[Crash-utility] [PATCH v2] x86_64: Make the conversion between 4level and 5level paging automatically
Currently, Crash only enable support for kernel-only 5-level page tables by
entering the command line option "--machdep vm=5level". Since Linux 4.17,
the Linux kernel can be both 4level and 5level page tables. This command line
can't work well for this.
Using the "pgtable_l5_enabled" to detect whether the kernel proper for 5 level
page tables automatically. Also move the 5-level paging setup from machdep_init(PRE_GDB)
to machdep_init(POST_RELOC).
Signed-off-by: Dave Anderson <anderson(a)redhat.com>
Signed-off-by: Dou Liyang <douly.fnst(a)cn.fujitsu.com>
---
Changelog v1 --> v2
1. Make it support live systems suggested by Dave
2. Using __pgtable_l5_enabled for check.
3. Do some tests in both kdump(5level and 4level) and virsh dump(5level and 4level)
---
x86_64.c | 56 +++++++++++++++++++++++++++++++++++++-------------------
1 file changed, 37 insertions(+), 19 deletions(-)
diff --git a/x86_64.c b/x86_64.c
index 6d1ae2f..07b6aa9 100644
--- a/x86_64.c
+++ b/x86_64.c
@@ -294,25 +294,6 @@ x86_64_init(int when)
machdep->machspec->pgdir_shift = PGDIR_SHIFT;
machdep->machspec->ptrs_per_pgd = PTRS_PER_PGD;
break;
-
- case VM_5LEVEL:
- machdep->machspec->userspace_top = USERSPACE_TOP_5LEVEL;
- machdep->machspec->page_offset = PAGE_OFFSET_5LEVEL;
- machdep->machspec->vmalloc_start_addr = VMALLOC_START_ADDR_5LEVEL;
- machdep->machspec->vmalloc_end = VMALLOC_END_5LEVEL;
- machdep->machspec->modules_vaddr = MODULES_VADDR_5LEVEL;
- machdep->machspec->modules_end = MODULES_END_5LEVEL;
- machdep->machspec->vmemmap_vaddr = VMEMMAP_VADDR_5LEVEL;
- machdep->machspec->vmemmap_end = VMEMMAP_END_5LEVEL;
- if (symbol_exists("vmemmap_populate"))
- machdep->flags |= VMEMMAP;
- machdep->machspec->physical_mask_shift = __PHYSICAL_MASK_SHIFT_5LEVEL;
- machdep->machspec->pgdir_shift = PGDIR_SHIFT_5LEVEL;
- machdep->machspec->ptrs_per_pgd = PTRS_PER_PGD_5LEVEL;
- if ((machdep->machspec->p4d = (char *)malloc(PAGESIZE())) == NULL)
- error(FATAL, "cannot malloc p4d space.");
- machdep->machspec->last_p4d_read = 0;
- machdep->uvtop = x86_64_uvtop_level4; /* 5-level is optional per-task */
}
machdep->kvbase = (ulong)PAGE_OFFSET;
machdep->identity_map_base = (ulong)PAGE_OFFSET;
@@ -346,6 +327,43 @@ x86_64_init(int when)
break;
case POST_RELOC:
+ /* Check for 5-level paging */
+ if (!(machdep->flags & VM_5LEVEL)) {
+ int l5_enabled;
+ if ((string = pc->read_vmcoreinfo("NUMBER(pgtable_l5_enabled)"))) {
+ l5_enabled = 1;
+ free(string);
+ } else if (kernel_symbol_exists("__pgtable_l5_enabled"))
+ readmem(symbol_value("__pgtable_l5_enabled"), KVADDR,
+ &l5_enabled, sizeof(int), "__pgtable_l5_enabled",
+ FAULT_ON_ERROR);
+
+ if (l5_enabled)
+ machdep->flags |= VM_5LEVEL;
+ }
+ if (machdep->flags & VM_5LEVEL) {
+ machdep->machspec->userspace_top = USERSPACE_TOP_5LEVEL;
+ machdep->machspec->page_offset = PAGE_OFFSET_5LEVEL;
+ machdep->machspec->vmalloc_start_addr = VMALLOC_START_ADDR_5LEVEL;
+ machdep->machspec->vmalloc_end = VMALLOC_END_5LEVEL;
+ machdep->machspec->modules_vaddr = MODULES_VADDR_5LEVEL;
+ machdep->machspec->modules_end = MODULES_END_5LEVEL;
+ machdep->machspec->vmemmap_vaddr = VMEMMAP_VADDR_5LEVEL;
+ machdep->machspec->vmemmap_end = VMEMMAP_END_5LEVEL;
+ if (symbol_exists("vmemmap_populate"))
+ machdep->flags |= VMEMMAP;
+ machdep->machspec->physical_mask_shift = __PHYSICAL_MASK_SHIFT_5LEVEL;
+ machdep->machspec->pgdir_shift = PGDIR_SHIFT_5LEVEL;
+ machdep->machspec->ptrs_per_pgd = PTRS_PER_PGD_5LEVEL;
+ if ((machdep->machspec->p4d = (char *)malloc(PAGESIZE())) == NULL)
+ error(FATAL, "cannot malloc p4d space.");
+ machdep->machspec->last_p4d_read = 0;
+ machdep->uvtop = x86_64_uvtop_level4; /* 5-level is optional per-task */
+ machdep->kvbase = (ulong)PAGE_OFFSET;
+ machdep->identity_map_base = (ulong)PAGE_OFFSET;
+
+ }
+
/*
* Check for CONFIG_RANDOMIZE_MEMORY, and set page_offset here.
* The remainder of the virtual address range setups will get
--
2.14.3