[PATCH fixes] riscv: Fix CONFIG_AS_HAS_INSN for new .insn usage

[PATCH fixes] riscv: Fix CONFIG_AS_HAS_INSN for new .insn usage

[Nathan Chancellor]

After commit 44aa25c000b4 ("riscv: asm: use .insn for making custom
instructions"), builds using LLVM older that 19 or binutils older than
2.38 fail with:

  arch/riscv/include/asm/vdso/processor.h: Assembler messages:
  arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
  arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
  arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
  arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
  make[4]: *** [scripts/Makefile.build:287: arch/riscv/kernel/vdso/vgettimeofday.o] Error 1

  In file included from <built-in>:4:
  In file included from lib/vdso/gettimeofday.c:6:
  In file included from include/vdso/datapage.h:21:
  In file included from include/vdso/processor.h:10:
  arch/riscv/include/asm/vdso/processor.h:23:2: error: expected instruction format
     23 |         ALT_RISCV_PAUSE();
        |         ^
  arch/riscv/include/asm/errata_list.h:47:3: note: expanded from macro 'ALT_RISCV_PAUSE'
     47 |                 RISCV_PAUSE, /* Original RISC‑V pause insn */ \
        |                 ^
  arch/riscv/include/asm/insn-def.h:259:21: note: expanded from macro 'RISCV_PAUSE'
    259 | #define RISCV_PAUSE     ASM_INSN_I("0x100000f")
        |                         ^
  arch/riscv/include/asm/asm.h:16:26: note: expanded from macro 'ASM_INSN_I'
     16 | #define ASM_INSN_I(__x) ".insn " __x
        |                          ^
  <inline asm>:5:7: note: instantiated into assembly here
      5 | .insn 0x100000f
        |       ^

binutils gained support for '.insn <value>' in 2.38 [1] and LLVM gained
support in 19 [2]. Adjust the test for CONFIG_AS_HAS_INSN to ensure that
all versions of .insn are supported before being used.

Fixes: 44aa25c000b4 ("riscv: asm: use .insn for making custom instructions")
Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=a262b82fdbf4cda3b0648b1adc32245ca3f78b7a [1]
Link: https://github.com/llvm/llvm-project/commit/2a086dce691e3cc34a2fc27f4fb255bb2cbbfac9 [2]
Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 arch/riscv/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 22cda9c452d2..fadec20b87a8 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -367,7 +367,7 @@ config RISCV_NONSTANDARD_CACHE_OPS
 	  systems to handle cache management.
 
 config AS_HAS_INSN
-	def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
+	def_bool $(as-instr,.insn 0x100000f)
 
 config AS_HAS_OPTION_ARCH
 	# https://github.com/llvm/llvm-project/commit/9e8ed3403c191ab9c4903e8eeb8f732ff8a43cb4

---
base-commit: a882126c42fc53275ac91969d460d939191db7b0
change-id: 20251107-riscv-fix-new-insn-usage-2261377c2d38

Best regards,
--  
Nathan Chancellor <nathan@kernel.org>


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Re: [PATCH fixes] riscv: Fix CONFIG_AS_HAS_INSN for new .insn usage

[Andrew Jones]

On Fri, Nov 07, 2025 at 02:56:59PM -0700, Nathan Chancellor wrote:
> After commit 44aa25c000b4 ("riscv: asm: use .insn for making custom
> instructions"), builds using LLVM older that 19 or binutils older than
> 2.38 fail with:
> 
>   arch/riscv/include/asm/vdso/processor.h: Assembler messages:
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   make[4]: *** [scripts/Makefile.build:287: arch/riscv/kernel/vdso/vgettimeofday.o] Error 1
> 
>   In file included from <built-in>:4:
>   In file included from lib/vdso/gettimeofday.c:6:
>   In file included from include/vdso/datapage.h:21:
>   In file included from include/vdso/processor.h:10:
>   arch/riscv/include/asm/vdso/processor.h:23:2: error: expected instruction format
>      23 |         ALT_RISCV_PAUSE();
>         |         ^
>   arch/riscv/include/asm/errata_list.h:47:3: note: expanded from macro 'ALT_RISCV_PAUSE'
>      47 |                 RISCV_PAUSE, /* Original RISC‑V pause insn */ \
>         |                 ^
>   arch/riscv/include/asm/insn-def.h:259:21: note: expanded from macro 'RISCV_PAUSE'
>     259 | #define RISCV_PAUSE     ASM_INSN_I("0x100000f")
>         |                         ^
>   arch/riscv/include/asm/asm.h:16:26: note: expanded from macro 'ASM_INSN_I'
>      16 | #define ASM_INSN_I(__x) ".insn " __x
>         |                          ^
>   <inline asm>:5:7: note: instantiated into assembly here
>       5 | .insn 0x100000f
>         |       ^
> 
> binutils gained support for '.insn <value>' in 2.38 [1] and LLVM gained
> support in 19 [2]. Adjust the test for CONFIG_AS_HAS_INSN to ensure that
> all versions of .insn are supported before being used.
> 
> Fixes: 44aa25c000b4 ("riscv: asm: use .insn for making custom instructions")
> Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=a262b82fdbf4cda3b0648b1adc32245ca3f78b7a [1]
> Link: https://github.com/llvm/llvm-project/commit/2a086dce691e3cc34a2fc27f4fb255bb2cbbfac9 [2]
> Suggested-by: Andrew Jones <ajones@ventanamicro.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>  arch/riscv/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 22cda9c452d2..fadec20b87a8 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -367,7 +367,7 @@ config RISCV_NONSTANDARD_CACHE_OPS
>  	  systems to handle cache management.
>  
>  config AS_HAS_INSN
> -	def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero)
> +	def_bool $(as-instr,.insn 0x100000f)
>  
>  config AS_HAS_OPTION_ARCH
>  	# https://github.com/llvm/llvm-project/commit/9e8ed3403c191ab9c4903e8eeb8f732ff8a43cb4
> 
> ---
> base-commit: a882126c42fc53275ac91969d460d939191db7b0
> change-id: 20251107-riscv-fix-new-insn-usage-2261377c2d38
> 
> Best regards,
> --  
> Nathan Chancellor <nathan@kernel.org>
>

Thanks for posting this Nathan.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

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Re: [PATCH fixes] riscv: Fix CONFIG_AS_HAS_INSN for new .insn usage

[Paul Walmsley]

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Hi Nathan,

On Fri, 7 Nov 2025, Nathan Chancellor wrote:

> After commit 44aa25c000b4 ("riscv: asm: use .insn for making custom
> instructions"), builds using LLVM older that 19 or binutils older than
> 2.38 fail with:
> 
>   arch/riscv/include/asm/vdso/processor.h: Assembler messages:
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   make[4]: *** [scripts/Makefile.build:287: arch/riscv/kernel/vdso/vgettimeofday.o] Error 1
> 
>   In file included from <built-in>:4:
>   In file included from lib/vdso/gettimeofday.c:6:
>   In file included from include/vdso/datapage.h:21:
>   In file included from include/vdso/processor.h:10:
>   arch/riscv/include/asm/vdso/processor.h:23:2: error: expected instruction format
>      23 |         ALT_RISCV_PAUSE();
>         |         ^
>   arch/riscv/include/asm/errata_list.h:47:3: note: expanded from macro 'ALT_RISCV_PAUSE'
>      47 |                 RISCV_PAUSE, /* Original RISC‑V pause insn */ \
>         |                 ^
>   arch/riscv/include/asm/insn-def.h:259:21: note: expanded from macro 'RISCV_PAUSE'
>     259 | #define RISCV_PAUSE     ASM_INSN_I("0x100000f")
>         |                         ^
>   arch/riscv/include/asm/asm.h:16:26: note: expanded from macro 'ASM_INSN_I'
>      16 | #define ASM_INSN_I(__x) ".insn " __x
>         |                          ^
>   <inline asm>:5:7: note: instantiated into assembly here
>       5 | .insn 0x100000f
>         |       ^
> 
> binutils gained support for '.insn <value>' in 2.38 [1] and LLVM gained
> support in 19 [2]. Adjust the test for CONFIG_AS_HAS_INSN to ensure that
> all versions of .insn are supported before being used.
> 
> Fixes: 44aa25c000b4 ("riscv: asm: use .insn for making custom instructions")
> Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=a262b82fdbf4cda3b0648b1adc32245ca3f78b7a [1]
> Link: https://github.com/llvm/llvm-project/commit/2a086dce691e3cc34a2fc27f4fb255bb2cbbfac9 [2]
> Suggested-by: Andrew Jones <ajones@ventanamicro.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
>  arch/riscv/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

Thanks for the fast fix, and sorry for the trouble. 

Clearly we're not doing sufficiently broad build testing here, either 
before branch submission, or on -next.  We'll fix this ASAP on the branch 
submission case, and work on improving -next autobuilds.

Queued for v6.18-rc.


- Paul

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Re: [PATCH fixes] riscv: Fix CONFIG_AS_HAS_INSN for new .insn usage

[patchwork-bot+linux-riscv]

Hello:

This patch was applied to riscv/linux.git (fixes)
by Paul Walmsley <pjw@kernel.org>:

On Fri, 07 Nov 2025 14:56:59 -0700 you wrote:
> After commit 44aa25c000b4 ("riscv: asm: use .insn for making custom
> instructions"), builds using LLVM older that 19 or binutils older than
> 2.38 fail with:
> 
>   arch/riscv/include/asm/vdso/processor.h: Assembler messages:
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   arch/riscv/include/asm/vdso/processor.h:27: Error: unrecognized opcode `0x100000f'
>   make[4]: *** [scripts/Makefile.build:287: arch/riscv/kernel/vdso/vgettimeofday.o] Error 1
> 
> [...]

Here is the summary with links:
  - [fixes] riscv: Fix CONFIG_AS_HAS_INSN for new .insn usage
    https://git.kernel.org/riscv/c/dc20452e6caf

You are awesome, thank you!
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