[PATCH v10 3/7] EDAC/ghes: Prepare to make ghes_edac a proper module

Jia He
2022-10-18T08:27:59Z

To make ghes_edac a proper module, prepare to decouple its dependencies
on ghes.

ghes_edac_register() is too late to set module flag ghes_edac.force_load.
Also, other edac drivers should not be able to control this flag. Move this
flag to the module parameter in ghes and make it static.

Introduce a helper ghes_get_devices(), which returns the dev list GHES
probed when the platform-check passes on the system.

The previous force_load check is not needed in ghes_edac_unregister()
since it will be checked in module_init of ghes_edac later.

Suggested-by: Toshi Kani <toshi.kani@hpe.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jia He <justin.he@arm.com>
---
drivers/acpi/apei/ghes.c | 46 ++++++++++++++++++++++++++++++++++++++++
drivers/edac/ghes_edac.c | 35 ++----------------------------
include/acpi/ghes.h | 6 ++++++
3 files changed, 54 insertions(+), 33 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 8cb65f757d06..6a0dcb8c0901 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -109,6 +109,13 @@ static inline bool is_hest_type_generic_v2(struct ghes *ghes)
bool ghes_disable;
module_param_named(disable, ghes_disable, bool, 0);

+/*
+ * "ghes.edac_force_enable" forcibly enables ghes_edac and skips the platform
+ * check.
+ */
+static bool ghes_edac_force_enable;
+module_param_named(edac_force_enable, ghes_edac_force_enable, bool, 0);
+
/*
* All error sources notified with HED (Hardware Error Device) share a
* single notifier callback, so they need to be linked and checked one
@@ -120,6 +127,9 @@ module_param_named(disable, ghes_disable, bool, 0);
static LIST_HEAD(ghes_hed);
static DEFINE_MUTEX(ghes_list_mutex);

+static LIST_HEAD(ghes_devs);
+static DEFINE_MUTEX(ghes_devs_mutex);
+
/*
* Because the memory area used to transfer hardware error information
* from BIOS to Linux can be determined only in NMI, IRQ or timer
@@ -1380,6 +1390,12 @@ static int ghes_probe(struct platform_device *ghes_dev)

ghes_edac_register(ghes, &ghes_dev->dev);

+ ghes->dev = &ghes_dev->dev;
+
+ mutex_lock(&ghes_devs_mutex);
+ list_add_tail(&ghes->elist, &ghes_devs);
+ mutex_unlock(&ghes_devs_mutex);
+
/* Handle any pending errors right away */
spin_lock_irqsave(&ghes_notify_lock_irq, flags);
ghes_proc(ghes);
@@ -1444,6 +1460,10 @@ static int ghes_remove(struct platform_device *ghes_dev)

ghes_edac_unregister(ghes);

+ mutex_lock(&ghes_devs_mutex);
+ list_del(&ghes->elist);
+ mutex_unlock(&ghes_devs_mutex);
+
kfree(ghes);

platform_set_drvdata(ghes_dev, NULL);
@@ -1500,6 +1520,32 @@ void __init acpi_ghes_init(void)
pr_info(GHES_PFX "Failed to enable APEI firmware first mode.\n");
}

+/*
+ * Known x86 systems that prefer GHES error reporting:
+ */
+static struct acpi_platform_list plat_list[] = {
+ {"HPE ", "Server ", 0, ACPI_SIG_FADT, all_versions},
+ { } /* End */
+};
+
+struct list_head *ghes_get_devices(void)
+{
+ int idx = -1;
+
+ if (IS_ENABLED(CONFIG_X86)) {
+ idx = acpi_match_platform_list(plat_list);
+ if (idx < 0) {
+ if (!ghes_edac_force_enable)
+ return NULL;
+
+ pr_warn_once("Force-loading ghes_edac on an unsupported platform. You're on your own!\n");
+ }
+ }
+
+ return &ghes_devs;
+}
+EXPORT_SYMBOL_GPL(ghes_get_devices);
+
void ghes_register_report_chain(struct notifier_block *nb)
{
atomic_notifier_chain_register(&ghes_report_chain, nb);
diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index 7b8d56a769f6..b85a545d1cb0 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -54,10 +54,6 @@ static DEFINE_MUTEX(ghes_reg_mutex);
*/
static DEFINE_SPINLOCK(ghes_lock);

-/* "ghes_edac.force_load=1" skips the platform check */
-static bool __read_mostly force_load;
-module_param(force_load, bool, 0);
-
static bool system_scanned;

/* Memory Device - Type 17 of SMBIOS spec */
@@ -387,14 +383,6 @@ static struct notifier_block ghes_edac_mem_err_nb = {
.priority = 0,
};

-/*
- * Known systems that are safe to enable this module.
- */
-static struct acpi_platform_list plat_list[] = {
- {"HPE ", "Server ", 0, ACPI_SIG_FADT, all_versions},
- { } /* End */
-};
-
int ghes_edac_register(struct ghes *ghes, struct device *dev)
{
bool fake = false;
@@ -402,19 +390,8 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
struct ghes_pvt *pvt;
struct edac_mc_layer layers[1];
unsigned long flags;
- int idx = -1;
int rc = 0;

- if (IS_ENABLED(CONFIG_X86)) {
- /* Check if safe to enable on this system */
- idx = acpi_match_platform_list(plat_list);
- if (!force_load && idx < 0)
- return -ENODEV;
- } else {
- force_load = true;
- idx = 0;
- }
-
/* finish another registration/unregistration instance first */
mutex_lock(&ghes_reg_mutex);

@@ -458,15 +435,10 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
pr_info("This system has a very crappy BIOS: It doesn't even list the DIMMS.\n");
pr_info("Its SMBIOS info is wrong. It is doubtful that the error report would\n");
pr_info("work on such system. Use this driver with caution\n");
- } else if (idx < 0) {
- pr_info("This EDAC driver relies on BIOS to enumerate memory and get error reports.\n");
- pr_info("Unfortunately, not all BIOSes reflect the memory layout correctly.\n");
- pr_info("So, the end result of using this driver varies from vendor to vendor.\n");
- pr_info("If you find incorrect reports, please contact your hardware vendor\n");
- pr_info("to correct its BIOS.\n");
- pr_info("This system has %d DIMM sockets.\n", ghes_hw.num_dimms);
}

+ pr_info("This system has %d DIMM sockets.\n", ghes_hw.num_dimms);
+
if (!fake) {
struct dimm_info *src, *dst;
int i = 0;
@@ -535,9 +507,6 @@ void ghes_edac_unregister(struct ghes *ghes)
struct mem_ctl_info *mci;
unsigned long flags;

- if (!force_load)
- return;
-
mutex_lock(&ghes_reg_mutex);

system_scanned = false;
diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
index 5cbd38b6e4e1..ce693e9f07a0 100644
--- a/include/acpi/ghes.h
+++ b/include/acpi/ghes.h
@@ -27,6 +27,8 @@ struct ghes {
struct timer_list timer;
unsigned int irq;
};
+ struct device *dev;
+ struct list_head elist;
};

struct ghes_estatus_node {
@@ -80,6 +82,8 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev);

void ghes_edac_unregister(struct ghes *ghes);

+struct list_head *ghes_get_devices(void);
+
#else
static inline int ghes_edac_register(struct ghes *ghes, struct device *dev)
{
@@ -89,6 +93,8 @@ static inline int ghes_edac_register(struct ghes *ghes, struct device *dev)
static inline void ghes_edac_unregister(struct ghes *ghes)
{
}
+
+static inline struct list_head *ghes_get_devices(void) { return NULL; }
#endif

static inline int acpi_hest_get_version(struct acpi_hest_generic_data *gdata)
--
2.25.1