* Re: [PATCH v10 2/2] riscv: Add runtime constant support
[not found] ` <20250319-runtime_const_riscv-v10-2-745b31a11d65@rivosinc.com>
@ 2025-04-01 19:28 ` Nathan Chancellor
2025-04-01 20:43 ` Charlie Jenkins
0 siblings, 1 reply; 2+ messages in thread
From: Nathan Chancellor @ 2025-04-01 19:28 UTC (permalink / raw)
To: Charlie Jenkins
Cc: Paul Walmsley, Palmer Dabbelt, Ard Biesheuvel, Ben Dooks,
Pasha Bouzarjomehri, Emil Renner Berthing, Alexandre Ghiti,
Steven Rostedt, Masami Hiramatsu, Mark Rutland, Albert Ou,
Peter Zijlstra, Josh Poimboeuf, Jason Baron, Andrew Jones,
linux-riscv, linux-kernel, linux-trace-kernel, llvm
Hi Charlie,
On Wed, Mar 19, 2025 at 11:35:20AM -0700, Charlie Jenkins wrote:
> Implement the runtime constant infrastructure for riscv. Use this
> infrastructure to generate constants to be used by the d_hash()
> function.
>
> This is the riscv variant of commit 94a2bc0f611c ("arm64: add 'runtime
> constant' support") and commit e3c92e81711d ("runtime constants: add
> x86 architecture support").
>
> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
...
> diff --git a/arch/riscv/include/asm/runtime-const.h b/arch/riscv/include/asm/runtime-const.h
...
> +#define RISCV_RUNTIME_CONST_64_ZBA \
> + ".option push\n\t" \
> + ".option arch,+zba\n\t" \
> + "slli %[__tmp],%[__tmp],32\n\t" \
> + "add.uw %[__ret],%[__ret],%[__tmp]\n\t" \
> + "nop\n\t" \
> + "nop\n\t" \
> + ".option pop\n\t" \
...
> +#if defined(CONFIG_RISCV_ISA_ZBA) && defined(CONFIG_RISCV_ISA_ZBKB)
...
> +#elif defined(CONFIG_RISCV_ISA_ZBA)
> +#define runtime_const_ptr(sym) \
> +({ \
> + typeof(sym) __ret, __tmp; \
> + asm_inline(RISCV_RUNTIME_CONST_64_PREAMBLE \
> + ALTERNATIVE( \
> + RISCV_RUNTIME_CONST_64_BASE, \
> + RISCV_RUNTIME_CONST_64_ZBA, \
> + 0, RISCV_ISA_EXT_ZBA, 1 \
> + ) \
> + RISCV_RUNTIME_CONST_64_POSTAMBLE(sym) \
> + : [__ret] "=r" (__ret), [__tmp] "=r" (__tmp)); \
> + __ret; \
> +})
This breaks the build for clang versions 16 and earlier because they do
not support '.option arch' and it is used in CONFIG_RISCV_ISA_ZBA, which
has no dependencies and it is default on.
$ make -skj"$(nproc)" ARCH=riscv LLVM=1 mrproper defconfig fs/dcache.o
fs/dcache.c:117:9: warning: unknown option, expected 'push', 'pop', 'rvc', 'norvc', 'relax' or 'norelax' [-Winline-asm]
return runtime_const_ptr(dentry_hashtable) +
^
arch/riscv/include/asm/runtime-const.h:103:4: note: expanded from macro 'runtime_const_ptr'
RISCV_RUNTIME_CONST_64_ZBA, \
^
arch/riscv/include/asm/runtime-const.h:57:17: note: expanded from macro 'RISCV_RUNTIME_CONST_64_ZBA'
".option push\n\t" \
^
<inline asm>:32:10: note: instantiated into assembly here
.option arch,+zba
^
fs/dcache.c:117:9: error: instruction requires the following: 'Zba' (Address Generation Instructions)
return runtime_const_ptr(dentry_hashtable) +
^
arch/riscv/include/asm/runtime-const.h:103:4: note: expanded from macro 'runtime_const_ptr'
RISCV_RUNTIME_CONST_64_ZBA, \
^
arch/riscv/include/asm/runtime-const.h:59:30: note: expanded from macro 'RISCV_RUNTIME_CONST_64_ZBA'
"slli %[__tmp],%[__tmp],32\n\t" \
^
<inline asm>:34:2: note: instantiated into assembly here
add.uw a2,a2,a3
^
...
$ rg 'OPTION_ARCH|ZBA' .config
364:CONFIG_RISCV_ISA_ZBA=y
Should it grow a dependency on AS_HAS_OPTION_ARCH or should there be a
different fix?
Cheers,
Nathan
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v10 2/2] riscv: Add runtime constant support
2025-04-01 19:28 ` [PATCH v10 2/2] riscv: Add runtime constant support Nathan Chancellor
@ 2025-04-01 20:43 ` Charlie Jenkins
0 siblings, 0 replies; 2+ messages in thread
From: Charlie Jenkins @ 2025-04-01 20:43 UTC (permalink / raw)
To: Nathan Chancellor
Cc: Paul Walmsley, Palmer Dabbelt, Ard Biesheuvel, Ben Dooks,
Pasha Bouzarjomehri, Emil Renner Berthing, Alexandre Ghiti,
Steven Rostedt, Masami Hiramatsu, Mark Rutland, Albert Ou,
Peter Zijlstra, Josh Poimboeuf, Jason Baron, Andrew Jones,
linux-riscv, linux-kernel, linux-trace-kernel, llvm
On Tue, Apr 01, 2025 at 12:28:33PM -0700, Nathan Chancellor wrote:
> Hi Charlie,
>
> On Wed, Mar 19, 2025 at 11:35:20AM -0700, Charlie Jenkins wrote:
> > Implement the runtime constant infrastructure for riscv. Use this
> > infrastructure to generate constants to be used by the d_hash()
> > function.
> >
> > This is the riscv variant of commit 94a2bc0f611c ("arm64: add 'runtime
> > constant' support") and commit e3c92e81711d ("runtime constants: add
> > x86 architecture support").
> >
> > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> > Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> ...
> > diff --git a/arch/riscv/include/asm/runtime-const.h b/arch/riscv/include/asm/runtime-const.h
> ...
> > +#define RISCV_RUNTIME_CONST_64_ZBA \
> > + ".option push\n\t" \
> > + ".option arch,+zba\n\t" \
> > + "slli %[__tmp],%[__tmp],32\n\t" \
> > + "add.uw %[__ret],%[__ret],%[__tmp]\n\t" \
> > + "nop\n\t" \
> > + "nop\n\t" \
> > + ".option pop\n\t" \
> ...
> > +#if defined(CONFIG_RISCV_ISA_ZBA) && defined(CONFIG_RISCV_ISA_ZBKB)
> ...
> > +#elif defined(CONFIG_RISCV_ISA_ZBA)
> > +#define runtime_const_ptr(sym) \
> > +({ \
> > + typeof(sym) __ret, __tmp; \
> > + asm_inline(RISCV_RUNTIME_CONST_64_PREAMBLE \
> > + ALTERNATIVE( \
> > + RISCV_RUNTIME_CONST_64_BASE, \
> > + RISCV_RUNTIME_CONST_64_ZBA, \
> > + 0, RISCV_ISA_EXT_ZBA, 1 \
> > + ) \
> > + RISCV_RUNTIME_CONST_64_POSTAMBLE(sym) \
> > + : [__ret] "=r" (__ret), [__tmp] "=r" (__tmp)); \
> > + __ret; \
> > +})
>
> This breaks the build for clang versions 16 and earlier because they do
> not support '.option arch' and it is used in CONFIG_RISCV_ISA_ZBA, which
> has no dependencies and it is default on.
>
> $ make -skj"$(nproc)" ARCH=riscv LLVM=1 mrproper defconfig fs/dcache.o
> fs/dcache.c:117:9: warning: unknown option, expected 'push', 'pop', 'rvc', 'norvc', 'relax' or 'norelax' [-Winline-asm]
> return runtime_const_ptr(dentry_hashtable) +
> ^
> arch/riscv/include/asm/runtime-const.h:103:4: note: expanded from macro 'runtime_const_ptr'
> RISCV_RUNTIME_CONST_64_ZBA, \
> ^
> arch/riscv/include/asm/runtime-const.h:57:17: note: expanded from macro 'RISCV_RUNTIME_CONST_64_ZBA'
> ".option push\n\t" \
> ^
> <inline asm>:32:10: note: instantiated into assembly here
> .option arch,+zba
> ^
> fs/dcache.c:117:9: error: instruction requires the following: 'Zba' (Address Generation Instructions)
> return runtime_const_ptr(dentry_hashtable) +
> ^
> arch/riscv/include/asm/runtime-const.h:103:4: note: expanded from macro 'runtime_const_ptr'
> RISCV_RUNTIME_CONST_64_ZBA, \
> ^
> arch/riscv/include/asm/runtime-const.h:59:30: note: expanded from macro 'RISCV_RUNTIME_CONST_64_ZBA'
> "slli %[__tmp],%[__tmp],32\n\t" \
> ^
> <inline asm>:34:2: note: instantiated into assembly here
> add.uw a2,a2,a3
> ^
> ...
>
> $ rg 'OPTION_ARCH|ZBA' .config
> 364:CONFIG_RISCV_ISA_ZBA=y
>
> Should it grow a dependency on AS_HAS_OPTION_ARCH or should there be a
> different fix?
This should have been fixed by Alex's patch [1]. Zba is in an awkward
state because BPF generates Zba code without the need for toolchain
support.
[1] https://lore.kernel.org/all/20250328115422.253670-1-alexghiti@rivosinc.com/
>
> Cheers,
> Nathan
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-04-01 20:43 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
[not found] <20250319-runtime_const_riscv-v10-0-745b31a11d65@rivosinc.com>
[not found] ` <20250319-runtime_const_riscv-v10-2-745b31a11d65@rivosinc.com>
2025-04-01 19:28 ` [PATCH v10 2/2] riscv: Add runtime constant support Nathan Chancellor
2025-04-01 20:43 ` Charlie Jenkins
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox