[PATCH v5] ACPI: Move sdei_init and ghes_init ahead to handle platform errors earlier

[Shuai Xue]

On an ACPI system, ACPI is initialised very early from a
subsys_initcall(), while SDEI is not ready until a
subsys_initcall_sync(). This patch is to reduce the time before GHES
initialization.

The SDEI driver provides functions (e.g. apei_sdei_register_ghes(),
apei_sdei_unregister_ghes()) to register or unregister event callback
for dispatcher in firmware. When the GHES driver probing, it registers
the corresponding callback according to the notification type specified
by GHES. If the GHES notification type is SDEI, the GHES driver will
call apei_sdei_register_ghes() to register event call.

When the firmware emits an event, it migrates the handling of the event
into the kernel at the registered entry-point __sdei_asm_handler. And
finally, the kernel will call the registered event callback and return
status_code to indicate the status of event handling. SDEI_EV_FAILED
indicates that the kernel failed to handle the event.

Consequently, when an error occurs during kernel booting, the kernel is
unable to handle and report errors until the GHES driver is initialized
by device_initcall(), in which the event callback is registered.  For
example, when the kernel booting, the console logs many times from
firmware before GHES drivers init in our platform:

	Trip in MM PCIe RAS handle(Intr:910)
  	Clean PE[1.1.1] ERR_STS:0x4000100 -> 0 INT_STS:F0000000
	Find RP(98:1.0)
	--Walk dev(98:1.0) CE:0 UCE:4000
	...
	ERROR:   sdei_dispatch_event(32a) ret:-1
	--handler(910) end

This is because the callback function has not been registered yet.  Due
to the poor design of firmware, previously reported errors will be
overwritten by new ones. Therefore, all errors that occurred before GHES
initialization are missed and there is no chance to report and find them
again.

>From commit e147133a42cb ("ACPI / APEI: Make hest.c manage the estatus
memory pool") was merged, ghes_init() relies on acpi_hest_init() to manage
the estatus memory pool. On the other hand, ghes_init() relies on
sdei_init() to detect the SDEI version and the framework for registering
and unregistering events. The dependencies are as follows

	ghes_init() => acpi_hest_init() => acpi_bus_init() => acpi_init()
	ghes_init() => sdei_init()

Based on above, move sdei_init and ghes_init as far ahead as possible,
right after acpi_iort_init() in acpi_init(). After this patch, there are
still errors missing, but we have to tolerate it until the software
reporting capability is built. And this patch merely reduce the time
before GHES initialization. The boot dmesg before this patch:

	[    3.688586] HEST: Table parsing has been initialized.
	...
	[   33.204340] calling  sdei_init+0x0/0x120 @ 1
	[   33.208645] sdei: SDEIv1.0 (0x0) detected in firmware.
	...
	[   36.005390] calling  ghes_init+0x0/0x11c @ 1
	[   36.190021] GHES: APEI firmware first mode is enabled by APEI bit and WHEA _OSC.

After this patch, the boot dmesg like bellow:

	[    3.688664] HEST: Table parsing has been initialized.
	[    3.688691] sdei: SDEIv1.0 (0x0) detected in firmware.
	[    3.694557] GHES: APEI firmware first mode is enabled by APEI bit and WHEA _OSC.

As we can see, the initialization of GHES is advanced by 33 seconds.
(It should be noted that the effect of optimization varies with the
platform.)

Signed-off-by: Shuai Xue <xueshuai@xxxxxxxxxxxxxxxxx>
---
 drivers/acpi/apei/ghes.c    | 18 ++++++++----------
 drivers/acpi/bus.c          |  4 ++++
 drivers/acpi/pci_root.c     |  4 ++--
 drivers/firmware/arm_sdei.c | 13 ++-----------
 include/acpi/apei.h         |  2 ++
 include/linux/arm_sdei.h    |  2 ++
 6 files changed, 20 insertions(+), 23 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 0c5c9acc6254..64f24a9f213f 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -1457,27 +1457,26 @@ static struct platform_driver ghes_platform_driver = {
 	.remove		= ghes_remove,
 };
 
-static int __init ghes_init(void)
+void __init ghes_init(void)
 {
 	int rc;
 
 	if (acpi_disabled)
-		return -ENODEV;
+		return;
 
 	switch (hest_disable) {
 	case HEST_NOT_FOUND:
-		return -ENODEV;
+		pr_info(GHES_PFX "HEST is not found!\n");
+		return;
 	case HEST_DISABLED:
 		pr_info(GHES_PFX "HEST is not enabled!\n");
-		return -EINVAL;
+		return;
 	default:
 		break;
 	}
 
-	if (ghes_disable) {
+	if (ghes_disable)
 		pr_info(GHES_PFX "GHES is not enabled!\n");
-		return -EINVAL;
-	}
 
 	ghes_nmi_init_cxt();
 
@@ -1495,8 +1494,7 @@ static int __init ghes_init(void)
 	else
 		pr_info(GHES_PFX "Failed to enable APEI firmware first mode.\n");
 
-	return 0;
+	return;
 err:
-	return rc;
+	ghes_disable = 1;
 }
-device_initcall(ghes_init);
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 07f604832fd6..1dcd71df2cd5 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -30,6 +30,7 @@
 #include <linux/acpi_viot.h>
 #include <linux/pci.h>
 #include <acpi/apei.h>
+#include <linux/arm_sdei.h>
 #include <linux/suspend.h>
 #include <linux/prmt.h>
 
@@ -1331,6 +1332,9 @@ static int __init acpi_init(void)
 
 	pci_mmcfg_late_init();
 	acpi_iort_init();
+	acpi_hest_init();
+	sdei_init();
+	ghes_init();
 	acpi_scan_init();
 	acpi_ec_init();
 	acpi_debugfs_init();
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index b76db99cced3..14e20af44627 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -23,7 +23,7 @@
 #include <linux/dmi.h>
 #include <linux/platform_data/x86/apple.h>
 #include <acpi/apei.h>	/* for acpi_hest_init() */
-
+#include <linux/arm_sdei.h> /* for sdei_init() */
 #include "internal.h"
 
 #define ACPI_PCI_ROOT_CLASS		"pci_bridge"
@@ -943,7 +943,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 
 void __init acpi_pci_root_init(void)
 {
-	acpi_hest_init();
+
 	if (acpi_pci_disabled)
 		return;
 
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index a7e762c352f9..1e1a51510e83 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -1059,14 +1059,14 @@ static bool __init sdei_present_acpi(void)
 	return true;
 }
 
-static int __init sdei_init(void)
+void __init sdei_init(void)
 {
 	struct platform_device *pdev;
 	int ret;
 
 	ret = platform_driver_register(&sdei_driver);
 	if (ret || !sdei_present_acpi())
-		return ret;
+		return;
 
 	pdev = platform_device_register_simple(sdei_driver.driver.name,
 					       0, NULL, 0);
@@ -1076,17 +1076,8 @@ static int __init sdei_init(void)
 		pr_info("Failed to register ACPI:SDEI platform device %d\n",
 			ret);
 	}
-
-	return ret;
 }
 
-/*
- * On an ACPI system SDEI needs to be ready before HEST:GHES tries to register
- * its events. ACPI is initialised from a subsys_initcall(), GHES is initialised
- * by device_initcall(). We want to be called in the middle.
- */
-subsys_initcall_sync(sdei_init);
-
 int sdei_event_handler(struct pt_regs *regs,
 		       struct sdei_registered_event *arg)
 {
diff --git a/include/acpi/apei.h b/include/acpi/apei.h
index ece0a8af2bae..7dbd6363fda7 100644
--- a/include/acpi/apei.h
+++ b/include/acpi/apei.h
@@ -27,8 +27,10 @@ extern int hest_disable;
 extern int erst_disable;
 #ifdef CONFIG_ACPI_APEI_GHES
 extern bool ghes_disable;
+void __init ghes_init(void);
 #else
 #define ghes_disable 1
+static inline void ghes_init(void) { return; }
 #endif
 
 #ifdef CONFIG_ACPI_APEI
diff --git a/include/linux/arm_sdei.h b/include/linux/arm_sdei.h
index 0a241c5c911d..9c987188b692 100644
--- a/include/linux/arm_sdei.h
+++ b/include/linux/arm_sdei.h
@@ -46,9 +46,11 @@ int sdei_unregister_ghes(struct ghes *ghes);
 /* For use by arch code when CPU hotplug notifiers are not appropriate. */
 int sdei_mask_local_cpu(void);
 int sdei_unmask_local_cpu(void);
+void __init sdei_init(void);
 #else
 static inline int sdei_mask_local_cpu(void) { return 0; }
 static inline int sdei_unmask_local_cpu(void) { return 0; }
+static inline void sdei_init(void) { return ; }
 #endif /* CONFIG_ARM_SDE_INTERFACE */
 
 
-- 
2.20.1.12.g72788fdb