2024-04-10 21:04:12

by Stafford Horne

[permalink] [raw]
Subject: [PATCH] openrisc: Add support for more module relocations

When testing modules in OpenRISC I found R_OR32_AHI16 (signed adjusted
high 16-bit) and R_OR32_SLO16 (split low 16-bit) relocations are used in
modules but not implemented yet.

This patch adds the relocations. Note, we use the old naming R_OR32_*
instead or the new naming R_OR1K_* to avoid change as this header is
exported as a user api.

Signed-off-by: Stafford Horne <[email protected]>
---
arch/openrisc/include/uapi/asm/elf.h | 2 ++
arch/openrisc/kernel/module.c | 10 ++++++++++
2 files changed, 12 insertions(+)

diff --git a/arch/openrisc/include/uapi/asm/elf.h b/arch/openrisc/include/uapi/asm/elf.h
index 6868f81c281e..0c882a388524 100644
--- a/arch/openrisc/include/uapi/asm/elf.h
+++ b/arch/openrisc/include/uapi/asm/elf.h
@@ -43,6 +43,8 @@
#define R_OR32_JUMPTARG 6
#define R_OR32_VTINHERIT 7
#define R_OR32_VTENTRY 8
+#define R_OR32_AHI16 35
+#define R_OR32_SLO16 39

typedef unsigned long elf_greg_t;

diff --git a/arch/openrisc/kernel/module.c b/arch/openrisc/kernel/module.c
index 532013f523ac..01bda5616114 100644
--- a/arch/openrisc/kernel/module.c
+++ b/arch/openrisc/kernel/module.c
@@ -55,6 +55,16 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
value |= *location & 0xfc000000;
*location = value;
break;
+ case R_OR32_AHI16:
+ /* Adjust the operand to match with a signed LO16. */
+ value += 0x8000;
+ *((uint16_t *)location + 1) = value >> 16;
+ break;
+ case R_OR32_SLO16:
+ /* Split value lower 16-bits. */
+ value = ((value & 0xf800) << 10) | (value & 0x7ff);
+ *location = (*location & ~0x3e007ff) | value;
+ break;
default:
pr_err("module %s: Unknown relocation: %u\n",
me->name, ELF32_R_TYPE(rel[i].r_info));
--
2.44.0



2024-04-11 12:25:32

by Geert Uytterhoeven

[permalink] [raw]
Subject: Re: [PATCH] openrisc: Add support for more module relocations

Hi Stafford,

On Wed, Apr 10, 2024 at 10:52 PM Stafford Horne <[email protected]> wrote:
> This patch adds the relocations. Note, we use the old naming R_OR32_*
> instead or the new naming R_OR1K_* to avoid change as this header is
> exported as a user api.

> --- a/arch/openrisc/include/uapi/asm/elf.h
> +++ b/arch/openrisc/include/uapi/asm/elf.h
> @@ -43,6 +43,8 @@
> #define R_OR32_JUMPTARG 6
> #define R_OR32_VTINHERIT 7
> #define R_OR32_VTENTRY 8
> +#define R_OR32_AHI16 35
> +#define R_OR32_SLO16 39

Would it make sense to switch to the new names, e.g.

#define R_OR1K_NONE 0

and add definitions for backwards compatibility?

#define R_OR32_NONE R_OR1K_NONE

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68korg

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

2024-04-11 17:23:17

by Stafford Horne

[permalink] [raw]
Subject: Re: [PATCH] openrisc: Add support for more module relocations

On Thu, Apr 11, 2024 at 02:12:59PM +0200, Geert Uytterhoeven wrote:
> Hi Stafford,
>
> On Wed, Apr 10, 2024 at 10:52 PM Stafford Horne <[email protected]> wrote:
> > This patch adds the relocations. Note, we use the old naming R_OR32_*
> > instead or the new naming R_OR1K_* to avoid change as this header is
> > exported as a user api.
>
> > --- a/arch/openrisc/include/uapi/asm/elf.h
> > +++ b/arch/openrisc/include/uapi/asm/elf.h
> > @@ -43,6 +43,8 @@
> > #define R_OR32_JUMPTARG 6
> > #define R_OR32_VTINHERIT 7
> > #define R_OR32_VTENTRY 8
> > +#define R_OR32_AHI16 35
> > +#define R_OR32_SLO16 39
>
> Would it make sense to switch to the new names, e.g.
>
> #define R_OR1K_NONE 0
>
> and add definitions for backwards compatibility?
>
> #define R_OR32_NONE R_OR1K_NONE
>

Hi Geert,

Actually I had a patch doing this and added all 38 or so relocation definitions.
But I dropped it at the last moment in favor of simplicity.

Let me rework it and add it back.

-Stafford