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Subject[RFC PATCH v4] ACPI: Move sdei_init and ghes_init ahead to handle platform errors earlier
On an ACPI system, ACPI is initialised very early from a subsys_initcall(),
while SDEI is not ready until a subsys_initcall_sync().

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. 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. By the way, I don't figure out why acpi_hest_init
is called in acpi_pci_root_init, it don't rely on any other thing. May it
could be moved further, following acpi_iort_init in acpi_init.

sdei_init() relies on ACPI table which is initialized subsys_initcall():
acpi_init(), acpi_bus_init(), acpi_load_tables(), acpi_tb_laod_namespace().
May it should be also moved further, after acpi_load_tables.

In this patch, move sdei_init and ghes_init as far ahead as possible, right
after acpi_hest_init().

Signed-off-by: Shuai Xue <>
drivers/acpi/apei/ghes.c | 18 ++++++++----------
drivers/acpi/pci_root.c | 5 ++++-
drivers/firmware/arm_sdei.c | 13 ++-----------
include/acpi/apei.h | 2 ++
include/linux/arm_sdei.h | 2 ++
5 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 0c8330ed1ffd..b11e46fb4b3d 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) {
- return -ENODEV;
+ pr_info(GHES_PFX "HEST is not found!\n");
+ return;
pr_info(GHES_PFX "HEST is not enabled!\n");
- return -EINVAL;
+ return;

- if (ghes_disable) {
+ if (ghes_disable)
pr_info(GHES_PFX "GHES is not enabled!\n");
- return -EINVAL;
- }


@@ -1495,8 +1494,7 @@ static int __init ghes_init(void)
pr_info(GHES_PFX "Failed to enable APEI firmware first mode.\n");

- return 0;
+ return;
- return rc;
+ ghes_disable = 1;
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index ab2f7dfb0c44..1260bb556184 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"
@@ -946,6 +946,9 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
void __init acpi_pci_root_init(void)
+ sdei_init();
+ ghes_init();
if (acpi_pci_disabled)

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(,
0, NULL, 0);
@@ -1076,17 +1076,8 @@ static int __init sdei_init(void)
pr_info("Failed to register ACPI:SDEI platform device %d\n",
- 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.
- */
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;
extern bool ghes_disable;
+void __init ghes_init(void);
#define ghes_disable 1
+static inline void ghes_init(void) { return; }

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);
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 ; }

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