From: "Alex Bennée" <alex.bennee@linaro.org>
To: Dave Martin <Dave.Martin@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org,
libc-alpha@sourceware.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Richard Sandiford <richard.sandiford@arm.com>,
kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH 12/27] arm64/sve: Support vector length resetting for new processes
Date: Tue, 22 Aug 2017 16:22:00 -0000 [thread overview]
Message-ID: <871so3bmj0.fsf@linaro.org> (raw)
In-Reply-To: <1502280338-23002-13-git-send-email-Dave.Martin@arm.com>
Dave Martin <Dave.Martin@arm.com> writes:
> It's desirable to be able to reset the vector length to some sane
> default for new processes, since the new binary and its libraries
> processes may or may not be SVE-aware.
>
> This patch tracks the desired post-exec vector length (if any) in a
> new thread member sve_vl_onexec, and adds a new thread flag
> TIF_SVE_VL_INHERIT to control whether to inherit or reset the
> vector length. Currently these are inactive. Subsequent patches
> will provide the capability to configure them.
>
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> ---
> arch/arm64/include/asm/processor.h | 1 +
> arch/arm64/include/asm/thread_info.h | 1 +
> arch/arm64/kernel/fpsimd.c | 13 +++++++++++++
> 3 files changed, 15 insertions(+)
>
> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> index 969feed..da8802a 100644
> --- a/arch/arm64/include/asm/processor.h
> +++ b/arch/arm64/include/asm/processor.h
> @@ -87,6 +87,7 @@ struct thread_struct {
> struct fpsimd_state fpsimd_state;
> void *sve_state; /* SVE registers, if any */
> u16 sve_vl; /* SVE vector length */
> + u16 sve_vl_onexec; /* SVE vl after next
> exec */
Inconsistent size usage here as well...
> unsigned long fault_address; /* fault info */
> unsigned long fault_code; /* ESR_EL1 value */
> struct debug_info debug; /* debugging */
> diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
> index 1a4b30b..bf9c552 100644
> --- a/arch/arm64/include/asm/thread_info.h
> +++ b/arch/arm64/include/asm/thread_info.h
> @@ -97,6 +97,7 @@ struct thread_info {
> #define TIF_SINGLESTEP 21
> #define TIF_32BIT 22 /* 32bit process */
> #define TIF_SVE 23 /* Scalable Vector Extension in use */
> +#define TIF_SVE_VL_INHERIT 24 /* Inherit sve_vl_onexec across exec */
>
> #define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
> #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
> diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
> index 37dd1b2..80ecb2d 100644
> --- a/arch/arm64/kernel/fpsimd.c
> +++ b/arch/arm64/kernel/fpsimd.c
> @@ -108,6 +108,9 @@ static void task_fpsimd_save(void);
> */
> static DEFINE_PER_CPU(struct fpsimd_state *, fpsimd_last_state);
>
> +/* Default VL for tasks that don't set it explicitly: */
> +static int sve_default_vl = -1;
> +
> static void sve_free(struct task_struct *task)
> {
> kfree(task->thread.sve_state);
> @@ -392,6 +395,9 @@ void fpsimd_flush_thread(void)
> clear_thread_flag(TIF_SVE);
> sve_free(current);
>
> + current->thread.sve_vl = current->thread.sve_vl_onexec ?
> + current->thread.sve_vl_onexec : sve_default_vl;
> +
> /*
> * User tasks must have a valid vector length set, but tasks
> * forked early (e.g., init) may not initially have one.
> @@ -401,6 +407,13 @@ void fpsimd_flush_thread(void)
> * If not, something went badly wrong.
> */
> BUG_ON(!sve_vl_valid(current->thread.sve_vl));
> +
> + /*
> + * If the task is not set to inherit, ensure that the vector
> + * length will be reset by a subsequent exec:
> + */
> + if (!test_thread_flag(TIF_SVE_VL_INHERIT))
> + current->thread.sve_vl_onexec = 0;
> }
>
> set_thread_flag(TIF_FOREIGN_FPSTATE);
--
Alex Bennée
next prev parent reply other threads:[~2017-08-22 16:22 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-09 12:05 [PATCH 00/27] ARM Scalable Vector Extension (SVE) Dave Martin
2017-08-09 12:06 ` [PATCH 08/27] arm64/sve: Kconfig update and conditional compilation support Dave Martin
2017-08-21 10:12 ` Alex Bennée
2017-08-09 12:06 ` [PATCH 07/27] arm64/sve: Low-level SVE architectural state manipulation functions Dave Martin
2017-08-21 10:11 ` Alex Bennée
2017-08-21 14:38 ` Dave Martin
2017-08-09 12:06 ` [PATCH 03/27] arm64: efi: Add missing Kconfig dependency on KERNEL_MODE_NEON Dave Martin
2017-08-18 12:02 ` Alex Bennée
2017-08-09 12:06 ` [PATCH 05/27] arm64: fpsimd: Simplify uses of {set,clear}_ti_thread_flag() Dave Martin
2017-08-15 17:11 ` Ard Biesheuvel
2017-08-18 16:36 ` [PATCH 05/27] arm64: fpsimd: Simplify uses of {set, clear}_ti_thread_flag() Alex Bennée
2017-08-09 12:06 ` [PATCH 04/27] arm64: Port deprecated instruction emulation to new sysctl interface Dave Martin
2017-08-18 12:09 ` Alex Bennée
2017-08-09 12:06 ` [PATCH 02/27] arm64: KVM: Hide unsupported AArch64 CPU features from guests Dave Martin
2017-08-16 11:11 ` Marc Zyngier
2017-08-16 20:32 ` Dave Martin
2017-08-17 8:46 ` Marc Zyngier
2017-08-17 9:57 ` Dave Martin
2017-08-09 12:06 ` [PATCH 01/27] regset: Add support for dynamically sized regsets Dave Martin
2017-08-18 11:52 ` Alex Bennée
2017-08-09 12:06 ` [PATCH 09/27] arm64/sve: Signal frame and context structure definition Dave Martin
2017-08-22 10:22 ` Alex Bennée
2017-08-22 11:17 ` Dave Martin
2017-08-22 13:53 ` Alex Bennée
2017-08-22 14:21 ` Dave Martin
2017-08-22 15:03 ` Alex Bennée
2017-08-22 15:41 ` Dave Martin
2017-08-09 12:07 ` [PATCH 15/27] arm64/sve: Probe SVE capabilities and usable vector lengths Dave Martin
2017-08-16 17:48 ` Suzuki K Poulose
2017-08-17 10:04 ` Dave Martin
2017-08-17 10:46 ` Suzuki K Poulose
2017-08-09 12:07 ` [PATCH 06/27] arm64/sve: System register and exception syndrome definitions Dave Martin
2017-08-21 9:34 ` Alex Bennée
2017-08-21 12:34 ` Alex Bennée
2017-08-21 14:26 ` Dave Martin
2017-08-21 14:50 ` Alex Bennée
2017-08-21 15:20 ` Dave Martin
2017-08-21 15:34 ` Alex Bennée
2017-08-21 13:57 ` Dave Martin
2017-08-21 14:36 ` Alex Bennée
2017-08-09 12:07 ` [PATCH 17/27] arm64/sve: Preserve SVE registers around EFI runtime service calls Dave Martin
2017-08-15 17:46 ` Ard Biesheuvel
2017-08-16 9:13 ` Dave Martin
2017-08-09 12:07 ` [PATCH 10/27] arm64/sve: Low-level CPU setup Dave Martin
2017-08-22 15:04 ` Alex Bennée
2017-08-22 15:33 ` Dave Martin
2017-08-09 12:07 ` [PATCH 14/27] arm64/sve: Backend logic for setting the vector length Dave Martin
2017-08-23 15:33 ` Alex Bennée
2017-08-23 17:30 ` Dave Martin
2017-08-09 12:07 ` [PATCH 11/27] arm64/sve: Core task context handling Dave Martin
2017-08-15 17:36 ` Ard Biesheuvel
2017-08-16 10:40 ` Dave Martin
2017-08-17 16:42 ` Dave Martin
2017-08-17 16:46 ` Ard Biesheuvel
2017-08-22 16:21 ` Alex Bennée
2017-08-22 17:20 ` Dave Martin
2017-08-22 18:39 ` Alex Bennée
2017-08-09 12:07 ` [PATCH 12/27] arm64/sve: Support vector length resetting for new processes Dave Martin
2017-08-22 16:22 ` Alex Bennée [this message]
2017-08-22 17:22 ` Dave Martin
2017-08-09 12:07 ` [PATCH 13/27] arm64/sve: Signal handling support Dave Martin
2017-08-23 9:38 ` Alex Bennée
2017-08-23 11:30 ` Dave Martin
2017-08-09 12:08 ` [PATCH 20/27] arm64/sve: Add sysctl to set the default vector length for new processes Dave Martin
2017-08-09 12:08 ` [PATCH 16/27] arm64/sve: Preserve SVE registers around kernel-mode NEON use Dave Martin
2017-08-15 17:38 ` Ard Biesheuvel
2017-08-09 12:08 ` [PATCH 23/27] arm64/sve: KVM: Hide SVE from CPU features exposed to guests Dave Martin
2017-08-15 16:38 ` Marc Zyngier
2017-08-16 10:55 ` Dave Martin
2017-08-16 11:11 ` Marc Zyngier
2017-08-16 11:22 ` Dave Martin
2017-08-09 12:08 ` [RFC PATCH 27/27] arm64/sve: signal: Include SVE when computing AT_MINSIGSTKSZ Dave Martin
2017-08-09 12:08 ` [PATCH 18/27] arm64/sve: ptrace and ELF coredump support Dave Martin
2017-08-09 12:08 ` [PATCH 24/27] arm64/sve: Detect SVE and activate runtime support Dave Martin
2017-08-16 17:53 ` Suzuki K Poulose
2017-08-17 10:01 ` Dave Martin
2017-08-09 12:08 ` [PATCH 22/27] arm64/sve: KVM: Treat guest SVE use as undefined instruction execution Dave Martin
2017-08-09 12:08 ` [PATCH 21/27] arm64/sve: KVM: Prevent guests from using SVE Dave Martin
2017-08-15 16:33 ` Marc Zyngier
2017-08-16 10:50 ` Dave Martin
2017-08-16 11:20 ` Marc Zyngier
2017-08-16 11:23 ` Marc Zyngier
2017-08-16 11:35 ` Dave Martin
2017-08-09 12:08 ` [PATCH 19/27] arm64/sve: Add prctl controls for userspace vector length management Dave Martin
2017-08-09 12:08 ` [RFC PATCH 26/27] arm64: signal: Report signal frame size to userspace via auxv Dave Martin
2017-08-09 12:08 ` [PATCH 25/27] arm64/sve: Add documentation Dave Martin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=871so3bmj0.fsf@linaro.org \
--to=alex.bennee@linaro.org \
--cc=Dave.Martin@arm.com \
--cc=ard.biesheuvel@linaro.org \
--cc=catalin.marinas@arm.com \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=libc-alpha@sourceware.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=richard.sandiford@arm.com \
--cc=szabolcs.nagy@arm.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).