From: Matt Helsley <mhelsley@vmware.com>
To: <linux-kernel@vger.kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Sami Tolvanen <samitolvanen@google.com>,
Julien Thierry <jthierry@redhat.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Matt Helsley <mhelsley@vmware.com>
Subject: [RFC][PATCH v4 18/32] objtool: mcount: Move nop_mcount()
Date: Tue, 2 Jun 2020 12:50:11 -0700 [thread overview]
Message-ID: <7109ceb239a88c2901eeb7f52c29f69cdb413cd3.1591125127.git.mhelsley@vmware.com> (raw)
In-Reply-To: <cover.1591125127.git.mhelsley@vmware.com>
The nop_mcount() function overwrites mcount calls that should be
ignored with no-ops. This operation varies by architecture and
wordsize so we retain the function pointers used to implement
the fundamental operation while nop_mcount() itself is responsible
for walking the relocations, determining if they should be turned
into no-ops, then calling the arch-specific code. Since none of
these use the recordmcount ELF wrappers anymore we can move it out
of the wrapper.
Signed-off-by: Matt Helsley <mhelsley@vmware.com>
---
tools/objtool/recordmcount.c | 47 +++++++++++++++++++++++++++++++++
tools/objtool/recordmcount.h | 50 ------------------------------------
2 files changed, 47 insertions(+), 50 deletions(-)
diff --git a/tools/objtool/recordmcount.c b/tools/objtool/recordmcount.c
index 89762908290e..88998a505859 100644
--- a/tools/objtool/recordmcount.c
+++ b/tools/objtool/recordmcount.c
@@ -398,6 +398,53 @@ static int find_section_sym_index(unsigned const txtndx,
return missing_sym;
}
+/*
+ * Read the relocation table again, but this time its called on sections
+ * that are not going to be traced. The mcount calls here will be converted
+ * into nops.
+ */
+static int nop_mcount(struct section * const rels,
+ const char *const txtname)
+{
+ struct reloc *reloc;
+ struct section *txts = find_section_by_index(lf, rels->sh.sh_info);
+ unsigned mcountsym = 0;
+ int once = 0;
+
+ list_for_each_entry(reloc, &rels->reloc_list, list) {
+ int ret = -1;
+
+ if (!mcountsym)
+ mcountsym = get_mcountsym(reloc);
+
+ if (mcountsym == GELF_R_INFO(reloc->sym->idx, reloc->type) && !is_fake_mcount(reloc)) {
+ if (make_nop) {
+ ret = make_nop(txts, reloc->offset);
+ if (ret < 0)
+ return -1;
+ }
+ if (warn_on_notrace_sect && !once) {
+ printf("Section %s has mcount callers being ignored\n",
+ txtname);
+ once = 1;
+ /* just warn? */
+ if (!make_nop)
+ return 0;
+ }
+ }
+
+ /*
+ * If we successfully removed the mcount, mark the relocation
+ * as a nop (don't do anything with it).
+ */
+ if (!ret) {
+ reloc->type = rel_type_nop;
+ rels->changed = true;
+ }
+ }
+ return 0;
+}
+
/* 32 bit and 64 bit are very similar */
#include "recordmcount.h"
#define RECORD_MCOUNT_64
diff --git a/tools/objtool/recordmcount.h b/tools/objtool/recordmcount.h
index 6754bde0bacc..e033b600bd61 100644
--- a/tools/objtool/recordmcount.h
+++ b/tools/objtool/recordmcount.h
@@ -20,7 +20,6 @@
#undef append_func
#undef mcount_adjust
#undef sift_rel_mcount
-#undef nop_mcount
#undef has_rel_mcount
#undef tot_relsize
#undef do_func
@@ -37,7 +36,6 @@
#ifdef RECORD_MCOUNT_64
# define append_func append64
# define sift_rel_mcount sift64_rel_mcount
-# define nop_mcount nop_mcount_64
# define has_rel_mcount has64_rel_mcount
# define tot_relsize tot64_relsize
# define do_func do64
@@ -53,7 +51,6 @@
#else
# define append_func append32
# define sift_rel_mcount sift32_rel_mcount
-# define nop_mcount nop_mcount_32
# define has_rel_mcount has32_rel_mcount
# define tot_relsize tot32_relsize
# define do_func do32
@@ -171,53 +168,6 @@ static uint_t *sift_rel_mcount(uint_t *mlocp,
return mlocp;
}
-/*
- * Read the relocation table again, but this time its called on sections
- * that are not going to be traced. The mcount calls here will be converted
- * into nops.
- */
-static int nop_mcount(struct section * const rels,
- const char *const txtname)
-{
- struct reloc *reloc;
- struct section *txts = find_section_by_index(lf, rels->sh.sh_info);
- unsigned mcountsym = 0;
- int once = 0;
-
- list_for_each_entry(reloc, &rels->reloc_list, list) {
- int ret = -1;
-
- if (!mcountsym)
- mcountsym = get_mcountsym(reloc);
-
- if (mcountsym == GELF_R_INFO(reloc->sym->idx, reloc->type) && !is_fake_mcount(reloc)) {
- if (make_nop) {
- ret = make_nop(txts, reloc->offset);
- if (ret < 0)
- return -1;
- }
- if (warn_on_notrace_sect && !once) {
- printf("Section %s has mcount callers being ignored\n",
- txtname);
- once = 1;
- /* just warn? */
- if (!make_nop)
- return 0;
- }
- }
-
- /*
- * If we successfully removed the mcount, mark the relocation
- * as a nop (don't do anything with it).
- */
- if (!ret) {
- reloc->type = rel_type_nop;
- rels->changed = true;
- }
- }
- return 0;
-}
-
static char const *has_rel_mcount(const struct section * const rels)
{
const struct section *txts;
--
2.20.1
next prev parent reply other threads:[~2020-06-02 19:52 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-02 19:49 [RFC][PATCH v4 00/32] objtool: Make recordmcount a subcommand Matt Helsley
2020-06-02 19:49 ` [RFC][PATCH v4 01/32] objtool: Prepare to merge recordmcount Matt Helsley
2020-06-09 8:54 ` Julien Thierry
2020-06-09 15:42 ` Matt Helsley
2020-06-09 19:31 ` Julien Thierry
2020-06-02 19:49 ` [RFC][PATCH v4 02/32] objtool: Make recordmcount into mcount subcmd Matt Helsley
2020-06-09 9:00 ` Julien Thierry
2020-06-09 18:39 ` Matt Helsley
2020-06-09 18:52 ` Steven Rostedt
2020-06-09 18:56 ` Matt Helsley
2020-06-09 19:11 ` Julien Thierry
2020-06-02 19:49 ` [RFC][PATCH v4 03/32] objtool: recordmcount: Start using objtool's elf wrapper Matt Helsley
2020-06-02 19:49 ` [RFC][PATCH v4 04/32] objtool: recordmcount: Search for __mcount_loc before walking the sections Matt Helsley
2020-06-02 19:49 ` [RFC][PATCH v4 05/32] objtool: recordmcount: Convert do_func() relhdrs Matt Helsley
2020-06-02 19:49 ` [RFC][PATCH v4 06/32] objtool: mcount: Remove unused fname parameter Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 07/32] objtool: mcount: Use libelf for section header names Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 08/32] objtool: mcount: Walk objtool Elf structs in find_secsym_ndx Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 09/32] objtool: mcount: Use symbol structs to find mcount relocations Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 10/32] objtool: mcount: Walk relocation lists Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 11/32] objtool: mcount: Move get_mcountsym Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 12/32] objtool: mcount: Replace MIPS offset types Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 13/32] objtool: mcount: Move is_fake_mcount() Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 14/32] objtool: mcount: Stop using ehdr in find_section_sym_index Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 15/32] objtool: mcount: Move find_section_sym_index() Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 16/32] objtool: mcount: Restrict using ehdr in append_func() Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 17/32] objtool: mcount: Use objtool ELF to write Matt Helsley
2020-06-02 19:50 ` Matt Helsley [this message]
2020-06-12 13:26 ` [RFC][PATCH v4 18/32] objtool: mcount: Move nop_mcount() Peter Zijlstra
2020-06-12 16:05 ` Peter Zijlstra
2020-06-17 17:36 ` Matt Helsley
2020-06-17 18:30 ` Peter Zijlstra
2020-06-13 19:49 ` Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 19/32] objtool: mcount: Move has_rel_mcount() and tot_relsize() Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 20/32] objtool: mcount: Move relocation entry size detection Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 21/32] objtool: mcount: Only keep ELF file size Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 22/32] objtool: mcount: Use ELF header from objtool Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 23/32] objtool: mcount: Remove unused file mapping Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 24/32] objtool: mcount: Reduce usage of _size wrapper Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 25/32] objtool: mcount: Move mcount_adjust out of wrapper Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 26/32] objtool: mcount: Pre-allocate new ELF sections Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 27/32] objtool: mcount: Generic location and relocation table types Matt Helsley
2020-06-09 6:41 ` Kamalesh Babulal
2020-06-09 18:12 ` Matt Helsley
2020-06-10 4:35 ` Kamalesh Babulal
2020-06-02 19:50 ` [RFC][PATCH v4 28/32] objtool: mcount: Move sift_rel_mcount out of wrapper file Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 29/32] objtool: mcount: Remove wrapper for ELF relocation type Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 30/32] objtool: mcount: Remove wrapper double-include trick Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 31/32] objtool: mcount: Remove endian wrappers Matt Helsley
2020-06-02 19:50 ` [RFC][PATCH v4 32/32] objtool: mcount: Rename Matt Helsley
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7109ceb239a88c2901eeb7f52c29f69cdb413cd3.1591125127.git.mhelsley@vmware.com \
--to=mhelsley@vmware.com \
--cc=jpoimboe@redhat.com \
--cc=jthierry@redhat.com \
--cc=kamalesh@linux.vnet.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=samitolvanen@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).