From: "Alex Bennée" <alex.bennee@linaro.org>
To: Dave Martin <Dave.Martin@arm.com>
Cc: 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,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 17/28] arm64/sve: Preserve SVE registers around kernel-mode NEON use
Date: Thu, 14 Sep 2017 11:52:22 +0100 [thread overview]
Message-ID: <87efr9a6xl.fsf@linaro.org> (raw)
In-Reply-To: <1504198860-12951-18-git-send-email-Dave.Martin@arm.com>
Dave Martin <Dave.Martin@arm.com> writes:
> Kernel-mode NEON will corrupt the SVE vector registers, due to the
> way they alias the FPSIMD vector registers in the hardware.
>
> This patch ensures that any live SVE register content for the task
> is saved by kernel_neon_begin(). The data will be restored in the
> usual way on return to userspace.
>
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
> ---
> arch/arm64/kernel/fpsimd.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
> index cea05a7..dd89acf 100644
> --- a/arch/arm64/kernel/fpsimd.c
> +++ b/arch/arm64/kernel/fpsimd.c
> @@ -744,8 +744,10 @@ void kernel_neon_begin(void)
> __this_cpu_write(kernel_neon_busy, true);
>
> /* Save unsaved task fpsimd state, if any: */
> - if (current->mm && !test_and_set_thread_flag(TIF_FOREIGN_FPSTATE))
> - fpsimd_save_state(¤t->thread.fpsimd_state);
> + if (current->mm) {
> + task_fpsimd_save();
> + set_thread_flag(TIF_FOREIGN_FPSTATE);
> + }
>
> /* Invalidate any task state remaining in the fpsimd regs: */
> __this_cpu_write(fpsimd_last_state, NULL);
--
Alex Bennée
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kvmarm@lists.cs.columbia.edu
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WARNING: multiple messages have this Message-ID (diff)
From: "Alex Bennée" <alex.bennee@linaro.org>
To: Dave Martin <Dave.Martin@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Richard Sandiford <richard.sandiford@arm.com>,
kvmarm@lists.cs.columbia.edu, libc-alpha@sourceware.org,
linux-arch@vger.kernel.org
Subject: Re: [PATCH v2 17/28] arm64/sve: Preserve SVE registers around kernel-mode NEON use
Date: Thu, 14 Sep 2017 11:52:22 +0100 [thread overview]
Message-ID: <87efr9a6xl.fsf@linaro.org> (raw)
Message-ID: <20170914105222.96CwNKLHLYO0afN_tTzZ6kyPOjDNOM2PReR_LTsD50c@z> (raw)
In-Reply-To: <1504198860-12951-18-git-send-email-Dave.Martin@arm.com>
Dave Martin <Dave.Martin@arm.com> writes:
> Kernel-mode NEON will corrupt the SVE vector registers, due to the
> way they alias the FPSIMD vector registers in the hardware.
>
> This patch ensures that any live SVE register content for the task
> is saved by kernel_neon_begin(). The data will be restored in the
> usual way on return to userspace.
>
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
> ---
> arch/arm64/kernel/fpsimd.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
> index cea05a7..dd89acf 100644
> --- a/arch/arm64/kernel/fpsimd.c
> +++ b/arch/arm64/kernel/fpsimd.c
> @@ -744,8 +744,10 @@ void kernel_neon_begin(void)
> __this_cpu_write(kernel_neon_busy, true);
>
> /* Save unsaved task fpsimd state, if any: */
> - if (current->mm && !test_and_set_thread_flag(TIF_FOREIGN_FPSTATE))
> - fpsimd_save_state(¤t->thread.fpsimd_state);
> + if (current->mm) {
> + task_fpsimd_save();
> + set_thread_flag(TIF_FOREIGN_FPSTATE);
> + }
>
> /* Invalidate any task state remaining in the fpsimd regs: */
> __this_cpu_write(fpsimd_last_state, NULL);
--
Alex Bennée
WARNING: multiple messages have this Message-ID (diff)
From: alex.bennee@linaro.org (Alex Bennée)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 17/28] arm64/sve: Preserve SVE registers around kernel-mode NEON use
Date: Thu, 14 Sep 2017 11:52:22 +0100 [thread overview]
Message-ID: <87efr9a6xl.fsf@linaro.org> (raw)
In-Reply-To: <1504198860-12951-18-git-send-email-Dave.Martin@arm.com>
Dave Martin <Dave.Martin@arm.com> writes:
> Kernel-mode NEON will corrupt the SVE vector registers, due to the
> way they alias the FPSIMD vector registers in the hardware.
>
> This patch ensures that any live SVE register content for the task
> is saved by kernel_neon_begin(). The data will be restored in the
> usual way on return to userspace.
>
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Alex Benn?e <alex.bennee@linaro.org>
> ---
> arch/arm64/kernel/fpsimd.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
> index cea05a7..dd89acf 100644
> --- a/arch/arm64/kernel/fpsimd.c
> +++ b/arch/arm64/kernel/fpsimd.c
> @@ -744,8 +744,10 @@ void kernel_neon_begin(void)
> __this_cpu_write(kernel_neon_busy, true);
>
> /* Save unsaved task fpsimd state, if any: */
> - if (current->mm && !test_and_set_thread_flag(TIF_FOREIGN_FPSTATE))
> - fpsimd_save_state(¤t->thread.fpsimd_state);
> + if (current->mm) {
> + task_fpsimd_save();
> + set_thread_flag(TIF_FOREIGN_FPSTATE);
> + }
>
> /* Invalidate any task state remaining in the fpsimd regs: */
> __this_cpu_write(fpsimd_last_state, NULL);
--
Alex Benn?e
next prev parent reply other threads:[~2017-09-14 10:52 UTC|newest]
Thread overview: 224+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-31 17:00 [PATCH v2 00/28] ARM Scalable Vector Extension (SVE) Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 01/28] regset: Add support for dynamically sized regsets Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 02/28] arm64: KVM: Hide unsupported AArch64 CPU features from guests Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-13 14:37 ` Alex Bennée
2017-09-13 14:37 ` Alex Bennée
2017-09-13 14:37 ` Alex Bennée
2017-09-15 0:04 ` Dave Martin
2017-09-15 0:04 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 03/28] arm64: efi: Add missing Kconfig dependency on KERNEL_MODE_NEON Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 04/28] arm64: Port deprecated instruction emulation to new sysctl interface Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 05/28] arm64: fpsimd: Simplify uses of {set,clear}_ti_thread_flag() Dave Martin
2017-08-31 17:00 ` [PATCH v2 05/28] arm64: fpsimd: Simplify uses of {set, clear}_ti_thread_flag() Dave Martin
2017-08-31 17:00 ` [PATCH v2 06/28] arm64/sve: System register and exception syndrome definitions Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-13 14:48 ` Alex Bennée
2017-09-13 14:48 ` Alex Bennée
2017-09-13 14:48 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 07/28] arm64/sve: Low-level SVE architectural state manipulation functions Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-13 15:39 ` Alex Bennée
2017-09-13 15:39 ` Alex Bennée
2017-09-13 15:39 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 08/28] arm64/sve: Kconfig update and conditional compilation support Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 09/28] arm64/sve: Signal frame and context structure definition Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-13 13:36 ` Catalin Marinas
2017-09-13 13:36 ` Catalin Marinas
2017-09-13 21:33 ` Dave Martin
2017-09-13 21:33 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 10/28] arm64/sve: Low-level CPU setup Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-13 13:32 ` Catalin Marinas
2017-09-13 13:32 ` Catalin Marinas
2017-09-13 19:21 ` Dave Martin
2017-09-13 19:21 ` Dave Martin
2017-09-13 19:21 ` Dave Martin
2017-10-05 10:47 ` Dave Martin
2017-10-05 10:47 ` Dave Martin
2017-10-05 11:04 ` Suzuki K Poulose
2017-10-05 11:04 ` Suzuki K Poulose
2017-10-05 11:22 ` Dave Martin
2017-10-05 11:22 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 11/28] arm64/sve: Core task context handling Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-13 14:33 ` Catalin Marinas
2017-09-13 14:33 ` Catalin Marinas
2017-09-14 19:55 ` Dave Martin
2017-09-14 19:55 ` Dave Martin
2017-09-20 13:58 ` Catalin Marinas
2017-09-20 13:58 ` Catalin Marinas
2017-10-03 11:11 ` Dave Martin
2017-10-03 11:11 ` Dave Martin
2017-10-04 17:29 ` Catalin Marinas
2017-10-04 17:29 ` Catalin Marinas
2017-10-03 11:33 ` Dave Martin
2017-10-03 11:33 ` Dave Martin
2017-10-05 11:28 ` Catalin Marinas
2017-10-05 11:28 ` Catalin Marinas
2017-10-06 13:10 ` Dave Martin
2017-10-06 13:10 ` Dave Martin
2017-10-06 13:36 ` Catalin Marinas
2017-10-06 13:36 ` Catalin Marinas
2017-10-06 15:15 ` Dave Martin
2017-10-06 15:15 ` Dave Martin
2017-10-06 15:33 ` Catalin Marinas
2017-10-06 15:33 ` Catalin Marinas
2017-09-13 17:26 ` Catalin Marinas
2017-09-13 17:26 ` Catalin Marinas
2017-09-13 19:17 ` Dave Martin
2017-09-13 19:17 ` Dave Martin
2017-09-13 22:21 ` Catalin Marinas
2017-09-13 22:21 ` Catalin Marinas
2017-09-14 19:40 ` Dave Martin
2017-09-14 19:40 ` Dave Martin
2017-09-19 17:13 ` Catalin Marinas
2017-09-19 17:13 ` Catalin Marinas
2017-08-31 17:00 ` [PATCH v2 12/28] arm64/sve: Support vector length resetting for new processes Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 8:47 ` Alex Bennée
2017-09-14 8:47 ` Alex Bennée
2017-09-14 8:47 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 13/28] arm64/sve: Signal handling support Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 9:30 ` Alex Bennée
2017-09-14 9:30 ` Alex Bennée
2017-09-14 9:30 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 14/28] arm64/sve: Backend logic for setting the vector length Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-13 17:29 ` Catalin Marinas
2017-09-13 17:29 ` Catalin Marinas
2017-09-13 19:06 ` Dave Martin
2017-09-13 19:06 ` Dave Martin
2017-09-13 22:11 ` Catalin Marinas
2017-09-13 22:11 ` Catalin Marinas
2017-10-05 16:42 ` Dave Martin
2017-10-05 16:42 ` Dave Martin
2017-10-05 16:53 ` Catalin Marinas
2017-10-05 16:53 ` Catalin Marinas
2017-10-05 17:04 ` Dave Martin
2017-10-05 17:04 ` Dave Martin
2017-09-20 10:57 ` Alan Hayward
2017-09-20 10:57 ` Alan Hayward
2017-09-20 10:59 ` Alan Hayward
2017-09-20 10:59 ` Alan Hayward
2017-09-20 11:09 ` Dave Martin
2017-09-20 11:09 ` Dave Martin
2017-09-20 18:08 ` Alan Hayward
2017-09-20 18:08 ` Alan Hayward
2017-09-21 11:19 ` Dave Martin
2017-09-21 11:19 ` Dave Martin
2017-09-21 11:57 ` Alan Hayward
2017-09-21 11:57 ` Alan Hayward
2017-08-31 17:00 ` [PATCH v2 15/28] arm64: cpufeature: Move sys_caps_initialised declarations Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 9:33 ` Alex Bennée
2017-09-14 9:33 ` Alex Bennée
2017-09-14 9:33 ` Alex Bennée
2017-09-14 9:35 ` Suzuki K Poulose
2017-09-14 9:35 ` Suzuki K Poulose
2017-08-31 17:00 ` [PATCH v2 16/28] arm64/sve: Probe SVE capabilities and usable vector lengths Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 9:45 ` Alex Bennée
2017-09-14 9:45 ` Alex Bennée
2017-09-14 9:45 ` Alex Bennée
2017-09-28 14:22 ` Dave Martin
2017-09-28 14:22 ` Dave Martin
2017-09-28 17:32 ` Alex Bennée
2017-09-28 17:32 ` Alex Bennée
2017-09-28 17:32 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 17/28] arm64/sve: Preserve SVE registers around kernel-mode NEON use Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 10:52 ` Alex Bennée [this message]
2017-09-14 10:52 ` Alex Bennée
2017-09-14 10:52 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 18/28] arm64/sve: Preserve SVE registers around EFI runtime service calls Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 11:01 ` Alex Bennée
2017-09-14 11:01 ` Alex Bennée
2017-09-14 11:01 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 19/28] arm64/sve: ptrace and ELF coredump support Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-06 16:21 ` Okamoto, Takayuki
2017-09-06 16:21 ` Okamoto, Takayuki
2017-09-06 18:16 ` Dave Martin
2017-09-06 18:16 ` Dave Martin
2017-09-07 5:11 ` Okamoto, Takayuki
2017-09-07 5:11 ` Okamoto, Takayuki
2017-09-07 5:11 ` Okamoto, Takayuki
2017-09-08 13:11 ` Dave Martin
2017-09-08 13:11 ` Dave Martin
2017-09-14 12:57 ` Alex Bennée
2017-09-14 12:57 ` Alex Bennée
2017-09-14 12:57 ` Alex Bennée
2017-09-28 14:57 ` Dave Martin
2017-09-28 14:57 ` Dave Martin
2017-09-29 12:46 ` Dave Martin
2017-09-29 12:46 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 20/28] arm64/sve: Add prctl controls for userspace vector length management Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 13:02 ` Alex Bennée
2017-09-14 13:02 ` Alex Bennée
2017-09-14 13:02 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 21/28] arm64/sve: Add sysctl to set the default vector length for new processes Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 13:05 ` Alex Bennée
2017-09-14 13:05 ` Alex Bennée
2017-09-14 13:05 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 22/28] arm64/sve: KVM: Prevent guests from using SVE Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 13:28 ` Alex Bennée
2017-09-14 13:28 ` Alex Bennée
2017-09-14 13:28 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 23/28] arm64/sve: KVM: Treat guest SVE use as undefined instruction execution Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 13:30 ` Alex Bennée
2017-09-14 13:30 ` Alex Bennée
2017-09-14 13:30 ` Alex Bennée
2017-09-14 13:31 ` Alex Bennée
2017-09-14 13:31 ` Alex Bennée
2017-09-14 13:31 ` Alex Bennée
2017-09-29 13:00 ` Dave Martin
2017-09-29 13:00 ` Dave Martin
2017-09-29 14:43 ` Alex Bennée
2017-09-29 14:43 ` Alex Bennée
2017-09-29 14:43 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 24/28] arm64/sve: KVM: Hide SVE from CPU features exposed to guests Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-09-14 13:32 ` Alex Bennée
2017-09-14 13:32 ` Alex Bennée
2017-09-14 13:32 ` Alex Bennée
2017-08-31 17:00 ` [PATCH v2 25/28] arm64/sve: Detect SVE and activate runtime support Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-08-31 17:00 ` [PATCH v2 26/28] arm64/sve: Add documentation Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-10-05 16:39 ` Szabolcs Nagy
2017-10-05 16:39 ` Szabolcs Nagy
2017-10-05 17:02 ` Dave Martin
2017-10-05 17:02 ` Dave Martin
2017-10-06 15:43 ` Szabolcs Nagy
2017-10-06 15:43 ` Szabolcs Nagy
2017-10-06 17:37 ` Dave Martin
2017-10-06 17:37 ` Dave Martin
2017-10-09 9:34 ` Alex Bennée
2017-10-09 9:34 ` Alex Bennée
2017-10-09 9:34 ` Alex Bennée
2017-10-09 9:49 ` Dave Martin
2017-10-09 9:49 ` Dave Martin
2017-10-09 14:07 ` Alex Bennée
2017-10-09 14:07 ` Alex Bennée
2017-10-09 14:07 ` Alex Bennée
2017-10-09 16:20 ` Dave Martin
2017-10-09 16:20 ` Dave Martin
2017-08-31 17:00 ` [RFC PATCH v2 27/28] arm64: signal: Report signal frame size to userspace via auxv Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-08-31 17:00 ` Dave Martin
2017-08-31 17:01 ` [RFC PATCH v2 28/28] arm64/sve: signal: Include SVE when computing AT_MINSIGSTKSZ Dave Martin
2017-08-31 17:01 ` Dave Martin
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