diff options
| author | Borislav Petkov <[email protected]> | 2016-04-05 08:29:51 +0200 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2016-04-13 11:37:42 +0200 |
| commit | 425d8c2fc5e6dddbad083502bb77c7beae545620 (patch) | |
| tree | 0612d3e8554dcf951705018cee9a915cd189d555 | |
| parent | 78df526c74a4db696e1e058b9869471937d0773b (diff) | |
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]>
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 54f7b44dcf01..c343a54bed39 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 |