Message-ID:
 <SN6PR02MB41579B83CD295C9FEE40EED6D4FCA@SN6PR02MB4157.namprd02.prod.outlook.com>
Date: Mon, 27 Oct 2025 01:19:10 +0000
From: Michael Kelley <mhklinux@...look.com>
To: Josh Poimboeuf <jpoimboe@...nel.org>, "x86@...nel.org" <x86@...nel.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Petr Mladek
	<pmladek@...e.com>, Miroslav Benes <mbenes@...e.cz>, Joe Lawrence
	<joe.lawrence@...hat.com>, "live-patching@...r.kernel.org"
	<live-patching@...r.kernel.org>, Song Liu <song@...nel.org>, laokz
	<laokz@...mail.com>, Jiri Kosina <jikos@...nel.org>, Marcos Paulo de Souza
	<mpdesouza@...e.com>, Weinan Liu <wnliu@...gle.com>, Fazla Mehrab
	<a.mehrab@...edance.com>, Chen Zhongjin <chenzhongjin@...wei.com>, Puranjay
 Mohan <puranjay@...nel.org>, Dylan Hatch <dylanbhatch@...gle.com>, Peter
 Zijlstra <peterz@...radead.org>
Subject: RE: [PATCH v4 49/63] objtool/klp: Add --checksum option to generate
 per-function checksums

From: Josh Poimboeuf <jpoimboe@...nel.org> Sent: Wednesday, September 17, 2025 9:04 AM
> 
> In preparation for the objtool klp diff subcommand, add a command-line
> option to generate a unique checksum for each function.  This will
> enable detection of functions which have changed between two versions of
> an object file.
> 
> Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
> ---
>  tools/objtool/Makefile                        |  38 +++--
>  tools/objtool/builtin-check.c                 |  11 +-
>  tools/objtool/check.c                         | 140 +++++++++++++++++-
>  tools/objtool/elf.c                           |  46 +++++-
>  tools/objtool/include/objtool/builtin.h       |   5 +-
>  tools/objtool/include/objtool/check.h         |   5 +-
>  tools/objtool/include/objtool/checksum.h      |  42 ++++++
>  .../objtool/include/objtool/checksum_types.h  |  25 ++++
>  tools/objtool/include/objtool/elf.h           |   4 +-
>  9 files changed, 289 insertions(+), 27 deletions(-)
>  create mode 100644 tools/objtool/include/objtool/checksum.h
>  create mode 100644 tools/objtool/include/objtool/checksum_types.h
> 
> diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
> index fc82d47f2b9a7..958761c05b7c3 100644
> --- a/tools/objtool/Makefile
> +++ b/tools/objtool/Makefile
> @@ -2,6 +2,27 @@
>  include ../scripts/Makefile.include
>  include ../scripts/Makefile.arch
> 
> +ifeq ($(SRCARCH),x86)
> +	BUILD_ORC    := y
> +	ARCH_HAS_KLP := y
> +endif
> +
> +ifeq ($(SRCARCH),loongarch)
> +	BUILD_ORC	   := y
> +endif
> +
> +ifeq ($(ARCH_HAS_KLP),y)
> +	HAVE_XXHASH = $(shell echo "int main() {}" | \
> +		      $(HOSTCC) -xc - -o /dev/null -lxxhash 2> /dev/null && echo y || echo n)
> +	ifeq ($(HAVE_XXHASH),y)
> +		LIBXXHASH_CFLAGS := $(shell $(HOSTPKG_CONFIG) libxxhash --cflags 2>/dev/null) \
> +				    -DBUILD_KLP
> +		LIBXXHASH_LIBS   := $(shell $(HOSTPKG_CONFIG) libxxhash --libs 2>/dev/null || echo -lxxhash)
> +	endif
> +endif

I ran into an interesting issue with xxhash when building the linux-next20251024
kernel on Ubuntu 20.04 for x86/x64. My first result was the new error that this
patch adds (as modified by Boris Petkov's follow-up patch):

error: objtool: --checksum not supported; install xxhash-devel/libxxhash-dev and recompile

OK, not a big deal. I installed libxxhash-dev using:

# apt install libxxhash-dev

Then objtool got a compile error when building:

  CC      /data/linux-next20251024/tools/objtool/libsubcmd/exec-cmd.o
  CC      /data/linux-next20251024/tools/objtool/libsubcmd/help.o
  CC      /data/linux-next20251024/tools/objtool/libsubcmd/pager.o
  CC      /data/linux-next20251024/tools/objtool/libsubcmd/parse-options.o
  CC      /data/linux-next20251024/tools/objtool/libsubcmd/run-command.o
  CC      /data/linux-next20251024/tools/objtool/libsubcmd/sigchain.o
  CC      /data/linux-next20251024/tools/objtool/libsubcmd/subcmd-config.o
  LD      /data/linux-next20251024/tools/objtool/libsubcmd/libsubcmd-in.o
  AR      /data/linux-next20251024/tools/objtool/libsubcmd/libsubcmd.a
  INSTALL libsubcmd_headers
  CC      /data/linux-next20251024/tools/objtool/arch/x86/special.o
In file included from /data/linux-next20251024/tools/objtool/include/objtool/elf.h:18,
                 from /data/linux-next20251024/tools/objtool/include/objtool/objtool.h:13,
                 from /data/linux-next20251024/tools/objtool/include/objtool/arch.h:11,
                 from /data/linux-next20251024/tools/objtool/include/objtool/check.h:11,
                 from /data/linux-next20251024/tools/objtool/include/objtool/special.h:10,
                 from arch/x86/special.c:4:
/data/linux-next20251024/tools/objtool/include/objtool/checksum_types.h:15:9: error: unknown type name 'XXH3_state_t'
   15 |         XXH3_state_t *state;
      |         ^~~~~~~~~~~~

It turns out that Ubuntu 20.04 installed the 0.7.3-1 version of libxxhash. But from a
quick look at the README on the xxhash github site, XXH3 is first supported by the
0.8.0 version, so the compile error probably makes sense. I found a PPA that offers
the 0.8.3 version of xxhash for Ubuntu 20.04, and that solved the problem.

So the Makefile steps above that figure out if xxhash is present probably aren't
sufficient, as the version of xxhash matters. And the "--checksum not supported"
error message should be more specific about the required version.

I reproduced the behavior on two different Ubuntu 20.04 systems, but
someone who knows this xxhash stuff better than I do should confirm
my conclusions. Maybe the way to fix the check for the presence of xxhash is
to augment the inline test program to include a reference to XXH3_state, but
I haven't tried to put together a patch to do that, pending any further discussion
or ideas.

Michael

> +
> +export BUILD_ORC
> +
>  ifeq ($(srctree),)
>  srctree := $(patsubst %/,%,$(dir $(CURDIR)))
>  srctree := $(patsubst %/,%,$(dir $(srctree)))
> @@ -36,10 +57,10 @@ INCLUDES := -I$(srctree)/tools/include \
>  	    -I$(srctree)/tools/objtool/arch/$(SRCARCH)/include \
>  	    -I$(LIBSUBCMD_OUTPUT)/include
> 
> -OBJTOOL_CFLAGS  := -std=gnu11 -fomit-frame-pointer -O2 -g \
> -		   $(WARNINGS) $(INCLUDES) $(LIBELF_FLAGS) $(HOSTCFLAGS)
> +OBJTOOL_CFLAGS  := -std=gnu11 -fomit-frame-pointer -O2 -g $(WARNINGS)	\
> +		   $(INCLUDES) $(LIBELF_FLAGS) $(LIBXXHASH_CFLAGS)
> $(HOSTCFLAGS)
> 
> -OBJTOOL_LDFLAGS := $(LIBSUBCMD) $(LIBELF_LIBS) $(HOSTLDFLAGS)
> +OBJTOOL_LDFLAGS := $(LIBSUBCMD) $(LIBELF_LIBS) $(LIBXXHASH_LIBS)
> $(HOSTLDFLAGS)
> 
>  # Allow old libelf to be used:
>  elfshdr := $(shell echo '$(pound)include <libelf.h>' | $(HOSTCC) $(OBJTOOL_CFLAGS) -x
> c -E - 2>/dev/null | grep elf_getshdr)
> @@ -51,17 +72,6 @@ HOST_OVERRIDES := CC="$(HOSTCC)" LD="$(HOSTLD)"
> AR="$(HOSTAR)"
>  AWK = awk
>  MKDIR = mkdir
> 
> -BUILD_ORC := n
> -
> -ifeq ($(SRCARCH),x86)
> -	BUILD_ORC := y
> -endif
> -
> -ifeq ($(SRCARCH),loongarch)
> -	BUILD_ORC := y
> -endif
> -
> -export BUILD_ORC
>  export srctree OUTPUT CFLAGS SRCARCH AWK
>  include $(srctree)/tools/build/Makefile.include
> 
> diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
> index 07983cdeded0f..101f05606a990 100644
> --- a/tools/objtool/builtin-check.c
> +++ b/tools/objtool/builtin-check.c
> @@ -73,6 +73,7 @@ static int parse_hacks(const struct option *opt, const char *str, int unset)
> 
>  static const struct option check_options[] = {
>  	OPT_GROUP("Actions:"),
> +	OPT_BOOLEAN(0,		 "checksum", &opts.checksum, "generate per-function checksums"),
>  	OPT_BOOLEAN(0,		 "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
>  	OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
>  	OPT_BOOLEAN('i',	 "ibt", &opts.ibt, "validate and annotate IBT"),
> @@ -160,7 +161,15 @@ static bool opts_valid(void)
>  		return false;
>  	}
> 
> -	if (opts.hack_jump_label	||
> +#ifndef BUILD_KLP
> +	if (opts.checksum) {
> +		ERROR("--checksum not supported; install xxhash-devel and recompile");
> +		return false;
> +	}
> +#endif
> +
> +	if (opts.checksum		||
> +	    opts.hack_jump_label	||
>  	    opts.hack_noinstr		||
>  	    opts.ibt			||
>  	    opts.mcount			||
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index 969a61766f4a6..fec53407428e2 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -14,6 +14,7 @@
>  #include <objtool/check.h>
>  #include <objtool/special.h>
>  #include <objtool/warn.h>
> +#include <objtool/checksum.h>
> 
>  #include <linux/objtool_types.h>
>  #include <linux/hashtable.h>
> @@ -971,6 +972,59 @@ static int create_direct_call_sections(struct objtool_file *file)
>  	return 0;
>  }
> 
> +#ifdef BUILD_KLP
> +static int create_sym_checksum_section(struct objtool_file *file)
> +{
> +	struct section *sec;
> +	struct symbol *sym;
> +	unsigned int idx = 0;
> +	struct sym_checksum *checksum;
> +	size_t entsize = sizeof(struct sym_checksum);
> +
> +	sec = find_section_by_name(file->elf, ".discard.sym_checksum");
> +	if (sec) {
> +		if (!opts.dryrun)
> +			WARN("file already has .discard.sym_checksum section,
> skipping");
> +
> +		return 0;
> +	}
> +
> +	for_each_sym(file->elf, sym)
> +		if (sym->csum.checksum)
> +			idx++;
> +
> +	if (!idx)
> +		return 0;
> +
> +	sec = elf_create_section_pair(file->elf, ".discard.sym_checksum", entsize,
> +				      idx, idx);
> +	if (!sec)
> +		return -1;
> +
> +	idx = 0;
> +	for_each_sym(file->elf, sym) {
> +		if (!sym->csum.checksum)
> +			continue;
> +
> +		if (!elf_init_reloc(file->elf, sec->rsec, idx, idx * entsize,
> +				    sym, 0, R_TEXT64))
> +			return -1;
> +
> +		checksum = (struct sym_checksum *)sec->data->d_buf + idx;
> +		checksum->addr = 0; /* reloc */
> +		checksum->checksum = sym->csum.checksum;
> +
> +		mark_sec_changed(file->elf, sec, true);
> +
> +		idx++;
> +	}
> +
> +	return 0;
> +}
> +#else
> +static int create_sym_checksum_section(struct objtool_file *file) { return -EINVAL; }
> +#endif
> +
>  /*
>   * Warnings shouldn't be reported for ignored functions.
>   */
> @@ -1748,6 +1802,7 @@ static int handle_group_alt(struct objtool_file *file,
>  		nop->type = INSN_NOP;
>  		nop->sym = orig_insn->sym;
>  		nop->alt_group = new_alt_group;
> +		nop->fake = 1;
>  	}
> 
>  	if (!special_alt->new_len) {
> @@ -2527,6 +2582,14 @@ static void mark_holes(struct objtool_file *file)
>  	}
>  }
> 
> +static bool validate_branch_enabled(void)
> +{
> +	return opts.stackval ||
> +	       opts.orc ||
> +	       opts.uaccess ||
> +	       opts.checksum;
> +}
> +
>  static int decode_sections(struct objtool_file *file)
>  {
>  	mark_rodata(file);
> @@ -2555,7 +2618,7 @@ static int decode_sections(struct objtool_file *file)
>  	 * Must be before add_jump_destinations(), which depends on 'func'
>  	 * being set for alternatives, to enable proper sibling call detection.
>  	 */
> -	if (opts.stackval || opts.orc || opts.uaccess || opts.noinstr) {
> +	if (validate_branch_enabled() || opts.noinstr) {
>  		if (add_special_section_alts(file))
>  			return -1;
>  	}
> @@ -3527,6 +3590,50 @@ static bool skip_alt_group(struct instruction *insn)
>  	return alt_insn->type == INSN_CLAC || alt_insn->type == INSN_STAC;
>  }
> 
> +static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
> +				 struct instruction *insn)
> +{
> +	struct reloc *reloc = insn_reloc(file, insn);
> +	unsigned long offset;
> +	struct symbol *sym;
> +
> +	if (insn->fake)
> +		return;
> +
> +	checksum_update(func, insn, insn->sec->data->d_buf + insn->offset, insn-
> >len);
> +
> +	if (!reloc) {
> +		struct symbol *call_dest = insn_call_dest(insn);
> +
> +		if (call_dest)
> +			checksum_update(func, insn, call_dest->demangled_name,
> +					strlen(call_dest->demangled_name));
> +		return;
> +	}
> +
> +	sym = reloc->sym;
> +	offset = arch_insn_adjusted_addend(insn, reloc);
> +
> +	if (is_string_sec(sym->sec)) {
> +		char *str;
> +
> +		str = sym->sec->data->d_buf + sym->offset + offset;
> +		checksum_update(func, insn, str, strlen(str));
> +		return;
> +	}
> +
> +	if (is_sec_sym(sym)) {
> +		sym = find_symbol_containing(reloc->sym->sec, offset);
> +		if (!sym)
> +			return;
> +
> +		offset -= sym->offset;
> +	}
> +
> +	checksum_update(func, insn, sym->demangled_name, strlen(sym-
> >demangled_name));
> +	checksum_update(func, insn, &offset, sizeof(offset));
> +}
> +
>  /*
>   * Follow the branch starting at the given instruction, and recursively follow
>   * any other branches (jumps).  Meanwhile, track the frame pointer state at
> @@ -3547,6 +3654,9 @@ static int validate_branch(struct objtool_file *file, struct
> symbol *func,
>  	while (1) {
>  		next_insn = next_insn_to_validate(file, insn);
> 
> +		if (opts.checksum && func && insn->sec)
> +			checksum_update_insn(file, func, insn);
> +
>  		if (func && insn_func(insn) && func != insn_func(insn)->pfunc) {
>  			/* Ignore KCFI type preambles, which always fall through */
>  			if (is_prefix_func(func))
> @@ -3796,7 +3906,13 @@ static int validate_unwind_hint(struct objtool_file *file,
>  				  struct insn_state *state)
>  {
>  	if (insn->hint && !insn->visited) {
> -		int ret = validate_branch(file, insn_func(insn), insn, *state);
> +		struct symbol *func = insn_func(insn);
> +		int ret;
> +
> +		if (opts.checksum)
> +			checksum_init(func);
> +
> +		ret = validate_branch(file, func, insn, *state);
>  		if (ret)
>  			BT_INSN(insn, "<=== (hint)");
>  		return ret;
> @@ -4175,6 +4291,7 @@ static int validate_symbol(struct objtool_file *file, struct
> section *sec,
>  			   struct symbol *sym, struct insn_state *state)
>  {
>  	struct instruction *insn;
> +	struct symbol *func;
>  	int ret;
> 
>  	if (!sym->len) {
> @@ -4192,9 +4309,18 @@ static int validate_symbol(struct objtool_file *file, struct
> section *sec,
>  	if (opts.uaccess)
>  		state->uaccess = sym->uaccess_safe;
> 
> -	ret = validate_branch(file, insn_func(insn), insn, *state);
> +	func = insn_func(insn);
> +
> +	if (opts.checksum)
> +		checksum_init(func);
> +
> +	ret = validate_branch(file, func, insn, *state);
>  	if (ret)
>  		BT_INSN(insn, "<=== (sym)");
> +
> +	if (opts.checksum)
> +		checksum_finish(func);
> +
>  	return ret;
>  }
> 
> @@ -4712,7 +4838,7 @@ int check(struct objtool_file *file)
>  	if (opts.retpoline)
>  		warnings += validate_retpoline(file);
> 
> -	if (opts.stackval || opts.orc || opts.uaccess) {
> +	if (validate_branch_enabled()) {
>  		int w = 0;
> 
>  		w += validate_functions(file);
> @@ -4791,6 +4917,12 @@ int check(struct objtool_file *file)
>  	if (opts.noabs)
>  		warnings += check_abs_references(file);
> 
> +	if (opts.checksum) {
> +		ret = create_sym_checksum_section(file);
> +		if (ret)
> +			goto out;
> +	}
> +
>  	if (opts.orc && nr_insns) {
>  		ret = orc_create(file);
>  		if (ret)
> diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
> index 6095baba8e9c5..0119b3b4c5540 100644
> --- a/tools/objtool/elf.c
> +++ b/tools/objtool/elf.c
> @@ -17,6 +17,7 @@
>  #include <unistd.h>
>  #include <errno.h>
>  #include <libgen.h>
> +#include <ctype.h>
>  #include <linux/interval_tree_generic.h>
>  #include <objtool/builtin.h>
>  #include <objtool/elf.h>
> @@ -412,7 +413,38 @@ static int read_sections(struct elf *elf)
>  	return 0;
>  }
> 
> -static void elf_add_symbol(struct elf *elf, struct symbol *sym)
> +static const char *demangle_name(struct symbol *sym)
> +{
> +	char *str;
> +
> +	if (!is_local_sym(sym))
> +		return sym->name;
> +
> +	if (!is_func_sym(sym) && !is_object_sym(sym))
> +		return sym->name;
> +
> +	if (!strstarts(sym->name, "__UNIQUE_ID_") && !strchr(sym->name, '.'))
> +		return sym->name;
> +
> +	str = strdup(sym->name);
> +	if (!str) {
> +		ERROR_GLIBC("strdup");
> +		return NULL;
> +	}
> +
> +	for (int i = strlen(str) - 1; i >= 0; i--) {
> +		char c = str[i];
> +
> +		if (!isdigit(c) && c != '.') {
> +			str[i + 1] = '\0';
> +			break;
> +		}
> +	};
> +
> +	return str;
> +}
> +
> +static int elf_add_symbol(struct elf *elf, struct symbol *sym)
>  {
>  	struct list_head *entry;
>  	struct rb_node *pnode;
> @@ -456,6 +488,12 @@ static void elf_add_symbol(struct elf *elf, struct symbol *sym)
>  	if (is_func_sym(sym) && strstr(sym->name, ".cold"))
>  		sym->cold = 1;
>  	sym->pfunc = sym->cfunc = sym;
> +
> +	sym->demangled_name = demangle_name(sym);
> +	if (!sym->demangled_name)
> +		return -1;
> +
> +	return 0;
>  }
> 
>  static int read_symbols(struct elf *elf)
> @@ -529,7 +567,8 @@ static int read_symbols(struct elf *elf)
>  		} else
>  			sym->sec = find_section_by_index(elf, 0);
> 
> -		elf_add_symbol(elf, sym);
> +		if (elf_add_symbol(elf, sym))
> +			return -1;
>  	}
> 
>  	if (opts.stats) {
> @@ -867,7 +906,8 @@ struct symbol *elf_create_symbol(struct elf *elf, const char
> *name,
>  		mark_sec_changed(elf, symtab_shndx, true);
>  	}
> 
> -	elf_add_symbol(elf, sym);
> +	if (elf_add_symbol(elf, sym))
> +		return NULL;
> 
>  	return sym;
>  }
> diff --git a/tools/objtool/include/objtool/builtin.h
> b/tools/objtool/include/objtool/builtin.h
> index 7d559a2c13b7b..338bdab6b9ad8 100644
> --- a/tools/objtool/include/objtool/builtin.h
> +++ b/tools/objtool/include/objtool/builtin.h
> @@ -9,12 +9,15 @@
> 
>  struct opts {
>  	/* actions: */
> +	bool cfi;
> +	bool checksum;
>  	bool dump_orc;
>  	bool hack_jump_label;
>  	bool hack_noinstr;
>  	bool hack_skylake;
>  	bool ibt;
>  	bool mcount;
> +	bool noabs;
>  	bool noinstr;
>  	bool orc;
>  	bool retpoline;
> @@ -25,8 +28,6 @@ struct opts {
>  	bool static_call;
>  	bool uaccess;
>  	int prefix;
> -	bool cfi;
> -	bool noabs;
> 
>  	/* options: */
>  	bool backtrace;
> diff --git a/tools/objtool/include/objtool/check.h
> b/tools/objtool/include/objtool/check.h
> index 0f4e7ac929ef0..d73b0c3ae1ee3 100644
> --- a/tools/objtool/include/objtool/check.h
> +++ b/tools/objtool/include/objtool/check.h
> @@ -65,8 +65,9 @@ struct instruction {
>  	    unret		: 1,
>  	    visited		: 4,
>  	    no_reloc		: 1,
> -	    hole		: 1;
> -		/* 10 bit hole */
> +	    hole		: 1,
> +	    fake		: 1;
> +		/* 9 bit hole */
> 
>  	struct alt_group *alt_group;
>  	struct instruction *jump_dest;
> diff --git a/tools/objtool/include/objtool/checksum.h
> b/tools/objtool/include/objtool/checksum.h
> new file mode 100644
> index 0000000000000..927ca74b5c39e
> --- /dev/null
> +++ b/tools/objtool/include/objtool/checksum.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +#ifndef _OBJTOOL_CHECKSUM_H
> +#define _OBJTOOL_CHECKSUM_H
> +
> +#include <objtool/elf.h>
> +
> +#ifdef BUILD_KLP
> +
> +static inline void checksum_init(struct symbol *func)
> +{
> +	if (func && !func->csum.state) {
> +		func->csum.state = XXH3_createState();
> +		XXH3_64bits_reset(func->csum.state);
> +	}
> +}
> +
> +static inline void checksum_update(struct symbol *func,
> +				   struct instruction *insn,
> +				   const void *data, size_t size)
> +{
> +	XXH3_64bits_update(func->csum.state, data, size);
> +}
> +
> +static inline void checksum_finish(struct symbol *func)
> +{
> +	if (func && func->csum.state) {
> +		func->csum.checksum = XXH3_64bits_digest(func->csum.state);
> +		func->csum.state = NULL;
> +	}
> +}
> +
> +#else /* !BUILD_KLP */
> +
> +static inline void checksum_init(struct symbol *func) {}
> +static inline void checksum_update(struct symbol *func,
> +				   struct instruction *insn,
> +				   const void *data, size_t size) {}
> +static inline void checksum_finish(struct symbol *func) {}
> +
> +#endif /* !BUILD_KLP */
> +
> +#endif /* _OBJTOOL_CHECKSUM_H */
> diff --git a/tools/objtool/include/objtool/checksum_types.h
> b/tools/objtool/include/objtool/checksum_types.h
> new file mode 100644
> index 0000000000000..507efdd8ab5b9
> --- /dev/null
> +++ b/tools/objtool/include/objtool/checksum_types.h
> @@ -0,0 +1,25 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _OBJTOOL_CHECKSUM_TYPES_H
> +#define _OBJTOOL_CHECKSUM_TYPES_H
> +
> +struct sym_checksum {
> +	u64 addr;
> +	u64 checksum;
> +};
> +
> +#ifdef BUILD_KLP
> +
> +#include <xxhash.h>
> +
> +struct checksum {
> +	XXH3_state_t *state;
> +	XXH64_hash_t checksum;
> +};
> +
> +#else /* !BUILD_KLP */
> +
> +struct checksum {};
> +
> +#endif /* !BUILD_KLP */
> +
> +#endif /* _OBJTOOL_CHECKSUM_TYPES_H */
> diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
> index 814cfc0bbf16b..bc7d8a6167f8f 100644
> --- a/tools/objtool/include/objtool/elf.h
> +++ b/tools/objtool/include/objtool/elf.h
> @@ -15,6 +15,7 @@
>  #include <linux/jhash.h>
> 
>  #include <objtool/endianness.h>
> +#include <objtool/checksum_types.h>
>  #include <arch/elf.h>
> 
>  #define SYM_NAME_LEN		512
> @@ -61,7 +62,7 @@ struct symbol {
>  	struct elf_hash_node name_hash;
>  	GElf_Sym sym;
>  	struct section *sec;
> -	const char *name;
> +	const char *name, *demangled_name;
>  	unsigned int idx, len;
>  	unsigned long offset;
>  	unsigned long __subtree_last;
> @@ -84,6 +85,7 @@ struct symbol {
>  	struct list_head pv_target;
>  	struct reloc *relocs;
>  	struct section *group_sec;
> +	struct checksum csum;
>  };
> 
>  struct reloc {
> --
> 2.50.0
> 

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