN_BITFIELD)
 	unsigned	sp_reg:4;
 	unsigned	bp_reg:4;
-	unsigned	type:2;
+	unsigned	type:3;
 	unsigned	signal:1;
-	unsigned	end:1;
 #elif defined(__BIG_ENDIAN_BITFIELD)
 	unsigned	bp_reg:4;
 	unsigned	sp_reg:4;
 	unsigned	unused:4;
-	unsigned	end:1;
 	unsigned	signal:1;
-	unsigned	type:2;
+	unsigned	type:3;
 #endif
 } __packed;
 
diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h
index 4c0f28d665eb..01cb9692b160 100644
--- a/arch/x86/include/asm/unwind_hints.h
+++ b/arch/x86/include/asm/unwind_hints.h
@@ -7,13 +7,17 @@
 
 #ifdef __ASSEMBLY__
 
-.macro UNWIND_HINT_EMPTY
-	UNWIND_HINT type=UNWIND_HINT_TYPE_CALL end=1
+.macro UNWIND_HINT_END_OF_STACK
+	UNWIND_HINT type=UNWIND_HINT_TYPE_END_OF_STACK
+.endm
+
+.macro UNWIND_HINT_UNDEFINED
+	UNWIND_HINT type=UNWIND_HINT_TYPE_UNDEFINED
 .endm
 
 .macro UNWIND_HINT_ENTRY
 	VALIDATE_UNRET_BEGIN
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 .endm
 
 .macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0 signal=1
@@ -73,7 +77,7 @@
 #else
 
 #define UNWIND_HINT_FUNC \
-	UNWIND_HINT(UNWIND_HINT_TYPE_FUNC, ORC_REG_SP, 8, 0, 0)
+	UNWIND_HINT(UNWIND_HINT_TYPE_FUNC, ORC_REG_SP, 8, 0)
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
index 1265ad519249..0387732e9c3f 100644
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@ -340,7 +340,7 @@ STACK_FRAME_NON_STANDARD_FP(__fentry__)
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 SYM_CODE_START(return_to_handler)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_UNDEFINED
 	ANNOTATE_NOENDBR
 	subq  $16, %rsp
 
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index ee3ed15ee1f8..8d8d25c64827 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -42,7 +42,7 @@ L3_START_KERNEL = pud_index(__START_KERNEL_map)
 	__HEAD
 	.code64
 SYM_CODE_START_NOALIGN(startup_64)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	/*
 	 * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
 	 * and someone has loaded an identity mapped page table
@@ -105,7 +105,7 @@ SYM_CODE_START_NOALIGN(startup_64)
 	lretq
 
 .Lon_kernel_cs:
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 
 	/* Sanitize CPU configuration */
 	call verify_cpu
@@ -127,7 +127,7 @@ SYM_CODE_START_NOALIGN(startup_64)
 SYM_CODE_END(startup_64)
 
 SYM_CODE_START(secondary_startup_64)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	ANNOTATE_NOENDBR
 	/*
 	 * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
@@ -156,7 +156,7 @@ SYM_CODE_START(secondary_startup_64)
 	 * verify_cpu() above to make sure NX is enabled.
 	 */
 SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	ANNOTATE_NOENDBR
 
 	/*
@@ -238,7 +238,7 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
 	ANNOTATE_RETPOLINE_SAFE
 	jmp	*%rax
 1:
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	ANNOTATE_NOENDBR // above
 
 	/*
@@ -371,7 +371,7 @@ SYM_CODE_END(secondary_startup_64)
  */
 SYM_CODE_START(start_cpu0)
 	ANNOTATE_NOENDBR
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	movq	initial_stack(%rip), %rsp
 	jmp	.Ljump_to_C_code
 SYM_CODE_END(start_cpu0)
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index 4a73351f87f8..56cab1bb25f5 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -43,7 +43,7 @@
 	.code64
 SYM_CODE_START_NOALIGN(relocate_range)
 SYM_CODE_START_NOALIGN(relocate_kernel)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	ANNOTATE_NOENDBR
 	/*
 	 * %rdi indirection_page
@@ -113,7 +113,7 @@ SYM_CODE_START_NOALIGN(relocate_kernel)
 SYM_CODE_END(relocate_kernel)
 
 SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	/* set return address to 0 if not preserving context */
 	pushq	$0
 	/* store the start address on the stack */
@@ -231,7 +231,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
 SYM_CODE_END(identity_mapped)
 
 SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	ANNOTATE_NOENDBR // RET target, above
 	movq	RSP(%r8), %rsp
 	movq	CR4(%r8), %rax
@@ -256,8 +256,8 @@ SYM_CODE_END(virtual_mapped)
 
 	/* Do the copies */
 SYM_CODE_START_LOCAL_NOALIGN(swap_pages)
-	UNWIND_HINT_EMPTY
-	movq	%rdi, %rcx 	/* Put the page_list in %rcx */
+	UNWIND_HINT_END_OF_STACK
+	movq	%rdi, %rcx	/* Put the page_list in %rcx */
 	xorl	%edi, %edi
 	xorl	%esi, %esi
 	jmp	1f
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 8348ac581de3..3ac50b7298d1 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -158,7 +158,6 @@ static struct orc_entry orc_fp_entry = {
 	.sp_offset	= 16,
 	.bp_reg		= ORC_REG_PREV_SP,
 	.bp_offset	= -16,
-	.end		= 0,
 };
 
 static struct orc_entry *orc_find(unsigned long ip)
@@ -250,13 +249,13 @@ static int orc_sort_cmp(const void *_a, const void *_b)
 		return -1;
 
 	/*
-	 * The "weak" section terminator entries need to always be on the left
+	 * The "weak" section terminator entries need to always be first
 	 * to ensure the lookup code skips them in favor of real entries.
 	 * These terminator entries exist to handle any gaps created by
 	 * whitelisted .o files which didn't get objtool generation.
 	 */
 	orc_a = cur_orc_table + (a - cur_orc_ip_table);
-	return orc_a->sp_reg == ORC_REG_UNDEFINED && !orc_a->end ? -1 : 1;
+	return orc_a->type == ORC_TYPE_UNDEFINED ? -1 : 1;
 }
 
 void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
@@ -474,14 +473,12 @@ bool unwind_next_frame(struct unwind_state *state)
 		 */
 		orc = &orc_fp_entry;
 		state->error = true;
-	}
-
-	/* End-of-stack check for kernel threads: */
-	if (orc->sp_reg == ORC_REG_UNDEFINED) {
-		if (!orc->end)
+	} else {
+		if (orc->type == ORC_TYPE_UNDEFINED)
 			goto err;
 
-		goto the_end;
+		if (orc->type == ORC_TYPE_END_OF_STACK)
+			goto the_end;
 	}
 
 	state->signal = orc->signal;
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index 5f61c65322be..27ef53fab6bd 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -33,7 +33,7 @@
 
 	.align RETPOLINE_THUNK_SIZE
 SYM_INNER_LABEL(__x86_indirect_thunk_\reg, SYM_L_GLOBAL)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_UNDEFINED
 	ANNOTATE_NOENDBR
 
 	ALTERNATIVE_2 __stringify(RETPOLINE \reg), \
@@ -75,7 +75,7 @@ SYM_CODE_END(__x86_indirect_thunk_array)
 	.align RETPOLINE_THUNK_SIZE
 
 SYM_INNER_LABEL(__x86_indirect_call_thunk_\reg, SYM_L_GLOBAL)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_UNDEFINED
 	ANNOTATE_NOENDBR
 
 	CALL_DEPTH_ACCOUNT
@@ -103,7 +103,7 @@ SYM_CODE_END(__x86_indirect_call_thunk_array)
 	.align RETPOLINE_THUNK_SIZE
 
 SYM_INNER_LABEL(__x86_indirect_jump_thunk_\reg, SYM_L_GLOBAL)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_UNDEFINED
 	ANNOTATE_NOENDBR
 	POLINE \reg
 	ANNOTATE_UNRET_SAFE
diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S
index 7fe564eaf228..c4365a05ab83 100644
--- a/arch/x86/platform/pvh/head.S
+++ b/arch/x86/platform/pvh/head.S
@@ -50,7 +50,7 @@
 #define PVH_DS_SEL		(PVH_GDT_ENTRY_DS * 8)
 
 SYM_CODE_START_LOCAL(pvh_start_xen)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	cld
 
 	lgdt (_pa(gdt))
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index 4a184f6e4e4d..08f1ceb9eb81 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -165,7 +165,7 @@ xen_pv_trap asm_exc_xen_hypervisor_callback
 SYM_CODE_START(xen_early_idt_handler_array)
 	i = 0
 	.rept NUM_EXCEPTION_VECTORS
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_UNDEFINED
 	ENDBR
 	pop %rcx
 	pop %r11
@@ -193,7 +193,7 @@ hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
  * rsp->rax		}
  */
 SYM_CODE_START(xen_iret)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_UNDEFINED
 	ANNOTATE_NOENDBR
 	pushq $0
 	jmp hypercall_iret
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index e36ea4268bd2..6eafdd17c242 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -45,7 +45,7 @@ SYM_CODE_END(hypercall_page)
 #ifdef CONFIG_XEN_PV
 	__INIT
 SYM_CODE_START(startup_xen)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	ANNOTATE_NOENDBR
 	cld
 
@@ -71,7 +71,7 @@ SYM_CODE_END(startup_xen)
 #ifdef CONFIG_XEN_PV_SMP
 .pushsection .text
 SYM_CODE_START(asm_cpu_bringup_and_idle)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_END_OF_STACK
 	ENDBR
 
 	call cpu_bringup_and_idle
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 5aa475118820..03f82c2c2ebf 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -10,7 +10,7 @@
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(type, sp_reg, sp_offset, signal, end)	\
+#define UNWIND_HINT(type, sp_reg, sp_offset, signal)	\
 	"987: \n\t"						\
 	".pushsection .discard.unwind_hints\n\t"		\
 	/* struct unwind_hint */				\
@@ -19,7 +19,6 @@
 	".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"
 
@@ -91,7 +90,7 @@
  * 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
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
 .Lhere_\@:
 	.pushsection .discard.unwind_hints
 		/* struct unwind_hint */
@@ -100,7 +99,6 @@
 		.byte \sp_reg
 		.byte \type
 		.byte \signal
-		.byte \end
 		.balign 4
 	.popsection
 .endm
@@ -153,14 +151,14 @@
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(type, sp_reg, sp_offset, 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
index 9787ad0f2ef4..453a4f4ef39d 100644
--- a/include/linux/objtool_types.h
+++ b/include/linux/objtool_types.h
@@ -16,12 +16,18 @@ struct unwind_hint {
 	u8		sp_reg;
 	u8		type;
 	u8		signal;
-	u8		end;
 };
 
 #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.
@@ -32,17 +38,20 @@ struct unwind_hint {
  * 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.
+ * 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_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc.
+ * UNWIND_HINT_TYPE_{SAVE,RESTORE}: Save the unwind metadata at a certain
+ * location so that it can be restored later.
  */
-#define UNWIND_HINT_TYPE_CALL		0
-#define UNWIND_HINT_TYPE_REGS		1
-#define UNWIND_HINT_TYPE_REGS_PARTIAL	2
+#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		3
-#define UNWIND_HINT_TYPE_SAVE		4
-#define UNWIND_HINT_TYPE_RESTORE	5
+#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/scripts/sorttable.h b/scripts/sorttable.h
index deb7c1d3e979..7bd0184380d3 100644
--- a/scripts/sorttable.h
+++ b/scripts/sorttable.h
@@ -128,7 +128,7 @@ static int orc_sort_cmp(const void *_a, const void *_b)
 	 * whitelisted .o files which didn't get objtool generation.
 	 */
 	orc_a = g_orc_table + (a - g_orc_ip_table);
-	return orc_a->sp_reg == ORC_REG_UNDEFINED && !orc_a->end ? -1 : 1;
+	return orc_a->type == ORC_TYPE_UNDEFINED ? -1 : 1;
 }
 
 static void *sort_orctable(void *arg)
diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h
index b4d4ec78589e..46d7e06763c9 100644
--- a/tools/arch/x86/include/asm/orc_types.h
+++ b/tools/arch/x86/include/asm/orc_types.h
@@ -39,9 +39,11 @@
 #define ORC_REG_SP_INDIRECT		9
 #define ORC_REG_MAX			15
 
-#define ORC_TYPE_CALL			0
-#define ORC_TYPE_REGS			1
-#define ORC_TYPE_REGS_PARTIAL		2
+#define ORC_TYPE_UNDEFINED		0
+#define ORC_TYPE_END_OF_STACK		1
+#define ORC_TYPE_CALL			2
+#define ORC_TYPE_REGS			3
+#define ORC_TYPE_REGS_PARTIAL		4
 
 #ifndef __ASSEMBLY__
 #include <asm/byteorder.h>
@@ -60,16 +62,14 @@ struct orc_entry {
 #if defined(__LITTLE_ENDIAN_BITFIELD)
 	unsigned	sp_reg:4;
 	unsigned	bp_reg:4;
-	unsigned	type:2;
+	unsigned	type:3;
 	unsigned	signal:1;
-	unsigned	end:1;
 #elif defined(__BIG_ENDIAN_BITFIELD)
 	unsigned	bp_reg:4;
 	unsigned	sp_reg:4;
 	unsigned	unused:4;
-	unsigned	end:1;
 	unsigned	signal:1;
-	unsigned	type:2;
+	unsigned	type:3;
 #endif
 } __packed;
 
diff --git a/tools/include/linux/objtool_types.h b/tools/include/linux/objtool_types.h
index 9787ad0f2ef4..453a4f4ef39d 100644
--- a/tools/include/linux/objtool_types.h
+++ b/tools/include/linux/objtool_types.h
@@ -16,12 +16,18 @@ struct unwind_hint {
 	u8		sp_reg;
 	u8		type;
 	u8		signal;
-	u8		end;
 };
 
 #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.
@@ -32,17 +38,20 @@ struct unwind_hint {
  * 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.
+ * 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_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc.
+ * UNWIND_HINT_TYPE_{SAVE,RESTORE}: Save the unwind metadata at a certain
+ * location so that it can be restored later.
  */
-#define UNWIND_HINT_TYPE_CALL		0
-#define UNWIND_HINT_TYPE_REGS		1
-#define UNWIND_HINT_TYPE_REGS_PARTIAL	2
+#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		3
-#define UNWIND_HINT_TYPE_SAVE		4
-#define UNWIND_HINT_TYPE_RESTORE	5
+#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/tools/objtool/check.c b/tools/objtool/check.c
index 10be80b3fe67..cae6ac6ff246 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2243,6 +2243,7 @@ static void set_func_state(struct cfi_state *state)
 	memcpy(&state->regs, &initial_func_cfi.regs,
 	       CFI_NUM_REGS * sizeof(struct cfi_reg));
 	state->stack_size = initial_func_cfi.cfa.offset;
+	state->type = UNWIND_HINT_TYPE_CALL;
 }
 
 static int read_unwind_hints(struct objtool_file *file)
@@ -2327,7 +2328,6 @@ static int read_unwind_hints(struct objtool_file *file)
 		cfi.cfa.offset = bswap_if_needed(file->elf, hint->sp_offset);
 		cfi.type = hint->type;
 		cfi.signal = hint->signal;
-		cfi.end = hint->end;
 
 		insn->cfi = cfi_hash_find_or_add(&cfi);
 	}
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index 97ecbb8b9034..0e183bb1c720 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -38,6 +38,10 @@ static const char *reg_name(unsigned int reg)
 static const char *orc_type_name(unsigned int type)
 {
 	switch (type) {
+	case ORC_TYPE_UNDEFINED:
+		return "(und)";
+	case ORC_TYPE_END_OF_STACK:
+		return "end";
 	case ORC_TYPE_CALL:
 		return "call";
 	case ORC_TYPE_REGS:
@@ -201,6 +205,7 @@ int orc_dump(const char *_objname)
 			printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
 		}
 
+		printf("type:%s", orc_type_name(orc[i].type));
 
 		printf(" sp:");
 
@@ -210,8 +215,7 @@ int orc_dump(const char *_objname)
 
 		print_reg(orc[i].bp_reg, bswap_if_needed(&dummy_elf, orc[i].bp_offset));
 
-		printf(" type:%s signal:%d end:%d\n",
-		       orc_type_name(orc[i].type), orc[i].signal, orc[i].end);
+		printf(" signal:%d\n", orc[i].signal);
 	}
 
 	elf_end(elf);
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index e85bbb996f6c..b327f9ccfe73 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -21,12 +21,22 @@ static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
 	memset(orc, 0, sizeof(*orc));
 
 	if (!cfi) {
-		orc->end = 0;
-		orc->sp_reg = ORC_REG_UNDEFINED;
+		/*
+		 * This is usually either unreachable nops/traps (which don't
+		 * trigger unreachable instruction warnings), or
+		 * STACK_FRAME_NON_STANDARD functions.
+		 */
+		orc->type = ORC_TYPE_UNDEFINED;
 		return 0;
 	}
 
 	switch (cfi->type) {
+	case UNWIND_HINT_TYPE_UNDEFINED:
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	case UNWIND_HINT_TYPE_END_OF_STACK:
+		orc->type = ORC_TYPE_END_OF_STACK;
+		return 0;
 	case UNWIND_HINT_TYPE_CALL:
 		orc->type = ORC_TYPE_CALL;
 		break;
@@ -42,14 +52,8 @@ static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
 		return -1;
 	}
 
-	orc->end = cfi->end;
 	orc->signal = cfi->signal;
 
-	if (cfi->cfa.base == CFI_UNDEFINED) {
-		orc->sp_reg = ORC_REG_UNDEFINED;
-		return 0;
-	}
-
 	switch (cfi->cfa.base) {
 	case CFI_SP:
 		orc->sp_reg = ORC_REG_SP;
@@ -163,11 +167,7 @@ int orc_create(struct objtool_file *file)
 	struct orc_list_entry *entry;
 	struct list_head orc_list;
 
-	struct orc_entry null = {
-		.sp_reg  = ORC_REG_UNDEFINED,
-		.bp_reg  = ORC_REG_UNDEFINED,
-		.type    = ORC_TYPE_CALL,
-	};
+	struct orc_entry null = { .type = ORC_TYPE_UNDEFINED };
 
 	/* Build a deduplicated list of ORC entries: */
 	INIT_LIST_HEAD(&orc_list);