Messages in this thread | | | Date | Tue, 06 Jul 2021 13:27:30 -0700 (PDT) | Subject | Re: [PATCH v7 1/1] RISC-V: Use SBI SRST extension when available | From | Palmer Dabbelt <> |
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On Mon, 21 Jun 2021 21:46:46 PDT (-0700), anup@brainfault.org wrote: > Hi Palmer, > > On Wed, Jun 9, 2021 at 5:43 PM Anup Patel <anup.patel@wdc.com> wrote: >> >> The SBI SRST extension provides a standard way to poweroff and >> reboot the system irrespective to whether Linux RISC-V S-mode >> is running natively (HS-mode) or inside Guest/VM (VS-mode). >> >> The SBI SRST extension is available in the SBI v0.3 specification. >> (Refer, https://github.com/riscv/riscv-sbi-doc/releases/tag/v0.3.0-rc1) > > Can you please consider this patch for Linux-5.14-rc1 ? > > The SBI v0.3 spec is already frozen and this patch has been > floating on LKML for quite a few months now.
I didn't realize that SBI-0.3 had been frozed. That link is to a RC, the cooresponding v0.3.0 tag isn't in that repo. Can you give me a pointer to the frozen spec?
> > Regards, > Anup > >> >> This patch extends Linux RISC-V SBI implementation to detect >> and use SBI SRST extension. >> >> Signed-off-by: Anup Patel <anup.patel@wdc.com> >> Reviewed-by: Atish Patra <atish.patra@wdc.com> >> --- >> arch/riscv/include/asm/sbi.h | 24 ++++++++++++++++++++++++ >> arch/riscv/kernel/sbi.c | 35 +++++++++++++++++++++++++++++++++++ >> 2 files changed, 59 insertions(+) >> >> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h >> index 0d42693cb65e..289621da4a2a 100644 >> --- a/arch/riscv/include/asm/sbi.h >> +++ b/arch/riscv/include/asm/sbi.h >> @@ -27,6 +27,7 @@ enum sbi_ext_id { >> SBI_EXT_IPI = 0x735049, >> SBI_EXT_RFENCE = 0x52464E43, >> SBI_EXT_HSM = 0x48534D, >> + SBI_EXT_SRST = 0x53525354, >> }; >> >> enum sbi_ext_base_fid { >> @@ -70,6 +71,21 @@ enum sbi_hsm_hart_status { >> SBI_HSM_HART_STATUS_STOP_PENDING, >> }; >> >> +enum sbi_ext_srst_fid { >> + SBI_EXT_SRST_RESET = 0, >> +}; >> + >> +enum sbi_srst_reset_type { >> + SBI_SRST_RESET_TYPE_SHUTDOWN = 0, >> + SBI_SRST_RESET_TYPE_COLD_REBOOT, >> + SBI_SRST_RESET_TYPE_WARM_REBOOT, >> +}; >> + >> +enum sbi_srst_reset_reason { >> + SBI_SRST_RESET_REASON_NONE = 0, >> + SBI_SRST_RESET_REASON_SYS_FAILURE, >> +}; >> + >> #define SBI_SPEC_VERSION_DEFAULT 0x1 >> #define SBI_SPEC_VERSION_MAJOR_SHIFT 24 >> #define SBI_SPEC_VERSION_MAJOR_MASK 0x7f >> @@ -148,6 +164,14 @@ static inline unsigned long sbi_minor_version(void) >> return sbi_spec_version & SBI_SPEC_VERSION_MINOR_MASK; >> } >> >> +/* Make SBI version */ >> +static inline unsigned long sbi_mk_version(unsigned long major, >> + unsigned long minor) >> +{ >> + return ((major & SBI_SPEC_VERSION_MAJOR_MASK) << >> + SBI_SPEC_VERSION_MAJOR_SHIFT) | minor; >> +} >> + >> int sbi_err_map_linux_errno(int err); >> #else /* CONFIG_RISCV_SBI */ >> static inline int sbi_remote_fence_i(const unsigned long *hart_mask) { return -1; } >> diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c >> index 7402a417f38e..9a84f0cb5175 100644 >> --- a/arch/riscv/kernel/sbi.c >> +++ b/arch/riscv/kernel/sbi.c >> @@ -7,6 +7,7 @@ >> >> #include <linux/init.h> >> #include <linux/pm.h> >> +#include <linux/reboot.h> >> #include <asm/sbi.h> >> #include <asm/smp.h> >> >> @@ -501,6 +502,32 @@ int sbi_remote_hfence_vvma_asid(const unsigned long *hart_mask, >> } >> EXPORT_SYMBOL(sbi_remote_hfence_vvma_asid); >> >> +static void sbi_srst_reset(unsigned long type, unsigned long reason) >> +{ >> + sbi_ecall(SBI_EXT_SRST, SBI_EXT_SRST_RESET, type, reason, >> + 0, 0, 0, 0); >> + pr_warn("%s: type=0x%lx reason=0x%lx failed\n", >> + __func__, type, reason); >> +} >> + >> +static int sbi_srst_reboot(struct notifier_block *this, >> + unsigned long mode, void *cmd) >> +{ >> + sbi_srst_reset((mode == REBOOT_WARM || mode == REBOOT_SOFT) ? >> + SBI_SRST_RESET_TYPE_WARM_REBOOT : >> + SBI_SRST_RESET_TYPE_COLD_REBOOT, >> + SBI_SRST_RESET_REASON_NONE); >> + return NOTIFY_DONE; >> +} >> + >> +static struct notifier_block sbi_srst_reboot_nb; >> + >> +static void sbi_srst_power_off(void) >> +{ >> + sbi_srst_reset(SBI_SRST_RESET_TYPE_SHUTDOWN, >> + SBI_SRST_RESET_REASON_NONE); >> +} >> + >> /** >> * sbi_probe_extension() - Check if an SBI extension ID is supported or not. >> * @extid: The extension ID to be probed. >> @@ -608,6 +635,14 @@ void __init sbi_init(void) >> } else { >> __sbi_rfence = __sbi_rfence_v01; >> } >> + if ((sbi_spec_version >= sbi_mk_version(0, 3)) && >> + (sbi_probe_extension(SBI_EXT_SRST) > 0)) { >> + pr_info("SBI SRST extension detected\n"); >> + pm_power_off = sbi_srst_power_off; >> + sbi_srst_reboot_nb.notifier_call = sbi_srst_reboot; >> + sbi_srst_reboot_nb.priority = 192; >> + register_restart_handler(&sbi_srst_reboot_nb); >> + } >> } else { >> __sbi_set_timer = __sbi_set_timer_v01; >> __sbi_send_ipi = __sbi_send_ipi_v01; >> -- >> 2.25.1 >>
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