[RFC PATCH 03/10] arm64/sve: Set CPU vector length to match current task
Dave Martin <[email protected]>
| Newsgroups | gmane.comp.lib.glibc.alpha,gmane.linux.ports.arm.kernel,gmane.linux.kernel.cross-arch,gmane.comp.gdb.devel |
|---|---|
| Message-ID | <[email protected]> |
This patch adds the necessary code to configure the CPU for the task's vector length, whenever SVE state is loaded for a task. No special action is needed on sched-out: only user tasks with SVE state care what the CPU's VL is set to. Signed-off-by: Dave Martin <[email protected]> --- arch/arm64/include/asm/fpsimd.h | 3 ++- arch/arm64/include/asm/fpsimdmacros.h | 7 ++++++- arch/arm64/kernel/entry-fpsimd.S | 2 +- arch/arm64/kernel/fpsimd.c | 10 +++++++--- 4 files changed, 16 insertions(+), 6 deletions(-) diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index e13259e..22d09c0 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -100,7 +100,8 @@ extern void __init fpsimd_init_task_struct_size(void); extern void *__task_sve_state(struct task_struct *task); extern void sve_save_state(void *state, u32 *pfpsr); -extern void sve_load_state(void const *state, u32 const *pfpsr); +extern void sve_load_state(void const *state, u32 const *pfpsr, + unsigned long vq_minus_1); extern unsigned int sve_get_vl(void); /* diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h index e2bb032..7b53bc1 100644 --- a/arch/arm64/include/asm/fpsimdmacros.h +++ b/arch/arm64/include/asm/fpsimdmacros.h @@ -254,7 +254,12 @@ .purgem savep .endm -.macro sve_load nb, xpfpsr, ntmp +.macro sve_load nb, xpfpsr, xvqminus1 ntmp + mrs_s x\ntmp, ZCR_EL1 + bic x\ntmp, x\ntmp, ZCR_EL1_LEN_MASK + orr x\ntmp, x\ntmp, \xvqminus1 + msr_s ZCR_EL1, x\ntmp // self-synchronising + .macro loadz n _zldrv \n, \nb, (\n) - 34 .endm diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S index 5dcec55..0a3fdcb 100644 --- a/arch/arm64/kernel/entry-fpsimd.S +++ b/arch/arm64/kernel/entry-fpsimd.S @@ -73,7 +73,7 @@ ENTRY(sve_save_state) ENDPROC(sve_save_state) ENTRY(sve_load_state) - sve_load 0, x1, 2 + sve_load 0, x1, x2, 3 ret ENDPROC(sve_load_state) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 6065707..ab2bb62 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -175,10 +175,14 @@ extern void *__task_pffr(struct task_struct *task); static void task_fpsimd_load(struct task_struct *task) { if (IS_ENABLED(CONFIG_ARM64_SVE) && - test_tsk_thread_flag(task, TIF_SVE)) + test_tsk_thread_flag(task, TIF_SVE)) { + unsigned int vl = task->thread.sve_vl; + + BUG_ON(!sve_vl_valid(vl)); sve_load_state(__task_pffr(task), - &task->thread.fpsimd_state.fpsr); - else + &task->thread.fpsimd_state.fpsr, + sve_vq_from_vl(vl) - 1); + } else fpsimd_load_state(&task->thread.fpsimd_state); /* -- 2.1.4