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* [PATCH] arch: um: rust: Use the generated target.json again
@ 2024-05-29  9:33 David Gow
  2024-05-30 17:00 ` Boqun Feng
  2024-06-11 22:08 ` Miguel Ojeda
  0 siblings, 2 replies; 4+ messages in thread
From: David Gow @ 2024-05-29  9:33 UTC (permalink / raw)
  To: Rae Moar, Thomas Gleixner, Ingo Molnar, Miguel Ojeda,
	H . Peter Anvin, Masahiro Yamada, Jamie Cunliffe, Catalin Marinas,
	Richard Weinberger, Anton Ivanov, Johannes Berg
  Cc: David Gow, kunit-dev, linux-kernel, linux-um, rust-for-linux, x86,
	Wedson Almeida Filho, Borislav Petkov, Dave Hansen, Alex Gaynor,
	Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
	Andreas Hindborg, Alice Ryhl

The Rust compiler can take a target config from 'target.json', which is
generated by scripts/generate_rust_target.rs. It used to be that all
Linux architectures used this to generate a target.json, but now
architectures must opt-in to this, or they will default to the Rust
compiler's built-in target definition.

This is mostly okay for (64-bit) x86 and UML, except that it can
generate SSE instructions, which we can't use in the kernel. So
re-instate the custom target.json, which disables SSE (and generally
enables the 'soft-float' feature). This fixes the following compile
error:

error: <unknown>:0:0: in function _RNvMNtCs5QSdWC790r4_4core3f32f7next_up float (float): SSE register return with SSE disabled

Fixes: f82811e22b48 ("rust: Refactor the build target to allow the use of builtin targets")
Signed-off-by: David Gow <davidgow@google.com>
---
 arch/x86/Makefile.um | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/Makefile.um b/arch/x86/Makefile.um
index 2106a2bd152b..a46b1397ad01 100644
--- a/arch/x86/Makefile.um
+++ b/arch/x86/Makefile.um
@@ -9,6 +9,7 @@ core-y += arch/x86/crypto/
 #
 ifeq ($(CONFIG_CC_IS_CLANG),y)
 KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
+KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
 KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
 endif
 
-- 
2.45.1.288.g0e0cd299f1-goog


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH] arch: um: rust: Use the generated target.json again
  2024-05-29  9:33 [PATCH] arch: um: rust: Use the generated target.json again David Gow
@ 2024-05-30 17:00 ` Boqun Feng
  2024-06-11 22:08 ` Miguel Ojeda
  1 sibling, 0 replies; 4+ messages in thread
From: Boqun Feng @ 2024-05-30 17:00 UTC (permalink / raw)
  To: David Gow
  Cc: Rae Moar, Thomas Gleixner, Ingo Molnar, Miguel Ojeda,
	H . Peter Anvin, Masahiro Yamada, Jamie Cunliffe, Catalin Marinas,
	Richard Weinberger, Anton Ivanov, Johannes Berg, kunit-dev,
	linux-kernel, linux-um, rust-for-linux, x86, Wedson Almeida Filho,
	Borislav Petkov, Dave Hansen, Alex Gaynor, Gary Guo,
	Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl

On Wed, May 29, 2024 at 05:33:35PM +0800, David Gow wrote:
> The Rust compiler can take a target config from 'target.json', which is
> generated by scripts/generate_rust_target.rs. It used to be that all
> Linux architectures used this to generate a target.json, but now
> architectures must opt-in to this, or they will default to the Rust
> compiler's built-in target definition.
> 
> This is mostly okay for (64-bit) x86 and UML, except that it can
> generate SSE instructions, which we can't use in the kernel. So
> re-instate the custom target.json, which disables SSE (and generally
> enables the 'soft-float' feature). This fixes the following compile
> error:
> 
> error: <unknown>:0:0: in function _RNvMNtCs5QSdWC790r4_4core3f32f7next_up float (float): SSE register return with SSE disabled
> 
> Fixes: f82811e22b48 ("rust: Refactor the build target to allow the use of builtin targets")
> Signed-off-by: David Gow <davidgow@google.com>

Reviewed-by: Boqun Feng <boqun.feng@gmail.com>

Regards,
Boqun

> ---
>  arch/x86/Makefile.um | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/Makefile.um b/arch/x86/Makefile.um
> index 2106a2bd152b..a46b1397ad01 100644
> --- a/arch/x86/Makefile.um
> +++ b/arch/x86/Makefile.um
> @@ -9,6 +9,7 @@ core-y += arch/x86/crypto/
>  #
>  ifeq ($(CONFIG_CC_IS_CLANG),y)
>  KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
> +KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
>  KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
>  endif
>  
> -- 
> 2.45.1.288.g0e0cd299f1-goog
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] arch: um: rust: Use the generated target.json again
  2024-05-29  9:33 [PATCH] arch: um: rust: Use the generated target.json again David Gow
  2024-05-30 17:00 ` Boqun Feng
@ 2024-06-11 22:08 ` Miguel Ojeda
  2024-06-13 20:25   ` Richard Weinberger
  1 sibling, 1 reply; 4+ messages in thread
From: Miguel Ojeda @ 2024-06-11 22:08 UTC (permalink / raw)
  To: David Gow
  Cc: Rae Moar, Thomas Gleixner, Ingo Molnar, Miguel Ojeda,
	H . Peter Anvin, Masahiro Yamada, Jamie Cunliffe, Catalin Marinas,
	Richard Weinberger, Anton Ivanov, Johannes Berg, kunit-dev,
	linux-kernel, linux-um, rust-for-linux, x86, Wedson Almeida Filho,
	Borislav Petkov, Dave Hansen, Alex Gaynor, Boqun Feng, Gary Guo,
	Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl

On Wed, May 29, 2024 at 11:33 AM David Gow <davidgow@google.com> wrote:
>
> The Rust compiler can take a target config from 'target.json', which is
> generated by scripts/generate_rust_target.rs. It used to be that all
> Linux architectures used this to generate a target.json, but now
> architectures must opt-in to this, or they will default to the Rust
> compiler's built-in target definition.
>
> This is mostly okay for (64-bit) x86 and UML, except that it can
> generate SSE instructions, which we can't use in the kernel. So
> re-instate the custom target.json, which disables SSE (and generally
> enables the 'soft-float' feature). This fixes the following compile
> error:
>
> error: <unknown>:0:0: in function _RNvMNtCs5QSdWC790r4_4core3f32f7next_up float (float): SSE register return with SSE disabled
>
> Fixes: f82811e22b48 ("rust: Refactor the build target to allow the use of builtin targets")
> Signed-off-by: David Gow <davidgow@google.com>

I guess this should go through UML, but please let me know otherwise
(I don't see it in next).

Tested-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>

Should this have a

Cc: stable@vger.kernel.org

too?

Thanks!

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] arch: um: rust: Use the generated target.json again
  2024-06-11 22:08 ` Miguel Ojeda
@ 2024-06-13 20:25   ` Richard Weinberger
  0 siblings, 0 replies; 4+ messages in thread
From: Richard Weinberger @ 2024-06-13 20:25 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: davidgow, Rae Moar, tglx, mingo, Miguel Ojeda, hpa, masahiroy,
	Jamie Cunliffe, Catalin Marinas, anton ivanov, Johannes Berg,
	kunit-dev, linux-kernel, linux-um, Rust for Linux Kernel, x86,
	Wedson Almeida Filho, bp, dave hansen, Alex Gaynor, Boqun Feng,
	Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg,
	Alice Ryhl

----- Ursprüngliche Mail -----
> Von: "Miguel Ojeda" <miguel.ojeda.sandonis@gmail.com>
>> Fixes: f82811e22b48 ("rust: Refactor the build target to allow the use of
>> builtin targets")
>> Signed-off-by: David Gow <davidgow@google.com>
> 
> I guess this should go through UML, but please let me know otherwise

Yeah, that's the plan.

> Tested-by: Miguel Ojeda <ojeda@kernel.org>
> Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
> 
> Should this have a
> 
> Cc: stable@vger.kernel.org
> 
> too?

Ok!

Thanks,
//richard

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2024-06-13 20:25 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2024-05-29  9:33 [PATCH] arch: um: rust: Use the generated target.json again David Gow
2024-05-30 17:00 ` Boqun Feng
2024-06-11 22:08 ` Miguel Ojeda
2024-06-13 20:25   ` Richard Weinberger

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