x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption

Some features (Intel MKTME, AMD SME) reduce the number of effectively
available physical address bits. cpuinfo_x86::x86_phys_bits is adjusted
accordingly during the early cpu feature detection.

Though if get_cpu_cap() is called later again then this adjustement is
overwritten. That happens in setup_pku(), which is called after
detect_tme().

To address this, extract the address sizes enumeration into a separate
function, which is only called only from early_identify_cpu() and from
generic_identify().

This makes get_cpu_cap() safe to be called later during boot proccess
without overwriting cpuinfo_x86::x86_phys_bits.

[ tglx: Massaged changelog ]

Fixes: cb06d8e3d020 ("x86/tme: Detect if TME and MKTME is activated by BIOS")
Reported-by: Kai Huang <kai.huang@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: linux-mm@kvack.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180410092704.41106-1-kirill.shutemov@linux.intel.com

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 348cf48..2981bf2 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -848,18 +848,6 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
                c->x86_power = edx;
        }
 
-       if (c->extended_cpuid_level >= 0x80000008) {
-               cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
-
-               c->x86_virt_bits = (eax >> 8) & 0xff;
-               c->x86_phys_bits = eax & 0xff;
-               c->x86_capability[CPUID_8000_0008_EBX] = ebx;
-       }
-#ifdef CONFIG_X86_32
-       else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36))
-               c->x86_phys_bits = 36;
-#endif
-
        if (c->extended_cpuid_level >= 0x8000000a)
                c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a);
 
@@ -874,6 +862,23 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
        apply_forced_caps(c);
 }
 
+static void get_cpu_address_sizes(struct cpuinfo_x86 *c)
+{
+       u32 eax, ebx, ecx, edx;
+
+       if (c->extended_cpuid_level >= 0x80000008) {
+               cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
+
+               c->x86_virt_bits = (eax >> 8) & 0xff;
+               c->x86_phys_bits = eax & 0xff;
+               c->x86_capability[CPUID_8000_0008_EBX] = ebx;
+       }
+#ifdef CONFIG_X86_32
+       else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36))
+               c->x86_phys_bits = 36;
+#endif
+}
+
 static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
 {
 #ifdef CONFIG_X86_32
@@ -965,6 +970,7 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
                cpu_detect(c);
                get_cpu_vendor(c);
                get_cpu_cap(c);
+               get_cpu_address_sizes(c);
                setup_force_cpu_cap(X86_FEATURE_CPUID);
 
                if (this_cpu->c_early_init)
@@ -1097,6 +1103,8 @@ static void generic_identify(struct cpuinfo_x86 *c)
 
        get_cpu_cap(c);
 
+       get_cpu_address_sizes(c);
+
        if (c->cpuid_level >= 0x00000001) {
                c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF;
 #ifdef CONFIG_X86_32