[Crash-utility] [PATCH][v2] x86_64: vtop supports 1G huge pages

[Li RongQing]

Crash utility currently does not supporting virtual to physical
address translation for 1G huge pages on x86_64, This patch tries
to address this issue by providing address translation
support for huge pages in 'vtop' command.

Without this patch:
crash> vtop 7f6e40000000
VIRTUAL     PHYSICAL
vtop: seek error: physical address: 3f53f000f000  type: "page table"
crash>

With this patch:
crash> vtop 7f6e40000000
VIRTUAL     PHYSICAL
7f6e40000000  1d40000000

   PGD: 1fdb6cc7f0 => 80000001e715f067
   PUD: 1e715fdc8 => 8000001d400008e7
  PAGE: 1d40000000  (1GB)

      PTE          PHYSICAL   FLAGS
8000001d400008e7  1d40000000  (PRESENT|RW|USER|ACCESSED|DIRTY|PSE|NX)

      VMA           START       END     FLAGS FILE
ffff99869b7791f8 7f6e40000000 7f6ec0000000 c4400fb /var/lib/libvirt/qemu/hugetlbfs/qemu_back_mem._objects_ram-node0.WjBfNa

      PAGE         PHYSICAL      MAPPING       INDEX CNT FLAGS
ffffd90cf5000000 1d40000000 ffff996836978650        0  7 17ffffc000801c referenced,uptodate,dirty,head
crash>

add the 1G huge pages translation for kvtop as HAGIO KAZUHITO suggested

Signed-off-by: Li RongQing <lirongqing at baidu.com>
Signed-off-by: chukaiping <chukaiping at foxmail.com>
---
diff with v1: add the 1G huge pages translation for kvtop as HAGIO KAZUHITO suggested

 defs.h   |  1 +
 x86_64.c | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/defs.h b/defs.h
index aba58ff..e73778b 100644
--- a/defs.h
+++ b/defs.h
@@ -5996,6 +5996,7 @@ struct machine_specific {
 #define VM_FLAGS (VM_ORIG|VM_2_6_11|VM_XEN|VM_XEN_RHEL4|VM_5LEVEL)
 
 #define _2MB_PAGE_MASK (~((MEGABYTES(2))-1))
+#define _1GB_PAGE_MASK (~((GIGABYTES(1))-1))
 
 #endif
 
diff --git a/x86_64.c b/x86_64.c
index 4f1a6d7..fc05e8a 100644
--- a/x86_64.c
+++ b/x86_64.c
@@ -2020,6 +2020,19 @@ x86_64_uvtop_level4(struct task_context *tc, ulong uvaddr, physaddr_t *paddr, in
 	if (!(pud_pte & _PAGE_PRESENT))
 		goto no_upage;
 
+	if (pud_pte & _PAGE_PSE) {
+		if (verbose) {
+			fprintf(fp, "  PAGE: %lx  (1GB)\n\n",
+			       PAGEBASE(pud_pte) & PHYSICAL_PAGE_MASK);
+			x86_64_translate_pte(pud_pte, 0, 0);
+		}
+
+		physpage = (PAGEBASE(pud_pte) & PHYSICAL_PAGE_MASK) +
+			       (uvaddr & ~_1GB_PAGE_MASK);
+		*paddr = physpage;
+		return TRUE;
+	}
+
 	/*
          *  pmd = pmd_offset(pud, address);
 	 */
@@ -2429,6 +2442,19 @@ start_vtop_with_pagetable:
 	if (!(pud_pte & _PAGE_PRESENT))
 		goto no_kpage;
 
+	if (pud_pte & _PAGE_PSE) {
+		if (verbose) {
+			fprintf(fp, "  PAGE: %lx  (1GB)\n\n",
+			       PAGEBASE(pud_pte) & PHYSICAL_PAGE_MASK);
+			x86_64_translate_pte(pud_pte, 0, 0);
+		}
+
+		physpage = (PAGEBASE(pud_pte) & PHYSICAL_PAGE_MASK) +
+			       (kvaddr & ~_1GB_PAGE_MASK);
+		*paddr = physpage;
+		return TRUE;
+	}
+
 	/*
          *  pmd = pmd_offset(pud, address);
 	 */
-- 
2.16.2