From: Dave Martin <Dave.Martin@arm.com> To: linux-arm-kernel@lists.infradead.org Cc: Will Deacon <will.deacon@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Marc Zyngier <Marc.Zyngier@arm.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Florian Weimer <fweimer@redhat.com>, Joseph Myers <joseph@codesourcery.com>, Szabolcs Nagy <szabolcs.nagy@arm.com>, Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org Subject: [RFC PATCH v2 33/41] arm64/sve: Wire up vector length control prctl() calls Date: Wed, 22 Mar 2017 14:51:03 +0000 [thread overview] Message-ID: <1490194274-30569-34-git-send-email-Dave.Martin@arm.com> (raw) In-Reply-To: <1490194274-30569-1-git-send-email-Dave.Martin@arm.com> This patch provides implementation for the PR_SVE_SET_VL and PR_SVE_GET_VL prctls, which allow a task to set and query its vector length and associated control flags (although no flags are defined in this patch). Currently any thread can set its VL, allowing a mix of VLs within a single process -- this behaviour will be refined in susequent patches. Signed-off-by: Dave Martin <Dave.Martin@arm.com> --- arch/arm64/include/asm/fpsimd.h | 3 ++ arch/arm64/kernel/fpsimd.c | 65 +++++++++++++++++++++++++++++++++++++++-- 2 files changed, 66 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 557e755..764da0f 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -109,6 +109,9 @@ extern void fpsimd_sync_to_sve(struct task_struct *task); extern void sve_sync_to_fpsimd(struct task_struct *task); extern void sve_sync_from_fpsimd_zeropad(struct task_struct *task); +extern int sve_set_vector_length(struct task_struct *task, + unsigned long vl, unsigned long flags); + extern int sve_set_task_vl(struct task_struct *task, unsigned long vector_length, unsigned long flags); extern int sve_get_task_vl(struct task_struct *task); diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index daceeae..c9934bb 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -221,17 +221,78 @@ void do_sve_acc(unsigned int esr, struct pt_regs *regs) task_fpsimd_load(current); } +int sve_set_vector_length(struct task_struct *task, + unsigned long vl, unsigned long flags) +{ + BUG_ON(task == current && preemptible()); + + if (flags) + return -EINVAL; /* No flags defined yet */ + + if (!sve_vl_valid(vl)) + return -EINVAL; + + if (vl > sve_max_vl) { + BUG_ON(!sve_vl_valid(sve_max_vl)); + vl = sve_max_vl; + } + + /* + * To ensure the FPSIMD bits of the SVE vector registers are preserved, + * write any live register state back to task_struct, and convert to a + * non-SVE thread. + */ + if (vl != task->thread.sve_vl) { + if (task == current && + !test_and_set_thread_flag(TIF_FOREIGN_FPSTATE)) + task_fpsimd_save(current); + + if (test_and_clear_tsk_thread_flag(task, TIF_SVE)) + sve_to_fpsimd(task); + + /* + * To avoid surprises, also zero out the SVE regs storage. + * This means that the P-regs, FFR and high bits of Z-regs + * will read as zero on next access: + */ + clear_sve_regs(task); + } + + task->thread.sve_vl = vl; + + fpsimd_flush_task_state(task); + + return 0; +} + /* PR_SVE_SET_VL */ int sve_set_task_vl(struct task_struct *task, unsigned long vector_length, unsigned long flags) { - return -EINVAL; + int ret; + + if (!(elf_hwcap & HWCAP_SVE)) + return -EINVAL; + + BUG_ON(task != current); + + preempt_disable(); + ret = sve_set_vector_length(current, vector_length, flags); + preempt_enable(); + + if (ret) + return ret; + + return task->thread.sve_vl; } /* PR_SVE_GET_VL */ int sve_get_task_vl(struct task_struct *task) { - return -EINVAL; + if (!(elf_hwcap & HWCAP_SVE)) + return -EINVAL; + + return task->thread.sve_vl; } #else /* ! CONFIG_ARM64_SVE */ -- 2.1.4
WARNING: multiple messages have this Message-ID (diff)
From: Dave.Martin@arm.com (Dave Martin) To: linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH v2 33/41] arm64/sve: Wire up vector length control prctl() calls Date: Wed, 22 Mar 2017 14:51:03 +0000 [thread overview] Message-ID: <1490194274-30569-34-git-send-email-Dave.Martin@arm.com> (raw) In-Reply-To: <1490194274-30569-1-git-send-email-Dave.Martin@arm.com> This patch provides implementation for the PR_SVE_SET_VL and PR_SVE_GET_VL prctls, which allow a task to set and query its vector length and associated control flags (although no flags are defined in this patch). Currently any thread can set its VL, allowing a mix of VLs within a single process -- this behaviour will be refined in susequent patches. Signed-off-by: Dave Martin <Dave.Martin@arm.com> --- arch/arm64/include/asm/fpsimd.h | 3 ++ arch/arm64/kernel/fpsimd.c | 65 +++++++++++++++++++++++++++++++++++++++-- 2 files changed, 66 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 557e755..764da0f 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -109,6 +109,9 @@ extern void fpsimd_sync_to_sve(struct task_struct *task); extern void sve_sync_to_fpsimd(struct task_struct *task); extern void sve_sync_from_fpsimd_zeropad(struct task_struct *task); +extern int sve_set_vector_length(struct task_struct *task, + unsigned long vl, unsigned long flags); + extern int sve_set_task_vl(struct task_struct *task, unsigned long vector_length, unsigned long flags); extern int sve_get_task_vl(struct task_struct *task); diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index daceeae..c9934bb 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -221,17 +221,78 @@ void do_sve_acc(unsigned int esr, struct pt_regs *regs) task_fpsimd_load(current); } +int sve_set_vector_length(struct task_struct *task, + unsigned long vl, unsigned long flags) +{ + BUG_ON(task == current && preemptible()); + + if (flags) + return -EINVAL; /* No flags defined yet */ + + if (!sve_vl_valid(vl)) + return -EINVAL; + + if (vl > sve_max_vl) { + BUG_ON(!sve_vl_valid(sve_max_vl)); + vl = sve_max_vl; + } + + /* + * To ensure the FPSIMD bits of the SVE vector registers are preserved, + * write any live register state back to task_struct, and convert to a + * non-SVE thread. + */ + if (vl != task->thread.sve_vl) { + if (task == current && + !test_and_set_thread_flag(TIF_FOREIGN_FPSTATE)) + task_fpsimd_save(current); + + if (test_and_clear_tsk_thread_flag(task, TIF_SVE)) + sve_to_fpsimd(task); + + /* + * To avoid surprises, also zero out the SVE regs storage. + * This means that the P-regs, FFR and high bits of Z-regs + * will read as zero on next access: + */ + clear_sve_regs(task); + } + + task->thread.sve_vl = vl; + + fpsimd_flush_task_state(task); + + return 0; +} + /* PR_SVE_SET_VL */ int sve_set_task_vl(struct task_struct *task, unsigned long vector_length, unsigned long flags) { - return -EINVAL; + int ret; + + if (!(elf_hwcap & HWCAP_SVE)) + return -EINVAL; + + BUG_ON(task != current); + + preempt_disable(); + ret = sve_set_vector_length(current, vector_length, flags); + preempt_enable(); + + if (ret) + return ret; + + return task->thread.sve_vl; } /* PR_SVE_GET_VL */ int sve_get_task_vl(struct task_struct *task) { - return -EINVAL; + if (!(elf_hwcap & HWCAP_SVE)) + return -EINVAL; + + return task->thread.sve_vl; } #else /* ! CONFIG_ARM64_SVE */ -- 2.1.4
next prev parent reply other threads:[~2017-03-22 14:54 UTC|newest] Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-22 14:50 [RFC PATCH v2 00/41] Scalable Vector Extension (SVE) core support Dave Martin 2017-03-22 14:50 ` Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 01/41] arm64: signal: Refactor sigcontext parsing in rt_sigreturn Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 02/41] arm64: signal: factor frame layout and population into separate passes Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 03/41] arm64: signal: factor out signal frame record allocation Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 04/41] arm64: signal: Allocate extra sigcontext space as needed Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 05/41] arm64: signal: Parse extra_context during sigreturn Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 06/41] arm64: efi: Add missing Kconfig dependency on KERNEL_MODE_NEON Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 07/41] arm64/sve: Allow kernel-mode NEON to be disabled in Kconfig Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 08/41] arm64/sve: Low-level save/restore code Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 09/41] arm64/sve: Boot-time feature detection and reporting Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 10/41] arm64/sve: Boot-time feature enablement Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 11/41] arm64/sve: Expand task_struct for Scalable Vector Extension state Dave Martin 2017-03-22 16:20 ` Mark Rutland 2017-03-23 10:49 ` Dave Martin 2017-03-23 11:26 ` Mark Rutland 2017-03-22 14:50 ` [RFC PATCH v2 12/41] arm64/sve: Save/restore SVE state on context switch paths Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 13/41] arm64/sve: [BROKEN] Basic support for KERNEL_MODE_NEON Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 14/41] Revert "arm64/sve: Allow kernel-mode NEON to be disabled in Kconfig" Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 15/41] arm64/sve: Restore working FPSIMD save/restore around signals Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 16/41] arm64/sve: signal: Add SVE state record to sigcontext Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 17/41] arm64/sve: signal: Dump Scalable Vector Extension registers to user stack Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 18/41] arm64/sve: signal: Restore FPSIMD/SVE state in rt_sigreturn Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 19/41] arm64/sve: Avoid corruption when replacing the SVE state Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 20/41] arm64/sve: traps: Add descriptive string for SVE exceptions Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 21/41] arm64/sve: Enable SVE on demand for userspace Dave Martin 2017-03-22 16:48 ` Mark Rutland 2017-03-23 11:24 ` Dave Martin 2017-03-23 11:30 ` Suzuki K Poulose 2017-03-23 11:52 ` Mark Rutland 2017-03-23 12:07 ` Dave Martin 2017-03-23 13:40 ` Mark Rutland 2017-03-23 13:45 ` Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 22/41] arm64/sve: Implement FPSIMD-only context for tasks not using SVE Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 23/41] arm64/sve: Move ZEN handling to the common task_fpsimd_load() path Dave Martin 2017-03-22 16:55 ` Mark Rutland 2017-03-23 11:52 ` Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 24/41] arm64/sve: Discard SVE state on system call Dave Martin 2017-03-22 17:03 ` Mark Rutland 2017-03-23 11:59 ` Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 25/41] arm64/sve: Avoid preempt_disable() during sigreturn Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 26/41] arm64/sve: Avoid stale user register state after SVE access exception Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 27/41] arm64/sve: ptrace support Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 28/41] arm64: KVM: Treat SVE use by guests as undefined instruction execution Dave Martin 2017-03-22 17:06 ` Mark Rutland 2017-03-23 12:10 ` Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 29/41] prctl: Add skeleton for PR_SVE_{SET,GET}_VL controls Dave Martin 2017-03-22 14:50 ` [RFC PATCH v2 29/41] prctl: Add skeleton for PR_SVE_{SET, GET}_VL controls Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 30/41] arm64/sve: Track vector length for each task Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 31/41] arm64/sve: Set CPU vector length to match current task Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 32/41] arm64/sve: Factor out clearing of tasks' SVE regs Dave Martin 2017-03-22 14:51 ` Dave Martin [this message] 2017-03-22 14:51 ` [RFC PATCH v2 33/41] arm64/sve: Wire up vector length control prctl() calls Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 34/41] arm64/sve: Disallow VL setting for individual threads by default Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 35/41] arm64/sve: Add vector length inheritance control Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 36/41] arm64/sve: ptrace: Wire up vector length control and reporting Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 37/41] arm64/sve: Enable default vector length control via procfs Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 38/41] arm64/sve: Detect SVE via the cpufeature framework Dave Martin 2017-03-23 14:11 ` Suzuki K Poulose 2017-03-23 14:37 ` Dave Martin 2017-03-23 14:43 ` Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 39/41] arm64/sve: Migrate to cpucap based detection for runtime SVE code Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 40/41] arm64/sve: Allocate task SVE context storage dynamically Dave Martin 2017-03-22 14:51 ` [RFC PATCH v2 41/41] arm64/sve: Documentation: Add overview of the SVE userspace ABI Dave Martin 2017-03-22 14:51 ` Dave Martin 2017-03-31 15:28 ` [RFC PATCH v2 00/41] Scalable Vector Extension (SVE) core support Ard Biesheuvel 2017-03-31 15:28 ` Ard Biesheuvel 2017-04-03 9:45 ` Dave Martin 2017-04-03 9:45 ` Dave Martin 2017-04-03 10:01 ` Ard Biesheuvel 2017-04-03 10:01 ` Ard Biesheuvel 2017-04-03 10:51 ` Dave Martin 2017-04-03 10:51 ` Dave Martin 2017-04-03 10:55 ` Ard Biesheuvel 2017-04-03 10:55 ` Ard Biesheuvel
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