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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-23 15:13:45 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-23 15:13:45 -0800
commit414eece95b98b209cef0f49cfcac108fd00b8ced (patch)
tree82de6f145dee0b6261d4a62cb2f9d7d143ace44b /tools/objtool
parent6dd580b93da8de5cab4ac1f24f343086318b664e (diff)
parent5e95325fbbbdea96de91e7bdb05fe95a3031e37d (diff)
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Merge tag 'clang-lto-v5.12-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull more clang LTO updates from Kees Cook: "Clang LTO x86 enablement. Full disclosure: while this has _not_ been in linux-next (since it initially looked like the objtool dependencies weren't going to make v5.12), it has been under daily build and runtime testing by Sami for quite some time. These x86 portions have been discussed on lkml, with Peter, Josh, and others helping nail things down. The bulk of the changes are to get objtool working happily. The rest of the x86 enablement is very small. Summary: - Generate __mcount_loc in objtool (Peter Zijlstra) - Support running objtool against vmlinux.o (Sami Tolvanen) - Clang LTO enablement for x86 (Sami Tolvanen)" Link: https://lore.kernel.org/lkml/20201013003203.4168817-26-samitolvanen@google.com/ Link: https://lore.kernel.org/lkml/cover.1611263461.git.jpoimboe@redhat.com/ * tag 'clang-lto-v5.12-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: kbuild: lto: force rebuilds when switching CONFIG_LTO x86, build: allow LTO to be selected x86, cpu: disable LTO for cpu.c x86, vdso: disable LTO only for vDSO kbuild: lto: postpone objtool objtool: Split noinstr validation from --vmlinux x86, build: use objtool mcount tracing: add support for objtool mcount objtool: Don't autodetect vmlinux.o objtool: Fix __mcount_loc generation with Clang's assembler objtool: Add a pass for generating __mcount_loc
Diffstat (limited to 'tools/objtool')
-rw-r--r--tools/objtool/builtin-check.c10
-rw-r--r--tools/objtool/check.c97
-rw-r--r--tools/objtool/include/objtool/builtin.h2
-rw-r--r--tools/objtool/include/objtool/check.h1
-rw-r--r--tools/objtool/include/objtool/objtool.h1
-rw-r--r--tools/objtool/objtool.c1
6 files changed, 104 insertions, 8 deletions
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index f47951e19c9d..c3a85d8f6c5c 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -18,7 +18,7 @@
#include <objtool/builtin.h>
#include <objtool/objtool.h>
-bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux;
+bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount, noinstr;
static const char * const check_usage[] = {
"objtool check [<options>] file.o",
@@ -34,13 +34,15 @@ const struct option check_options[] = {
OPT_BOOLEAN('a', "uaccess", &uaccess, "enable uaccess checking"),
OPT_BOOLEAN('s', "stats", &stats, "print statistics"),
OPT_BOOLEAN('d', "duplicate", &validate_dup, "duplicate validation for vmlinux.o"),
+ OPT_BOOLEAN('n', "noinstr", &noinstr, "noinstr validation for vmlinux.o"),
OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"),
+ OPT_BOOLEAN('M', "mcount", &mcount, "generate __mcount_loc"),
OPT_END(),
};
int cmd_check(int argc, const char **argv)
{
- const char *objname, *s;
+ const char *objname;
struct objtool_file *file;
int ret;
@@ -51,10 +53,6 @@ int cmd_check(int argc, const char **argv)
objname = argv[0];
- s = strstr(objname, "vmlinux.o");
- if (s && !s[9])
- vmlinux = true;
-
file = objtool_open_read(objname);
if (!file)
return 1;
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 331a763d8775..080a3d6cbd75 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -249,7 +249,7 @@ static void init_insn_state(struct insn_state *state, struct section *sec)
* not correctly determine insn->call_dest->sec (external symbols do
* not have a section).
*/
- if (vmlinux && sec)
+ if (vmlinux && noinstr && sec)
state->noinstr = sec->noinstr;
}
@@ -548,6 +548,78 @@ static int create_static_call_sections(struct objtool_file *file)
return 0;
}
+static int create_mcount_loc_sections(struct objtool_file *file)
+{
+ struct section *sec, *reloc_sec;
+ struct reloc *reloc;
+ unsigned long *loc;
+ struct instruction *insn;
+ int idx;
+
+ sec = find_section_by_name(file->elf, "__mcount_loc");
+ if (sec) {
+ INIT_LIST_HEAD(&file->mcount_loc_list);
+ WARN("file already has __mcount_loc section, skipping");
+ return 0;
+ }
+
+ if (list_empty(&file->mcount_loc_list))
+ return 0;
+
+ idx = 0;
+ list_for_each_entry(insn, &file->mcount_loc_list, mcount_loc_node)
+ idx++;
+
+ sec = elf_create_section(file->elf, "__mcount_loc", 0, sizeof(unsigned long), idx);
+ if (!sec)
+ return -1;
+
+ reloc_sec = elf_create_reloc_section(file->elf, sec, SHT_RELA);
+ if (!reloc_sec)
+ return -1;
+
+ idx = 0;
+ list_for_each_entry(insn, &file->mcount_loc_list, mcount_loc_node) {
+
+ loc = (unsigned long *)sec->data->d_buf + idx;
+ memset(loc, 0, sizeof(unsigned long));
+
+ reloc = malloc(sizeof(*reloc));
+ if (!reloc) {
+ perror("malloc");
+ return -1;
+ }
+ memset(reloc, 0, sizeof(*reloc));
+
+ if (insn->sec->sym) {
+ reloc->sym = insn->sec->sym;
+ reloc->addend = insn->offset;
+ } else {
+ reloc->sym = find_symbol_containing(insn->sec, insn->offset);
+
+ if (!reloc->sym) {
+ WARN("missing symbol for insn at offset 0x%lx\n",
+ insn->offset);
+ return -1;
+ }
+
+ reloc->addend = insn->offset - reloc->sym->offset;
+ }
+
+ reloc->type = R_X86_64_64;
+ reloc->offset = idx * sizeof(unsigned long);
+ reloc->sec = reloc_sec;
+ elf_add_reloc(file->elf, reloc);
+
+ idx++;
+ }
+
+ if (elf_rebuild_reloc_section(file->elf, reloc_sec))
+ return -1;
+
+ return 0;
+}
+
/*
* Warnings shouldn't be reported for ignored functions.
*/
@@ -975,6 +1047,22 @@ static int add_call_destinations(struct objtool_file *file)
insn->type = INSN_NOP;
}
+ if (mcount && !strcmp(insn->call_dest->name, "__fentry__")) {
+ if (reloc) {
+ reloc->type = R_NONE;
+ elf_write_reloc(file->elf, reloc);
+ }
+
+ elf_write_insn(file->elf, insn->sec,
+ insn->offset, insn->len,
+ arch_nop_insn(insn->len));
+
+ insn->type = INSN_NOP;
+
+ list_add_tail(&insn->mcount_loc_node,
+ &file->mcount_loc_list);
+ }
+
/*
* Whatever stack impact regular CALLs have, should be undone
* by the RETURN of the called function.
@@ -3048,6 +3136,13 @@ int check(struct objtool_file *file)
goto out;
warnings += ret;
+ if (mcount) {
+ ret = create_mcount_loc_sections(file);
+ if (ret < 0)
+ goto out;
+ warnings += ret;
+ }
+
out:
/*
* For now, don't fail the kernel build on fatal warnings. These
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index 85c979caa367..2502bb27de17 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -8,7 +8,7 @@
#include <subcmd/parse-options.h>
extern const struct option check_options[];
-extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux;
+extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount, noinstr;
extern int cmd_check(int argc, const char **argv);
extern int cmd_orc(int argc, const char **argv);
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index 4891ead0e85f..f5be798107bc 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -40,6 +40,7 @@ struct instruction {
struct list_head list;
struct hlist_node hash;
struct list_head static_call_node;
+ struct list_head mcount_loc_node;
struct section *sec;
unsigned long offset;
unsigned int len;
diff --git a/tools/objtool/include/objtool/objtool.h b/tools/objtool/include/objtool/objtool.h
index e114642efb65..e68e37476c15 100644
--- a/tools/objtool/include/objtool/objtool.h
+++ b/tools/objtool/include/objtool/objtool.h
@@ -19,6 +19,7 @@ struct objtool_file {
struct list_head insn_list;
DECLARE_HASHTABLE(insn_hash, 20);
struct list_head static_call_list;
+ struct list_head mcount_loc_list;
bool ignore_unreachables, c_file, hints, rodata;
};
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index e848feb0a5fc..7b97ce499405 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -62,6 +62,7 @@ struct objtool_file *objtool_open_read(const char *_objname)
INIT_LIST_HEAD(&file.insn_list);
hash_init(file.insn_hash);
INIT_LIST_HEAD(&file.static_call_list);
+ INIT_LIST_HEAD(&file.mcount_loc_list);
file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment");
file.ignore_unreachables = no_unreachable;
file.hints = false;