[PATCH] EDAC, {skx|i10nm}_edac: Fix randconfig build error

Luck, Tony
2019-03-21T22:13:43Z

From: Qiuxu Zhuo <qiuxu.zhuo@intel.com>

Kbuild failed on the kernel configurations below:

CONFIG_ACPI_NFIT=y
CONFIG_EDAC_DEBUG=y
CONFIG_EDAC_SKX=m
CONFIG_EDAC_I10NM=y
or
CONFIG_ACPI_NFIT=y
CONFIG_EDAC_DEBUG=y
CONFIG_EDAC_SKX=y
CONFIG_EDAC_I10NM=m

Failed log:
...
CC [M] drivers/edac/skx_common.o
...
.../skx_common.o:.../skx_common.c:672: undefined reference to `__this_module'

That is because if one of the two drivers {skx|i10nm}_edac is built-in
and the other one is built as a module, the shared file skx_common.c is
built to an object in module style by kbuild. Therefore, when linking for
vmlinux, the '__this_module' symbol used in debugfs isn't defined.

Fix it by moving all debugfs code from skx_common.c to {skx|i10nm}_base.c
respectively. Thus, skx_common.c is a module independent file which doesn't
refer to '__this_module' symbol anymore.

Fixes: d4dc89d069aa ("EDAC, i10nm: Add a driver for Intel 10nm server processors")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
---

Arnd: I couldn't get your Kconfig trick (to disallow mixing module with
builtin) working. Qiuxu made this better cleanup of the skx_common.c file that
moves out all of the debugfs bits, and adds a comment to the top of the
file warning future developers of the mixed mode issue.

drivers/edac/i10nm_base.c | 52 +++++++++++++++++++++++++++++++++++++--
drivers/edac/skx_base.c | 50 ++++++++++++++++++++++++++++++++++++-
drivers/edac/skx_common.c | 51 +++++---------------------------------
drivers/edac/skx_common.h | 8 ------
4 files changed, 105 insertions(+), 56 deletions(-)

diff --git a/drivers/edac/i10nm_base.c b/drivers/edac/i10nm_base.c
index c334fb7c63df..6f06aec4877c 100644
--- a/drivers/edac/i10nm_base.c
+++ b/drivers/edac/i10nm_base.c
@@ -181,6 +181,54 @@ static struct notifier_block i10nm_mce_dec = {
.priority = MCE_PRIO_EDAC,
};

+#ifdef CONFIG_EDAC_DEBUG
+/*
+ * Debug feature.
+ * Exercise the address decode logic by writing an address to
+ * /sys/kernel/debug/edac/i10nm_test/addr.
+ */
+static struct dentry *i10nm_test;
+
+static int debugfs_u64_set(void *data, u64 val)
+{
+ struct mce m;
+
+ pr_warn_once("Fake error to 0x%llx injected via debugfs\n", val);
+
+ memset(&m, 0, sizeof(m));
+ /* ADDRV + MemRd + Unknown channel */
+ m.status = MCI_STATUS_ADDRV + 0x90;
+ /* One corrected error */
+ m.status |= BIT_ULL(MCI_STATUS_CEC_SHIFT);
+ m.addr = val;
+ skx_mce_check_error(NULL, 0, &m);
+
+ return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
+
+static void setup_i10nm_debug(void)
+{
+ i10nm_test = edac_debugfs_create_dir("i10nm_test");
+ if (!i10nm_test)
+ return;
+
+ if (!edac_debugfs_create_file("addr", 0200, i10nm_test,
+ NULL, &fops_u64_wo)) {
+ debugfs_remove(i10nm_test);
+ i10nm_test = NULL;
+ }
+}
+
+static void teardown_i10nm_debug(void)
+{
+ debugfs_remove_recursive(i10nm_test);
+}
+#else
+static inline void setup_i10nm_debug(void) {}
+static inline void teardown_i10nm_debug(void) {}
+#endif /*CONFIG_EDAC_DEBUG*/
+
static int __init i10nm_init(void)
{
u8 mc = 0, src_id = 0, node_id = 0;
@@ -249,7 +297,7 @@ static int __init i10nm_init(void)

opstate_init();
mce_register_decode_chain(&i10nm_mce_dec);
- setup_skx_debug("i10nm_test");
+ setup_i10nm_debug();

i10nm_printk(KERN_INFO, "%s\n", I10NM_REVISION);

@@ -262,7 +310,7 @@ static int __init i10nm_init(void)
static void __exit i10nm_exit(void)
{
edac_dbg(2, "\n");
- teardown_skx_debug();
+ teardown_i10nm_debug();
mce_unregister_decode_chain(&i10nm_mce_dec);
skx_adxl_put();
skx_remove();
diff --git a/drivers/edac/skx_base.c b/drivers/edac/skx_base.c
index adae4c848ca1..a5c8fa3a249a 100644
--- a/drivers/edac/skx_base.c
+++ b/drivers/edac/skx_base.c
@@ -540,6 +540,54 @@ static struct notifier_block skx_mce_dec = {
.priority = MCE_PRIO_EDAC,
};

+#ifdef CONFIG_EDAC_DEBUG
+/*
+ * Debug feature.
+ * Exercise the address decode logic by writing an address to
+ * /sys/kernel/debug/edac/skx_test/addr.
+ */
+static struct dentry *skx_test;
+
+static int debugfs_u64_set(void *data, u64 val)
+{
+ struct mce m;
+
+ pr_warn_once("Fake error to 0x%llx injected via debugfs\n", val);
+
+ memset(&m, 0, sizeof(m));
+ /* ADDRV + MemRd + Unknown channel */
+ m.status = MCI_STATUS_ADDRV + 0x90;
+ /* One corrected error */
+ m.status |= BIT_ULL(MCI_STATUS_CEC_SHIFT);
+ m.addr = val;
+ skx_mce_check_error(NULL, 0, &m);
+
+ return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
+
+static void setup_skx_debug(void)
+{
+ skx_test = edac_debugfs_create_dir("skx_test");
+ if (!skx_test)
+ return;
+
+ if (!edac_debugfs_create_file("addr", 0200, skx_test,
+ NULL, &fops_u64_wo)) {
+ debugfs_remove(skx_test);
+ skx_test = NULL;
+ }
+}
+
+static void teardown_skx_debug(void)
+{
+ debugfs_remove_recursive(skx_test);
+}
+#else
+static inline void setup_skx_debug(void) {}
+static inline void teardown_skx_debug(void) {}
+#endif /*CONFIG_EDAC_DEBUG*/
+
/*
* skx_init:
* make sure we are running on the correct cpu model
@@ -619,7 +667,7 @@ static int __init skx_init(void)
/* Ensure that the OPSTATE is set correctly for POLL or NMI */
opstate_init();

- setup_skx_debug("skx_test");
+ setup_skx_debug();

mce_register_decode_chain(&skx_mce_dec);

diff --git a/drivers/edac/skx_common.c b/drivers/edac/skx_common.c
index 0e96e7b5b0a7..6b11d6f4ae07 100644
--- a/drivers/edac/skx_common.c
+++ b/drivers/edac/skx_common.c
@@ -3,6 +3,12 @@
* Common codes for both the skx_edac driver and Intel 10nm server EDAC driver.
* Originally split out from the skx_edac driver.
*
+ * This file is used for both {skx|i10nm}_edac drivers. If one of them is
+ * built-in and the other one is built as a module, this file is built to
+ * an object in module style by kbuid. Therefore, to avoid linking errors
+ * from undefined module symbols, please don't add any functionality which
+ * would involve modules (e.g., debugfs code) to this file.
+ *
* Copyright (c) 2018, Intel Corporation.
*/

@@ -644,48 +650,3 @@ void skx_remove(void)
kfree(d);
}
}
-
-#ifdef CONFIG_EDAC_DEBUG
-/*
- * Debug feature.
- * Exercise the address decode logic by writing an address to
- * /sys/kernel/debug/edac/dirname/addr.
- */
-static struct dentry *skx_test;
-
-static int debugfs_u64_set(void *data, u64 val)
-{
- struct mce m;
-
- pr_warn_once("Fake error to 0x%llx injected via debugfs\n", val);
-
- memset(&m, 0, sizeof(m));
- /* ADDRV + MemRd + Unknown channel */
- m.status = MCI_STATUS_ADDRV + 0x90;
- /* One corrected error */
- m.status |= BIT_ULL(MCI_STATUS_CEC_SHIFT);
- m.addr = val;
- skx_mce_check_error(NULL, 0, &m);
-
- return 0;
-}
-DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
-
-void setup_skx_debug(const char *dirname)
-{
- skx_test = edac_debugfs_create_dir(dirname);
- if (!skx_test)
- return;
-
- if (!edac_debugfs_create_file("addr", 0200, skx_test,
- NULL, &fops_u64_wo)) {
- debugfs_remove(skx_test);
- skx_test = NULL;
- }
-}
-
-void teardown_skx_debug(void)
-{
- debugfs_remove_recursive(skx_test);
-}
-#endif /*CONFIG_EDAC_DEBUG*/
diff --git a/drivers/edac/skx_common.h b/drivers/edac/skx_common.h
index d25374e34d4f..d18fa98669af 100644
--- a/drivers/edac/skx_common.h
+++ b/drivers/edac/skx_common.h
@@ -141,12 +141,4 @@ int skx_mce_check_error(struct notifier_block *nb, unsigned long val,

void skx_remove(void);

-#ifdef CONFIG_EDAC_DEBUG
-void setup_skx_debug(const char *dirname);
-void teardown_skx_debug(void);
-#else
-static inline void setup_skx_debug(const char *dirname) {}
-static inline void teardown_skx_debug(void) {}
-#endif /*CONFIG_EDAC_DEBUG*/
-
#endif /* _SKX_COMM_EDAC_H */
--
2.19.1