Messages in this thread | | | From | Baoquan He <> | Subject | [PATCH v4 0/3] Handle memmap and mem kernel options in boot stage kaslr | Date | Tue, 9 May 2017 13:57:49 +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, and it sits on top of tip:x86/boot branch.
Changelog
v3->v4: *Code improved patch 1/3 according to Kees's suggestion.
*Add 'Fall through' in switch case of parse_memmap() which is suggestd by Kees.
v2->v3: No functionality change in this round. *Use local static variable insted of global variable mem_avoid_memmap_index in patch 1/3.
*Fix a typo in patch 3/3.
v1->v2: *The original patch 1/4 has been put in tip:x86/boot and no update, so it's not included in this post.
*Use patch log Ingo reorganized.
*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.
*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 | 191 ++++++++++++++++-------- arch/x86/boot/string.c | 8 + 4 files changed, 144 insertions(+), 66 deletions(-)
-- 2.5.5
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