lkml.org 
[lkml]   [2018]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCHv2] x86/mm: Do not lose cpuinfo_x86::x86_phys_bits adjustment
Date
Some features (Intel MKTME, AMD SME) reduce number of effectively
available physical address bits. We adjust x86_phys_bits accordingly.

If get_cpu_cap() got called more than one time we lose this adjustement.

That's exactly what happens in setup_pku(): it gets called after
detect_tme() and cpuinfo_x86::x86_phys_bits gets overwritten.

Extract address sizes enumeration into a separate routine and get it
called only from early_identify_cpu() and from generic_identify().

It makes get_cpu_cap() safe to be called later during boot proccess
without risk to overwrite cpuinfo_x86::x86_phys_bits.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Kai Huang <kai.huang@linux.intel.com>
Fixes: cb06d8e3d020 ("x86/tme: Detect if TME and MKTME is activated by BIOS")
---
arch/x86/kernel/cpu/common.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 348cf4821240..2981bf287ef5 100644
--- 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
--
2.16.2
\
 
 \ /
  Last update: 2018-03-27 14:16    [W:0.145 / U:0.220 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site