Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d94a155c authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Thomas Gleixner
Browse files

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: cb06d8e3 ("x86/tme: Detect if TME and MKTME is activated by BIOS")
Reported-by: default avatarKai Huang <kai.huang@linux.intel.com>
Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarThomas 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
parent 92e830f2

arch/x86/kernel/cpu/common.c

+20 −12
Original line number Diff line number Diff line
@@ -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