Revert "kdump, vmcoreinfo: report memory sections virtual addresses"
Subsystems (4)
PATCH 1/2 Revert "kdump, vmcoreinfo: report memory sections virtual addresses"
This reverts commit 0549a3c02efb350776bc869685a361045efd3a29.
Commit 0549a3c tells user space utility - makedumpfile the randomized base address of these memmory sections when mm kaslr enabled. However below patchset makes makedumpfile not need them any more. Besides we should use VMCOREINFO_NUMBER to export value of variable so that we can use the existing number_table mechanism of Makedumpfile to fetch it. So revert it now. If needed, can add it later.
http://lists.infradead.org/pipermail/kexec/2016-October/017540.html
--- arch/x86/kernel/machine_kexec_64.c | 3 --- include/linux/kexec.h | 6 ------ 2 files changed, 9 deletions(-)
arch/x86/kernel/machine_kexec_64.c +0 -3
@@ -337,9 +337,6 @@ void arch_crash_save_vmcoreinfo(void)#endif vmcoreinfo_append_str ("KERNELOFFSET=%lx\n" ,kaslr_offset ()); -VMCOREINFO_PAGE_OFFSET (PAGE_OFFSET ); -VMCOREINFO_VMALLOC_START (VMALLOC_START ); -VMCOREINFO_VMEMMAP_START (VMEMMAP_START ); }/* arch-dependent functionality related to kexec file-based syscall */
include/linux/kexec.h +0 -6
@@ -259,12 +259,6 @@ phys_addr_t paddr_vmcoreinfo_note(void); vmcoreinfo_append_str("NUMBER(%s)=%ld\n", #name, (long)name)#define VMCOREINFO_CONFIG (name) \ vmcoreinfo_append_str("CONFIG_%s=y\n", #name) -#define VMCOREINFO_PAGE_OFFSET (value) \ - vmcoreinfo_append_str("PAGE_OFFSET=%lx\n", (unsigned long)value) -#define VMCOREINFO_VMALLOC_START (value) \ - vmcoreinfo_append_str("VMALLOC_START=%lx\n", (unsigned long)value) -#define VMCOREINFO_VMEMMAP_START (value) \ - vmcoreinfo_append_str("VMEMMAP_START=%lx\n", (unsigned long)value)extern struct kimage *kexec_image;extern struct kimage *kexec_crash_image;
Signature · 1 line
2.5.5
PATCH 2/2 kexec: Change to 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.
--- arch/x86/kernel/machine_kexec_64.c | 3 ++- kernel/kexec_core.c | 3 --- 2 files changed, 2 insertions(+), 4 deletions(-)
arch/x86/kernel/machine_kexec_64.c +2 -1
@@ -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 */
kernel/kexec_core.c +0 -3
@@ -1467,9 +1467,6 @@ static int __init crash_save_vmcoreinfo_init(void)#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
Signature · 1 line
2.5.5