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author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-02 16:46:35 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-02 16:46:35 +0300 |
commit | b6a09416e83ffe4eccfb4ef1b91b3b66483fa810 (patch) | |
tree | b30f266e85047244dcdb47d5afc134e76aec530d /arch/x86/boot/compressed/pgtable_64.c | |
parent | db809859c8cee415293b830e67178f526d1eb2be (diff) | |
parent | 30a7acd573899fd8b8ac39236eff6468b195ac7d (diff) | |
download | linux-b6a09416e83ffe4eccfb4ef1b91b3b66483fa810.tar.xz |
Merge 4.15-rc6 into char-misc-next
We want the fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/boot/compressed/pgtable_64.c')
-rw-r--r-- | arch/x86/boot/compressed/pgtable_64.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c new file mode 100644 index 000000000000..b4469a37e9a1 --- /dev/null +++ b/arch/x86/boot/compressed/pgtable_64.c @@ -0,0 +1,28 @@ +#include <asm/processor.h> + +/* + * __force_order is used by special_insns.h asm code to force instruction + * serialization. + * + * It is not referenced from the code, but GCC < 5 with -fPIE would fail + * due to an undefined symbol. Define it to make these ancient GCCs work. + */ +unsigned long __force_order; + +int l5_paging_required(void) +{ + /* Check if leaf 7 is supported. */ + + if (native_cpuid_eax(0) < 7) + return 0; + + /* Check if la57 is supported. */ + if (!(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) + return 0; + + /* Check if 5-level paging has already been enabled. */ + if (native_read_cr4() & X86_CR4_LA57) + return 0; + + return 1; +} |