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x86/CPU/AMD: Move TOPOEXT reenablement before reading smp_num_siblings
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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().

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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suryasaimadhu authored and KAGA-KOKO committed Jun 22, 2018
1 parent 11e34e6 commit 7ce2f03
Showing 1 changed file with 17 additions and 20 deletions.
37 changes: 17 additions & 20 deletions arch/x86/kernel/cpu/amd.c
Original file line number Diff line number Diff line change
Expand Up @@ -318,12 +318,8 @@ static void legacy_fixup_core_id(struct cpuinfo_x86 *c)

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;
}

/*
Expand All @@ -345,7 +341,6 @@ 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;
Expand Down Expand Up @@ -622,6 +617,7 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c)

static void early_init_amd(struct cpuinfo_x86 *c)
{
u64 value;
u32 dummy;

early_init_amd_mc(c);
Expand Down Expand Up @@ -693,6 +689,20 @@ static void early_init_amd(struct cpuinfo_x86 *c)

early_detect_mem_encrypt(c);

/* 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);
}

Expand Down Expand Up @@ -785,19 +795,6 @@ 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.
Expand Down

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