[Crash-utility] [PATCH v3 1/2] Call x86_64_kvtop during symtab_init() for sadump
This patch changes x86_64_kvtop() so that it can be called during
symtab_init().
To solve kaslr problem of sadump, kaslr offset and phys_base need to be
calculated before symbol data is loaded. This calculation needs
translation of kernel virtual address to physical address. Current
x86_64_kvtop() implementation tries to use x86_64_VTOP for translation
at first, but this does not work for this purpose because x86_64_VTOP
uses phys_base. x86_64_kvtop() need to be changed to skip x86_64_VTOP()
during sadump initialization.
Signed-off-by: Takao Indoh <indou.takao(a)jp.fujitsu.com>
---
x86_64.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/x86_64.c b/x86_64.c
index 6e60dda..2f9e6db 100644
--- a/x86_64.c
+++ b/x86_64.c
@@ -194,6 +194,9 @@ x86_64_init(int when)
machdep->machspec->kernel_image_size = dtol(string, QUIET, NULL);
free(string);
}
+ if (SADUMP_DUMPFILE())
+ /* Need for calculation of kaslr_offset and phys_base */
+ machdep->kvtop = x86_64_kvtop;
break;
case PRE_GDB:
@@ -2019,6 +2022,22 @@ x86_64_kvtop(struct task_context *tc, ulong kvaddr, physaddr_t
*paddr, int verbo
ulong pte;
physaddr_t physpage;
+ if (SADUMP_DUMPFILE() && !(machdep->flags & KSYMS_START)) {
+ /*
+ * In the case of sadump, to calculate kaslr_offset and
+ * phys_base, kvtop is called during symtab_init(). In this
+ * stage phys_base is not initialized yet and x86_64_VTOP()
+ * does not work. Jump to the code of pagetable translation.
+ */
+ FILL_PML4();
+ pml4 = ((ulong *)machdep->machspec->pml4) + pml4_index(kvaddr);
+ if (verbose) {
+ fprintf(fp, "PML4 DIRECTORY: %lx\n", vt->kernel_pgd[0]);
+ fprintf(fp, "PAGE DIRECTORY: %lx\n", *pml4);
+ }
+ goto start_vtop_with_pagetable;
+ }
+
if (!IS_KVADDR(kvaddr))
return FALSE;
@@ -2065,6 +2084,8 @@ x86_64_kvtop(struct task_context *tc, ulong kvaddr, physaddr_t
*paddr, int verbo
fprintf(fp, "PAGE DIRECTORY: %lx\n", *pml4);
}
}
+
+start_vtop_with_pagetable:
if (!(*pml4) & _PAGE_PRESENT)
goto no_kpage;
pgd_paddr = (*pml4) & PHYSICAL_PAGE_MASK;
--
2.9.5