diff options
| author | David Woodhouse <dwmw@amazon.co.uk> | 2024-12-05 18:05:17 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2024-12-06 12:42:00 +0300 |
| commit | b7155dfd4999211247cce40be2665c71235ab094 (patch) | |
| tree | 377933655a074aa2813273182f305abefe66078f | |
| parent | b3adabae8a96fee62184f4236bf60313b35244e9 (diff) | |
| download | linux-b7155dfd4999211247cce40be2665c71235ab094.tar.xz | |
x86/kexec: Eliminate writes through kernel mapping of relocate_kernel page
All writes to the relocate_kernel control page are now done *after* the
%cr3 switch via simple %rip-relative addressing, which means the DATA()
macro with its pointer arithmetic can also now be removed.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/r/20241205153343.3275139-12-dwmw2@infradead.org
| -rw-r--r-- | arch/x86/kernel/relocate_kernel_64.S | 29 |
1 files changed, 14 insertions, 15 deletions
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index d52c3bb25b5e..739041c5bca3 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -61,21 +61,24 @@ SYM_CODE_START_NOALIGN(relocate_kernel) pushq %r15 pushf - movq %rsp, saved_rsp(%rip) - movq %cr0, %rax - movq %rax, saved_cr0(%rip) - movq %cr3, %rax - movq %rax, saved_cr3(%rip) - movq %cr4, %rax - movq %rax, saved_cr4(%rip) - - /* Save CR4. Required to enable the right paging mode later. */ - movq %rax, %r13 - /* zero out flags, and disable interrupts */ pushq $0 popfq + /* Switch to the identity mapped page tables */ + movq %cr3, %rax + movq kexec_pa_table_page(%rip), %r9 + movq %r9, %cr3 + + /* Save %rsp and CRs. */ + movq %rsp, saved_rsp(%rip) + movq %rax, saved_cr3(%rip) + movq %cr0, %rax + movq %rax, saved_cr0(%rip) + /* Leave CR4 in %r13 to enable the right paging mode later. */ + movq %cr4, %r13 + movq %r13, saved_cr4(%rip) + /* Save SME active flag */ movq %r8, %r12 @@ -85,10 +88,6 @@ SYM_CODE_START_NOALIGN(relocate_kernel) /* Save the preserve_context to %r11 as swap_pages clobbers %rcx. */ movq %rcx, %r11 - /* Switch to the identity mapped page tables */ - movq kexec_pa_table_page(%rip), %r9 - movq %r9, %cr3 - /* Physical address of control page */ movq %rsi, %r8 |