Messages in this thread | | | From | Baoquan He <> | Subject | [PATCH v2 0/3] Handle memmap and mem kernel options in boot stage kaslr | Date | Mon, 24 Apr 2017 10:40:47 +0800 |
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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.
*) kernel-parameters.txt doesn't tell the updated behaviour of memmap=.
This patchset tries to solve above issues.
Changelog: 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.
e) This patchset sits on top of tip:x86/boot branch.
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 | 185 +++++++++++++++--------- arch/x86/boot/string.c | 8 + 4 files changed, 138 insertions(+), 66 deletions(-)
-- 2.5.5
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