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authorAndy Lutomirski <luto@kernel.org>2016-09-29 12:48:11 -0700
committerThomas Gleixner <tglx@linutronix.de>2016-09-30 12:37:40 +0200
commit192d1dccbfc5b901b66527df9df80304693cf06e (patch)
tree8ee15ef8ca5f7bc9887dbd61f66c171013c4aae5
parente1bfc11c5a6f40222a698a818dc269113245820e (diff)
downloadlinux-sh-192d1dccbfc5b901b66527df9df80304693cf06e.tar.gz
x86/boot: Fix another __read_cr4() case on 486
The condition for reading CR4 was wrong: there are some CPUs with CPUID but not CR4. Rather than trying to make the condition exact, use __read_cr4_safe(). Fixes: 18bc7bd523e0 ("x86/boot: Synchronize trampoline_cr4_features and mmu_cr4_features directly") Reported-by: david@saggiorato.net Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Link: http://lkml.kernel.org/r/8c453a61c4f44ab6ff43c29780ba04835234d2e5.1475178369.git.luto@kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--arch/x86/kernel/setup.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 0fa60f5f5a16..98c9cd6f3b5d 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1137,9 +1137,7 @@ void __init setup_arch(char **cmdline_p)
* auditing all the early-boot CR4 manipulation would be needed to
* rule it out.
*/
- if (boot_cpu_data.cpuid_level >= 0)
- /* A CPU has %cr4 if and only if it has CPUID. */
- mmu_cr4_features = __read_cr4();
+ mmu_cr4_features = __read_cr4_safe();
memblock_set_current_limit(get_max_mapped());