[U-Boot] [PATCH v5 1/1] efi_loader: PSCI reset and shutdown

[U-Boot] [PATCH v5 1/1] efi_loader: PSCI reset and shutdown

[Heinrich Schuchardt]

When an operating system started via bootefi tries to reset or power off
this is done by calling the EFI runtime ResetSystem(). On most ARMv8 system
the actual reset relies on PSCI. Depending on whether the PSCI firmware
resides the hypervisor (EL2) or in the secure monitor (EL3) either an HVC
or an SMC command has to be issued.

The current implementation always uses SMC. This results in crashes on
systems where the PSCI firmware is implemented in the hypervisor, e.g.
qemu-arm64_defconfig.

The logic to decide which call is needed based on the device tree is
already implemented in the PSCI firmware driver. During the EFI runtime
the device driver model is not available. But we can minimize code
duplication by merging the EFI runtime reset and poweroff code with
the PSCI firmware driver.

As the same HVC/SMC problem is also evident for the ARMv8 do_poweroff
and reset_misc routines let's move them into the same code module.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Tested-by: Sumit Garg <sumit.garg@linaro.org>
---
Travis reporteded no errors in
https://travis-ci.org/xypron2/u-boot/builds/442613876

v5:
	depend on CONFIG_PSCI_reset for EFI runtime support
v4:
	fix reset_misc() too
	avoid switch statement
v3:
	update commit message
v2:
	Use PSCI firmware driver to detect call method.
	Thanks to Sumit for pointing me at dtb parsing as part of
	"psci_probe()
---
 arch/arm/cpu/armv7/smccc-call.S |   2 +
 arch/arm/cpu/armv8/Kconfig      |   1 +
 arch/arm/cpu/armv8/fwcall.c     |  52 ++---------------
 arch/arm/cpu/armv8/smccc-call.S |   2 +
 drivers/firmware/psci.c         | 100 +++++++++++++++++++++++++++-----
 include/linux/psci.h            |   6 +-
 6 files changed, 96 insertions(+), 67 deletions(-)

diff --git a/arch/arm/cpu/armv7/smccc-call.S b/arch/arm/cpu/armv7/smccc-call.S
index 0d8b59eb6b..eae69e36c3 100644
--- a/arch/arm/cpu/armv7/smccc-call.S
+++ b/arch/arm/cpu/armv7/smccc-call.S
@@ -7,6 +7,8 @@
 #include <asm/opcodes-sec.h>
 #include <asm/opcodes-virt.h>
 
+	.section	.text.efi_runtime
+
 #define UNWIND(x...)
 	/*
 	 * Wrap c macros in asm macros to delay expansion until after the
diff --git a/arch/arm/cpu/armv8/Kconfig b/arch/arm/cpu/armv8/Kconfig
index c8bebabdf6..d643981b73 100644
--- a/arch/arm/cpu/armv8/Kconfig
+++ b/arch/arm/cpu/armv8/Kconfig
@@ -96,6 +96,7 @@ endmenu
 config PSCI_RESET
 	bool "Use PSCI for reset and shutdown"
 	default y
+	select ARM_SMCCC if OF_CONTROL
 	depends on !ARCH_EXYNOS7 && !ARCH_BCM283X && \
 		   !TARGET_LS2080A_SIMU && !TARGET_LS2080AQDS && \
 		   !TARGET_LS2080ARDB && !TARGET_LS2080A_EMU && \
diff --git a/arch/arm/cpu/armv8/fwcall.c b/arch/arm/cpu/armv8/fwcall.c
index 0ba3dad8cc..9957c2974b 100644
--- a/arch/arm/cpu/armv8/fwcall.c
+++ b/arch/arm/cpu/armv8/fwcall.c
@@ -7,7 +7,6 @@
 
 #include <asm-offsets.h>
 #include <config.h>
-#include <efi_loader.h>
 #include <version.h>
 #include <asm/macro.h>
 #include <asm/psci.h>
@@ -19,7 +18,7 @@
  * x0~x7: input arguments
  * x0~x3: output arguments
  */
-static void __efi_runtime hvc_call(struct pt_regs *args)
+static void hvc_call(struct pt_regs *args)
 {
 	asm volatile(
 		"ldr x0, %0\n"
@@ -53,7 +52,7 @@ static void __efi_runtime hvc_call(struct pt_regs *args)
  * x0~x3: output arguments
  */
 
-void __efi_runtime smc_call(struct pt_regs *args)
+void smc_call(struct pt_regs *args)
 {
 	asm volatile(
 		"ldr x0, %0\n"
@@ -83,9 +82,9 @@ void __efi_runtime smc_call(struct pt_regs *args)
  * use PSCI on U-Boot running below a hypervisor, please detect
  * this and set the flag accordingly.
  */
-static const __efi_runtime_data bool use_smc_for_psci = true;
+static const bool use_smc_for_psci = true;
 
-void __noreturn __efi_runtime psci_system_reset(void)
+void __noreturn psci_system_reset(void)
 {
 	struct pt_regs regs;
 
@@ -100,7 +99,7 @@ void __noreturn __efi_runtime psci_system_reset(void)
 		;
 }
 
-void __noreturn __efi_runtime psci_system_off(void)
+void __noreturn psci_system_off(void)
 {
 	struct pt_regs regs;
 
@@ -114,44 +113,3 @@ void __noreturn __efi_runtime psci_system_off(void)
 	while (1)
 		;
 }
-
-#ifdef CONFIG_CMD_POWEROFF
-int do_poweroff(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
-{
-	puts("poweroff ...\n");
-
-	udelay(50000); /* wait 50 ms */
-
-	disable_interrupts();
-
-	psci_system_off();
-
-	/*NOTREACHED*/
-	return 0;
-}
-#endif
-
-#ifdef CONFIG_PSCI_RESET
-void reset_misc(void)
-{
-	psci_system_reset();
-}
-
-#ifdef CONFIG_EFI_LOADER
-void __efi_runtime EFIAPI efi_reset_system(
-			enum efi_reset_type reset_type,
-			efi_status_t reset_status,
-			unsigned long data_size, void *reset_data)
-{
-	if (reset_type == EFI_RESET_COLD ||
-	    reset_type == EFI_RESET_WARM ||
-	    reset_type == EFI_RESET_PLATFORM_SPECIFIC) {
-		psci_system_reset();
-	} else if (reset_type == EFI_RESET_SHUTDOWN) {
-		psci_system_off();
-	}
-
-	while (1) { }
-}
-#endif /* CONFIG_EFI_LOADER */
-#endif /* CONFIG_PSCI_RESET */
diff --git a/arch/arm/cpu/armv8/smccc-call.S b/arch/arm/cpu/armv8/smccc-call.S
index 16c9e298b4..86de4b4089 100644
--- a/arch/arm/cpu/armv8/smccc-call.S
+++ b/arch/arm/cpu/armv8/smccc-call.S
@@ -6,6 +6,8 @@
 #include <linux/arm-smccc.h>
 #include <generated/asm-offsets.h>
 
+	.section	.text.efi_runtime
+
 	.macro SMCCC instr
 	.cfi_startproc
 	\instr	#0
diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 2cb35f356f..7ec5eb094b 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -9,31 +9,38 @@
 #include <common.h>
 #include <dm.h>
 #include <dm/lists.h>
+#include <efi_loader.h>
 #include <linux/libfdt.h>
 #include <linux/arm-smccc.h>
 #include <linux/errno.h>
 #include <linux/printk.h>
 #include <linux/psci.h>
 
-psci_fn *invoke_psci_fn;
+#define DRIVER_NAME "psci"
 
-static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
-			unsigned long arg0, unsigned long arg1,
-			unsigned long arg2)
-{
-	struct arm_smccc_res res;
+#define PSCI_METHOD_HVC 1
+#define PSCI_METHOD_SMC 2
 
-	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
-	return res.a0;
-}
+int __efi_runtime_data psci_method;
 
-static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
-			unsigned long arg0, unsigned long arg1,
-			unsigned long arg2)
+unsigned long __efi_runtime invoke_psci_fn
+		(unsigned long function_id, unsigned long arg0,
+		 unsigned long arg1, unsigned long arg2)
 {
 	struct arm_smccc_res res;
 
-	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	/*
+	 * In the __efi_runtime we need to avoid the switch statement. In some
+	 * cases the compiler creates lookup tables to implement switch. These
+	 * tables are not correctly relocated when SetVirtualAddressMap is
+	 * called.
+	 */
+	if (psci_method == PSCI_METHOD_SMC)
+		arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	else if (psci_method == PSCI_METHOD_HVC)
+		arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	else
+		res.a0 = PSCI_RET_DISABLED;
 	return res.a0;
 }
 
@@ -67,9 +74,9 @@ static int psci_probe(struct udevice *dev)
 	}
 
 	if (!strcmp("hvc", method)) {
-		invoke_psci_fn = __invoke_psci_fn_hvc;
+		psci_method = PSCI_METHOD_HVC;
 	} else if (!strcmp("smc", method)) {
-		invoke_psci_fn = __invoke_psci_fn_smc;
+		psci_method = PSCI_METHOD_SMC;
 	} else {
 		pr_warn("invalid \"method\" property: %s\n", method);
 		return -EINVAL;
@@ -78,6 +85,67 @@ static int psci_probe(struct udevice *dev)
 	return 0;
 }
 
+/**
+ * void do_psci_probe() - probe PSCI firmware driver
+ *
+ * Ensure that psci_method is initialized.
+ */
+static void __maybe_unused do_psci_probe(void)
+{
+	struct udevice *dev;
+
+	uclass_get_device_by_name(UCLASS_FIRMWARE, DRIVER_NAME, &dev);
+}
+
+#if IS_ENABLED(CONFIG_EFI_LOADER) && IS_ENABLED(CONFIG_PSCI_RESET)
+efi_status_t efi_reset_system_init(void)
+{
+	do_psci_probe();
+	return EFI_SUCCESS;
+}
+
+void __efi_runtime EFIAPI efi_reset_system(enum efi_reset_type reset_type,
+					   efi_status_t reset_status,
+					   unsigned long data_size,
+					   void *reset_data)
+{
+	if (reset_type == EFI_RESET_COLD ||
+	    reset_type == EFI_RESET_WARM ||
+	    reset_type == EFI_RESET_PLATFORM_SPECIFIC) {
+		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
+	} else if (reset_type == EFI_RESET_SHUTDOWN) {
+		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
+	}
+	while (1)
+		;
+}
+#endif /* IS_ENABLED(CONFIG_EFI_LOADER) && IS_ENABLED(CONFIG_PSCI_RESET) */
+
+#ifdef CONFIG_PSCI_RESET
+void reset_misc(void)
+{
+	do_psci_probe();
+	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
+}
+#endif /* CONFIG_PSCI_RESET */
+
+#ifdef CONFIG_CMD_POWEROFF
+int do_poweroff(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	do_psci_probe();
+
+	puts("poweroff ...\n");
+	udelay(50000); /* wait 50 ms */
+
+	disable_interrupts();
+	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
+	enable_interrupts();
+
+	log_err("Power off not supported on this platform\n");
+	return CMD_RET_FAILURE;
+}
+#endif
+
 static const struct udevice_id psci_of_match[] = {
 	{ .compatible = "arm,psci" },
 	{ .compatible = "arm,psci-0.2" },
@@ -86,7 +154,7 @@ static const struct udevice_id psci_of_match[] = {
 };
 
 U_BOOT_DRIVER(psci) = {
-	.name = "psci",
+	.name = DRIVER_NAME,
 	.id = UCLASS_FIRMWARE,
 	.of_match = psci_of_match,
 	.bind = psci_bind,
diff --git a/include/linux/psci.h b/include/linux/psci.h
index 8d13bd2702..9433df836b 100644
--- a/include/linux/psci.h
+++ b/include/linux/psci.h
@@ -88,10 +88,8 @@
 #define PSCI_RET_DISABLED			-8
 
 #ifdef CONFIG_ARM_PSCI_FW
-typedef unsigned long (psci_fn)(unsigned long, unsigned long,
-				unsigned long, unsigned long);
-
-extern psci_fn *invoke_psci_fn;
+unsigned long invoke_psci_fn(unsigned long a0, unsigned long a1,
+			     unsigned long a2, unsigned long a3);
 #else
 unsigned long invoke_psci_fn(unsigned long a0, unsigned long a1,
 			     unsigned long a2, unsigned long a3)
-- 
2.19.1