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* [PATCH] riscv module: remove (NOLOAD)
@ 2022-02-18  8:26 Fangrui Song
  2022-02-19 16:45 ` Nathan Chancellor
  0 siblings, 1 reply; 6+ messages in thread
From: Fangrui Song @ 2022-02-18  8:26 UTC (permalink / raw)
  To: Paul Walmsley, Palmer Dabbelt, linux-riscv
  Cc: Nathan Chancellor, linux-kernel, llvm, Fangrui Song

On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually
inappropriate for .plt, .got, and .got.plt sections which are always
SHT_PROGBITS.

In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway
and (NOLOAD) will be essentially ignored. In ld.lld, since
https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to
customize the output section type"), ld.lld will report a `section type
mismatch` error. Just remove (NOLOAD) to fix the error.

[1] https://lld.llvm.org/ELF/linker_script.html As of today, "The
section should be marked as not loadable" on
https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is
outdated for ELF.
---
 arch/riscv/include/asm/module.lds.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/module.lds.h b/arch/riscv/include/asm/module.lds.h
index 4254ff2ff049..1075beae1ac6 100644
--- a/arch/riscv/include/asm/module.lds.h
+++ b/arch/riscv/include/asm/module.lds.h
@@ -2,8 +2,8 @@
 /* Copyright (C) 2017 Andes Technology Corporation */
 #ifdef CONFIG_MODULE_SECTIONS
 SECTIONS {
-	.plt (NOLOAD) : { BYTE(0) }
-	.got (NOLOAD) : { BYTE(0) }
-	.got.plt (NOLOAD) : { BYTE(0) }
+	.plt : { BYTE(0) }
+	.got : { BYTE(0) }
+	.got.plt : { BYTE(0) }
 }
 #endif
-- 
2.35.1.265.g69c8d7142f-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH] riscv module: remove (NOLOAD)
  2022-02-18  8:26 [PATCH] riscv module: remove (NOLOAD) Fangrui Song
@ 2022-02-19 16:45 ` Nathan Chancellor
  2022-03-18 23:18   ` Palmer Dabbelt
  0 siblings, 1 reply; 6+ messages in thread
From: Nathan Chancellor @ 2022-02-19 16:45 UTC (permalink / raw)
  To: Fangrui Song
  Cc: Paul Walmsley, Palmer Dabbelt, linux-riscv, linux-kernel, llvm

On Fri, Feb 18, 2022 at 12:26:11AM -0800, Fangrui Song wrote:
> On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually
> inappropriate for .plt, .got, and .got.plt sections which are always
> SHT_PROGBITS.
> 
> In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway
> and (NOLOAD) will be essentially ignored. In ld.lld, since
> https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to
> customize the output section type"), ld.lld will report a `section type
> mismatch` error. Just remove (NOLOAD) to fix the error.
> 
> [1] https://lld.llvm.org/ELF/linker_script.html As of today, "The
> section should be marked as not loadable" on
> https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is
> outdated for ELF.

Thank you for the patch! As mentioned on the arm64 patch, this needs
your Signed-off-by tag. With that provided:

Cc: stable@vger.kernel.org
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>

This needs to go to stable so that older trees with a newer toolchain do
not warn.

> ---
>  arch/riscv/include/asm/module.lds.h | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/module.lds.h b/arch/riscv/include/asm/module.lds.h
> index 4254ff2ff049..1075beae1ac6 100644
> --- a/arch/riscv/include/asm/module.lds.h
> +++ b/arch/riscv/include/asm/module.lds.h
> @@ -2,8 +2,8 @@
>  /* Copyright (C) 2017 Andes Technology Corporation */
>  #ifdef CONFIG_MODULE_SECTIONS
>  SECTIONS {
> -	.plt (NOLOAD) : { BYTE(0) }
> -	.got (NOLOAD) : { BYTE(0) }
> -	.got.plt (NOLOAD) : { BYTE(0) }
> +	.plt : { BYTE(0) }
> +	.got : { BYTE(0) }
> +	.got.plt : { BYTE(0) }
>  }
>  #endif
> -- 
> 2.35.1.265.g69c8d7142f-goog
> 
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] riscv module: remove (NOLOAD)
  2022-02-19 16:45 ` Nathan Chancellor
@ 2022-03-18 23:18   ` Palmer Dabbelt
  2022-03-22  1:26     ` [PATCH v2] " Fangrui Song
  0 siblings, 1 reply; 6+ messages in thread
From: Palmer Dabbelt @ 2022-03-18 23:18 UTC (permalink / raw)
  To: maskray, nathan; +Cc: Paul Walmsley, linux-riscv, linux-kernel, llvm

On Sat, 19 Feb 2022 08:45:10 PST (-0800), nathan@kernel.org wrote:
> On Fri, Feb 18, 2022 at 12:26:11AM -0800, Fangrui Song wrote:
>> On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually
>> inappropriate for .plt, .got, and .got.plt sections which are always
>> SHT_PROGBITS.
>>
>> In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway
>> and (NOLOAD) will be essentially ignored. In ld.lld, since
>> https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to
>> customize the output section type"), ld.lld will report a `section type
>> mismatch` error. Just remove (NOLOAD) to fix the error.
>>
>> [1] https://lld.llvm.org/ELF/linker_script.html As of today, "The
>> section should be marked as not loadable" on
>> https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is
>> outdated for ELF.
>
> Thank you for the patch! As mentioned on the arm64 patch, this needs
> your Signed-off-by tag. With that provided:
>
> Cc: stable@vger.kernel.org
> Reviewed-by: Nathan Chancellor <nathan@kernel.org>
> Tested-by: Nathan Chancellor <nathan@kernel.org>
>
> This needs to go to stable so that older trees with a newer toolchain do
> not warn.

Yep, just checking on that SOB line.  A 

Fixes: 596b0474d3d9 ("kbuild: preprocess module linker script")

seems appropriate as well.

Thanks!

>
>> ---
>>  arch/riscv/include/asm/module.lds.h | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/riscv/include/asm/module.lds.h b/arch/riscv/include/asm/module.lds.h
>> index 4254ff2ff049..1075beae1ac6 100644
>> --- a/arch/riscv/include/asm/module.lds.h
>> +++ b/arch/riscv/include/asm/module.lds.h
>> @@ -2,8 +2,8 @@
>>  /* Copyright (C) 2017 Andes Technology Corporation */
>>  #ifdef CONFIG_MODULE_SECTIONS
>>  SECTIONS {
>> -	.plt (NOLOAD) : { BYTE(0) }
>> -	.got (NOLOAD) : { BYTE(0) }
>> -	.got.plt (NOLOAD) : { BYTE(0) }
>> +	.plt : { BYTE(0) }
>> +	.got : { BYTE(0) }
>> +	.got.plt : { BYTE(0) }
>>  }
>>  #endif
>> --
>> 2.35.1.265.g69c8d7142f-goog
>>
>>

^ permalink raw reply	[flat|nested] 6+ messages in thread
* [PATCH v2] riscv module: remove (NOLOAD)
  2022-03-18 23:18   ` Palmer Dabbelt
@ 2022-03-22  1:26     ` Fangrui Song
  2022-03-22  1:49       ` Nathan Chancellor
  2022-03-30  0:21       ` Palmer Dabbelt
  0 siblings, 2 replies; 6+ messages in thread
From: Fangrui Song @ 2022-03-22  1:26 UTC (permalink / raw)
  To: Paul Walmsley, Palmer Dabbelt, linux-riscv
  Cc: Nathan Chancellor, linux-kernel, llvm, Fangrui Song

On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually
inappropriate for .plt, .got, and .got.plt sections which are always
SHT_PROGBITS.

In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway
and (NOLOAD) will be essentially ignored. In ld.lld, since
https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to
customize the output section type"), ld.lld will report a `section type
mismatch` error (later changed to a warning). Just remove (NOLOAD) to
fix the warning.

[1] https://lld.llvm.org/ELF/linker_script.html As of today, "The
section should be marked as not loadable" on
https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is
outdated for ELF.

Link: https://github.com/ClangBuiltLinux/linux/issues/1597
Fixes: ab1ef68e5401 ("RISC-V: Add sections of PLT and GOT for kernel module")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Fangrui Song <maskray@google.com>
---
 arch/riscv/include/asm/module.lds.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/module.lds.h b/arch/riscv/include/asm/module.lds.h
index 4254ff2ff049..1075beae1ac6 100644
--- a/arch/riscv/include/asm/module.lds.h
+++ b/arch/riscv/include/asm/module.lds.h
@@ -2,8 +2,8 @@
 /* Copyright (C) 2017 Andes Technology Corporation */
 #ifdef CONFIG_MODULE_SECTIONS
 SECTIONS {
-	.plt (NOLOAD) : { BYTE(0) }
-	.got (NOLOAD) : { BYTE(0) }
-	.got.plt (NOLOAD) : { BYTE(0) }
+	.plt : { BYTE(0) }
+	.got : { BYTE(0) }
+	.got.plt : { BYTE(0) }
 }
 #endif
-- 
2.35.1.894.gb6a874cedc-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH v2] riscv module: remove (NOLOAD)
  2022-03-22  1:26     ` [PATCH v2] " Fangrui Song
@ 2022-03-22  1:49       ` Nathan Chancellor
  2022-03-30  0:21       ` Palmer Dabbelt
  1 sibling, 0 replies; 6+ messages in thread
From: Nathan Chancellor @ 2022-03-22  1:49 UTC (permalink / raw)
  To: Fangrui Song
  Cc: Paul Walmsley, Palmer Dabbelt, linux-riscv, linux-kernel, llvm

On Mon, Mar 21, 2022 at 06:26:17PM -0700, Fangrui Song wrote:
> On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually
> inappropriate for .plt, .got, and .got.plt sections which are always
> SHT_PROGBITS.
> 
> In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway
> and (NOLOAD) will be essentially ignored. In ld.lld, since
> https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to
> customize the output section type"), ld.lld will report a `section type
> mismatch` error (later changed to a warning). Just remove (NOLOAD) to
> fix the warning.
> 
> [1] https://lld.llvm.org/ELF/linker_script.html As of today, "The
> section should be marked as not loadable" on
> https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is
> outdated for ELF.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1597
> Fixes: ab1ef68e5401 ("RISC-V: Add sections of PLT and GOT for kernel module")
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Signed-off-by: Fangrui Song <maskray@google.com>

Thank you for the resend! I think the Fixes: tag you chose is more
accurate than Palmer's suggested one. Same tags as v1, if Palmer would
not mind taking them while applying:

Cc: stable@vger.kernel.org
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>

> ---
>  arch/riscv/include/asm/module.lds.h | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/module.lds.h b/arch/riscv/include/asm/module.lds.h
> index 4254ff2ff049..1075beae1ac6 100644
> --- a/arch/riscv/include/asm/module.lds.h
> +++ b/arch/riscv/include/asm/module.lds.h
> @@ -2,8 +2,8 @@
>  /* Copyright (C) 2017 Andes Technology Corporation */
>  #ifdef CONFIG_MODULE_SECTIONS
>  SECTIONS {
> -	.plt (NOLOAD) : { BYTE(0) }
> -	.got (NOLOAD) : { BYTE(0) }
> -	.got.plt (NOLOAD) : { BYTE(0) }
> +	.plt : { BYTE(0) }
> +	.got : { BYTE(0) }
> +	.got.plt : { BYTE(0) }
>  }
>  #endif
> -- 
> 2.35.1.894.gb6a874cedc-goog
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH v2] riscv module: remove (NOLOAD)
  2022-03-22  1:26     ` [PATCH v2] " Fangrui Song
  2022-03-22  1:49       ` Nathan Chancellor
@ 2022-03-30  0:21       ` Palmer Dabbelt
  1 sibling, 0 replies; 6+ messages in thread
From: Palmer Dabbelt @ 2022-03-30  0:21 UTC (permalink / raw)
  To: maskray; +Cc: Paul Walmsley, linux-riscv, nathan, linux-kernel, llvm, maskray

On Mon, 21 Mar 2022 18:26:17 PDT (-0700), maskray@google.com wrote:
> On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually
> inappropriate for .plt, .got, and .got.plt sections which are always
> SHT_PROGBITS.
>
> In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway
> and (NOLOAD) will be essentially ignored. In ld.lld, since
> https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to
> customize the output section type"), ld.lld will report a `section type
> mismatch` error (later changed to a warning). Just remove (NOLOAD) to
> fix the warning.
>
> [1] https://lld.llvm.org/ELF/linker_script.html As of today, "The
> section should be marked as not loadable" on
> https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is
> outdated for ELF.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1597
> Fixes: ab1ef68e5401 ("RISC-V: Add sections of PLT and GOT for kernel module")
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Signed-off-by: Fangrui Song <maskray@google.com>
> ---
>  arch/riscv/include/asm/module.lds.h | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/include/asm/module.lds.h b/arch/riscv/include/asm/module.lds.h
> index 4254ff2ff049..1075beae1ac6 100644
> --- a/arch/riscv/include/asm/module.lds.h
> +++ b/arch/riscv/include/asm/module.lds.h
> @@ -2,8 +2,8 @@
>  /* Copyright (C) 2017 Andes Technology Corporation */
>  #ifdef CONFIG_MODULE_SECTIONS
>  SECTIONS {
> -	.plt (NOLOAD) : { BYTE(0) }
> -	.got (NOLOAD) : { BYTE(0) }
> -	.got.plt (NOLOAD) : { BYTE(0) }
> +	.plt : { BYTE(0) }
> +	.got : { BYTE(0) }
> +	.got.plt : { BYTE(0) }
>  }
>  #endif

Thanks, this is on for-next (it'd be OK for fixes as well, but it's the 
merge window so I'm just on one branch).

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-03-30  0:21 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-18  8:26 [PATCH] riscv module: remove (NOLOAD) Fangrui Song
2022-02-19 16:45 ` Nathan Chancellor
2022-03-18 23:18   ` Palmer Dabbelt
2022-03-22  1:26     ` [PATCH v2] " Fangrui Song
2022-03-22  1:49       ` Nathan Chancellor
2022-03-30  0:21       ` Palmer Dabbelt

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