The following commit has been merged into the x86/boot branch of tip: Commit-ID: 93e489ad7a4694bb2fe8110f5012f85bd3eee65a Gitweb: https://git.kernel.org/tip/93e489ad7a4694bb2fe8110f5012f85bd3eee65a Author: David Woodhouse <dwmw@xxxxxxxxxxxx> AuthorDate: Thu, 05 Dec 2024 15:05:18 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Fri, 06 Dec 2024 10:42:00 +01:00 x86/kexec: Clean up register usage in relocate_kernel() The memory encryption flag is passed in %r8 because that's where the calling convention puts it. Instead of moving it to %r12 and then using %r8 for other things, just leave it in %r8 and use other registers instead. Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Cc: Dave Young <dyoung@xxxxxxxxxx> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Link: https://lore.kernel.org/r/20241205153343.3275139-13-dwmw2@xxxxxxxxxxxxx --- arch/x86/kernel/relocate_kernel_64.S | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index 739041c..8bc86a1 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -79,24 +79,18 @@ SYM_CODE_START_NOALIGN(relocate_kernel) movq %cr4, %r13 movq %r13, saved_cr4(%rip) - /* Save SME active flag */ - movq %r8, %r12 - /* save indirection list for jumping back */ movq %rdi, pa_backup_pages_map(%rip) /* Save the preserve_context to %r11 as swap_pages clobbers %rcx. */ movq %rcx, %r11 - /* Physical address of control page */ - movq %rsi, %r8 - /* setup a new stack at the end of the physical control page */ - lea PAGE_SIZE(%r8), %rsp + lea PAGE_SIZE(%rsi), %rsp /* jump to identity mapped page */ - addq $(identity_mapped - relocate_kernel), %r8 - pushq %r8 + addq $(identity_mapped - relocate_kernel), %rsi + pushq %rsi ANNOTATE_UNRET_SAFE ret int3 @@ -107,8 +101,9 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped) /* * %rdi indirection page * %rdx start address + * %r8 host_mem_enc_active + * %r9 page table page * %r11 preserve_context - * %r12 host_mem_enc_active * %r13 original CR4 when relocate_kernel() was invoked */ @@ -161,7 +156,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped) * entries that will conflict with the now unencrypted memory * used by kexec. Flush the caches before copying the kernel. */ - testq %r12, %r12 + testq %r8, %r8 jz .Lsme_off wbinvd .Lsme_off:
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