From 203e9e41219b4e7357104e525e91ac609fba2c6c Mon Sep 17 00:00:00 2001 From: Xunlei Pang Date: Wed, 12 Jul 2017 14:33:14 -0700 Subject: kexec: move vmcoreinfo out of the kernel's .bss section As Eric said, "what we need to do is move the variable vmcoreinfo_note out of the kernel's .bss section. And modify the code to regenerate and keep this information in something like the control page. Definitely something like this needs a page all to itself, and ideally far away from any other kernel data structures. I clearly was not watching closely the data someone decided to keep this silly thing in the kernel's .bss section." This patch allocates extra pages for these vmcoreinfo_XXX variables, one advantage is that it enhances some safety of vmcoreinfo, because vmcoreinfo now is kept far away from other kernel data structures. Link: http://lkml.kernel.org/r/1493281021-20737-1-git-send-email-xlpang@redhat.com Signed-off-by: Xunlei Pang Tested-by: Michael Holzheu Reviewed-by: Juergen Gross Suggested-by: Eric Biederman Cc: Benjamin Herrenschmidt Cc: Dave Young Cc: Hari Bathini Cc: Mahesh Salgaonkar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/crash_core.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h index 4090a42578a8..87506a02e914 100644 --- a/include/linux/crash_core.h +++ b/include/linux/crash_core.h @@ -19,7 +19,7 @@ CRASH_CORE_NOTE_NAME_BYTES + \ CRASH_CORE_NOTE_DESC_BYTES) -#define VMCOREINFO_BYTES (4096) +#define VMCOREINFO_BYTES PAGE_SIZE #define VMCOREINFO_NOTE_NAME "VMCOREINFO" #define VMCOREINFO_NOTE_NAME_BYTES ALIGN(sizeof(VMCOREINFO_NOTE_NAME), 4) #define VMCOREINFO_NOTE_SIZE ((CRASH_CORE_NOTE_HEAD_BYTES * 2) + \ @@ -56,7 +56,7 @@ phys_addr_t paddr_vmcoreinfo_note(void); #define VMCOREINFO_CONFIG(name) \ vmcoreinfo_append_str("CONFIG_%s=y\n", #name) -extern u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4]; +extern u32 *vmcoreinfo_note; extern size_t vmcoreinfo_size; extern size_t vmcoreinfo_max_size; -- cgit v1.2.3