linux-kernel - [PATCH 1/2] efi/reboot: Add support for EFI_RESET_PLATFORM

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Message-ID: <20251114085058.2195900-2-sumit.garg@kernel.org>
Date: Fri, 14 Nov 2025 14:20:57 +0530
From: Sumit Garg <sumit.garg@...nel.org>
To: linux-arm-kernel@...ts.infradead.org,
	linux-efi@...r.kernel.org,
	linux-arm-msm@...r.kernel.org
Cc: catalin.marinas@....com,
	will@...nel.org,
	ardb@...nel.org,
	mark.rutland@....com,
	andersson@...nel.org,
	konradybcio@...nel.org,
	dmitry.baryshkov@....qualcomm.com,
	shivendra.pratap@....qualcomm.com,
	leif.lindholm@....qualcomm.com,
	linux-kernel@...r.kernel.org,
	Sumit Garg <sumit.garg@....qualcomm.com>
Subject: [PATCH 1/2] efi/reboot: Add support for EFI_RESET_PLATFORM_SPECIFIC

From: Sumit Garg <sumit.garg@....qualcomm.com>

UEFI specification provides support for EfiResetPlatformSpecific reset
type as follows:

"
ResetSystem:

Calling this interface with ResetType of EfiResetPlatformSpecific
causes a system-wide reset. The exact type of the reset is defined
by the EFI_GUID that follows the Null-terminated Unicode string passed
into ResetData. If the platform does not recognize the EFI_GUID in
ResetData the platform must pick a supported reset type to perform.
The platform may optionally log the parameters from any non-normal
reset that occurs.
"

Lets use the ResetData to pass the platform specific reboot command
issued and leave it's interpretation to UEFI implementation following
the specification.

Signed-off-by: Sumit Garg <sumit.garg@....qualcomm.com>
---
 drivers/firmware/efi/reboot.c | 25 +++++++++++++++----------
 include/linux/efi.h           |  5 +++--
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/firmware/efi/reboot.c b/drivers/firmware/efi/reboot.c
index ceae84c19d22..23a2fc68e9c9 100644
--- a/drivers/firmware/efi/reboot.c
+++ b/drivers/firmware/efi/reboot.c
@@ -10,7 +10,7 @@ static struct sys_off_handler *efi_sys_off_handler;
 
 int efi_reboot_quirk_mode = -1;
 
-void efi_reboot(enum reboot_mode reboot_mode, const char *__unused)
+void efi_reboot(enum reboot_mode reboot_mode, const char *data)
 {
 	const char *str[] = { "cold", "warm", "shutdown", "platform" };
 	int efi_mode, cap_reset_mode;
@@ -18,14 +18,18 @@ void efi_reboot(enum reboot_mode reboot_mode, const char *__unused)
 	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_RESET_SYSTEM))
 		return;
 
-	switch (reboot_mode) {
-	case REBOOT_WARM:
-	case REBOOT_SOFT:
-		efi_mode = EFI_RESET_WARM;
-		break;
-	default:
-		efi_mode = EFI_RESET_COLD;
-		break;
+	if (data) {
+		efi_mode = EFI_RESET_PLATFORM_SPECIFIC;
+	} else {
+		switch (reboot_mode) {
+		case REBOOT_WARM:
+		case REBOOT_SOFT:
+			efi_mode = EFI_RESET_WARM;
+			break;
+		default:
+			efi_mode = EFI_RESET_COLD;
+			break;
+		}
 	}
 
 	/*
@@ -43,7 +47,8 @@ void efi_reboot(enum reboot_mode reboot_mode, const char *__unused)
 		efi_mode = cap_reset_mode;
 	}
 
-	efi.reset_system(efi_mode, EFI_SUCCESS, 0, NULL);
+	efi.reset_system(efi_mode, EFI_SUCCESS, sizeof(data),
+			 (efi_char16_t *)data);
 }
 
 bool __weak efi_poweroff_required(void)
diff --git a/include/linux/efi.h b/include/linux/efi.h
index a98cc39e7aaa..5324db1518b6 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -256,6 +256,7 @@ typedef union efi_boot_services efi_boot_services_t;
 #define EFI_RESET_COLD 0
 #define EFI_RESET_WARM 1
 #define EFI_RESET_SHUTDOWN 2
+#define EFI_RESET_PLATFORM_SPECIFIC 3
 
 /*
  * EFI Runtime Services table
@@ -874,7 +875,7 @@ static inline bool efi_enabled(int feature)
 {
 	return test_bit(feature, &efi.flags) != 0;
 }
-extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
+extern void efi_reboot(enum reboot_mode reboot_mode, const char *data);
 
 bool __pure __efi_soft_reserve_enabled(void);
 
@@ -895,7 +896,7 @@ static inline bool efi_enabled(int feature)
 	return false;
 }
 static inline void
-efi_reboot(enum reboot_mode reboot_mode, const char *__unused) {}
+efi_reboot(enum reboot_mode reboot_mode, const char *data) {}
 
 static inline bool efi_soft_reserve_enabled(void)
 {
-- 
2.48.1