17 files changed, 509 insertions, 251 deletions
diff --git a/tools/objtool/Documentation/objtool.txt b/tools/objtool/Documentation/objtool.txt
index 7c3ee959b63c..28ac57b9e102 100644
--- a/tools/objtool/Documentation/objtool.txt
+++ b/tools/objtool/Documentation/objtool.txt
@@ -28,6 +28,15 @@ Objtool has the following features:
   sites, enabling the kernel to patch them inline, to prevent "thunk
   funneling" for both security and performance reasons
 
+- Return thunk validation -- validates return thunks are used for
+  certain CPU mitigations including Retbleed and SRSO
+
+- Return thunk annotation -- annotates all return thunk sites so kernel
+  can patch them inline, depending on enabled mitigations
+
+- Return thunk training valiation -- validate that all entry paths
+  untrain a "safe return" before the first return (or call)
+
 - Non-instrumentation validation -- validates non-instrumentable
   ("noinstr") code rules, preventing instrumentation in low-level C
   entry code
@@ -53,6 +62,9 @@ Objtool has the following features:
 - Function entry annotation -- annotates function entries, enabling
   kernel function tracing
 
+- Function preamble (prefix) annotation and/or symbol generation -- used
+  for FineIBT and call depth tracking
+
 - Other toolchain hacks which will go unmentioned at this time...
 
 Each feature can be enabled individually or in combination using the
@@ -197,19 +209,17 @@ To achieve the validation, objtool enforces the following rules:
 
 1. Each callable function must be annotated as such with the ELF
    function type.  In asm code, this is typically done using the
-   ENTRY/ENDPROC macros.  If objtool finds a return instruction
+   SYM_FUNC_{START,END} macros.  If objtool finds a return instruction
    outside of a function, it flags an error since that usually indicates
    callable code which should be annotated accordingly.
 
    This rule is needed so that objtool can properly identify each
    callable function in order to analyze its stack metadata.
 
-2. Conversely, each section of code which is *not* callable should *not*
-   be annotated as an ELF function.  The ENDPROC macro shouldn't be used
-   in this case.
-
-   This rule is needed so that objtool can ignore non-callable code.
-   Such code doesn't have to follow any of the other rules.
+2. Conversely, each section of code which is *not* callable, or is
+   otherwise doing funny things with the stack or registers, should
+   *not* be annotated as an ELF function.  Rather, SYM_CODE_{START,END}
+   should be used along with unwind hints.
 
 3. Each callable function which calls another function must have the
    correct frame pointer logic, if required by CONFIG_FRAME_POINTER or
@@ -221,7 +231,7 @@ To achieve the validation, objtool enforces the following rules:
    function B, the _caller_ of function A will be skipped on the stack
    trace.
 
-4. Dynamic jumps and jumps to undefined symbols are only allowed if:
+4. Indirect jumps and jumps to undefined symbols are only allowed if:
 
    a) the jump is part of a switch statement; or
 
@@ -304,29 +314,29 @@ the objtool maintainers.
    001e    2823e:  80 ce 02                or     $0x2,%dh
    ...
 
+
 2. file.o: warning: objtool: .text+0x53: unreachable instruction
 
    Objtool couldn't find a code path to reach the instruction.
 
    If the error is for an asm file, and the instruction is inside (or
    reachable from) a callable function, the function should be annotated
-   with the ENTRY/ENDPROC macros (ENDPROC is the important one).
-   Otherwise, the code should probably be annotated with the unwind hint
-   macros in asm/unwind_hints.h so objtool and the unwinder can know the
-   stack state associated with the code.
+   with the SYM_FUNC_START and SYM_FUNC_END macros.
 
-   If you're 100% sure the code won't affect stack traces, or if you're
-   a just a bad person, you can tell objtool to ignore it.  See the
-   "Adding exceptions" section below.
+   Otherwise, SYM_CODE_START can be used.  In that case the code needs
+   to be annotated with unwind hint macros.
 
-   If it's not actually in a callable function (e.g. kernel entry code),
-   change ENDPROC to END.
+   If you're sure the code won't affect the reliability of runtime stack
+   traces and want objtool to ignore it, see "Adding exceptions" below.
 
-3. file.o: warning: objtool: foo+0x48c: bar() is missing a __noreturn annotation
 
-   The call from foo() to bar() doesn't return, but bar() is missing the
-   __noreturn annotation.  NOTE: In addition to annotating the function
-   with __noreturn, please also add it to tools/objtool/noreturns.h.
+3. file.o: warning: objtool: foo+0x48c: bar() missing __noreturn in .c/.h or NORETURN() in noreturns.h
+
+   The call from foo() to bar() doesn't return, but bar() is incorrectly
+   annotated.  A noreturn function must be marked __noreturn in both its
+   declaration and its definition, and must have a NORETURN() annotation
+   in tools/objtool/noreturns.h.
+
 
 4. file.o: warning: objtool: func(): can't find starting instruction
    or
@@ -341,23 +351,21 @@ the objtool maintainers.
 
    This is a kernel entry/exit instruction like sysenter or iret.  Such
    instructions aren't allowed in a callable function, and are most
-   likely part of the kernel entry code.  They should usually not have
-   the callable function annotation (ENDPROC) and should always be
-   annotated with the unwind hint macros in asm/unwind_hints.h.
+   likely part of the kernel entry code.  Such code should probably be
+   placed in a SYM_FUNC_CODE block with unwind hints.
 
 
 6. file.o: warning: objtool: func()+0x26: sibling call from callable instruction with modified stack frame
 
-   This is a dynamic jump or a jump to an undefined symbol.  Objtool
-   assumed it's a sibling call and detected that the frame pointer
-   wasn't first restored to its original state.
+   This is a branch to an UNDEF symbol.  Objtool assumed it's a
+   sibling call and detected that the stack wasn't first restored to its
+   original state.
 
-   If it's not really a sibling call, you may need to move the
-   destination code to the local file.
+   If it's not really a sibling call, you may need to use unwind hints
+   and/or move the destination code to the local file.
 
    If the instruction is not actually in a callable function (e.g.
-   kernel entry code), change ENDPROC to END and annotate manually with
-   the unwind hint macros in asm/unwind_hints.h.
+   kernel entry code), use SYM_CODE_{START,END} and unwind hints.
 
 
 7. file: warning: objtool: func()+0x5c: stack state mismatch
@@ -373,8 +381,8 @@ the objtool maintainers.
 
    Another possibility is that the code has some asm or inline asm which
    does some unusual things to the stack or the frame pointer.  In such
-   cases it's probably appropriate to use the unwind hint macros in
-   asm/unwind_hints.h.
+   cases it's probably appropriate to use SYM_FUNC_CODE with unwind
+   hints.
 
 
 8. file.o: warning: objtool: funcA() falls through to next function funcB()
@@ -384,17 +392,16 @@ the objtool maintainers.
    can fall through into the next function.  There could be different
    reasons for this:
 
-   1) funcA()'s last instruction is a call to a "noreturn" function like
+   a) funcA()'s last instruction is a call to a "noreturn" function like
       panic().  In this case the noreturn function needs to be added to
       objtool's hard-coded global_noreturns array.  Feel free to bug the
       objtool maintainer, or you can submit a patch.
 
-   2) funcA() uses the unreachable() annotation in a section of code
+   b) funcA() uses the unreachable() annotation in a section of code
       that is actually reachable.
 
-   3) If funcA() calls an inline function, the object code for funcA()
-      might be corrupt due to a gcc bug.  For more details, see:
-      https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70646
+   c) Some undefined behavior like divide by zero.
+
 
 9. file.o: warning: objtool: funcA() call to funcB() with UACCESS enabled
 
@@ -432,24 +439,26 @@ the objtool maintainers.
     This limitation can be overcome by massaging the alternatives with
     NOPs to shift the stack changes around so they no longer conflict.
 
+
 11. file.o: warning: unannotated intra-function call
 
-   This warning means that a direct call is done to a destination which
-   is not at the beginning of a function. If this is a legit call, you
-   can remove this warning by putting the ANNOTATE_INTRA_FUNCTION_CALL
-   directive right before the call.
+    This warning means that a direct call is done to a destination which
+    is not at the beginning of a function. If this is a legit call, you
+    can remove this warning by putting the ANNOTATE_INTRA_FUNCTION_CALL
+    directive right before the call.
+
 
 12. file.o: warning: func(): not an indirect call target
 
-   This means that objtool is running with --ibt and a function expected
-   to be an indirect call target is not. In particular, this happens for
-   init_module() or cleanup_module() if a module relies on these special
-   names and does not use module_init() / module_exit() macros to create
-   them.
+    This means that objtool is running with --ibt and a function
+    expected to be an indirect call target is not. In particular, this
+    happens for init_module() or cleanup_module() if a module relies on
+    these special names and does not use module_init() / module_exit()
+    macros to create them.
 
 
 If the error doesn't seem to make sense, it could be a bug in objtool.
-Feel free to ask the objtool maintainer for help.
+Feel free to ask objtool maintainers for help.
 
 
 Adding exceptions
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index 7a65948892e5..8c20361dd100 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -37,7 +37,7 @@ OBJTOOL_CFLAGS := -Werror $(WARNINGS) $(KBUILD_HOSTCFLAGS) -g $(INCLUDES) $(LIBE
 OBJTOOL_LDFLAGS := $(LIBELF_LIBS) $(LIBSUBCMD) $(KBUILD_HOSTLDFLAGS)
 
 # Allow old libelf to be used:
-elfshdr := $(shell echo '$(pound)include <libelf.h>' | $(HOSTCC) $(OBJTOOL_CFLAGS) -x c -E - | grep elf_getshdr)
+elfshdr := $(shell echo '$(pound)include <libelf.h>' | $(HOSTCC) $(OBJTOOL_CFLAGS) -x c -E - 2>/dev/null | grep elf_getshdr)
 OBJTOOL_CFLAGS += $(if $(elfshdr),,-DLIBELF_USE_DEPRECATED)
 
 # Always want host compilation.
diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loongarch/decode.c
index 69b66994f2a1..02e490555966 100644
--- a/tools/objtool/arch/loongarch/decode.c
+++ b/tools/objtool/arch/loongarch/decode.c
@@ -5,10 +5,7 @@
 #include <asm/inst.h>
 #include <asm/orc_types.h>
 #include <linux/objtool_types.h>
-
-#ifndef EM_LOONGARCH
-#define EM_LOONGARCH	258
-#endif
+#include <arch/elf.h>
 
 int arch_ftrace_match(char *name)
 {
@@ -363,3 +360,26 @@ void arch_initial_func_cfi_state(struct cfi_init_state *state)
 	state->cfa.base = CFI_SP;
 	state->cfa.offset = 0;
 }
+
+unsigned int arch_reloc_size(struct reloc *reloc)
+{
+	switch (reloc_type(reloc)) {
+	case R_LARCH_32:
+	case R_LARCH_32_PCREL:
+		return 4;
+	default:
+		return 8;
+	}
+}
+
+unsigned long arch_jump_table_sym_offset(struct reloc *reloc, struct reloc *table)
+{
+	switch (reloc_type(reloc)) {
+	case R_LARCH_32_PCREL:
+	case R_LARCH_64_PCREL:
+		return reloc->sym->offset + reloc_addend(reloc) -
+		       (reloc_offset(reloc) - reloc_offset(table));
+	default:
+		return reloc->sym->offset + reloc_addend(reloc);
+	}
+}
diff --git a/tools/objtool/arch/loongarch/include/arch/elf.h b/tools/objtool/arch/loongarch/include/arch/elf.h
index 9623d663220e..ec79062c9554 100644
--- a/tools/objtool/arch/loongarch/include/arch/elf.h
+++ b/tools/objtool/arch/loongarch/include/arch/elf.h
@@ -18,6 +18,13 @@
 #ifndef R_LARCH_32_PCREL
 #define R_LARCH_32_PCREL	99
 #endif
+#ifndef R_LARCH_64_PCREL
+#define R_LARCH_64_PCREL	109
+#endif
+
+#ifndef EM_LOONGARCH
+#define EM_LOONGARCH		258
+#endif
 
 #define R_NONE			R_LARCH_NONE
 #define R_ABS32			R_LARCH_32
diff --git a/tools/objtool/arch/loongarch/special.c b/tools/objtool/arch/loongarch/special.c
index 87230ed570fd..e39f86d97002 100644
--- a/tools/objtool/arch/loongarch/special.c
+++ b/tools/objtool/arch/loongarch/special.c
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
+#include <string.h>
 #include <objtool/special.h>
+#include <objtool/warn.h>
 
 bool arch_support_alt_relocation(struct special_alt *special_alt,
 				 struct instruction *insn,
@@ -8,9 +10,164 @@ bool arch_support_alt_relocation(struct special_alt *special_alt,
 	return false;
 }
 
+struct table_info {
+	struct list_head jump_info;
+	unsigned long insn_offset;
+	unsigned long rodata_offset;
+};
+
+static void get_rodata_table_size_by_table_annotate(struct objtool_file *file,
+						    struct instruction *insn,
+						    unsigned long *table_size)
+{
+	struct section *rsec;
+	struct reloc *reloc;
+	struct list_head table_list;
+	struct table_info *orig_table;
+	struct table_info *next_table;
+	unsigned long tmp_insn_offset;
+	unsigned long tmp_rodata_offset;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.tablejump_annotate");
+	if (!rsec)
+		return;
+
+	INIT_LIST_HEAD(&table_list);
+
+	for_each_reloc(rsec, reloc) {
+		orig_table = malloc(sizeof(struct table_info));
+		if (!orig_table) {
+			WARN("malloc failed");
+			return;
+		}
+
+		orig_table->insn_offset = reloc->sym->offset + reloc_addend(reloc);
+		reloc++;
+		orig_table->rodata_offset = reloc->sym->offset + reloc_addend(reloc);
+
+		list_add_tail(&orig_table->jump_info, &table_list);
+
+		if (reloc_idx(reloc) + 1 == sec_num_entries(rsec))
+			break;
+	}
+
+	list_for_each_entry(orig_table, &table_list, jump_info) {
+		next_table = list_next_entry(orig_table, jump_info);
+		list_for_each_entry_from(next_table, &table_list, jump_info) {
+			if (next_table->rodata_offset < orig_table->rodata_offset) {
+				tmp_insn_offset = next_table->insn_offset;
+				tmp_rodata_offset = next_table->rodata_offset;
+				next_table->insn_offset = orig_table->insn_offset;
+				next_table->rodata_offset = orig_table->rodata_offset;
+				orig_table->insn_offset = tmp_insn_offset;
+				orig_table->rodata_offset = tmp_rodata_offset;
+			}
+		}
+	}
+
+	list_for_each_entry(orig_table, &table_list, jump_info) {
+		if (insn->offset == orig_table->insn_offset) {
+			next_table = list_next_entry(orig_table, jump_info);
+			if (&next_table->jump_info == &table_list) {
+				*table_size = 0;
+				return;
+			}
+
+			while (next_table->rodata_offset == orig_table->rodata_offset) {
+				next_table = list_next_entry(next_table, jump_info);
+				if (&next_table->jump_info == &table_list) {
+					*table_size = 0;
+					return;
+				}
+			}
+
+			*table_size = next_table->rodata_offset - orig_table->rodata_offset;
+		}
+	}
+}
+
+static struct reloc *find_reloc_by_table_annotate(struct objtool_file *file,
+						  struct instruction *insn,
+						  unsigned long *table_size)
+{
+	struct section *rsec;
+	struct reloc *reloc;
+	unsigned long offset;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.tablejump_annotate");
+	if (!rsec)
+		return NULL;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->sec->rodata)
+			continue;
+
+		if (strcmp(insn->sec->name, reloc->sym->sec->name))
+			continue;
+
+		offset = reloc->sym->offset + reloc_addend(reloc);
+		if (insn->offset == offset) {
+			get_rodata_table_size_by_table_annotate(file, insn, table_size);
+			reloc++;
+			return reloc;
+		}
+	}
+
+	return NULL;
+}
+
+static struct reloc *find_reloc_of_rodata_c_jump_table(struct section *sec,
+						       unsigned long offset,
+						       unsigned long *table_size)
+{
+	struct section *rsec;
+	struct reloc *reloc;
+
+	rsec = sec->rsec;
+	if (!rsec)
+		return NULL;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc_offset(reloc) > offset)
+			break;
+
+		if (!strcmp(reloc->sym->sec->name, C_JUMP_TABLE_SECTION)) {
+			*table_size = 0;
+			return reloc;
+		}
+	}
+
+	return NULL;
+}
+
 struct reloc *arch_find_switch_table(struct objtool_file *file,
 				     struct instruction *insn,
 				     unsigned long *table_size)
 {
-	return NULL;
+	struct reloc *annotate_reloc;
+	struct reloc *rodata_reloc;
+	struct section *table_sec;
+	unsigned long table_offset;
+
+	annotate_reloc = find_reloc_by_table_annotate(file, insn, table_size);
+	if (!annotate_reloc) {
+		annotate_reloc = find_reloc_of_rodata_c_jump_table(
+				 insn->sec, insn->offset, table_size);
+		if (!annotate_reloc)
+			return NULL;
+	}
+
+	table_sec = annotate_reloc->sym->sec;
+	table_offset = annotate_reloc->sym->offset + reloc_addend(annotate_reloc);
+
+	/*
+	 * Each table entry has a rela associated with it.  The rela
+	 * should reference text in the same function as the original
+	 * instruction.
+	 */
+	rodata_reloc = find_reloc_by_dest(file->elf, table_sec, table_offset);
+	if (!rodata_reloc)
+		return NULL;
+
+	return rodata_reloc;
 }
diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c
index 53b55690f320..c851c51d4bd3 100644
--- a/tools/objtool/arch/powerpc/decode.c
+++ b/tools/objtool/arch/powerpc/decode.c
@@ -55,12 +55,17 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 
 	switch (opcode) {
 	case 18: /* b[l][a] */
-		if ((ins & 3) == 1) /* bl */
+		if (ins == 0x48000005)	/* bl .+4 */
+			typ = INSN_OTHER;
+		else if (ins & 1)	/* bl[a] */
 			typ = INSN_CALL;
+		else		/* b[a] */
+			typ = INSN_JUMP_UNCONDITIONAL;
 
 		imm = ins & 0x3fffffc;
 		if (imm & 0x2000000)
 			imm -= 0x4000000;
+		imm |= ins & 2;	/* AA flag */
 		break;
 	}
 
@@ -77,6 +82,9 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 
 unsigned long arch_jump_destination(struct instruction *insn)
 {
+	if (insn->immediate & 2)
+		return insn->immediate & ~2;
+
 	return insn->offset + insn->immediate;
 }
 
@@ -106,3 +114,17 @@ void arch_initial_func_cfi_state(struct cfi_init_state *state)
 	state->regs[CFI_RA].base = CFI_CFA;
 	state->regs[CFI_RA].offset = 0;
 }
+
+unsigned int arch_reloc_size(struct reloc *reloc)
+{
+	switch (reloc_type(reloc)) {
+	case R_PPC_REL32:
+	case R_PPC_ADDR32:
+	case R_PPC_UADDR32:
+	case R_PPC_PLT32:
+	case R_PPC_PLTREL32:
+		return 4;
+	default:
+		return 8;
+	}
+}
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index fe1362c34564..7567c893f45e 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -850,5 +850,19 @@ bool arch_is_rethunk(struct symbol *sym)
 bool arch_is_embedded_insn(struct symbol *sym)
 {
 	return !strcmp(sym->name, "retbleed_return_thunk") ||
+	       !strcmp(sym->name, "srso_alias_safe_ret") ||
 	       !strcmp(sym->name, "srso_safe_ret");
 }
+
+unsigned int arch_reloc_size(struct reloc *reloc)
+{
+	switch (reloc_type(reloc)) {
+	case R_X86_64_32:
+	case R_X86_64_32S:
+	case R_X86_64_PC32:
+	case R_X86_64_PLT32:
+		return 4;
+	default:
+		return 8;
+	}
+}
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 387d56a7f5fb..5f761f420b8c 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -6,6 +6,10 @@
 #include <subcmd/parse-options.h>
 #include <string.h>
 #include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/sendfile.h>
 #include <objtool/builtin.h>
 #include <objtool/objtool.h>
 
@@ -14,6 +18,8 @@
 		"error: objtool: " format "\n",		\
 		##__VA_ARGS__)
 
+const char *objname;
+
 struct opts opts;
 
 static const char * const check_usage[] = {
@@ -71,7 +77,7 @@ static const struct option check_options[] = {
 	OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
 	OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
 	OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
-	OPT_BOOLEAN('o', "orc", &opts.orc, "generate ORC metadata"),
+	OPT_BOOLEAN(0,   "orc", &opts.orc, "generate ORC metadata"),
 	OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
 	OPT_BOOLEAN(0,   "rethunk", &opts.rethunk, "validate and annotate rethunk usage"),
 	OPT_BOOLEAN(0,   "unret", &opts.unret, "validate entry unret placement"),
@@ -84,16 +90,17 @@ static const struct option check_options[] = {
 	OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
 
 	OPT_GROUP("Options:"),
-	OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
-	OPT_BOOLEAN(0, "backup", &opts.backup, "create .orig files before modification"),
-	OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
-	OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
-	OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
-	OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"),
-	OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
-	OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
-	OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
+	OPT_BOOLEAN(0,   "backtrace", &opts.backtrace, "unwind on error"),
+	OPT_BOOLEAN(0,   "dry-run", &opts.dryrun, "don't write modifications"),
+	OPT_BOOLEAN(0,   "link", &opts.link, "object is a linked object"),
+	OPT_BOOLEAN(0,   "module", &opts.module, "object is part of a kernel module"),
+	OPT_BOOLEAN(0,   "mnop", &opts.mnop, "nop out mcount call sites"),
+	OPT_BOOLEAN(0,   "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
+	OPT_STRING('o',  "output", &opts.output, "file", "output file name"),
+	OPT_BOOLEAN(0,   "sec-address", &opts.sec_address, "print section addresses in warnings"),
+	OPT_BOOLEAN(0,   "stats", &opts.stats, "print statistics"),
 	OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
+	OPT_BOOLEAN(0,   "Werror", &opts.werror, "return error on warnings"),
 
 	OPT_END(),
 };
@@ -131,6 +138,26 @@ int cmd_parse_options(int argc, const char **argv, const char * const usage[])
 
 static bool opts_valid(void)
 {
+	if (opts.mnop && !opts.mcount) {
+		ERROR("--mnop requires --mcount");
+		return false;
+	}
+
+	if (opts.noinstr && !opts.link) {
+		ERROR("--noinstr requires --link");
+		return false;
+	}
+
+	if (opts.ibt && !opts.link) {
+		ERROR("--ibt requires --link");
+		return false;
+	}
+
+	if (opts.unret && !opts.link) {
+		ERROR("--unret requires --link");
+		return false;
+	}
+
 	if (opts.hack_jump_label	||
 	    opts.hack_noinstr		||
 	    opts.ibt			||
@@ -151,11 +178,6 @@ static bool opts_valid(void)
 		return true;
 	}
 
-	if (opts.unret && !opts.rethunk) {
-		ERROR("--unret requires --rethunk");
-		return false;
-	}
-
 	if (opts.dump_orc)
 		return true;
 
@@ -163,76 +185,156 @@ static bool opts_valid(void)
 	return false;
 }
 
-static bool mnop_opts_valid(void)
+static int copy_file(const char *src, const char *dst)
 {
-	if (opts.mnop && !opts.mcount) {
-		ERROR("--mnop requires --mcount");
-		return false;
+	size_t to_copy, copied;
+	int dst_fd, src_fd;
+	struct stat stat;
+	off_t offset = 0;
+
+	src_fd = open(src, O_RDONLY);
+	if (src_fd == -1) {
+		ERROR("can't open '%s' for reading", src);
+		return 1;
 	}
 
-	return true;
-}
-
-static bool link_opts_valid(struct objtool_file *file)
-{
-	if (opts.link)
-		return true;
+	dst_fd = open(dst, O_WRONLY | O_CREAT | O_TRUNC, 0400);
+	if (dst_fd == -1) {
+		ERROR("can't open '%s' for writing", dst);
+		return 1;
+	}
 
-	if (has_multiple_files(file->elf)) {
-		ERROR("Linked object detected, forcing --link");
-		opts.link = true;
-		return true;
+	if (fstat(src_fd, &stat) == -1) {
+		perror("fstat");
+		return 1;
 	}
 
-	if (opts.noinstr) {
-		ERROR("--noinstr requires --link");
-		return false;
+	if (fchmod(dst_fd, stat.st_mode) == -1) {
+		perror("fchmod");
+		return 1;
 	}
 
-	if (opts.ibt) {
-		ERROR("--ibt requires --link");
-		return false;
+	for (to_copy = stat.st_size; to_copy > 0; to_copy -= copied) {
+		copied = sendfile(dst_fd, src_fd, &offset, to_copy);
+		if (copied == -1) {
+			perror("sendfile");
+			return 1;
+		}
 	}
 
-	if (opts.unret) {
-		ERROR("--unret requires --link");
-		return false;
+	close(dst_fd);
+	close(src_fd);
+	return 0;
+}
+
+static char **save_argv(int argc, const char **argv)
+{
+	char **orig_argv;
+
+	orig_argv = calloc(argc, sizeof(char *));
+	if (!orig_argv) {
+		perror("calloc");
+		return NULL;
 	}
 
-	return true;
+	for (int i = 0; i < argc; i++) {
+		orig_argv[i] = strdup(argv[i]);
+		if (!orig_argv[i]) {
+			perror("strdup");
+			return NULL;
+		}
+	};
+
+	return orig_argv;
 }
 
+#define ORIG_SUFFIX ".orig"
+
 int objtool_run(int argc, const char **argv)
 {
-	const char *objname;
 	struct objtool_file *file;
-	int ret;
+	char *backup = NULL;
+	char **orig_argv;
+	int ret = 0;
 
-	argc = cmd_parse_options(argc, argv, check_usage);
-	objname = argv[0];
+	orig_argv = save_argv(argc, argv);
+	if (!orig_argv)
+		return 1;
+
+	cmd_parse_options(argc, argv, check_usage);
 
 	if (!opts_valid())
 		return 1;
 
+	objname = argv[0];
+
 	if (opts.dump_orc)
 		return orc_dump(objname);
 
+	if (!opts.dryrun && opts.output) {
+		/* copy original .o file to output file */
+		if (copy_file(objname, opts.output))
+			return 1;
+
+		/* from here on, work directly on the output file */
+		objname = opts.output;
+	}
+
 	file = objtool_open_read(objname);
 	if (!file)
-		return 1;
+		goto err;
 
-	if (!mnop_opts_valid())
-		return 1;
-
-	if (!link_opts_valid(file))
-		return 1;
+	if (!opts.link && has_multiple_files(file->elf)) {
+		ERROR("Linked object requires --link");
+		goto err;
+	}
 
 	ret = check(file);
 	if (ret)
-		return ret;
+		goto err;
 
-	if (file->elf->changed)
-		return elf_write(file->elf);
+	if (!opts.dryrun && file->elf->changed && elf_write(file->elf))
+		goto err;
 
 	return 0;
+
+err:
+	if (opts.dryrun)
+		goto err_msg;
+
+	if (opts.output) {
+		unlink(opts.output);
+		goto err_msg;
+	}
+
+	/*
+	 * Make a backup before kbuild deletes the file so the error
+	 * can be recreated without recompiling or relinking.
+	 */
+	backup = malloc(strlen(objname) + strlen(ORIG_SUFFIX) + 1);
+	if (!backup) {
+		perror("malloc");
+		return 1;
+	}
+
+	strcpy(backup, objname);
+	strcat(backup, ORIG_SUFFIX);
+	if (copy_file(objname, backup))
+		return 1;
+
+err_msg:
+	fprintf(stderr, "%s", orig_argv[0]);
+
+	for (int i = 1; i < argc; i++) {
+		char *arg = orig_argv[i];
+
+		if (backup && !strcmp(arg, objname))
+			fprintf(stderr, " %s -o %s", backup, objname);
+		else
+			fprintf(stderr, " %s", arg);
+	}
+
+	fprintf(stderr, "\n");
+
+	return 1;
 }
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index ce973d9d8e6d..ca3435acc326 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1284,15 +1284,6 @@ static void annotate_call_site(struct objtool_file *file,
 	if (!sym)
 		sym = reloc->sym;
 
-	/*
-	 * Alternative replacement code is just template code which is
-	 * sometimes copied to the original instruction. For now, don't
-	 * annotate it. (In the future we might consider annotating the
-	 * original instruction if/when it ever makes sense to do so.)
-	 */
-	if (!strcmp(insn->sec->name, ".altinstr_replacement"))
-		return;
-
 	if (sym->static_call_tramp) {
 		list_add_tail(&insn->call_node, &file->static_call_list);
 		return;
@@ -1350,7 +1341,8 @@ static void annotate_call_site(struct objtool_file *file,
 		return;
 	}
 
-	if (insn->type == INSN_CALL && !insn->sec->init)
+	if (insn->type == INSN_CALL && !insn->sec->init &&
+	    !insn->_call_dest->embedded_insn)
 		list_add_tail(&insn->call_node, &file->call_list);
 
 	if (!sibling && dead_end_function(file, sym))
@@ -1944,6 +1936,11 @@ out:
 	return ret;
 }
 
+__weak unsigned long arch_jump_table_sym_offset(struct reloc *reloc, struct reloc *table)
+{
+	return reloc->sym->offset + reloc_addend(reloc);
+}
+
 static int add_jump_table(struct objtool_file *file, struct instruction *insn,
 			  struct reloc *next_table)
 {
@@ -1954,6 +1951,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
 	unsigned int prev_offset = 0;
 	struct reloc *reloc = table;
 	struct alternative *alt;
+	unsigned long sym_offset;
 
 	/*
 	 * Each @reloc is a switch table relocation which points to the target
@@ -1968,12 +1966,13 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
 			break;
 
 		/* Make sure the table entries are consecutive: */
-		if (prev_offset && reloc_offset(reloc) != prev_offset + 8)
+		if (prev_offset && reloc_offset(reloc) != prev_offset + arch_reloc_size(reloc))
 			break;
 
+		sym_offset = arch_jump_table_sym_offset(reloc, table);
+
 		/* Detect function pointers from contiguous objects: */
-		if (reloc->sym->sec == pfunc->sec &&
-		    reloc_addend(reloc) == pfunc->offset)
+		if (reloc->sym->sec == pfunc->sec && sym_offset == pfunc->offset)
 			break;
 
 		/*
@@ -1981,10 +1980,10 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
 		 * which point to the end of the function.  Ignore them.
 		 */
 		if (reloc->sym->sec == pfunc->sec &&
-		    reloc_addend(reloc) == pfunc->offset + pfunc->len)
+		    sym_offset == pfunc->offset + pfunc->len)
 			goto next;
 
-		dest_insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		dest_insn = find_insn(file, reloc->sym->sec, sym_offset);
 		if (!dest_insn)
 			break;
 
@@ -2023,6 +2022,7 @@ static void find_jump_table(struct objtool_file *file, struct symbol *func,
 	struct reloc *table_reloc;
 	struct instruction *dest_insn, *orig_insn = insn;
 	unsigned long table_size;
+	unsigned long sym_offset;
 
 	/*
 	 * Backward search using the @first_jump_src links, these help avoid
@@ -2046,7 +2046,10 @@ static void find_jump_table(struct objtool_file *file, struct symbol *func,
 		table_reloc = arch_find_switch_table(file, insn, &table_size);
 		if (!table_reloc)
 			continue;
-		dest_insn = find_insn(file, table_reloc->sym->sec, reloc_addend(table_reloc));
+
+		sym_offset = table_reloc->sym->offset + reloc_addend(table_reloc);
+
+		dest_insn = find_insn(file, table_reloc->sym->sec, sym_offset);
 		if (!dest_insn || !insn_func(dest_insn) || insn_func(dest_insn)->pfunc != func)
 			continue;
 
@@ -4449,35 +4452,6 @@ static int validate_sls(struct objtool_file *file)
 	return warnings;
 }
 
-static bool ignore_noreturn_call(struct instruction *insn)
-{
-	struct symbol *call_dest = insn_call_dest(insn);
-
-	/*
-	 * FIXME: hack, we need a real noreturn solution
-	 *
-	 * Problem is, exc_double_fault() may or may not return, depending on
-	 * whether CONFIG_X86_ESPFIX64 is set.  But objtool has no visibility
-	 * to the kernel config.
-	 *
-	 * Other potential ways to fix it:
-	 *
-	 *   - have compiler communicate __noreturn functions somehow
-	 *   - remove CONFIG_X86_ESPFIX64
-	 *   - read the .config file
-	 *   - add a cmdline option
-	 *   - create a generic objtool annotation format (vs a bunch of custom
-	 *     formats) and annotate it
-	 */
-	if (!strcmp(call_dest->name, "exc_double_fault")) {
-		/* prevent further unreachable warnings for the caller */
-		insn->sym->warned = 1;
-		return true;
-	}
-
-	return false;
-}
-
 static int validate_reachable_instructions(struct objtool_file *file)
 {
 	struct instruction *insn, *prev_insn;
@@ -4494,8 +4468,8 @@ static int validate_reachable_instructions(struct objtool_file *file)
 		prev_insn = prev_insn_same_sec(file, insn);
 		if (prev_insn && prev_insn->dead_end) {
 			call_dest = insn_call_dest(prev_insn);
-			if (call_dest && !ignore_noreturn_call(prev_insn)) {
-				WARN_INSN(insn, "%s() is missing a __noreturn annotation",
+			if (call_dest) {
+				WARN_INSN(insn, "%s() missing __noreturn in .c/.h or NORETURN() in noreturns.h",
 					  call_dest->name);
 				warnings++;
 				continue;
@@ -4565,7 +4539,7 @@ static int disas_warned_funcs(struct objtool_file *file)
 	char *funcs = NULL, *tmp;
 
 	for_each_sym(file, sym) {
-		if (sym->warned) {
+		if (sym->warnings) {
 			if (!funcs) {
 				funcs = malloc(strlen(sym->name) + 1);
 				strcpy(funcs, sym->name);
@@ -4623,8 +4597,10 @@ int check(struct objtool_file *file)
 	init_cfi_state(&force_undefined_cfi);
 	force_undefined_cfi.force_undefined = true;
 
-	if (!cfi_hash_alloc(1UL << (file->elf->symbol_bits - 3)))
+	if (!cfi_hash_alloc(1UL << (file->elf->symbol_bits - 3))) {
+		ret = -1;
 		goto out;
+	}
 
 	cfi_hash_add(&init_cfi);
 	cfi_hash_add(&func_cfi);
@@ -4641,7 +4617,7 @@ int check(struct objtool_file *file)
 	if (opts.retpoline) {
 		ret = validate_retpoline(file);
 		if (ret < 0)
-			return ret;
+			goto out;
 		warnings += ret;
 	}
 
@@ -4677,7 +4653,7 @@ int check(struct objtool_file *file)
 		 */
 		ret = validate_unrets(file);
 		if (ret < 0)
-			return ret;
+			goto out;
 		warnings += ret;
 	}
 
@@ -4740,7 +4716,7 @@ int check(struct objtool_file *file)
 	if (opts.prefix) {
 		ret = add_prefix_symbols(file);
 		if (ret < 0)
-			return ret;
+			goto out;
 		warnings += ret;
 	}
 
@@ -4772,9 +4748,18 @@ int check(struct objtool_file *file)
 
 out:
 	/*
-	 *  For now, don't fail the kernel build on fatal warnings.  These
-	 *  errors are still fairly common due to the growing matrix of
-	 *  supported toolchains and their recent pace of change.
+	 * CONFIG_OBJTOOL_WERROR upgrades all warnings (and errors) to actual
+	 * errors.
+	 *
+	 * Note that even "fatal" type errors don't actually return an error
+	 * without CONFIG_OBJTOOL_WERROR.  That probably needs improved at some
+	 * point.
 	 */
+	if (opts.werror && (ret || warnings)) {
+		if (warnings)
+			WARN("%d warning(s) upgraded to errors", warnings);
+		return 1;
+	}
+
 	return 0;
 }
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 6f64d611faea..be4f4b62730c 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -1302,9 +1302,6 @@ int elf_write(struct elf *elf)
 	struct section *sec;
 	Elf_Scn *s;
 
-	if (opts.dryrun)
-		return 0;
-
 	/* Update changed relocation sections and section headers: */
 	list_for_each_entry(sec, &elf->sections, list) {
 		if (sec->truncate)
diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h
index d63b46a19f39..089a1acc48a8 100644
--- a/tools/objtool/include/objtool/arch.h
+++ b/tools/objtool/include/objtool/arch.h
@@ -97,4 +97,7 @@ int arch_rewrite_retpolines(struct objtool_file *file);
 
 bool arch_pc_relative_reloc(struct reloc *reloc);
 
+unsigned int arch_reloc_size(struct reloc *reloc);
+unsigned long arch_jump_table_sym_offset(struct reloc *reloc, struct reloc *table);
+
 #endif /* _ARCH_H */
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index fcca6662c8b4..0fafd0f7a209 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -29,15 +29,16 @@ struct opts {
 
 	/* options: */
 	bool backtrace;
-	bool backup;
 	bool dryrun;
 	bool link;
 	bool mnop;
 	bool module;
 	bool no_unreachable;
+	const char *output;
 	bool sec_address;
 	bool stats;
 	bool verbose;
+	bool werror;
 };
 
 extern struct opts opts;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index d7e815c2fd15..223ac1c24b90 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -65,10 +65,10 @@ struct symbol {
 	u8 return_thunk      : 1;
 	u8 fentry            : 1;
 	u8 profiling_func    : 1;
-	u8 warned	     : 1;
 	u8 embedded_insn     : 1;
 	u8 local_label       : 1;
 	u8 frame_pointer     : 1;
+	u8 warnings	     : 2;
 	struct list_head pv_target;
 	struct reloc *relocs;
 };
diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
index ac04d3fe4dd9..e72b9d630551 100644
--- a/tools/objtool/include/objtool/warn.h
+++ b/tools/objtool/include/objtool/warn.h
@@ -43,8 +43,10 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 
 #define WARN(format, ...)				\
 	fprintf(stderr,					\
-		"%s: warning: objtool: " format "\n",	\
-		objname, ##__VA_ARGS__)
+		"%s: %s: objtool: " format "\n",	\
+		objname,				\
+		opts.werror ? "error" : "warning",	\
+		##__VA_ARGS__)
 
 #define WARN_FUNC(format, sec, offset, ...)		\
 ({							\
@@ -53,14 +55,22 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 	free(_str);					\
 })
 
+#define WARN_LIMIT 2
+
 #define WARN_INSN(insn, format, ...)					\
 ({									\
 	struct instruction *_insn = (insn);				\
-	if (!_insn->sym || !_insn->sym->warned)				\
+	BUILD_BUG_ON(WARN_LIMIT > 2);					\
+	if (!_insn->sym || _insn->sym->warnings < WARN_LIMIT) {		\
 		WARN_FUNC(format, _insn->sec, _insn->offset,		\
 			  ##__VA_ARGS__);				\
-	if (_insn->sym)							\
-		_insn->sym->warned = 1;					\
+		if (_insn->sym)						\
+			_insn->sym->warnings++;				\
+	} else if (_insn->sym && _insn->sym->warnings == WARN_LIMIT) {	\
+		WARN_FUNC("skipping duplicate warning(s)",		\
+			  _insn->sec, _insn->offset);			\
+		_insn->sym->warnings++;					\
+	}								\
 })
 
 #define BT_INSN(insn, format, ...)				\
diff --git a/tools/objtool/noreturns.h b/tools/objtool/noreturns.h
index 6bb7edda3094..eacfe3b0a8d1 100644
--- a/tools/objtool/noreturns.h
+++ b/tools/objtool/noreturns.h
@@ -16,6 +16,7 @@ NORETURN(__tdx_hypercall_failed)
 NORETURN(__ubsan_handle_builtin_unreachable)
 NORETURN(__x64_sys_exit)
 NORETURN(__x64_sys_exit_group)
+NORETURN(acpi_processor_ffh_play_dead)
 NORETURN(arch_cpu_idle_dead)
 NORETURN(bch2_trans_in_restart_error)
 NORETURN(bch2_trans_restart_error)
@@ -34,6 +35,7 @@ NORETURN(kunit_try_catch_throw)
 NORETURN(machine_real_restart)
 NORETURN(make_task_dead)
 NORETURN(mpt_halt_firmware)
+NORETURN(mwait_play_dead)
 NORETURN(nmi_panic_self_stop)
 NORETURN(panic)
 NORETURN(panic_smp_self_stop)
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index f40febdd6e36..1c73fb62fd57 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -18,87 +18,19 @@
 
 bool help;
 
-const char *objname;
 static struct objtool_file file;
 
-static bool objtool_create_backup(const char *_objname)
+struct objtool_file *objtool_open_read(const char *filename)
 {
-	int len = strlen(_objname);
-	char *buf, *base, *name = malloc(len+6);
-	int s, d, l, t;
-
-	if (!name) {
-		perror("failed backup name malloc");
-		return false;
-	}
-
-	strcpy(name, _objname);
-	strcpy(name + len, ".orig");
-
-	d = open(name, O_CREAT|O_WRONLY|O_TRUNC, 0644);
-	if (d < 0) {
-		perror("failed to create backup file");
-		return false;
-	}
-
-	s = open(_objname, O_RDONLY);
-	if (s < 0) {
-		perror("failed to open orig file");
-		return false;
-	}
-
-	buf = malloc(4096);
-	if (!buf) {
-		perror("failed backup data malloc");
-		return false;
-	}
-
-	while ((l = read(s, buf, 4096)) > 0) {
-		base = buf;
-		do {
-			t = write(d, base, l);
-			if (t < 0) {
-				perror("failed backup write");
-				return false;
-			}
-			base += t;
-			l -= t;
-		} while (l);
-	}
-
-	if (l < 0) {
-		perror("failed backup read");
-		return false;
-	}
-
-	free(name);
-	free(buf);
-	close(d);
-	close(s);
-
-	return true;
-}
-
-struct objtool_file *objtool_open_read(const char *_objname)
-{
-	if (objname) {
-		if (strcmp(objname, _objname)) {
-			WARN("won't handle more than one file at a time");
-			return NULL;
-		}
-		return &file;
+	if (file.elf) {
+		WARN("won't handle more than one file at a time");
+		return NULL;
 	}
-	objname = _objname;
 
-	file.elf = elf_open_read(objname, O_RDWR);
+	file.elf = elf_open_read(filename, O_RDWR);
 	if (!file.elf)
 		return NULL;
 
-	if (opts.backup && !objtool_create_backup(objname)) {
-		WARN("can't create backup file");
-		return NULL;
-	}
-
 	hash_init(file.insn_hash);
 	INIT_LIST_HEAD(&file.retpoline_call_list);
 	INIT_LIST_HEAD(&file.return_thunk_list);
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index a62247efb64f..05ef0e297837 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -10,7 +10,7 @@
 #include <objtool/warn.h>
 #include <objtool/endianness.h>
 
-int orc_dump(const char *_objname)
+int orc_dump(const char *filename)
 {
 	int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
 	struct orc_entry *orc = NULL;
@@ -26,12 +26,9 @@ int orc_dump(const char *_objname)
 	Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
 	struct elf dummy_elf = {};
 
-
-	objname = _objname;
-
 	elf_version(EV_CURRENT);
 
-	fd = open(objname, O_RDONLY);
+	fd = open(filename, O_RDONLY);
 	if (fd == -1) {
 		perror("open");
 		return -1;