Commit e1907d37 authored by Muralidhara M K's avatar Muralidhara M K Committed by Borislav Petkov
Browse files

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: default avatarMuralidhara M K <muralimk@amd.com>
Signed-off-by: default avatarNaveen Krishna Chatradhi <nchatrad@amd.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220324122729.221765-1-nchatrad@amd.com
parent 31231092

arch/x86/include/asm/amd_nb.h

+0 −1
Original line number Diff line number Diff line
@@ -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);

arch/x86/kernel/amd_nb.c

+3 −4
Original line number Diff line number Diff line
@@ -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

drivers/char/agp/amd64-agp.c

+1 −1
Original line number Diff line number Diff line
@@ -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))

drivers/edac/amd64_edac.c

+1 −1
Original line number Diff line number Diff line
@@ -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();