arm64 entry point

arm64 entry point

[Geoff Levand]

Hi,

There is some discrepancy between what booting.txt says and what our
linker script defines as the kernel entry point.

Here is booting.txt:

  The primary CPU must jump directly to the first instruction of the
  kernel image.

And the linker script:

  ENTRY(stext)

Should we change booting.txt, or the linker script?

-Geoff

arm64 entry point

[Will Deacon]

On Fri, May 16, 2014 at 12:06:31AM +0100, Geoff Levand wrote:
> Hi,

Hi Geoff,

> There is some discrepancy between what booting.txt says and what our
> linker script defines as the kernel entry point.
> 
> Here is booting.txt:
> 
>   The primary CPU must jump directly to the first instruction of the
>   kernel image.
> 
> And the linker script:
> 
>   ENTRY(stext)
> 
> Should we change booting.txt, or the linker script?

We should fix the linker script to have the correct entry address.

Care to send a patch?

Will

[PATCH] arm64: Fix linker script entry point

[Geoff Levand]

Change the arm64 linker script ENTRY() command to define _text as the
kernel entry point.

The arm64 boot protocol specifies that the kernel must be entered at the
beginning of the kernel image.  The existing ENTRY() command defined the
symbol stext as the entry point, which emitted an incorrect entry point,
but would not cause a runtime error because the existing entry code
immediately jumps to stext.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
Hi Will,

As requested, here is a fix for the linker script.  There are a lot of ways
we can define the entry point.  Let me know if you want to do it differently.

-Geoff

 arch/arm64/kernel/vmlinux.lds.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 4ba7a55..f1e6d5c 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -13,7 +13,7 @@
 #define ARM_EXIT_DISCARD(x)	x
 
 OUTPUT_ARCH(aarch64)
-ENTRY(stext)
+ENTRY(_text)
 
 jiffies = jiffies_64;
 
-- 
1.9.1

[PATCH] arm64: Fix linker script entry point

[Will Deacon]

On Fri, May 16, 2014 at 06:26:01PM +0100, Geoff Levand wrote:
> Change the arm64 linker script ENTRY() command to define _text as the
> kernel entry point.
> 
> The arm64 boot protocol specifies that the kernel must be entered at the
> beginning of the kernel image.  The existing ENTRY() command defined the
> symbol stext as the entry point, which emitted an incorrect entry point,
> but would not cause a runtime error because the existing entry code
> immediately jumps to stext.
> 
> Signed-off-by: Geoff Levand <geoff@infradead.org>
> ---
> Hi Will,
> 
> As requested, here is a fix for the linker script.  There are a lot of ways
> we can define the entry point.  Let me know if you want to do it differently.

Looks good to me, thanks:

  Acked-by: Will Deacon <will.deacon@arm.com>

Will

>  arch/arm64/kernel/vmlinux.lds.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
> index 4ba7a55..f1e6d5c 100644
> --- a/arch/arm64/kernel/vmlinux.lds.S
> +++ b/arch/arm64/kernel/vmlinux.lds.S
> @@ -13,7 +13,7 @@
>  #define ARM_EXIT_DISCARD(x)	x
>  
>  OUTPUT_ARCH(aarch64)
> -ENTRY(stext)
> +ENTRY(_text)
>  
>  jiffies = jiffies_64;
>  
> -- 
> 1.9.1
> 
> 
> 
>