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| author | Radim Krčmář <rkrcmar@redhat.com> | 2018-02-01 15:04:17 +0100 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2018-02-01 15:04:17 +0100 |
| commit | 7bf14c28ee776be567855bd39ed8ff795ea19f55 (patch) | |
| tree | 6113748c673e85fccc2c56c050697789c00c6bc2 /arch/x86/boot/compressed/head_64.S | |
| parent | 87cedc6be55954c6efd6eca2e694132513f65a2a (diff) | |
| parent | 5fa4ec9cb2e6679e2f828033726f758ea314b9c5 (diff) | |
Merge branch 'x86/hyperv' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Topic branch for stable KVM clockource under Hyper-V.
Thanks to Christoffer Dall for resolving the ARM conflict.
Diffstat (limited to 'arch/x86/boot/compressed/head_64.S')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 20919b4f3133..fc313e29fe2c 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -305,10 +305,18 @@ ENTRY(startup_64) leaq boot_stack_end(%rbx), %rsp #ifdef CONFIG_X86_5LEVEL - /* Check if 5-level paging has already enabled */ - movq %cr4, %rax - testl $X86_CR4_LA57, %eax - jnz lvl5 + /* + * Check if we need to enable 5-level paging. + * RSI holds real mode data and need to be preserved across + * a function call. + */ + pushq %rsi + call l5_paging_required + popq %rsi + + /* If l5_paging_required() returned zero, we're done here. */ + cmpq $0, %rax + je lvl5 /* * At this point we are in long mode with 4-level paging enabled, |