Re: [PATCH] objtool: support symtab_shndx during dump

2020-09-04 Thread Josh Poimboeuf 
On Fri, Sep 04, 2020 at 09:54:29AM +0200, Miroslav Benes wrote:
> On Thu, 3 Sep 2020, Josh Poimboeuf wrote:
> 
> > On Wed, Aug 12, 2020 at 10:57:11AM -0700, Kristen Carlson Accardi wrote:
> > 
> > >   if (GELF_ST_TYPE(sym.st_info) == STT_SECTION) {
> > > - scn = elf_getscn(elf, sym.st_shndx);
> > > + if ((sym.st_shndx > SHN_UNDEF &&
> > > +  sym.st_shndx < SHN_LORESERVE) ||
> > > + (xsymtab && sym.st_shndx == SHN_XINDEX)) {
> > > + if (sym.st_shndx != SHN_XINDEX)
> > > + shndx = sym.st_shndx;
> > 
> > The sym.st_shndx checks are redundant, if 'sym.st_shndx == SHN_XINDEX'
> > then 'sym.st_shndx != SHN_XINDEX' can't be true.
> 
> It is probably a copy-paste from read_symbols() in elf.c, where the logic 
> is different.

Yeah.

> > Actually I think this can be even further simplified to something like
> > 
> > if (!shndx)
> > shndx = sym.st_shndx;
> 
> This relies on the fact that gelf_getsymshndx() always initializes shndx, 
> no? I think it would be better to initialize it in orc_dump() too. Safer 
> and easier to read. It applies to Kristen's patch as well. I missed that.

Agreed.

-- 
Josh

Re: [PATCH] objtool: support symtab_shndx during dump

2020-09-04 Thread Miroslav Benes 
On Thu, 3 Sep 2020, Josh Poimboeuf wrote:

> On Wed, Aug 12, 2020 at 10:57:11AM -0700, Kristen Carlson Accardi wrote:
> 
> > if (GELF_ST_TYPE(sym.st_info) == STT_SECTION) {
> > -   scn = elf_getscn(elf, sym.st_shndx);
> > +   if ((sym.st_shndx > SHN_UNDEF &&
> > +sym.st_shndx < SHN_LORESERVE) ||
> > +   (xsymtab && sym.st_shndx == SHN_XINDEX)) {
> > +   if (sym.st_shndx != SHN_XINDEX)
> > +   shndx = sym.st_shndx;
> 
> The sym.st_shndx checks are redundant, if 'sym.st_shndx == SHN_XINDEX'
> then 'sym.st_shndx != SHN_XINDEX' can't be true.

It is probably a copy-paste from read_symbols() in elf.c, where the logic 
is different.

> Actually I think this can be even further simplified to something like
> 
>   if (!shndx)
>   shndx = sym.st_shndx;

This relies on the fact that gelf_getsymshndx() always initializes shndx, 
no? I think it would be better to initialize it in orc_dump() too. Safer 
and easier to read. It applies to Kristen's patch as well. I missed that.

Miroslav

Re: [PATCH] objtool: support symtab_shndx during dump

2020-09-03 Thread Josh Poimboeuf 
On Wed, Aug 12, 2020 at 10:57:11AM -0700, Kristen Carlson Accardi wrote:
> When getting the symbol index number, make sure to use the
> extended symbol table information in order to support symbol
> index's greater than 64K.

"indexes"

>   if (GELF_ST_TYPE(sym.st_info) == STT_SECTION) {
> - scn = elf_getscn(elf, sym.st_shndx);
> + if ((sym.st_shndx > SHN_UNDEF &&
> +  sym.st_shndx < SHN_LORESERVE) ||
> + (xsymtab && sym.st_shndx == SHN_XINDEX)) {
> + if (sym.st_shndx != SHN_XINDEX)
> + shndx = sym.st_shndx;

The sym.st_shndx checks are redundant, if 'sym.st_shndx == SHN_XINDEX'
then 'sym.st_shndx != SHN_XINDEX' can't be true.

Actually I think this can be even further simplified to something like

if (!shndx)
shndx = sym.st_shndx;

-- 
Josh

Re: [PATCH] objtool: support symtab_shndx during dump

2020-09-03 Thread Miroslav Benes 
On Wed, 12 Aug 2020, Kristen Carlson Accardi wrote:

> When getting the symbol index number, make sure to use the
> extended symbol table information in order to support symbol
> index's greater than 64K.
> 
> Signed-off-by: Kristen Carlson Accardi 

Reviewed-by: Miroslav Benes 

M

[PATCH] objtool: support symtab_shndx during dump

2020-08-12 Thread Kristen Carlson Accardi 
When getting the symbol index number, make sure to use the
extended symbol table information in order to support symbol
index's greater than 64K.

Signed-off-by: Kristen Carlson Accardi 
---
 tools/objtool/orc_dump.c | 20 
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index fca46e006fc2..cf835069724a 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -74,7 +74,8 @@ int orc_dump(const char *_objname)
GElf_Rela rela;
GElf_Sym sym;
Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
-
+   Elf_Data *xsymtab = NULL;
+   Elf32_Word shndx;
 
objname = _objname;
 
@@ -138,6 +139,8 @@ int orc_dump(const char *_objname)
orc_ip_addr = sh.sh_addr;
} else if (!strcmp(name, ".rela.orc_unwind_ip")) {
rela_orc_ip = data;
+   } else if (!strcmp(name, ".symtab_shndx")) {
+   xsymtab = data;
}
}
 
@@ -157,13 +160,22 @@ int orc_dump(const char *_objname)
return -1;
}
 
-   if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), 
)) {
-   WARN_ELF("gelf_getsym");
+   if (!gelf_getsymshndx(symtab, xsymtab,
+ GELF_R_SYM(rela.r_info),
+ , )) {
+   WARN_ELF("gelf_getsymshndx");
return -1;
}
 
if (GELF_ST_TYPE(sym.st_info) == STT_SECTION) {
-   scn = elf_getscn(elf, sym.st_shndx);
+   if ((sym.st_shndx > SHN_UNDEF &&
+sym.st_shndx < SHN_LORESERVE) ||
+   (xsymtab && sym.st_shndx == SHN_XINDEX)) {
+   if (sym.st_shndx != SHN_XINDEX)
+   shndx = sym.st_shndx;
+   }
+
+   scn = elf_getscn(elf, shndx);
if (!scn) {
WARN_ELF("elf_getscn");
return -1;
-- 
2.20.1