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arm64: fix memory layout 

Resolves: bz1930502 bz1895682
Upstream: crash-utility
Conflict: None

The series includes:
  f53b73e arm64: implement switchable PTOV()/VTOP() for kernels >= 5.10
  bf1379a arm64: use dedicated bits to record the VA space layout changes
  167d37e arm64: assign page_offset with VA_BITS kernel configuration value
  5719afc arm64: rename ARM64_PAGE_OFFSET_ACTUAL to ARM64_FLIP_PAGE_OFFSET_ACTUAL

Signed-off-by: Pingfan Liu <piliu@redhat.com>
This commit is contained in:
Pingfan Liu 2021-07-06 11:11:02 +08:00
parent ccbee1fd3e
commit cb7ba21ef8
5 changed files with 373 additions and 0 deletions
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61
0001-arm64-rename-ARM64_PAGE_OFFSET_ACTUAL-to-ARM64_FLIP_.patch Normal file
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@ -0,0 +1,61 @@
From 5719afc7a40868418405a87a2711088556e68a3b Mon Sep 17 00:00:00 2001
From: Pingfan Liu <piliu@redhat.com>
Date: Fri, 2 Jul 2021 10:14:21 +0800
Subject: [PATCH 1/4] arm64: rename ARM64_PAGE_OFFSET_ACTUAL to
ARM64_FLIP_PAGE_OFFSET_ACTUAL
Reflect the flipped layout of kernel VA, which is introduced by
kernel commit 14c127c957c1 ("arm64: mm: Flip kernel VA space").
Signed-off-by: Pingfan Liu <piliu@redhat.com>
---
arm64.c | 10 ++++++----
defs.h | 3 ++-
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/arm64.c b/arm64.c
index 8934961..9fe1a4a 100644
--- a/arm64.c
+++ b/arm64.c
@@ -217,10 +217,12 @@ arm64_init(int when)
arm64_calc_VA_BITS();
arm64_calc_KERNELPACMASK();
ms = machdep->machspec;
+
+ /* vabits_actual introduced after mm flip, so it should be flipped layout */
if (ms->VA_BITS_ACTUAL) {
- ms->page_offset = ARM64_PAGE_OFFSET_ACTUAL;
- machdep->identity_map_base = ARM64_PAGE_OFFSET_ACTUAL;
- machdep->kvbase = ARM64_PAGE_OFFSET_ACTUAL;
+ ms->page_offset = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
+ machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
+ machdep->kvbase = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
ms->userspace_top = ARM64_USERSPACE_TOP_ACTUAL;
} else {
ms->page_offset = ARM64_PAGE_OFFSET;
@@ -401,7 +403,7 @@ arm64_init(int when)
fprintf(fp, "CONFIG_ARM64_VA_BITS: %ld\n", ms->CONFIG_ARM64_VA_BITS);
fprintf(fp, " VA_BITS_ACTUAL: %ld\n", ms->VA_BITS_ACTUAL);
fprintf(fp, "(calculated) VA_BITS: %ld\n", ms->VA_BITS);
- fprintf(fp, " PAGE_OFFSET: %lx\n", ARM64_PAGE_OFFSET_ACTUAL);
+ fprintf(fp, " PAGE_OFFSET: %lx\n", ARM64_FLIP_PAGE_OFFSET_ACTUAL);
fprintf(fp, " VA_START: %lx\n", ms->VA_START);
fprintf(fp, " modules: %lx - %lx\n", ms->modules_vaddr, ms->modules_end);
fprintf(fp, " vmalloc: %lx - %lx\n", ms->vmalloc_start_addr, ms->vmalloc_end);
diff --git a/defs.h b/defs.h
index 5d32954..eb7ce6a 100644
--- a/defs.h
+++ b/defs.h
@@ -3233,7 +3233,8 @@ typedef signed int s32;
#define ARM64_PAGE_OFFSET ((0xffffffffffffffffUL) \
<< (machdep->machspec->VA_BITS - 1))
-#define ARM64_PAGE_OFFSET_ACTUAL ((0xffffffffffffffffUL) \
+/* kernels >= v5.4 the kernel VA space is flipped */
+#define ARM64_FLIP_PAGE_OFFSET_ACTUAL ((0xffffffffffffffffUL) \
- ((1UL) << machdep->machspec->VA_BITS_ACTUAL) + 1)
#define ARM64_USERSPACE_TOP ((1UL) << machdep->machspec->VA_BITS)
--
2.29.2

56
0002-arm64-assign-page_offset-with-VA_BITS-kernel-configu.patch Normal file
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@ -0,0 +1,56 @@
From 167d37e347fe35c6f7db826e8539e192c4375564 Mon Sep 17 00:00:00 2001
From: Pingfan Liu <piliu@redhat.com>
Date: Fri, 2 Jul 2021 10:14:22 +0800
Subject: [PATCH 2/4] arm64: assign page_offset with VA_BITS kernel
configuration value
On RHEL9, crash hits a bug when executing "crash /proc/kcore":
seek error: kernel virtual address: ffff6a0f3fff0000 type: "pmd page"
The kernel virtual address does not vary with vabits_actual, instead,
is determined by configuration value. But crash does not observe this
fact.
Since vabits_actual related kernel commit is introduced after arm64
mm layout flip commit, so changes are safe under the condition if
(ms->VA_BITS_ACTUAL), and keep the else branch untouched.
Signed-off-by: Pingfan Liu <piliu@redhat.com>
---
arm64.c | 7 ++++---
defs.h | 1 +
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/arm64.c b/arm64.c
index 9fe1a4a..149db36 100644
--- a/arm64.c
+++ b/arm64.c
@@ -220,9 +220,10 @@ arm64_init(int when)
/* vabits_actual introduced after mm flip, so it should be flipped layout */
if (ms->VA_BITS_ACTUAL) {
- ms->page_offset = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
- machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
- machdep->kvbase = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
+ ms->page_offset = ARM64_FLIP_PAGE_OFFSET;
+ /* useless on arm64 */
+ machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET;
+ machdep->kvbase = ARM64_FLIP_PAGE_OFFSET;
ms->userspace_top = ARM64_USERSPACE_TOP_ACTUAL;
} else {
ms->page_offset = ARM64_PAGE_OFFSET;
diff --git a/defs.h b/defs.h
index eb7ce6a..b7b20af 100644
--- a/defs.h
+++ b/defs.h
@@ -3234,6 +3234,7 @@ typedef signed int s32;
#define ARM64_PAGE_OFFSET ((0xffffffffffffffffUL) \
<< (machdep->machspec->VA_BITS - 1))
/* kernels >= v5.4 the kernel VA space is flipped */
+#define ARM64_FLIP_PAGE_OFFSET (-(1UL) << machdep->machspec->CONFIG_ARM64_VA_BITS)
#define ARM64_FLIP_PAGE_OFFSET_ACTUAL ((0xffffffffffffffffUL) \
- ((1UL) << machdep->machspec->VA_BITS_ACTUAL) + 1)
--
2.29.2

83
0003-arm64-use-dedicated-bits-to-record-the-VA-space-layo.patch Normal file
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@ -0,0 +1,83 @@
From bf1379a8b6ff8d6a8fa12978f7194f15f85c4380 Mon Sep 17 00:00:00 2001
From: Pingfan Liu <piliu@redhat.com>
Date: Fri, 2 Jul 2021 10:14:23 +0800
Subject: [PATCH 3/4] arm64: use dedicated bits to record the VA space layout
changes
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>
---
arm64.c | 10 ++++++++++
defs.h | 2 ++
2 files changed, 12 insertions(+)
diff --git a/arm64.c b/arm64.c
index 149db36..b04369f 100644
--- a/arm64.c
+++ b/arm64.c
@@ -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;
}
diff --git a/defs.h b/defs.h
index b7b20af..eca145c 100644
--- a/defs.h
+++ b/defs.h
@@ -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
--
2.29.2

165
0004-arm64-implement-switchable-PTOV-VTOP-for-kernels-5.1.patch Normal file
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@ -0,0 +1,165 @@
From f53b73e8380bca054cebd2b61ff118c46609429b Mon Sep 17 00:00:00 2001
From: Pingfan Liu <piliu@redhat.com>
Date: Fri, 2 Jul 2021 10:14:24 +0800
Subject: [PATCH 4/4] arm64: implement switchable PTOV()/VTOP() for kernels >=
5.10
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"
...
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 removed
physvirt_offset kernel variable and changed the PTOV()/VTOP() formulas.
Implement switchable PTOV()/VTOP() to cope with different kernel
version.
Signed-off-by: Pingfan Liu <piliu@redhat.com>
---
arm64.c | 37 +++++++++++++++++++++++++++++++++----
defs.h | 9 ++++-----
2 files changed, 37 insertions(+), 9 deletions(-)
diff --git a/arm64.c b/arm64.c
index b04369f..d73d5c5 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 +1182,21 @@ arm64_init_kernel_pgd(void)
vt->kernel_pgd[i] = value;
}
+ulong arm64_PTOV(ulong paddr)
+{
+ 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))
+ return (paddr - ms->phys_offset) | PAGE_OFFSET;
+ else
+ return paddr - ms->physvirt_offset;
+}
+
ulong
arm64_VTOP(ulong addr)
{
@@ -1188,8 +1207,18 @@ 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 eca145c..c91177a 100644
--- a/defs.h
+++ b/defs.h
@@ -3092,11 +3092,6 @@ 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)
@@ -3106,6 +3101,9 @@ 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)
@@ -5910,6 +5908,7 @@ 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

8
crash.spec
View File

@ -21,6 +21,10 @@ Patch0: lzo_snappy.patch
Patch1: 0001-Fix-for-kmem-s-S-option-on-Linux-5.7-and-later-kerne.patch
Patch2: 0001-memory-Add-support-for-SECTION_TAINT_ZONE_DEVICE-fla.patch
Patch3: 0002-memory-Fix-for-kmem-n-option-to-display-NID-correctl.patch
Patch4: 0001-arm64-rename-ARM64_PAGE_OFFSET_ACTUAL-to-ARM64_FLIP_.patch
Patch5: 0002-arm64-assign-page_offset-with-VA_BITS-kernel-configu.patch
Patch6: 0003-arm64-use-dedicated-bits-to-record-the-VA-space-layo.patch
Patch7: 0004-arm64-implement-switchable-PTOV-VTOP-for-kernels-5.1.patch
%description
The core analysis suite is a self-contained tool that can be used to
@ -44,6 +48,10 @@ offered by Mission Critical Linux, or the LKCD kernel patch.
%patch1 -p1
%patch2 -p1
%patch3 -p1
%patch4 -p1
%patch5 -p1
%patch6 -p1
%patch7 -p1
%build
# This package has an internal copy of GDB which has broken configure code for