xen/arm: Don't pad between function with x86 nops

[PATCH] xen/arm: Don't pad between function with x86 nops

Posted by Andrew Cooper 2 days, 20 hours ago

This was copy&paste from x86.  It causes the padding between functions to be:

  a000026dd64:   90909090        adrp    x16, 9ff2147d000 <start-0xded83000>

rather than:

  a000026dd64:   00000000        udf     #0

No functional change.

Fixes: 5da0d3123c0a ("arm: entry.S and head.S")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien@xen.org>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
CC: Bertrand Marquis <bertrand.marquis@arm.com>
CC: Michal Orzel <michal.orzel@amd.com>

Has no-one looked at disassembly and wondered why there are junk instructions
between functions?
---
 xen/arch/arm/xen.lds.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 2d5f1c516d03..d4d959403307 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -47,7 +47,7 @@ SECTIONS
 
        *(.gnu.warning)
        _etext = .;             /* End of text section */
-  } :text = 0x9090
+  } :text
 
   . = ALIGN(PAGE_SIZE);
   .rodata : {
-- 
2.39.5

Re: [PATCH] xen/arm: Don't pad between function with x86 nops

Posted by Orzel, Michal 2 days, 18 hours ago


On 31-Aug-26 11:56, Andrew Cooper wrote:
> This was copy&paste from x86.  It causes the padding between functions to be:
> 
>   a000026dd64:   90909090        adrp    x16, 9ff2147d000 <start-0xded83000>
> 
> rather than:
> 
>   a000026dd64:   00000000        udf     #0
> 
> No functional change.
> 
> Fixes: 5da0d3123c0a ("arm: entry.S and head.S")
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>

~Michal