Crash encounters a bug like the following:
...
SECTION_SIZE_BITS: 30
CONFIG_ARM64_VA_BITS: 52
VA_BITS_ACTUAL: 48
(calculated) VA_BITS: 48
PAGE_OFFSET: ffff000000000000
VA_START: ffff800000000000
modules: ffff800008000000 - ffff80000fffffff
vmalloc: ffff800010000000 - ffffffdfdffeffff
kernel image: ffff800010000000 - ffff800012750000
vmemmap: ffffffdfffe00000 - ffffffffffffffff
<readmem: ffff800011c53bc8, KVADDR, "nr_irqs", 4, (FOE), b47bdc>
<read_kdump: addr: ffff800011c53bc8 paddr: eb453bc8 cnt: 4>
read_netdump: addr: ffff800011c53bc8 paddr: eb453bc8 cnt: 4 offset: 1c73bc8
irq_stack_ptr:
type: 1, TYPE_CODE_PTR
target_typecode: 8, TYPE_CODE_INT
target_length: 8
length: 8
GNU_GET_DATATYPE[thread_union]: returned via gdb_error_hook
<readmem: ffff000b779c0050, KVADDR, "IRQ stack pointer", 8, (ROE), 3a37bea0>
<read_kdump: addr: ffff000b779c0050 paddr: fff1000bf79c0050 cnt: 8>
read_netdump: READ_ERROR: offset not found for paddr: fff1000bf79c0050
crash: read error: kernel virtual address: ffff000b779c0050 type: "IRQ
stack pointer"
<readmem: ffff000b77a60050, KVADDR, "IRQ stack pointer", 8, (ROE), 3a37bea8>
<read_kdump: addr: ffff000b77a60050 paddr: fff1000bf7a60050 cnt: 8>
read_netdump: READ_ERROR: offset not found for paddr: fff1000bf7a60050
...
Apparently, for a normal system, the 'paddr: fff1000bf79c0050' is
unreasonable.
This bug connects with kernel commit 7bc1a0f9e176 ("arm64: mm: use
single quantity to represent the PA to VA translation"), which removes
physvirt_offset kernel variable and change the PTOV()/VTOP() formulas.
Implement switchable PTOV()/VTOP() to cope with different kernel
version.
Signed-off-by: Pingfan Liu <[email protected]>
Cc: HAGIO KAZUHITO <[email protected]>
Cc: Lianbo Jiang <[email protected]>
Cc: Bhupesh Sharma <[email protected]>
To: [email protected]
---
arm64.c | 40 ++++++++++++++++++++++++++++++++++++----
defs.h | 9 ++++-----
2 files changed, 40 insertions(+), 9 deletions(-)
diff --git a/arm64.c b/arm64.c
index b04369f..75fe5d6 100644
--- a/arm64.c
+++ b/arm64.c
@@ -994,8 +994,6 @@ arm64_calc_physvirt_offset(void)
ulong physvirt_offset;
struct syment *sp;
- ms->physvirt_offset = ms->phys_offset - ms->page_offset;
-
if ((sp = kernel_symbol_search("physvirt_offset")) &&
machdep->machspec->kimage_voffset) {
if (READMEM(pc->mfd, &physvirt_offset, sizeof(physvirt_offset),
@@ -1003,8 +1001,13 @@ arm64_calc_physvirt_offset(void)
machdep->machspec->kimage_voffset) > 0) {
machdep->flags |= HAS_PHYSVIRT_OFFSET;
ms->physvirt_offset = physvirt_offset;
+ return;
}
}
+
+ /* Useless if no symbol 'physvirt_offset', just keep semantics */
+ ms->physvirt_offset = ms->phys_offset - ms->page_offset;
+
}
static void
@@ -1051,6 +1054,7 @@ arm64_calc_phys_offset(void)
if (READMEM(pc->mfd, &phys_offset, sizeof(phys_offset),
vaddr, paddr) > 0) {
ms->phys_offset = phys_offset;
+
return;
}
}
@@ -1178,6 +1182,24 @@ arm64_init_kernel_pgd(void)
vt->kernel_pgd[i] = value;
}
+ulong arm64_PTOV(ulong paddr)
+{
+ ulong v;
+ struct machine_specific *ms = machdep->machspec;
+
+ /*
+ * Either older kernel before kernel has 'physvirt_offset' or newer
kernel which
+ * removes 'physvirt_offset' has the same formula:
+ * #define __phys_to_virt(x) ((unsigned long)((x) - PHYS_OFFSET) |
PAGE_OFFSET)
+ */
+ if (!(machdep->flags & HAS_PHYSVIRT_OFFSET))
+ v = (paddr - ms->phys_offset) | PAGE_OFFSET;
+ else
+ v = paddr - ms->physvirt_offset;
+
+ return v;
+}
+
ulong
arm64_VTOP(ulong addr)
{
@@ -1188,8 +1210,18 @@ arm64_VTOP(ulong addr)
return addr - machdep->machspec->kimage_voffset;
}
- if (addr >= machdep->machspec->page_offset)
- return addr + machdep->machspec->physvirt_offset;
+ if (addr >= machdep->machspec->page_offset) {
+ if (machdep->flags & HAS_PHYSVIRT_OFFSET) {
+ return addr +
machdep->machspec->physvirt_offset;
+ } else {
+ /*
+ * Either older kernel before kernel has
'physvirt_offset' or newer kernel which
+ * removes 'physvirt_offset' has the same
formula:
+ * #define __lm_to_phys(addr) (((addr) &
~PAGE_OFFSET) + PHYS_OFFSET)
+ */
+ return (addr & ~ PAGE_OFFSET) +
machdep->machspec->phys_offset;
+ }
+ }
else if (machdep->machspec->kimage_voffset)
return addr - machdep->machspec->kimage_voffset;
else /* no randomness */
diff --git a/defs.h b/defs.h
index 4fe6562..5faa936 100644
--- a/defs.h
+++ b/defs.h
@@ -3091,11 +3091,6 @@ typedef u64 pte_t;
#define _64BIT_
#define MACHINE_TYPE "ARM64"
-#define PTOV(X) \
- ((unsigned long)(X) - (machdep->machspec->physvirt_offset))
-
-#define VTOP(X) arm64_VTOP((ulong)(X))
-
#define USERSPACE_TOP (machdep->machspec->userspace_top)
#define PAGE_OFFSET (machdep->machspec->page_offset)
#define VMALLOC_START (machdep->machspec->vmalloc_start_addr)
@@ -3105,6 +3100,9 @@ typedef u64 pte_t;
#define MODULES_VADDR (machdep->machspec->modules_vaddr)
#define MODULES_END (machdep->machspec->modules_end)
+#define PTOV(X) arm64_PTOV((ulong)(X))
+#define VTOP(X) arm64_VTOP((ulong)(X))
+
#define IS_VMALLOC_ADDR(X) arm64_IS_VMALLOC_ADDR((ulong)(X))
#define PAGEBASE(X) (((ulong)(X)) & (ulong)machdep->pagemask)
@@ -5909,6 +5907,7 @@ void unwind_backtrace(struct bt_info *);
void arm64_init(int);
void arm64_dump_machdep_table(ulong);
ulong arm64_VTOP(ulong);
+ulong arm64_PTOV(ulong);
int arm64_IS_VMALLOC_ADDR(ulong);
ulong arm64_swp_type(ulong);
ulong arm64_swp_offset(ulong);
--
2.29.2
--
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