Messages in this thread | | | From | Anup Patel <> | Date | Tue, 22 Aug 2023 11:46:22 +0530 | Subject | Re: [PATCH v2] riscv: suspend: Add syscore ops for suspend |
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On Tue, Aug 22, 2023 at 11:17 AM Nick Hu <nick.hu@sifive.com> wrote: > > If a task is the one who performs the suspend flow and it also do some > floating or vector operations before the suspend, we might lose the FPU > and vector states when it goes to the non-retention system suspend state. > Add syscore ops to save and restore the FPU and vector states of the > current task to fix the issue above.
This only applies to non-retentive system suspend so why do we need this before SBI system suspend is merged ?
Regards, Anup
> > Co-developed-by: Andy Chiu <andy.chiu@sifive.com> > Signed-off-by: Andy Chiu <andy.chiu@sifive.com> > Signed-off-by: Nick Hu <nick.hu@sifive.com> > --- > Changes in v2: > a) Add Co-developed-by and adjust the order of signed-off > b) Rephrase the commit message > > arch/riscv/kernel/suspend.c | 45 +++++++++++++++++++++++++++++++++++++ > 1 file changed, 45 insertions(+) > > diff --git a/arch/riscv/kernel/suspend.c b/arch/riscv/kernel/suspend.c > index 3c89b8ec69c4..ff69ff8a1974 100644 > --- a/arch/riscv/kernel/suspend.c > +++ b/arch/riscv/kernel/suspend.c > @@ -4,9 +4,14 @@ > * Copyright (c) 2022 Ventana Micro Systems Inc. > */ > > +#include <linux/cpu_pm.h> > #include <linux/ftrace.h> > +#include <linux/thread_info.h> > +#include <linux/syscore_ops.h> > #include <asm/csr.h> > #include <asm/suspend.h> > +#include <asm/switch_to.h> > +#include <asm/vector.h> > > void suspend_save_csrs(struct suspend_context *context) > { > @@ -85,3 +90,43 @@ int cpu_suspend(unsigned long arg, > > return rc; > } > + > +static int riscv_cpu_suspend(void) > +{ > + struct task_struct *cur_task = get_current(); > + struct pt_regs *regs = task_pt_regs(cur_task); > + > + if (has_fpu()) { > + if (unlikely(regs->status & SR_SD)) > + fstate_save(cur_task, regs); > + } > + if (has_vector()) { > + if (unlikely(regs->status & SR_SD)) > + riscv_v_vstate_save(cur_task, regs); > + } > + > + return 0; > +} > + > +static void riscv_cpu_resume(void) > +{ > + struct task_struct *cur_task = get_current(); > + struct pt_regs *regs = task_pt_regs(cur_task); > + > + if (has_fpu()) > + fstate_restore(cur_task, regs); > + if (has_vector()) > + riscv_v_vstate_restore(cur_task, regs); > +} > + > +static struct syscore_ops riscv_cpu_syscore_ops = { > + .suspend = riscv_cpu_suspend, > + .resume = riscv_cpu_resume, > +}; > + > +static int __init riscv_cpu_suspend_init(void) > +{ > + register_syscore_ops(&riscv_cpu_syscore_ops); > + return 0; > +} > +arch_initcall(riscv_cpu_suspend_init); > -- > 2.34.1 >
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