The patch titled
Subject: kexec: export the value of phys_base instead of symbol address
has been added to the -mm tree. Its filename is
kexec-change-to-export-the-value-of-phys_base-instead-of-symbol-address.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kexec-change-to-export-the-value-of-phys_base-instead-of-symbol-address.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kexec-change-to-export-the-value-of-phys_base-instead-of-symbol-address.patch
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From: Baoquan He <bhe@xxxxxxxxxx>
Subject: kexec: export the value of phys_base instead of symbol address
Currently in x86_64, the symbol address of phys_base is exported to
vmcoreinfo. Dave Anderson complained this is really useless for his Crash
implementation. Because in user-space utility Crash and Makedumpfile
which exported vmcore information is mainly used for, value of phys_base
is needed to covert virtual address of exported kernel symbol to physical
address. Especially init_level4_pgt, if we want to access and go over the
page table to look up a PA corresponding to VA, firstly we need calculate
page_dir = SYMBOL(init_level4_pgt) - __START_KERNEL_map + phys_base;
Now in Crash and Makedumpfile, we have to analyze the vmcore elf program
header to get value of phys_base. As Dave said, it would be preferable if
it were readily availabl in vmcoreinfo rather than depending upon the
PT_LOAD semantics.
Hence in this patch change to export the value of phys_base instead of its
virtual address.
And people also complained that KERNEL_IMAGE_SIZE exporting is x86_64
only, should be moved into arch dependent function
arch_crash_save_vmcoreinfo. Do the moving in this patch.
Link: http://lkml.kernel.org/r/1478568596-30060-2-git-send-email-bhe@xxxxxxxxxx
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Cc: Thomas Garnier <thgarnie@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H . Peter Anvin" <hpa@xxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Xunlei Pang <xlpang@xxxxxxxxxx>
Cc: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Eugene Surovegin <surovegin@xxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Cc: Atsushi Kumagai <ats-kumagai@xxxxxxxxxxxxx>
Cc: Dave Anderson <anderson@xxxxxxxxxx>
Cc: Pratyush Anand <panand@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/machine_kexec_64.c | 3 ++-
kernel/kexec_core.c | 3 ---
2 files changed, 2 insertions(+), 4 deletions(-)
diff -puN arch/x86/kernel/machine_kexec_64.c~kexec-change-to-export-the-value-of-phys_base-instead-of-symbol-address arch/x86/kernel/machine_kexec_64.c
--- a/arch/x86/kernel/machine_kexec_64.c~kexec-change-to-export-the-value-of-phys_base-instead-of-symbol-address
+++ a/arch/x86/kernel/machine_kexec_64.c
@@ -328,7 +328,7 @@ void machine_kexec(struct kimage *image)
void arch_crash_save_vmcoreinfo(void)
{
- VMCOREINFO_SYMBOL(phys_base);
+ VMCOREINFO_NUMBER(phys_base);
VMCOREINFO_SYMBOL(init_level4_pgt);
#ifdef CONFIG_NUMA
@@ -337,6 +337,7 @@ void arch_crash_save_vmcoreinfo(void)
#endif
vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
kaslr_offset());
+ VMCOREINFO_NUMBER(KERNEL_IMAGE_SIZE);
}
/* arch-dependent functionality related to kexec file-based syscall */
diff -puN kernel/kexec_core.c~kexec-change-to-export-the-value-of-phys_base-instead-of-symbol-address kernel/kexec_core.c
--- a/kernel/kexec_core.c~kexec-change-to-export-the-value-of-phys_base-instead-of-symbol-address
+++ a/kernel/kexec_core.c
@@ -1467,9 +1467,6 @@ static int __init crash_save_vmcoreinfo_
#endif
VMCOREINFO_NUMBER(PG_head_mask);
VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
-#ifdef CONFIG_X86
- VMCOREINFO_NUMBER(KERNEL_IMAGE_SIZE);
-#endif
#ifdef CONFIG_HUGETLB_PAGE
VMCOREINFO_NUMBER(HUGETLB_PAGE_DTOR);
#endif
_
Patches currently in -mm which might be from bhe@xxxxxxxxxx are
revert-kdump-vmcoreinfo-report-memory-sections-virtual-addresses.patch
kexec-change-to-export-the-value-of-phys_base-instead-of-symbol-address.patch
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