linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2013-08-09	x86: Don't clear olpc_ofw_header when sentinel is detected	Daniel Drake	1	-2/+2
	OpenFirmware wasn't quite following the protocol described in boot.txt and the kernel has detected this through use of the sentinel value in boot_params. OFW does zero out almost all of the stuff that it should do, but not the sentinel. This causes the kernel to clear olpc_ofw_header, which breaks x86 OLPC support. OpenFirmware has now been fixed. However, it would be nice if we could maintain Linux compatibility with old firmware versions. To do that, we just have to avoid zeroing out olpc_ofw_header. OFW does not write to any other parts of the header that are being zapped by the sentinel-detection code, and all users of olpc_ofw_header are somewhat protected through checking for the OLPC_OFW_SIG magic value before using it. So this should not cause any problems for anyone. Signed-off-by: Daniel Drake <dsd@laptop.org> Link: http://lkml.kernel.org/r/20130809221420.618E6FAB03@dev.laptop.org Acked-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: <stable@vger.kernel.org> # v3.9+
2013-03-06	x86, doc: Be explicit about what the x86 struct boot_params requires	Peter Jones	1	-1/+15
	If the sentinel triggers, we do not want the boot loader authors to just poke it and make the error go away, we want them to actually fix the problem. This should help avoid making the incorrect change in non-compliant bootloaders. [ hpa: dropped the Documentation/x86/boot.txt hunk pending clarifications ] Signed-off-by: Peter Jones <pjones@redhat.com> Link: http://lkml.kernel.org/r/1362592823-28967-1-git-send-email-pjones@redhat.com Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2013-03-06	x86: Don't clear efi_info even if the sentinel hits	Josh Boyer	1	-1/+3
	When boot_params->sentinel is set, all we really know is that some undefined set of fields in struct boot_params contain garbage. In the particular case of efi_info, however, there is a private magic for that substructure, so it is generally safe to leave it even if the bootloader is broken. kexec (for which we did the initial analysis) did not initialize this field, but of course all the EFI bootloaders do, and most EFI bootloaders are broken in this respect (and should be fixed.) Reported-by: Robin Holt <holt@sgi.com> Link: http://lkml.kernel.org/r/CA%2B5PVA51-FT14p4CRYKbicykugVb=PiaEycdQ57CK2km_OQuRQ@mail.gmail.com Tested-by: Josh Boyer <jwboyer@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2013-01-29	x86, boot: Sanitize boot_params if not zeroed on creation	H. Peter Anvin	1	-0/+38
	Use the new sentinel field to detect bootloaders which fail to follow protocol and don't initialize fields in struct boot_params that they do not explicitly initialize to zero. Based on an original patch and research by Yinghai Lu. Changed by hpa to be invoked both in the decompression path and in the kernel proper; the latter for the case where a bootloader takes over decompression. Originally-by: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1359058816-7615-26-git-send-email-yinghai@kernel.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>