[tip: x86/misc] x86/amd_nb: Clean up early_is_amd_nb()

[tip-bot2 for Yazen Ghannam]

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

Commit-ID:     e13f51b51814e2527c51998d2dae594ef9cb633a
Gitweb:        https://git.kernel.org/tip/e13f51b51814e2527c51998d2dae594ef9cb633a
Author:        Yazen Ghannam <yazen.ghannam@xxxxxxx>
AuthorDate:    Fri, 06 Dec 2024 16:11:56 
Committer:     Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Wed, 08 Jan 2025 10:47:22 +01:00

x86/amd_nb: Clean up early_is_amd_nb()

The check for early_is_amd_nb() is only useful for systems with GART or
the NB_CFG register.

Zen-based systems (both AMD and Hygon) have neither, so return early for
them.

Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20241206161210.163701-4-yazen.ghannam@xxxxxxx
---
 arch/x86/kernel/amd_nb.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
index 37b8244..ee20071 100644
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -385,7 +385,6 @@ static int amd_cache_northbridges(void)
  */
 bool __init early_is_amd_nb(u32 device)
 {
-	const struct pci_device_id *misc_ids = amd_nb_misc_ids;
 	const struct pci_device_id *id;
 	u32 vendor = device & 0xffff;
 
@@ -393,11 +392,11 @@ bool __init early_is_amd_nb(u32 device)
 	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
 		return false;
 
-	if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
-		misc_ids = hygon_nb_misc_ids;
+	if (cpu_feature_enabled(X86_FEATURE_ZEN))
+		return false;
 
 	device >>= 16;
-	for (id = misc_ids; id->vendor; id++)
+	for (id = amd_nb_misc_ids; id->vendor; id++)
 		if (vendor == id->vendor && device == id->device)
 			return true;
 	return false;