Messages in this thread Patch in this message | | | From | "Kirill A. Shutemov" <> | Subject | [PATCH] x86/kexec: Make kexec work in 5-level paging mode | Date | Mon, 29 Jan 2018 14:08:45 +0300 |
| |
I've missed that we need to change relocate_kernel() to set CR4.LA57 flag if the kernel has 5-level paging enabled.
I avoided to use ifdef CONFIG_X86_5LEVEL here and inferred if we need to enabled 5-level paging from previous CR4 value. This way the code is ready for boot-time switching between paging modes.
Fixes: 77ef56e4f0fb ("x86: Enable 5-level paging support via CONFIG_X86_5LEVEL=y") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Baoquan He <bhe@redhat.com> --- arch/x86/kernel/relocate_kernel_64.S | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index 307d3bac5f04..11eda21eb697 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -68,6 +68,9 @@ relocate_kernel: movq %cr4, %rax movq %rax, CR4(%r11) + /* Save CR4. Required to enable the right paging mode later. */ + movq %rax, %r13 + /* zero out flags, and disable interrupts */ pushq $0 popfq @@ -126,8 +129,13 @@ identity_mapped: /* * Set cr4 to a known state: * - physical address extension enabled + * - 5-level paging, if it was enabled before */ movl $X86_CR4_PAE, %eax + testq $X86_CR4_LA57, %r13 + jz 1f + orl $X86_CR4_LA57, %eax +1: movq %rax, %cr4 jmp 1f -- 2.15.1
| |