[tip: x86/misc] x86/amd_nb: Unexport amd_cache_northbridges()

[tip-bot2 for Muralidhara M K]

The following commit has been merged into the x86/misc branch of tip:

Commit-ID:     e1907d37514b8564ba18b4a768a35beee71cb011
Gitweb:        https://git.kernel.org/tip/e1907d37514b8564ba18b4a768a35beee71cb011
Author:        Muralidhara M K <muralimk@xxxxxxx>
AuthorDate:    Thu, 24 Mar 2022 17:57:29 +05:30
Committer:     Borislav Petkov <bp@xxxxxxx>
CommitterDate: Tue, 05 Apr 2022 19:22:27 +02:00

x86/amd_nb: Unexport amd_cache_northbridges()

amd_cache_northbridges() is exported by amd_nb.c and is called by
amd64-agp.c and amd64_edac.c modules at module_init() time so that NB
descriptors are properly cached before those drivers can use them.

However, the init_amd_nbs() initcall already does call
amd_cache_northbridges() unconditionally and thus makes sure the NB
descriptors are enumerated.

That initcall is a fs_initcall type which is on the 5th group (starting
from 0) of initcalls that gets run in increasing numerical order by the
init code.

The module_init() call is turned into an __initcall() in the MODULE=n
case and those are device-level initcalls, i.e., group 6.

Therefore, the northbridges caching is already finished by the time
module initialization starts and thus the correct initialization order
is retained.

Unexport amd_cache_northbridges(), update dependent modules to
call amd_nb_num() instead. While at it, simplify the checks in
amd_cache_northbridges().

  [ bp: Heavily massage and *actually* explain why the change is ok. ]

Signed-off-by: Muralidhara M K <muralimk@xxxxxxx>
Signed-off-by: Naveen Krishna Chatradhi <nchatrad@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lore.kernel.org/r/20220324122729.221765-1-nchatrad@xxxxxxx
---
 arch/x86/include/asm/amd_nb.h | 1 -
 arch/x86/kernel/amd_nb.c      | 7 +++----
 drivers/char/agp/amd64-agp.c  | 2 +-
 drivers/edac/amd64_edac.c     | 2 +-
 4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/amd_nb.h b/arch/x86/include/asm/amd_nb.h
index 00d1a40..ed0eaf6 100644
--- a/arch/x86/include/asm/amd_nb.h
+++ b/arch/x86/include/asm/amd_nb.h
@@ -16,7 +16,6 @@ extern const struct amd_nb_bus_dev_range amd_nb_bus_dev_ranges[];
 
 extern bool early_is_amd_nb(u32 value);
 extern struct resource *amd_get_mmconfig_range(struct resource *res);
-extern int amd_cache_northbridges(void);
 extern void amd_flush_garts(void);
 extern int amd_numa_init(void);
 extern int amd_get_subcaches(int);
diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
index 020c906..190e0f7 100644
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -188,7 +188,7 @@ int amd_smn_write(u16 node, u32 address, u32 value)
 EXPORT_SYMBOL_GPL(amd_smn_write);
 
 
-int amd_cache_northbridges(void)
+static int amd_cache_northbridges(void)
 {
 	const struct pci_device_id *misc_ids = amd_nb_misc_ids;
 	const struct pci_device_id *link_ids = amd_nb_link_ids;
@@ -210,14 +210,14 @@ int amd_cache_northbridges(void)
 	}
 
 	misc = NULL;
-	while ((misc = next_northbridge(misc, misc_ids)) != NULL)
+	while ((misc = next_northbridge(misc, misc_ids)))
 		misc_count++;
 
 	if (!misc_count)
 		return -ENODEV;
 
 	root = NULL;
-	while ((root = next_northbridge(root, root_ids)) != NULL)
+	while ((root = next_northbridge(root, root_ids)))
 		root_count++;
 
 	if (root_count) {
@@ -290,7 +290,6 @@ int amd_cache_northbridges(void)
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(amd_cache_northbridges);
 
 /*
  * Ignores subdevice/subvendor but as far as I can figure out
diff --git a/drivers/char/agp/amd64-agp.c b/drivers/char/agp/amd64-agp.c
index dc78a4f..84a4aa9 100644
--- a/drivers/char/agp/amd64-agp.c
+++ b/drivers/char/agp/amd64-agp.c
@@ -327,7 +327,7 @@ static int cache_nbs(struct pci_dev *pdev, u32 cap_ptr)
 {
 	int i;
 
-	if (amd_cache_northbridges() < 0)
+	if (!amd_nb_num())
 		return -ENODEV;
 
 	if (!amd_nb_has_feature(AMD_NB_GART))
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 812baa4..2f854fe 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -4336,7 +4336,7 @@ static int __init amd64_edac_init(void)
 	if (!x86_match_cpu(amd64_cpuids))
 		return -ENODEV;
 
-	if (amd_cache_northbridges() < 0)
+	if (!amd_nb_num())
 		return -ENODEV;
 
 	opstate_init();