From: Peter Zijlstra <peterz@infradead.org>
To: Matt Helsley <mhelsley@vmware.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
linux-kernel@vger.kernel.org, x86@kernel.org, dvyukov@google.com,
elver@google.com, andreyknvl@google.com, mark.rutland@arm.com,
rostedt@goodmis.org, jthierry@redhat.com, mbenes@suse.cz
Subject: Re: [RFC][PATCH 1/3] objtool: Clean up elf_write() condition
Date: Tue, 16 Jun 2020 10:32:33 +0200 [thread overview]
Message-ID: <20200616083233.GK2554@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200615184411.GH2531@hirez.programming.kicks-ass.net>
On Mon, Jun 15, 2020 at 08:44:11PM +0200, Peter Zijlstra wrote:
> On Mon, Jun 15, 2020 at 11:34:48AM -0700, Matt Helsley wrote:
> > On Fri, Jun 12, 2020 at 04:30:35PM +0200, Peter Zijlstra wrote:
> > > With there being multiple ways to change the ELF data, let's more
> > > concisely track modification.
> > >
> > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> >
> > Would it make sense to set the relocation section's "changed" flag in
> > addition to the elf struct's changed flag in elf_rebuild_reloc_section()?
> >
> > Right now I think the code is assuming that it's a newly created section
> > but it would be more defensive to set it during a rebuild too I think.
>
> Indeed, currently the code assumes (and this is so) elf_rebuild_rela_sections()
> is only called on an elf_create_reloc_section() result and thus setting
> ->changed is superfluous.
>
> But sure, I can certainly set them there too.
Delta to the patch.
---
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2740,7 +2740,7 @@ int check(const char *_objname, bool orc
objname = _objname;
- file.elf = elf_open_read(objname, orc ? O_RDWR : O_RDONLY);
+ file.elf = elf_open_read(objname, O_RDWR);
if (!file.elf)
return 1;
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -849,11 +849,14 @@ static int elf_rebuild_rela_section(stru
return 0;
}
-int elf_rebuild_reloc_section(struct section *sec)
+int elf_rebuild_reloc_section(struct elf *elf, struct section *sec)
{
struct reloc *reloc;
int nr;
+ sec->changed = true;
+ elf->changed = true;
+
nr = 0;
list_for_each_entry(reloc, &sec->reloc_list, list)
nr++;
--- a/tools/objtool/elf.h
+++ b/tools/objtool/elf.h
@@ -134,7 +134,7 @@ struct reloc *find_reloc_by_dest(const s
struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len);
struct symbol *find_func_containing(struct section *sec, unsigned long offset);
-int elf_rebuild_reloc_section(struct section *sec);
+int elf_rebuild_reloc_section(struct elf *elf, struct section *sec);
#define for_each_sec(file, sec) \
list_for_each_entry(sec, &file->elf->sections, list)
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -222,7 +222,7 @@ int create_orc_sections(struct objtool_f
}
}
- if (elf_rebuild_reloc_section(ip_relocsec))
+ if (elf_rebuild_reloc_section(file->elf, ip_relocsec))
return -1;
return 0;
next prev parent reply other threads:[~2020-06-16 8:32 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-12 14:30 [RFC][PATCH 0/3] objtool: KCOV vs noinstr Peter Zijlstra
2020-06-12 14:30 ` [RFC][PATCH 1/3] objtool: Clean up elf_write() condition Peter Zijlstra
2020-06-15 18:34 ` Matt Helsley
2020-06-15 18:44 ` Peter Zijlstra
2020-06-16 8:32 ` Peter Zijlstra [this message]
2020-06-12 14:30 ` [RFC][PATCH 2/3] objtool: Provide elf_write_{insn,reloc}() Peter Zijlstra
2020-06-16 9:12 ` Peter Zijlstra
2020-06-16 19:51 ` Matt Helsley
2020-06-12 14:30 ` [RFC][PATCH 3/3] objtool: Fix noinstr vs KCOV Peter Zijlstra
2020-06-15 7:41 ` Dmitry Vyukov
2020-06-13 19:54 ` [RFC][PATCH 0/3] objtool: KCOV vs noinstr Matt Helsley
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