[PATCH 0/2] riscv: Use EFI runtime services for poweroff and restart

[PATCH 0/2] riscv: Use EFI runtime services for poweroff and restart

[Atish Patra]

Today RISC-V always uses the SBI SRST extension for both poweroff and restart,
even when UEFI runtime services are available. This series makes RISC-V prefer
EFI runtime services for both paths when available. The reset via EFI is
required for EFI capsule updates and also documented as a preferred method
in BRS 1.0 spec (e.g. URT_030)[1] 

Behavior on SBI-only (non-EFI) systems is unchanged.

Tested under QEMU 'virt' with EDK2/UEFI firmware exposing runtime
ResetSystem().

[1] https://docs.riscv.org/reference/brs/uefi.html#uefi

Signed-off-by: Atish Patra <atishp@meta.com>
---
Atish Patra (2):
      riscv: efi: Power off via EFI runtime services when available
      riscv: Restart via EFI runtime services when available

 arch/riscv/kernel/efi.c   | 5 +++++
 arch/riscv/kernel/reset.c | 7 +++++++
 2 files changed, 12 insertions(+)
---
base-commit: 8cd9520d35a6c38db6567e97dd93b1f11f185dc6
change-id: 20260615-efi_reset_shutdown-792040a83f18

Best regards,
-- 
Atish Patra <atishp@meta.com>

[PATCH 1/2] riscv: efi: Power off via EFI runtime services when available

[Atish Patra]

From: Atish Patra <atishp@meta.com>

When booted via UEFI with runtime services enabled, EFI Reset Shutdown is
the firmware-preferred shutdown path: it lets firmware run its own
shutdown hooks which may invoke SBI SRST extension internally. However,
RISC-V always powers off via the SBI SRST extension today and EFI runtime
path is never used even when firmware provides it.

Enable the poweroff via EFI by overriding efi_poweroff_required()

Signed-off-by: Atish Patra <atishp@meta.com>
---
 arch/riscv/kernel/efi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/riscv/kernel/efi.c b/arch/riscv/kernel/efi.c
index b64bf1624a05..2d3cc57b4535 100644
--- a/arch/riscv/kernel/efi.c
+++ b/arch/riscv/kernel/efi.c
@@ -95,3 +95,8 @@ int __init efi_set_mapping_permissions(struct mm_struct *mm,
 				   md->num_pages << EFI_PAGE_SHIFT,
 				   set_permissions, md);
 }
+
+bool efi_poweroff_required(void)
+{
+	return efi_enabled(EFI_RUNTIME_SERVICES);
+}

-- 
2.53.0-Meta

Re: [PATCH 1/2] riscv: efi: Power off via EFI runtime services when available

[Sunil V L]

On Tue, Jun 16, 2026 at 4:59 AM Atish Patra <atish.patra@linux.dev> wrote:
>
> From: Atish Patra <atishp@meta.com>
>
> When booted via UEFI with runtime services enabled, EFI Reset Shutdown is
> the firmware-preferred shutdown path: it lets firmware run its own
> shutdown hooks which may invoke SBI SRST extension internally. However,
> RISC-V always powers off via the SBI SRST extension today and EFI runtime
> path is never used even when firmware provides it.
>
> Enable the poweroff via EFI by overriding efi_poweroff_required()
>
> Signed-off-by: Atish Patra <atishp@meta.com>
> ---
>  arch/riscv/kernel/efi.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/arch/riscv/kernel/efi.c b/arch/riscv/kernel/efi.c
> index b64bf1624a05..2d3cc57b4535 100644
> --- a/arch/riscv/kernel/efi.c
> +++ b/arch/riscv/kernel/efi.c
> @@ -95,3 +95,8 @@ int __init efi_set_mapping_permissions(struct mm_struct *mm,
>                                    md->num_pages << EFI_PAGE_SHIFT,
>                                    set_permissions, md);
>  }
> +
> +bool efi_poweroff_required(void)
> +{
> +       return efi_enabled(EFI_RUNTIME_SERVICES);
> +}
>
Reviewed-by: Sunil V L <sunilvl@oss.qualcomm.com>

[PATCH 2/2] riscv: Restart via EFI runtime services when available

[Atish Patra]

From: Atish Patra <atishp@meta.com>

Firmware-preferred reset and EFI capsule update support requires reset
via EFI runtime services rather than direction M-mode firmware invocation
via SBI. Unlike poweroff, restart mechanism is directly controlled from
machine_restart function though.

Prefer the EFI runtime ResetSystem() service for restart when UEFI
runtime services are available.

Signed-off-by: Atish Patra <atishp@meta.com>
---
 arch/riscv/kernel/reset.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
index 912288572226..541e2162c85a 100644
--- a/arch/riscv/kernel/reset.c
+++ b/arch/riscv/kernel/reset.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2012 Regents of the University of California
  */
 
+#include <linux/efi.h>
 #include <linux/reboot.h>
 #include <linux/pm.h>
 
@@ -17,6 +18,12 @@ EXPORT_SYMBOL(pm_power_off);
 
 void machine_restart(char *cmd)
 {
+	/*
+	 * UpdateCapsule() depends on the system being reset via ResetSystem().
+	 */
+	if (efi_enabled(EFI_RUNTIME_SERVICES))
+		efi_reboot(reboot_mode, NULL);
+
 	do_kernel_restart(cmd);
 	while (1);
 }

-- 
2.53.0-Meta

Re: [PATCH 2/2] riscv: Restart via EFI runtime services when available

[Sunil V L]

On Tue, Jun 16, 2026 at 4:59 AM Atish Patra <atish.patra@linux.dev> wrote:
>
> From: Atish Patra <atishp@meta.com>
>
> Firmware-preferred reset and EFI capsule update support requires reset
> via EFI runtime services rather than direction M-mode firmware invocation
> via SBI. Unlike poweroff, restart mechanism is directly controlled from
> machine_restart function though.
>
> Prefer the EFI runtime ResetSystem() service for restart when UEFI
> runtime services are available.
>
> Signed-off-by: Atish Patra <atishp@meta.com>
> ---
>  arch/riscv/kernel/reset.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
> index 912288572226..541e2162c85a 100644
> --- a/arch/riscv/kernel/reset.c
> +++ b/arch/riscv/kernel/reset.c
> @@ -3,6 +3,7 @@
>   * Copyright (C) 2012 Regents of the University of California
>   */
>
> +#include <linux/efi.h>
>  #include <linux/reboot.h>
>  #include <linux/pm.h>
>
> @@ -17,6 +18,12 @@ EXPORT_SYMBOL(pm_power_off);
>
>  void machine_restart(char *cmd)
>  {
> +       /*
> +        * UpdateCapsule() depends on the system being reset via ResetSystem().
> +        */
> +       if (efi_enabled(EFI_RUNTIME_SERVICES))
> +               efi_reboot(reboot_mode, NULL);
> +
>         do_kernel_restart(cmd);
>         while (1);
>  }
>
LGTM.
Reviewed-by: Sunil V L <sunilvl@oss.qualcomm.com>

Re: [PATCH 0/2] riscv: Use EFI runtime services for poweroff and restart

[Paul Walmsley]

On Mon, 15 Jun 2026, Atish Patra wrote:

> Today RISC-V always uses the SBI SRST extension for both poweroff and restart,
> even when UEFI runtime services are available. This series makes RISC-V prefer
> EFI runtime services for both paths when available. The reset via EFI is
> required for EFI capsule updates and also documented as a preferred method
> in BRS 1.0 spec (e.g. URT_030)[1] 
> 
> Behavior on SBI-only (non-EFI) systems is unchanged.
> 
> Tested under QEMU 'virt' with EDK2/UEFI firmware exposing runtime
> ResetSystem().
> 
> [1] https://docs.riscv.org/reference/brs/uefi.html#uefi
> 
> Signed-off-by: Atish Patra <atishp@meta.com>

Thanks, queued for v7.3.


- Paul