Commit-ID: 425d8c2fc5e6dddbad083502bb77c7beae545620
Gitweb: http://git.kernel.org/tip/425d8c2fc5e6dddbad083502bb77c7beae545620
Author: Borislav Petkov <[email protected]>
AuthorDate: Tue, 5 Apr 2016 08:29:51 +0200
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 13 Apr 2016 11:37:42 +0200
x86/cpu: Simplify extended APIC ID detection on AMD
Both if-branches are under if (boot_cpu_has(X86_FEATURE_APIC)), unify
them.
Also, simplify the test for bits:
- 17 ("ApicExtBrdCst: APIC extended broadcast enable") and
- 18 ("ApicExtId: APIC extended ID enable.")
in "D18F0x68 Link Transaction Control."
No functionality change.
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/kernel/cpu/amd.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 54f7b44..c343a54 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -565,14 +565,17 @@ static void early_init_amd(struct cpuinfo_x86 *c)
* can safely set X86_FEATURE_EXTD_APICID unconditionally for families
* after 16h.
*/
- if (boot_cpu_has(X86_FEATURE_APIC) && c->x86 > 0x16) {
- set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
- } else if (boot_cpu_has(X86_FEATURE_APIC) && c->x86 >= 0xf) {
- /* check CPU config space for extended APIC ID */
- unsigned int val;
- val = read_pci_config(0, 24, 0, 0x68);
- if ((val & ((1 << 17) | (1 << 18))) == ((1 << 17) | (1 << 18)))
+ if (boot_cpu_has(X86_FEATURE_APIC)) {
+ if (c->x86 > 0x16)
set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
+ else if (c->x86 >= 0xf) {
+ /* check CPU config space for extended APIC ID */
+ unsigned int val;
+
+ val = read_pci_config(0, 24, 0, 0x68);
+ if ((val >> 17 & 0x3) == 0x3)
+ set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
+ }
}
#endif
