2022-09-22 13:18:44

by Chen Zhongjin

Subject: [PATCH -next 2/3] arm64: head: Mark constants as data

Add data annotations to constants part of the image header.

Signed-off-by: Julien Thierry <[email protected]>
Signed-off-by: Chen Zhongjin <[email protected]>
Reviewed-by: Mark Brown <[email protected]>
---
arch/arm64/kernel/head.S | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 814b6587ccb7..f298e88e2d23 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -57,9 +57,10 @@
/*
* DO NOT MODIFY. Image header expected by Linux boot-loaders.
*/
- efi_signature_nop // special NOP to identity as PE/COFF executable
+SYM_DATA_LOCAL(efi_nop, efi_signature_nop) // special NOP to identity as PE/COFF executable
b primary_entry // branch to kernel start, magic
- .quad 0 // Image load offset from start of RAM, little-endian
+SYM_DATA_LOCAL(_zero_reserved, .quad 0) // Image load offset from start of RAM, little-endian
+SYM_DATA_START_LOCAL(_arm64_common_header)
le64sym _kernel_size_le // Effective size of kernel image, little-endian
le64sym _kernel_flags_le // Informative flags, little-endian
.quad 0 // reserved
@@ -67,6 +68,7 @@
.quad 0 // reserved
.ascii ARM64_IMAGE_MAGIC // Magic number
.long .Lpe_header_offset // Offset to the PE header.
+SYM_DATA_END(_arm64_common_header)

__EFI_PE_HEADER

--
2.17.1

2022-09-22 13:24:45

by Ard Biesheuvel

Subject: Re: [PATCH -next 2/3] arm64: head: Mark constants as data

On Thu, 22 Sept 2022 at 15:08, Chen Zhongjin <[email protected]> wrote:
>
> Add data annotations to constants part of the image header.
>
> Signed-off-by: Julien Thierry <[email protected]>
> Signed-off-by: Chen Zhongjin <[email protected]>
> Reviewed-by: Mark Brown <[email protected]>
> ---
> arch/arm64/kernel/head.S | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
> index 814b6587ccb7..f298e88e2d23 100644
> --- a/arch/arm64/kernel/head.S
> +++ b/arch/arm64/kernel/head.S
> @@ -57,9 +57,10 @@
> /*
> * DO NOT MODIFY. Image header expected by Linux boot-loaders.
> */
> - efi_signature_nop // special NOP to identity as PE/COFF executable
> +SYM_DATA_LOCAL(efi_nop, efi_signature_nop) // special NOP to identity as PE/COFF executable

This is an instruction not data

> b primary_entry // branch to kernel start, magic
> - .quad 0 // Image load offset from start of RAM, little-endian
> +SYM_DATA_LOCAL(_zero_reserved, .quad 0) // Image load offset from start of RAM, little-endian

Why convert this quad? And why does it need a symbol?

> +SYM_DATA_START_LOCAL(_arm64_common_header)
> le64sym _kernel_size_le // Effective size of kernel image, little-endian
> le64sym _kernel_flags_le // Informative flags, little-endian
> .quad 0 // reserved

But not this one?

> @@ -67,6 +68,7 @@
> .quad 0 // reserved
> .ascii ARM64_IMAGE_MAGIC // Magic number
> .long .Lpe_header_offset // Offset to the PE header.
> +SYM_DATA_END(_arm64_common_header)
>
> __EFI_PE_HEADER
>
> --
> 2.17.1
>