From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.skyhub.de ([2a01:4f8:190:11c2::b:1457]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hHUN7-00015I-HB for kexec@lists.infradead.org; Fri, 19 Apr 2019 14:20:11 +0000 Date: Fri, 19 Apr 2019 16:19:52 +0200 From: Borislav Petkov Subject: [PATCH] x86/boot: Disable RSDP parsing temporarily Message-ID: <20190419141952.GE10324@zn.tnic> References: <20190419101733.GA10324@zn.tnic> <20190419105014.GE11060@MiWiFi-R3L-srv> <20190419113413.GC10324@zn.tnic> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Kairui Song , Thomas Gleixner Cc: Juergen Gross , Tom Lendacky , Chao Fan , indou.takao@jp.fujitsu.com, Kees Cook , Baoquan He , Ard Biesheuvel , "x86@kernel.org" , "kexec@lists.infradead.org" , Linux Kernel Mailing List , Ingo Molnar , Dave Hansen , "H. Peter Anvin" , Junichi Nomura , msys.mizuma@gmail.com, Dave Young , "Kirill A. Shutemov" Ok, thinking about this more, we believe it is too late in the release cycle to keep experimenting so the only thing left to do is the below. This should bring the situation back to what it was before, at 5.0 times, and we'll have plenty of time now to address and properly fix all the outstanding issues. --- From: Borislav Petkov The original intention to move RDSP parsing very early, before KASLR does its ranges selection, was to accommodate movable memory regions machines (CONFIG_MEMORY_HOTREMOVE) to still be able to do memory hotplug. However, that broke kexec'ing a kernel on EFI machines because depending on where the EFI systab was mapped, on at least one machine it isn't present in the kexec mapping of the second kernel, leading to a triple fault in the early code. Fixing this properly requires significantly involved surgery and we cannot allow ourselves to do that, that close to the merge window. So disable the RSDP parsing code temporarily until it is fixed properly in the next release cycle. Signed-off-by: Borislav Petkov Cc: Ard Biesheuvel Cc: Baoquan He Cc: Chao Fan Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: indou.takao@jp.fujitsu.com Cc: Ingo Molnar Cc: Juergen Gross Cc: kasong@redhat.com Cc: Kees Cook Cc: "Kirill A. Shutemov" Cc: msys.mizuma@gmail.com Cc: Thomas Gleixner Cc: Tom Lendacky Cc: x86-ml --- arch/x86/boot/compressed/misc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index c0d6c560df69..5a237e8dbf8d 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -352,7 +352,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, boot_params->hdr.loadflags &= ~KASLR_FLAG; /* Save RSDP address for later use. */ - boot_params->acpi_rsdp_addr = get_rsdp_addr(); + /* boot_params->acpi_rsdp_addr = get_rsdp_addr(); */ sanitize_boot_params(boot_params); -- 2.21.0 -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec