Re: [PATCH v3 08/19] unwind/x86: Enable CONFIG_HAVE_UNWIND_USER_FP

Peter Zijlstra <[email protected]>
Newsgroups org.kernel.vger.linux-toolchains,org.kernel.vger.linux-kernel,org.kernel.vger.linux-perf-users
Message-ID <[email protected]>
On Mon, Oct 28, 2024 at 02:47:35PM -0700, Josh Poimboeuf wrote:
> Use ARCH_INIT_USER_FP_FRAME to describe how frame pointers are unwound
> on x86, and enable CONFIG_HAVE_UNWIND_USER_FP accordingly so the
> unwind_user interfaces can be used.
> 
> Signed-off-by: Josh Poimboeuf <[email protected]>
> ---
>  arch/x86/Kconfig                   |  1 +
>  arch/x86/include/asm/unwind_user.h | 11 +++++++++++
>  2 files changed, 12 insertions(+)
>  create mode 100644 arch/x86/include/asm/unwind_user.h
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 0bdb7a394f59..f91098d6f535 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -289,6 +289,7 @@ config X86
>  	select HAVE_SYSCALL_TRACEPOINTS
>  	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
>  	select HAVE_UNSTABLE_SCHED_CLOCK
> +	select HAVE_UNWIND_USER_FP		if X86_64
>  	select HAVE_USER_RETURN_NOTIFIER
>  	select HAVE_GENERIC_VDSO
>  	select VDSO_GETRANDOM			if X86_64
> diff --git a/arch/x86/include/asm/unwind_user.h b/arch/x86/include/asm/unwind_user.h
> new file mode 100644
> index 000000000000..19df26a65132
> --- /dev/null
> +++ b/arch/x86/include/asm/unwind_user.h
> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_X86_UNWIND_USER_H
> +#define _ASM_X86_UNWIND_USER_H
> +
> +#define ARCH_INIT_USER_FP_FRAME							\
> +	.ra_off		= (s32)sizeof(long) * -1,				\
> +	.cfa_off	= (s32)sizeof(long) * 2,				\
> +	.fp_off		= (s32)sizeof(long) * -2,				\
> +	.use_fp		= true,
> +
> +#endif /* _ASM_X86_UNWIND_USER_H */

What about compat / 32bit userspace?
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