Re: [Crash-utility] [PATCH 1/3] Introduce x86_64_kvtop_pagetable

-----Original Message----- From: Takao Indoh [mailto:indou.takao@jp.fujitsu.com] Sent: Tuesday, October 10, 2017 6:26 PM To: crash-utility(a)redhat.com; Hatayama, Daisuke/畑山 大輔 <d.hatayama(a)jp.fujitsu.com&gt; Subject: [PATCH 1/3] Introduce x86_64_kvtop_pagetable This patch introduces new function x86_64_kvtop_pagetable() to translate virtual address to physical address. Unlike x86_64_kvtop(), x86_64_kvtop_pagetable() simply converts given virtual address to physical address using pagetable. To solve kaslr problem of virsh dump and 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 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. So x86_64_kvtop_pagetable() is needed which does not use phys_base.

Signed-off-by: Takao Indoh <indou.takao(a)jp.fujitsu.com&gt; --- defs.h | 1 + x86_64.c | 26 +++++++++++++++++++++++++- 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/defs.h b/defs.h index fd97ffe..cddca93 100644 --- a/defs.h +++ b/defs.h @@ -5622,6 +5622,7 @@ void x86_64_display_idt_table(void); #define display_idt_table() x86_64_display_idt_table() long x86_64_exception_frame(ulong, ulong, char *, struct bt_info *, FILE *); #define EFRAME_INIT (0) +int x86_64_kvtop_pagetable(ulong, physaddr_t *, int); struct x86_64_pt_regs_offsets { long r15; diff --git a/x86_64.c b/x86_64.c index 44d0c98..fc48425 100644 --- a/x86_64.c +++ b/x86_64.c @@ -119,6 +119,7 @@ static int x86_64_verify_paddr(uint64_t); static void GART_init(void); static void x86_64_exception_stacks_init(void); static int in_START_KERNEL_map(ulong); +static int __x86_64_kvtop(struct task_context *, ulong, physaddr_t *, int, int); struct machine_specific x86_64_machine_specific = { 0 }; @@ -1964,6 +1965,17 @@ no_upage: return FALSE; } +int +x86_64_kvtop_pagetable(ulong kvaddr, physaddr_t *paddr, int verbose) +{ + return __x86_64_kvtop(NULL, kvaddr, paddr, verbose, 1); +} + +static int +x86_64_kvtop(struct task_context *tc, ulong kvaddr, physaddr_t *paddr, int verbose) +{ + return __x86_64_kvtop(tc, kvaddr, paddr, verbose, 0); +} /* * Translates a kernel virtual address to its physical address. cmd_vtop() @@ -1971,7 +1983,7 @@ no_upage: * other callers quietly accept the translation. */ static int -x86_64_kvtop(struct task_context *tc, ulong kvaddr, physaddr_t *paddr, int verbose) +__x86_64_kvtop(struct task_context *tc, ulong kvaddr, physaddr_t *paddr, int verbose, int use_pagetable) { ulong *pml4; ulong *pgd; @@ -1985,6 +1997,16 @@ x86_64_kvtop(struct task_context *tc, ulong kvaddr, physaddr_t *paddr, int verbo ulong pte; physaddr_t physpage; + if (use_pagetable) { + 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; @@ -2031,6 +2053,8 @@ 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