Re: [PATCH v8 0/2] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions

Chao Fan
2017-08-04T09:59:29Z

On Fri, Aug 04, 2017 at 05:22:41PM +0800, Baoquan He wrote:
>On 08/04/17 at 03:52pm, Baoquan He wrote:
>> Sorry, NACK this series, there's error to hang system. Before I just
>> halt system intentionally with error() to check the efi memmap printing,
>> didn't notice this. Checking the cause.
>
>I rebuilt the code or change the one of the replacement back, hang never
>seen again. Not sure if I copied the wrong kernel or any other mistakes.
>Have got a hardware system with efi enabled to try again, see if
>anything wrong will happen. It's really weird. And Chao also is helping
>to try on his side.

Hi Bao,

After testing for 10 times, no problem happened.
Maybe you did something wrong in the first time.

Thanks,
Chao Fan

>
>>
>> On 08/04/17 at 03:26pm, Baoquan He wrote:
>> > Patch 1/2 is newly added to add efi_memdesc_ptr helper to wrap the
>> > open code which gets the start of efi memmap descriptor and also
>> > explain why it need be done like that, Ingo suggested it.
>> >
>> > And also replace several places of the open code with efi_memdesc_ptr
>> > helper.
>> >
>> > And also use efi_memdesc_ptr in process_efi_entries() which handle efi
>> > mirror issue during KASLR.
>> >
>> >
>> > Change:
>> > v7->v8:
>> > Add efi_memdesc_ptr helper to wrap the open code which gets the
>> > start of map descriptor according to Ingo's suggestion.
>> >
>> > v6->v7:
>> > Ingo pointed out several incorrect line break issues and unclear
>> > description of patch log. Correct them and rewrite patch log.
>> >
>> > And also rewrite the EFI warning message that if EFI memmap is above
>> > 4G in 32bit system since 32bit system can not handle data above 4G at
>> > kernel decompression stage. This is suggested by Ingo too.
>> >
>> > v5->v6:
>> > Code style issue fix according to Kees's comment.
>> >
>> > This is based on tip/x86/boot, patch 1,2,3/4 in v5 post has
>> > been put into tip/x86/boot now.
>> >
>> >
>> >
>> > Baoquan He (2):
>> > efi: Introduce efi_memdesc_ptr to get pointer to memmap descriptor
>> > x86/boot/KASLR: Restrict kernel to be randomized in mirror regions
>> >
>> > arch/x86/boot/compressed/eboot.c | 2 +-
>> > arch/x86/boot/compressed/kaslr.c | 68 +++++++++++++++++++++++++-
>> > drivers/firmware/efi/libstub/efi-stub-helper.c | 4 +-
>> > include/linux/efi.h | 19 +++++++
>> > 4 files changed, 88 insertions(+), 5 deletions(-)
>> >
>> > --
>> > 2.5.5
>> >
>
>