EDAC/ghes: Prepare to make ghes_edac a proper module

To make ghes_edac a proper module, prepare to decouple its dependencies
from GHES.

Move the ghes_edac.force_load parameter to ghes.c in order to
properly control whether ghes_edac should be force-loaded: In
ghes_edac_register() it is too late to set the module flag.

Introduce a helper ghes_get_devices(), which returns the list of GHES
devices which got 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 the module's init function of ghes_edac
later.

  [ bp: Massage. ]

Suggested-by: Toshi Kani <toshi.kani@hpe.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jia He <justin.he@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221010023559.69655-4-justin.he@arm.com

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 55013e024ba39b098cc7bf654a858f888b0d7296..acab512741f6c545850371f1fa2a070105ef83ff 100644 (file)
--- 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 +127,13 @@ module_param_named(disable, ghes_disable, bool, 0);
 static LIST_HEAD(ghes_hed);
 static DEFINE_MUTEX(ghes_list_mutex);
 
+/*
+ * A list of GHES devices which are given to the corresponding EDAC driver
+ * ghes_edac for further use.
+ */
+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 +1394,12 @@ 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 +1464,10 @@ 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 +1524,32 @@ 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 7b8d56a769f6b3487ecc453c8682467d5189e314..b85a545d1cb030f022e22d71f314d7b5d8015691 100644 (file)
--- 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 5cbd38b6e4e13beefb001315819a77d56c0495f0..ce693e9f07a0d8a38b471b99531424d0613b0124 100644 (file)
--- 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)