On 04/27/17 at 03:57pm, YASUAKI ISHIMATSU wrote:
> Hi Baoquan,
>
>
> On 04/26/2017 06:16 AM, Baoquan He wrote:
> > People reported kernel panic occurs during system boots up with mem boot
> > option.
> > After checking code, several problems are found about memmap= and mem= in
> > boot stage
> > kaslr.
> >
> > *) In commit f28442497b5c ("x86/boot: Fix KASLR and memmap= collision"),
> > only one memmap
> > entry is considered and only the last one if multiple memmap entries are
> > specified.
> >
>
> > *) mem= and memmap=nn[KMG] are not considered yet. They are used to limit
> > max address
> > of system. Kernel can't be randomized to be above the limit.
>
> I confirmed that mem= works correctly.
>
> Tested-by: Yasuaki Ishimatsu <isimatu.yasu...@jp.fujitsu.com>
Thanks for your effort, Yasuaki Ishimatsu!
>
>
> >
> > *) kernel-parameters.txt doesn't tell the updated behaviour of memmap=.
> >
> > This patchset tries to solve above issues, and it sits on top of
> > tip:x86/boot branch.
> >
> > Changelog
> >
> > v2->v3:
> > No functionality change in this round.
> > a)Use local static variable insted of global variable
> > mem_avoid_memmap_index in patch 1/3.
> > b)Fix a typo in patch 3/3.
> >
> > v1->v2:
> > a)The original patch 1/4 has been put in tip:x86/boot and no update,
> > so it's not included in this post.
> > b)Use patch log Ingo reorganized.
> > c)lib/ctype.c and lib/cmdline.c are needed for kaslr.c, while those
> > EXPORT_SYMBOL(x) contained caused failure of build on 32-bit allmodconfig:
> > ......
> > ld: -r and -shared may not be used together
> > scripts/Makefile.build:294: recipe for target
> > 'arch/x86/boot/compressed/kaslr.o' failed
> > ......
> > Disabling the symbol exporting removes the build failure.
> > d)Use dynamic allocation to allocate memory to contain copied kernel cmdline
> > buffer, it's implemented in include/linux/decompress/mm.h.
> >
> >
> >
> > Baoquan He (3):
> > KASLR: Parse all memmap entries in cmdline
> > KASLR: Handle memory limit specified by memmap and mem option
> > Documentation/kernel-parameters.txt: Update 'memmap=' option
> > description
> >
> > Documentation/admin-guide/kernel-parameters.txt | 9 ++
> > arch/x86/boot/compressed/cmdline.c | 2 +-
> > arch/x86/boot/compressed/kaslr.c | 183
> > +++++++++++++++---------
> > arch/x86/boot/string.c | 8 ++
> > 4 files changed, 136 insertions(+), 66 deletions(-)
> >
