elfstructs: add relocation defines for i386

[PATCH for-4.15] elfstructs: add relocation defines for i386

Posted by Roger Pau Monne 3 years, 2 months ago

Those are need by the rombios relocation code in hvmloader. Fixes the
following build error:

32bitbios_support.c: In function 'relocate_32bitbios':
32bitbios_support.c:130:18: error: 'R_386_PC32' undeclared (first use in this function); did you mean 'R_X86_64_PC32'?
             case R_386_PC32:
                  ^~~~~~~~~~
                  R_X86_64_PC32
32bitbios_support.c:130:18: note: each undeclared identifier is reported only once for each function it appears in
32bitbios_support.c:134:18: error: 'R_386_32' undeclared (first use in this function)
             case R_386_32:
                  ^~~~~~~~

Only add the two defines that are actually used, which seems to match
what we do for amd64.

Fixes: 81b2b328a26c1b ('hvmloader: use Xen private header for elf structs')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
 xen/include/xen/elfstructs.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/xen/include/xen/elfstructs.h b/xen/include/xen/elfstructs.h
index 726ca8f60d..d1054ae380 100644
--- a/xen/include/xen/elfstructs.h
+++ b/xen/include/xen/elfstructs.h
@@ -348,6 +348,9 @@ typedef struct {
 #define ELF32_R_TYPE(i)		((unsigned char) (i))
 #define ELF32_R_INFO(s,t) 	(((s) << 8) + (unsigned char)(t))
 
+#define R_386_32           1            /* Direct 32 bit  */
+#define R_386_PC32         2            /* PC relative 32 bit */
+
 typedef struct {
 	Elf64_Addr	r_offset;	/* where to do it */
 	Elf64_Xword	r_info;		/* index & type of relocation */
-- 
2.30.1

Re: [PATCH for-4.15] elfstructs: add relocation defines for i386

Posted by Ian Jackson 3 years, 2 months ago

Roger Pau Monne writes ("[PATCH for-4.15] elfstructs: add relocation defines for i386"):
> Those are need by the rombios relocation code in hvmloader. Fixes the
> following build error:
> 
> 32bitbios_support.c: In function 'relocate_32bitbios':
> 32bitbios_support.c:130:18: error: 'R_386_PC32' undeclared (first use in this function); did you mean 'R_X86_64_PC32'?
>              case R_386_PC32:
>                   ^~~~~~~~~~
>                   R_X86_64_PC32
> 32bitbios_support.c:130:18: note: each undeclared identifier is reported only once for each function it appears in
> 32bitbios_support.c:134:18: error: 'R_386_32' undeclared (first use in this function)
>              case R_386_32:
>                   ^~~~~~~~
> 
> Only add the two defines that are actually used, which seems to match
> what we do for amd64.
> 
> Fixes: 81b2b328a26c1b ('hvmloader: use Xen private header for elf structs')
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

Release-Acked-by: Ian Jackson <iwj@xenproject.org>

Re: [PATCH for-4.15] elfstructs: add relocation defines for i386

Posted by Jan Beulich 3 years, 2 months ago

On 24.02.2021 15:58, Roger Pau Monne wrote:
> Those are need by the rombios relocation code in hvmloader. Fixes the
> following build error:
> 
> 32bitbios_support.c: In function 'relocate_32bitbios':
> 32bitbios_support.c:130:18: error: 'R_386_PC32' undeclared (first use in this function); did you mean 'R_X86_64_PC32'?
>              case R_386_PC32:
>                   ^~~~~~~~~~
>                   R_X86_64_PC32
> 32bitbios_support.c:130:18: note: each undeclared identifier is reported only once for each function it appears in
> 32bitbios_support.c:134:18: error: 'R_386_32' undeclared (first use in this function)
>              case R_386_32:
>                   ^~~~~~~~
> 
> Only add the two defines that are actually used, which seems to match
> what we do for amd64.
> 
> Fixes: 81b2b328a26c1b ('hvmloader: use Xen private header for elf structs')
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

In principle
Reviewed-by: Jan Beulich <jbeulich@suse.com>

But ...

> --- a/xen/include/xen/elfstructs.h
> +++ b/xen/include/xen/elfstructs.h
> @@ -348,6 +348,9 @@ typedef struct {
>  #define ELF32_R_TYPE(i)		((unsigned char) (i))
>  #define ELF32_R_INFO(s,t) 	(((s) << 8) + (unsigned char)(t))
>  
> +#define R_386_32           1            /* Direct 32 bit  */
> +#define R_386_PC32         2            /* PC relative 32 bit */
> +
>  typedef struct {
>  	Elf64_Addr	r_offset;	/* where to do it */
>  	Elf64_Xword	r_info;		/* index & type of relocation */

... I'm heavily inclined to move this a few lines down to where
the other relocation types get defined, and add a respective
comment.

Jan

Re: [PATCH for-4.15] elfstructs: add relocation defines for i386

Posted by Roger Pau Monné 3 years, 2 months ago

On Wed, Feb 24, 2021 at 04:01:13PM +0100, Jan Beulich wrote:
> On 24.02.2021 15:58, Roger Pau Monne wrote:
> > Those are need by the rombios relocation code in hvmloader. Fixes the
> > following build error:
> > 
> > 32bitbios_support.c: In function 'relocate_32bitbios':
> > 32bitbios_support.c:130:18: error: 'R_386_PC32' undeclared (first use in this function); did you mean 'R_X86_64_PC32'?
> >              case R_386_PC32:
> >                   ^~~~~~~~~~
> >                   R_X86_64_PC32
> > 32bitbios_support.c:130:18: note: each undeclared identifier is reported only once for each function it appears in
> > 32bitbios_support.c:134:18: error: 'R_386_32' undeclared (first use in this function)
> >              case R_386_32:
> >                   ^~~~~~~~
> > 
> > Only add the two defines that are actually used, which seems to match
> > what we do for amd64.
> > 
> > Fixes: 81b2b328a26c1b ('hvmloader: use Xen private header for elf structs')
> > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> 
> In principle
> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> 
> But ...
> 
> > --- a/xen/include/xen/elfstructs.h
> > +++ b/xen/include/xen/elfstructs.h
> > @@ -348,6 +348,9 @@ typedef struct {
> >  #define ELF32_R_TYPE(i)		((unsigned char) (i))
> >  #define ELF32_R_INFO(s,t) 	(((s) << 8) + (unsigned char)(t))
> >  
> > +#define R_386_32           1            /* Direct 32 bit  */
> > +#define R_386_PC32         2            /* PC relative 32 bit */
> > +
> >  typedef struct {
> >  	Elf64_Addr	r_offset;	/* where to do it */
> >  	Elf64_Xword	r_info;		/* index & type of relocation */
> 
> ... I'm heavily inclined to move this a few lines down to where
> the other relocation types get defined, and add a respective
> comment.

I've placed it together with the other 32bit ELF relocation structures
and macros, but I see the rest of the relocation defines are a bit
below, feel free to move it. For a comment:

/*
 * Relocation definitions required by the rombios hvmloader relocation
 * code.
 */

Does seem fine?

Thanks, Roger.