arm64: fix .data.rel.ro size assertion when CONFIG_LTO_CLANG

[PATCH] arm64: fix .data.rel.ro size assertion when CONFIG_LTO_CLANG

Posted by Masahiro Yamada 2 weeks, 3 days ago

Commit be2881824ae9 ("arm64/build: Assert for unwanted sections")
introduced an assertion to ensure that the .data.rel.ro section does
not exist.

However, this check does not work when CONFIG_LTO_CLANG is enabled,
because .data.rel.ro matches the .data.[0-9a-zA-Z_]* pattern in the
DATA_MAIN macro.

Move the ASSERT() above the RW_DATA() line.

Fixes: be2881824ae9 ("arm64/build: Assert for unwanted sections")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 arch/arm64/kernel/vmlinux.lds.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 58d89d997d05..f84c71f04d9e 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -287,6 +287,9 @@ SECTIONS
 	__initdata_end = .;
 	__init_end = .;
 
+	.data.rel.ro : { *(.data.rel.ro) }
+	ASSERT(SIZEOF(.data.rel.ro) == 0, "Unexpected RELRO detected!")
+
 	_data = .;
 	_sdata = .;
 	RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN)
@@ -343,9 +346,6 @@ SECTIONS
 		*(.plt) *(.plt.*) *(.iplt) *(.igot .igot.plt)
 	}
 	ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!")
-
-	.data.rel.ro : { *(.data.rel.ro) }
-	ASSERT(SIZEOF(.data.rel.ro) == 0, "Unexpected RELRO detected!")
 }
 
 #include "image-vars.h"
-- 
2.43.0

Re: [PATCH] arm64: fix .data.rel.ro size assertion when CONFIG_LTO_CLANG

Posted by Catalin Marinas 2 weeks, 2 days ago

On Thu, 07 Nov 2024 01:18:42 +0900, Masahiro Yamada wrote:
> Commit be2881824ae9 ("arm64/build: Assert for unwanted sections")
> introduced an assertion to ensure that the .data.rel.ro section does
> not exist.
> 
> However, this check does not work when CONFIG_LTO_CLANG is enabled,
> because .data.rel.ro matches the .data.[0-9a-zA-Z_]* pattern in the
> DATA_MAIN macro.
> 
> [...]

Applied to arm64 (for-next/misc), thanks!

[1/1] arm64: fix .data.rel.ro size assertion when CONFIG_LTO_CLANG
      https://git.kernel.org/arm64/c/340fd66c8566

-- 
Catalin

Re: [PATCH] arm64: fix .data.rel.ro size assertion when CONFIG_LTO_CLANG

Posted by Will Deacon 2 weeks, 2 days ago

On Thu, Nov 07, 2024 at 01:18:42AM +0900, Masahiro Yamada wrote:
> Commit be2881824ae9 ("arm64/build: Assert for unwanted sections")
> introduced an assertion to ensure that the .data.rel.ro section does
> not exist.
> 
> However, this check does not work when CONFIG_LTO_CLANG is enabled,
> because .data.rel.ro matches the .data.[0-9a-zA-Z_]* pattern in the
> DATA_MAIN macro.
> 
> Move the ASSERT() above the RW_DATA() line.
> 
> Fixes: be2881824ae9 ("arm64/build: Assert for unwanted sections")
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
> 
>  arch/arm64/kernel/vmlinux.lds.S | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
> index 58d89d997d05..f84c71f04d9e 100644
> --- a/arch/arm64/kernel/vmlinux.lds.S
> +++ b/arch/arm64/kernel/vmlinux.lds.S
> @@ -287,6 +287,9 @@ SECTIONS
>  	__initdata_end = .;
>  	__init_end = .;
>  
> +	.data.rel.ro : { *(.data.rel.ro) }
> +	ASSERT(SIZEOF(.data.rel.ro) == 0, "Unexpected RELRO detected!")
> +
>  	_data = .;
>  	_sdata = .;
>  	RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN)
> @@ -343,9 +346,6 @@ SECTIONS
>  		*(.plt) *(.plt.*) *(.iplt) *(.igot .igot.plt)
>  	}
>  	ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!")
> -
> -	.data.rel.ro : { *(.data.rel.ro) }
> -	ASSERT(SIZEOF(.data.rel.ro) == 0, "Unexpected RELRO detected!")
>  }
>  
>  #include "image-vars.h"

Acked-by: Will Deacon <will@kernel.org>

Catalin, please can you pick this up for 6.13?

Will