x86/CPU/AMD: Move TOPOEXT reenablement before reading smp_num_siblings

commit 7ce2f0393ea2396142b7faf6ee9b1f3676d08a5f upstream

The TOPOEXT reenablement is a workaround for broken BIOSen which didn't
enable the CPUID bit. amd_get_topology_early(), however, relies on
that bit being set so that it can read out the CPUID leaf and set
smp_num_siblings properly.

Move the reenablement up to early_init_amd(). While at it, simplify
amd_get_topology_early().

[dwmw2: Backport to 4.9]

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index fa2bdf5..6de5964 100644 (file)
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -300,12 +300,8 @@ static int nearby_node(int apicid)
 
 static void amd_get_topology_early(struct cpuinfo_x86 *c)
 {
-       if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
-               u32 eax, ebx, ecx, edx;
-
-               cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
-               smp_num_siblings = ((ebx >> 8) & 0xff) + 1;
-       }
+       if (cpu_has(c, X86_FEATURE_TOPOEXT))
+               smp_num_siblings = ((cpuid_ebx(0x8000001e) >> 8) & 0xff) + 1;
 }
 
 /*
@@ -326,7 +322,6 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
                cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
 
                node_id  = ecx & 0xff;
-               smp_num_siblings = ((ebx >> 8) & 0xff) + 1;
 
                if (c->x86 == 0x15)
                        c->cu_id = ebx & 0xff;
@@ -578,6 +573,8 @@ static void bsp_init_amd(struct cpuinfo_x86 *c)
 
 static void early_init_amd(struct cpuinfo_x86 *c)
 {
+       u64 value;
+
        early_init_amd_mc(c);
 
        /*
@@ -645,6 +642,21 @@ static void early_init_amd(struct cpuinfo_x86 *c)
        if (cpu_has_amd_erratum(c, amd_erratum_400))
                set_cpu_bug(c, X86_BUG_AMD_E400);
 
+
+       /* Re-enable TopologyExtensions if switched off by BIOS */
+       if (c->x86 == 0x15 &&
+           (c->x86_model >= 0x10 && c->x86_model <= 0x6f) &&
+           !cpu_has(c, X86_FEATURE_TOPOEXT)) {
+
+               if (msr_set_bit(0xc0011005, 54) > 0) {
+                       rdmsrl(0xc0011005, value);
+                       if (value & BIT_64(54)) {
+                               set_cpu_cap(c, X86_FEATURE_TOPOEXT);
+                               pr_info_once(FW_INFO "CPU: Re-enabling disabled Topology Extensions Support.\n");
+                       }
+               }
+       }
+
        amd_get_topology_early(c);
 }
 
@@ -737,19 +749,6 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
 {
        u64 value;
 
-       /* re-enable TopologyExtensions if switched off by BIOS */
-       if ((c->x86_model >= 0x10) && (c->x86_model <= 0x6f) &&
-           !cpu_has(c, X86_FEATURE_TOPOEXT)) {
-
-               if (msr_set_bit(0xc0011005, 54) > 0) {
-                       rdmsrl(0xc0011005, value);
-                       if (value & BIT_64(54)) {
-                               set_cpu_cap(c, X86_FEATURE_TOPOEXT);
-                               pr_info_once(FW_INFO "CPU: Re-enabling disabled Topology Extensions Support.\n");
-                       }
-               }
-       }
-
        /*
         * The way access filter has a performance penalty on some workloads.
         * Disable it on the affected CPUs.