Merge tag 'objtool-core-2023-03-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

 - Shrink 'struct instruction', to improve objtool performance & memory
   footprint

 - Other maximum memory usage reductions - this makes the build both
   faster, and fixes kernel build OOM failures on allyesconfig and
   similar configs when they try to build the final (large) vmlinux.o

 - Fix ORC unwinding when a kprobe (INT3) is set on a stack-modifying
   single-byte instruction (PUSH/POP or LEAVE). This requires the
   extension of the ORC metadata structure with a 'signal' field

 - Misc fixes & cleanups

* tag 'objtool-core-2023-03-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  objtool: Fix ORC 'signal' propagation
  objtool: Remove instruction::list
  x86: Fix FILL_RETURN_BUFFER
  objtool: Fix overlapping alternatives
  objtool: Union instruction::{call_dest,jump_table}
  objtool: Remove instruction::reloc
  objtool: Shrink instruction::{type,visited}
  objtool: Make instruction::alts a single-linked list
  objtool: Make instruction::stack_ops a single-linked list
  objtool: Change arch_decode_instruction() signature
  x86/entry: Fix unwinding from kprobe on PUSH/POP instruction
  x86/unwind/orc: Add 'signal' field to ORC metadata
  objtool: Optimize layout of struct special_alt
  objtool: Optimize layout of struct symbol
  objtool: Allocate multiple structures with calloc()
  objtool: Make struct check_options static
  objtool: Make struct entries[] static and const
  objtool: Fix HOSTCC flag usage
  objtool: Properly support make V=1
  objtool: Install libsubcmd in build
  ...

Author: torvalds

arch/x86/entry/entry_64.S

@@ -385,7 +385,14 @@ SYM_CODE_END(xen_error_entry)
  */
 .macro idtentry vector asmsym cfunc has_error_code:req
 SYM_CODE_START(\asmsym)
-	UNWIND_HINT_IRET_REGS offset=\has_error_code*8
+
+	.if \vector == X86_TRAP_BP
+		/* #BP advances %rip to the next instruction */
+		UNWIND_HINT_IRET_REGS offset=\has_error_code*8 signal=0
+	.else
+		UNWIND_HINT_IRET_REGS offset=\has_error_code*8
+	.endif
+
 	ENDBR
 	ASM_CLAC
 	cld

arch/x86/include/asm/nospec-branch.h

@@ -261,7 +261,7 @@
 .macro FILL_RETURN_BUFFER reg:req nr:req ftr:req ftr2=ALT_NOT(X86_FEATURE_ALWAYS)
 	ALTERNATIVE_2 "jmp .Lskip_rsb_\@", \
 		__stringify(__FILL_RETURN_BUFFER(\reg,\nr)), \ftr, \
-		__stringify(__FILL_ONE_RETURN), \ftr2
+		__stringify(nop;nop;__FILL_ONE_RETURN), \ftr2
 
 .Lskip_rsb_\@:
 .endm

arch/x86/include/asm/orc_types.h

@@ -57,12 +57,14 @@ struct orc_entry {
 	unsigned	sp_reg:4;
 	unsigned	bp_reg:4;
 	unsigned	type:2;
+	unsigned	signal:1;
 	unsigned	end:1;
 #elif defined(__BIG_ENDIAN_BITFIELD)
 	unsigned	bp_reg:4;
 	unsigned	sp_reg:4;
-	unsigned	unused:5;
+	unsigned	unused:4;
 	unsigned	end:1;
+	unsigned	signal:1;
 	unsigned	type:2;
 #endif
 } __packed;

arch/x86/include/asm/unwind_hints.h

@@ -15,7 +15,7 @@
 	UNWIND_HINT type=UNWIND_HINT_TYPE_ENTRY end=1
 .endm
 
-.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0
+.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0 signal=1
 	.if \base == %rsp
 		.if \indirect
 			.set sp_reg, ORC_REG_SP_INDIRECT
@@ -45,11 +45,11 @@
 		.set type, UNWIND_HINT_TYPE_REGS
 	.endif
 
-	UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+	UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type signal=\signal
 .endm
 
-.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0
-	UNWIND_HINT_REGS base=\base offset=\offset partial=1
+.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0 signal=1
+	UNWIND_HINT_REGS base=\base offset=\offset partial=1 signal=\signal
 .endm
 
 .macro UNWIND_HINT_FUNC
@@ -67,7 +67,7 @@
 #else
 
 #define UNWIND_HINT_FUNC \
-	UNWIND_HINT(ORC_REG_SP, 8, UNWIND_HINT_TYPE_FUNC, 0)
+	UNWIND_HINT(ORC_REG_SP, 8, UNWIND_HINT_TYPE_FUNC, 0, 0)
 
 #endif /* __ASSEMBLY__ */
 

arch/x86/kernel/unwind_orc.c

@@ -484,6 +484,8 @@ bool unwind_next_frame(struct unwind_state *state)
 		goto the_end;
 	}
 
+	state->signal = orc->signal;
+
 	/* Find the previous frame's stack: */
 	switch (orc->sp_reg) {
 	case ORC_REG_SP:
@@ -563,7 +565,6 @@ bool unwind_next_frame(struct unwind_state *state)
 		state->sp = sp;
 		state->regs = NULL;
 		state->prev_regs = NULL;
-		state->signal = false;
 		break;
 
 	case UNWIND_HINT_TYPE_REGS:
@@ -587,7 +588,6 @@ bool unwind_next_frame(struct unwind_state *state)
 		state->regs = (struct pt_regs *)sp;
 		state->prev_regs = NULL;
 		state->full_regs = true;
-		state->signal = true;
 		break;
 
 	case UNWIND_HINT_TYPE_REGS_PARTIAL:
@@ -604,7 +604,6 @@ bool unwind_next_frame(struct unwind_state *state)
 			state->prev_regs = state->regs;
 		state->regs = (void *)sp - IRET_FRAME_OFFSET;
 		state->full_regs = false;
-		state->signal = true;
 		break;
 
 	default:

include/linux/objtool.h

@@ -15,6 +15,7 @@ struct unwind_hint {
 	s16		sp_offset;
 	u8		sp_reg;
 	u8		type;
+	u8		signal;
 	u8		end;
 };
 #endif
@@ -49,14 +50,15 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, end)		\
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end)	\
 	"987: \n\t"						\
 	".pushsection .discard.unwind_hints\n\t"		\
 	/* struct unwind_hint */				\
 	".long 987b - .\n\t"					\
 	".short " __stringify(sp_offset) "\n\t"			\
 	".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"
@@ -129,14 +131,15 @@ 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 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
 .Lunwind_hint_ip_\@:
 	.pushsection .discard.unwind_hints
 		/* struct unwind_hint */
 		.long .Lunwind_hint_ip_\@ - .
 		.short \sp_offset
 		.byte \sp_reg
 		.byte \type
+		.byte \signal
 		.byte \end
 		.balign 4
 	.popsection
@@ -174,15 +177,15 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, end)	\
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
 	"\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 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
 .endm
 .macro STACK_FRAME_NON_STANDARD func:req
 .endm

tools/arch/x86/include/asm/orc_types.h

@@ -57,12 +57,14 @@ struct orc_entry {
 	unsigned	sp_reg:4;
 	unsigned	bp_reg:4;
 	unsigned	type:2;
+	unsigned	signal:1;
 	unsigned	end:1;
 #elif defined(__BIG_ENDIAN_BITFIELD)
 	unsigned	bp_reg:4;
 	unsigned	sp_reg:4;
-	unsigned	unused:5;
+	unsigned	unused:4;
 	unsigned	end:1;
+	unsigned	signal:1;
 	unsigned	type:2;
 #endif
 } __packed;

tools/include/linux/objtool.h

@@ -15,6 +15,7 @@ struct unwind_hint {
 	s16		sp_offset;
 	u8		sp_reg;
 	u8		type;
+	u8		signal;
 	u8		end;
 };
 #endif
@@ -49,14 +50,15 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, end)		\
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end)	\
 	"987: \n\t"						\
 	".pushsection .discard.unwind_hints\n\t"		\
 	/* struct unwind_hint */				\
 	".long 987b - .\n\t"					\
 	".short " __stringify(sp_offset) "\n\t"			\
 	".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"
@@ -129,14 +131,15 @@ 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 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
 .Lunwind_hint_ip_\@:
 	.pushsection .discard.unwind_hints
 		/* struct unwind_hint */
 		.long .Lunwind_hint_ip_\@ - .
 		.short \sp_offset
 		.byte \sp_reg
 		.byte \type
+		.byte \signal
 		.byte \end
 		.balign 4
 	.popsection
@@ -174,15 +177,15 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, end)	\
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
 	"\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 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
 .endm
 .macro STACK_FRAME_NON_STANDARD func:req
 .endm

tools/objtool/.gitignore

@@ -2,3 +2,4 @@
 arch/x86/lib/inat-tables.c
 /objtool
 fixdep
+libsubcmd/

tools/objtool/Build

@@ -16,8 +16,6 @@ objtool-y += libctype.o
 objtool-y += str_error_r.o
 objtool-y += librbtree.o
 
-CFLAGS += -I$(srctree)/tools/lib
-
 $(OUTPUT)libstring.o: ../lib/string.c FORCE
 	$(call rule_mkdir)
 	$(call if_changed_dep,cc_o_c)