[PATCH] riscv: fix computation of pc-relative relocation offset

[PATCH] riscv: fix computation of pc-relative relocation offset

[Andreas Schwab]

The offset calculation was missing the relocation addend.

Signed-off-by: Andreas Schwab <schwab@suse.de>
---
 util/grub-mkimagexx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/util/grub-mkimagexx.c b/util/grub-mkimagexx.c
index bc087c2b5..d16ec63a1 100644
--- a/util/grub-mkimagexx.c
+++ b/util/grub-mkimagexx.c
@@ -1232,8 +1232,7 @@ SUFFIX (relocate_addrs) (Elf_Ehdr *e, struct section_metadata *smd,
 		 grub_uint32_t *t32 = (grub_uint32_t *) target;
 		 grub_uint16_t *t16 = (grub_uint16_t *) target;
 		 grub_uint8_t *t8 = (grub_uint8_t *) target;
-		 grub_int64_t off = (long)sym_addr - target_section_addr - offset
-				    - image_target->vaddr_offset;
+		 grub_int64_t off;
 
 		 /*
 		  * Instructions and instruction encoding are documented in the RISC-V
@@ -1243,6 +1242,7 @@ SUFFIX (relocate_addrs) (Elf_Ehdr *e, struct section_metadata *smd,
 		  */
 
 		 sym_addr += addend;
+		 off = sym_addr - target_section_addr - offset - image_target->vaddr_offset;
 
 		 switch (ELF_R_TYPE (info))
 		   {
-- 
2.22.0

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: [PATCH] riscv: fix computation of pc-relative relocation offset

[Chester Lin]

On Wed, Jun 26, 2019 at 16:50:03 +0200, Andreas Schwab wrote:
> The offset calculation was missing the relocation addend.
> 
> Signed-off-by: Andreas Schwab <schwab@suse.de>
> ---
>  util/grub-mkimagexx.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/util/grub-mkimagexx.c b/util/grub-mkimagexx.c
> index bc087c2b5..d16ec63a1 100644
> --- a/util/grub-mkimagexx.c
> +++ b/util/grub-mkimagexx.c
> @@ -1232,8 +1232,7 @@ SUFFIX (relocate_addrs) (Elf_Ehdr *e, struct section_metadata *smd,
>  		 grub_uint32_t *t32 = (grub_uint32_t *) target;
>  		 grub_uint16_t *t16 = (grub_uint16_t *) target;
>  		 grub_uint8_t *t8 = (grub_uint8_t *) target;
> -		 grub_int64_t off = (long)sym_addr - target_section_addr - offset
> -				    - image_target->vaddr_offset;
> +		 grub_int64_t off;
>  
>  		 /*
>  		  * Instructions and instruction encoding are documented in the RISC-V
> @@ -1243,6 +1242,7 @@ SUFFIX (relocate_addrs) (Elf_Ehdr *e, struct section_metadata *smd,
>  		  */
>  
>  		 sym_addr += addend;
> +		 off = sym_addr - target_section_addr - offset - image_target->vaddr_offset;
>  
>  		 switch (ELF_R_TYPE (info))
>  		   {

This patch can fix a grub abort issue which randomly shows 'unaligned pointer'
warnings on console. I tried this patch on QEMU v4.0.50 + grub-2.0.4-rc1.

Tested-by: Chester Lin <clin@suse.com>

Re: [PATCH] riscv: fix computation of pc-relative relocation offset

[Daniel Kiper]

On Tue, Jul 09, 2019 at 07:06:45AM +0000, Chester Lin wrote:
> On Wed, Jun 26, 2019 at 16:50:03 +0200, Andreas Schwab wrote:
> > The offset calculation was missing the relocation addend.
> >
> > Signed-off-by: Andreas Schwab <schwab@suse.de>
> > ---
> >  util/grub-mkimagexx.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/util/grub-mkimagexx.c b/util/grub-mkimagexx.c
> > index bc087c2b5..d16ec63a1 100644
> > --- a/util/grub-mkimagexx.c
> > +++ b/util/grub-mkimagexx.c
> > @@ -1232,8 +1232,7 @@ SUFFIX (relocate_addrs) (Elf_Ehdr *e, struct section_metadata *smd,
> >  		 grub_uint32_t *t32 = (grub_uint32_t *) target;
> >  		 grub_uint16_t *t16 = (grub_uint16_t *) target;
> >  		 grub_uint8_t *t8 = (grub_uint8_t *) target;
> > -		 grub_int64_t off = (long)sym_addr - target_section_addr - offset
> > -				    - image_target->vaddr_offset;
> > +		 grub_int64_t off;
> >
> >  		 /*
> >  		  * Instructions and instruction encoding are documented in the RISC-V
> > @@ -1243,6 +1242,7 @@ SUFFIX (relocate_addrs) (Elf_Ehdr *e, struct section_metadata *smd,
> >  		  */
> >
> >  		 sym_addr += addend;
> > +		 off = sym_addr - target_section_addr - offset - image_target->vaddr_offset;
> >
> >  		 switch (ELF_R_TYPE (info))
> >  		   {
>
> This patch can fix a grub abort issue which randomly shows 'unaligned pointer'
> warnings on console. I tried this patch on QEMU v4.0.50 + grub-2.0.4-rc1.
>
> Tested-by: Chester Lin <clin@suse.com>

Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Daniel