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arm64: use dedicated bits to record the VA space layout changes

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arm64 memory layout experiences big changes due to the following kernel
commits in date descending order:
  5. 7bc1a0f9e176 arm64: mm: use single quantity to represent the PA to VA translation
  4. b6d00d47e81a arm64: mm: Introduce 52-bit Kernel VAs
  3. 5383cc6efed1 arm64: mm: Introduce vabits_actual
  2. 14c127c957c1 arm64: mm: Flip kernel VA space
  1. f80fb3a3d508 arm64: add support for kernel ASLR

For 1, crash has already used NEW_VMEMMAP to trace it.
For 2, crash lacks a flag to tag it and handle it differently.
For 3, two important kernel variables vabits_actual and physvirt_offset
are introduced.
For 4, since it comes immediately after 3, crash-utility does not need
to distinguish it.
For 5, kernel variable phyvirt_offset is removed

These changes have effects on PTOV()/VTOP() formula. So introducing
two bits HAS_PHYSVIRT_OFFSET and FLIPPED_VM as hint to apply different
formula.

Signed-off-by: Pingfan Liu <piliu@redhat.com>
This commit is contained in:
Pingfan Liu 2021-07-02 10:14:23 +08:00 committed by Kazuhito Hagio
parent 167d37e347
commit bf1379a8b6
2 changed files with 12 additions and 0 deletions
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10
arm64.c
View File

@ -563,6 +563,10 @@ arm64_dump_machdep_table(ulong arg)
fprintf(fp, "%sMACHDEP_BT_TEXT", others++ ? "|" : "");
if (machdep->flags & NEW_VMEMMAP)
fprintf(fp, "%sNEW_VMEMMAP", others++ ? "|" : "");
if (machdep->flags & FLIPPED_VM)
fprintf(fp, "%sFLIPPED_VM", others++ ? "|" : "");
if (machdep->flags & HAS_PHYSVIRT_OFFSET)
fprintf(fp, "%sHAS_PHYSVIRT_OFFSET", others++ ? "|" : "");
fprintf(fp, ")\n");
fprintf(fp, " kvbase: %lx\n", machdep->kvbase);
@ -997,6 +1001,7 @@ arm64_calc_physvirt_offset(void)
if (READMEM(pc->mfd, &physvirt_offset, sizeof(physvirt_offset),
sp->value, sp->value -
machdep->machspec->kimage_voffset) > 0) {
machdep->flags |= HAS_PHYSVIRT_OFFSET;
ms->physvirt_offset = physvirt_offset;
}
}
@ -3963,6 +3968,11 @@ arm64_calc_VA_BITS(void)
error(FATAL, "cannot determine VA_BITS_ACTUAL\n");
}
/*
* The mm flip commit is introduced before 52-bits VA, which is before the
* commit to export NUMBER(TCR_EL1_T1SZ)
*/
machdep->flags |= FLIPPED_VM;
return;
}

2
defs.h
View File

@ -3214,6 +3214,8 @@ typedef signed int s32;
#define NEW_VMEMMAP (0x80)
#define VM_L4_4K (0x100)
#define UNW_4_14 (0x200)
#define FLIPPED_VM (0x400)
#define HAS_PHYSVIRT_OFFSET (0x800)
/*
* Get kimage_voffset from /dev/crash