From e00ac9e5afb5d80c0168ec88d8e8662a54af8249 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 17 Feb 2026 12:09:35 +0100 Subject: [PATCH] x86/kexec: Copy ACPI root pointer address from config table Dave reports that kexec may fail when the first kernel boots via the EFI stub but without EFI runtime services, as in that case, the RSDP address field in struct bootparams is never assigned. Kexec copies this value into the version of struct bootparams that it provides to the incoming kernel, which may have no other means to locate the ACPI root pointer. So take the value from the EFI config tables if no root pointer has been set in the first kernel's struct bootparams. Fixes: a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot") Cc: # v6.1 Reported-by: Dave Young Tested-by: Dave Young Link: https://lore.kernel.org/linux-efi/aZQg_tRQmdKNadCg@darkstar.users.ipa.redhat.com/ Signed-off-by: Ard Biesheuvel --- arch/x86/kernel/kexec-bzimage64.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c index 7508d0ccc740..251edc5a040f 100644 --- a/arch/x86/kernel/kexec-bzimage64.c +++ b/arch/x86/kernel/kexec-bzimage64.c @@ -193,6 +193,13 @@ setup_efi_state(struct boot_params *params, unsigned long params_load_addr, struct efi_info *current_ei = &boot_params.efi_info; struct efi_info *ei = ¶ms->efi_info; + if (!params->acpi_rsdp_addr) { + if (efi.acpi20 != EFI_INVALID_TABLE_ADDR) + params->acpi_rsdp_addr = efi.acpi20; + else if (efi.acpi != EFI_INVALID_TABLE_ADDR) + params->acpi_rsdp_addr = efi.acpi; + } + if (!efi_enabled(EFI_RUNTIME_SERVICES)) return 0; -- 2.30.2