From: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> To: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, "H . Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org> Cc: Sai Praneeth <sai.praneeth.prakhya-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>, Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>, Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Lee Chun-Yi <jlee-IBi9RG/b67k@public.gmane.org>, Ravi Shankar <ravi.v.shankar-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, Ricardo Neri <ricardo.neri-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> Subject: [PATCH 3/5] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map Date: Fri, 26 May 2017 12:36:49 +0100 Message-ID: <20170526113652.21339-4-matt@codeblueprint.co.uk> (raw) In-Reply-To: <20170526113652.21339-1-matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> From: Sai Praneeth <sai.praneeth.prakhya-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> Booting kexec kernel with "efi=old_map" in kernel command line hits kernel panic as shown below. BUG: unable to handle kernel paging request at ffff88007fe78070 IP: virt_efi_set_variable.part.7+0x63/0x1b0 PGD 7ea28067 PUD 7ea2b067 PMD 7ea2d067 PTE 0 [...] Call Trace: virt_efi_set_variable+0x5d/0x70 efi_delete_dummy_variable+0x7a/0x80 efi_enter_virtual_mode+0x3f6/0x4a7 start_kernel+0x375/0x400 x86_64_start_reservations+0x2a/0x2c x86_64_start_kernel+0x168/0x176 start_cpu+0x14/0x14 [ efi=old_map was never intended to work with kexec. The problem with using efi=old_map is that the virtual addresses are assigned from the memory region used by other kernel mappings; vmalloc() space. Potentially there could be collisions when booting kexec if something else is mapped at the virtual address we allocated for runtime service regions in the initial boot - Matt Fleming ] Since kexec was never intended to work with efi=old_map, disable runtime services in kexec if booted with efi=old_map, so that we don't panic. Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> Cc: Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org> Cc: Ricardo Neri <ricardo.neri-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> Cc: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Cc: Ravi Shankar <ravi.v.shankar-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> Tested-by: Lee Chun-Yi <jlee-IBi9RG/b67k@public.gmane.org> Acked-by: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Signed-off-by: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> --- arch/x86/platform/efi/efi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 7e76a4d8304b..43b96f5f78ba 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -828,9 +828,11 @@ static void __init kexec_enter_virtual_mode(void) /* * We don't do virtual mode, since we don't do runtime services, on - * non-native EFI + * non-native EFI. With efi=old_map, we don't do runtime services in + * kexec kernel because in the initial boot something else might + * have been mapped at these virtual addresses. */ - if (!efi_is_native()) { + if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) { efi_memmap_unmap(); clear_bit(EFI_RUNTIME_SERVICES, &efi.flags); return; -- 2.12.2
next prev parent reply index Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-05-26 11:36 [GIT PULL 0/5] EFI urgent fixes Matt Fleming 2017-05-26 11:36 ` [PATCH 1/5] efi: Don't issue error message when booted under xen Matt Fleming [not found] ` <20170526113652.21339-1-matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> 2017-05-26 11:36 ` [PATCH 2/5] efi: Remove duplicate 'const' specifiers Matt Fleming 2017-05-26 11:36 ` Matt Fleming [this message] 2017-05-26 11:36 ` [PATCH 4/5] x86/efi: Correct ident mapping of efi old_map when kalsr enabled Matt Fleming 2017-05-26 11:36 ` [PATCH 5/5] efi/bgrt: Skip efi_bgrt_init in case of non-efi boot Matt Fleming
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20170526113652.21339-4-matt@codeblueprint.co.uk \ --to=matt-mf/unelci9gs6ibeejttw/xrex20p6io@public.gmane.org \ --cc=ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org \ --cc=bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org \ --cc=dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \ --cc=hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org \ --cc=jlee-IBi9RG/b67k@public.gmane.org \ --cc=linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \ --cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \ --cc=mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org \ --cc=ravi.v.shankar-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \ --cc=ricardo.neri-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \ --cc=sai.praneeth.prakhya-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \ --cc=tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
Linux-EFI Archive on lore.kernel.org Archives are clonable: git clone --mirror https://lore.kernel.org/linux-efi/0 linux-efi/git/0.git # If you have public-inbox 1.1+ installed, you may # initialize and index your mirror using the following commands: public-inbox-init -V2 linux-efi linux-efi/ https://lore.kernel.org/linux-efi \ linux-efi@vger.kernel.org public-inbox-index linux-efi Example config snippet for mirrors Newsgroup available over NNTP: nntp://nntp.lore.kernel.org/org.kernel.vger.linux-efi AGPL code for this site: git clone https://public-inbox.org/public-inbox.git