From: David Woodhouse Date: Thu, 9 Jan 2025 14:04:14 +0000 (+0000) Subject: x86/kexec: Ensure preserve_context flag is set on return to kernel X-Git-Tag: v6.14-rc1~119^2~8 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4d5f1da98f5e94ecc39d6e7a990db2efe0ae3810;p=thirdparty%2Flinux.git x86/kexec: Ensure preserve_context flag is set on return to kernel The swap_pages() function will only actually *swap*, as its name implies, if the preserve_context flag in the %r11 register is non-zero. On the way back from a ::preserve_context kexec, ensure that the %r11 register is non-zero so that the pages get swapped back. Fixes: 9e5683e2d0b5 ("x86/kexec: Only swap pages for ::preserve_context mode") Signed-off-by: David Woodhouse Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20250109140757.2841269-3-dwmw2@infradead.org --- diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index 9bd601dd86590..6fce4b459652c 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -220,6 +220,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped) movq kexec_pa_table_page(%rip), %rax movq %rax, %cr3 lea PAGE_SIZE(%r8), %rsp + movl $1, %r11d /* Ensure preserve_context flag is set */ call swap_pages movq kexec_va_control_page(%rip), %rax addq $(virtual_mapped - relocate_kernel), %rax