Re: [Crash-utility] [PATCHv8 1/4] crash-utility/arm64: introduce a dedicated field to record the mem layout changes
-----Original Message-----
At present, we have the following important changes for arm64 memory
layout:
-1. redesigned ARM64 kernel virtual memory layout and associated KASLR
support that was introduced in Linux 4.6. And NEW_VMEMMAP is used to
flag it.
-2. memory layout flipped just right before introducing 52-bits kernel.
-3. introducing of vabits_actual and phyvirt_offset in kernel
-4. removing phyvirt_offset.
These changes have effects on PTOV()/VTOP() formula. So introducing a
dedicate field mmlayout_flags to record it.
Among above, 2 and 3 are introduced closely, and are not distinguished
in current implement. And this patch also keep this practice and use
vabits_actual as a hint to flag mem flipped.
Signed-off-by: Pingfan Liu <piliu(a)redhat.com>
Cc: HAGIO KAZUHITO <k-hagio-ab(a)nec.com>
Cc: Lianbo Jiang <lijiang(a)redhat.com>
Cc: Bhupesh Sharma <bhupesh.sharma(a)linaro.org>
To: crash-utility(a)redhat.com
---
arm64.c | 11 +++++++++++
defs.h | 3 +++
2 files changed, 14 insertions(+)
diff --git a/arm64.c b/arm64.c
index 8934961..98138b2 100644
--- a/arm64.c
+++ b/arm64.c
@@ -560,6 +560,10 @@ 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);
@@ -994,6 +998,7 @@ 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;
}
}
@@ -3923,6 +3928,7 @@ arm64_calc_VA_BITS(void)
if (kernel_symbol_exists("vabits_actual")) {
if (pc->flags & PROC_KCORE) {
vabits_actual = symbol_value_from_proc_kallsyms("vabits_actual");
+ machdep->flags |= FLIPPED_VM;
if ((vabits_actual != BADVAL) && (READMEM(pc->mfd, &value,
sizeof(ulong),
vabits_actual, KCORE_USE_VADDR) > 0)) {
if (CRASHDEBUG(1))
@@ -3953,6 +3959,11 @@ arm64_calc_VA_BITS(void)
machdep->machspec->VA_BITS_ACTUAL = value;
machdep->machspec->VA_BITS = value;
machdep->machspec->VA_START =
_VA_START(machdep->machspec->VA_BITS_ACTUAL);
+ /*
+ * 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;
} else if (machdep->machspec->VA_BITS_ACTUAL) {
This "else if" is for "--machdep vabits_actual=" option for Linux 5.4
and
later not having the NUMBER(TCR_EL1_T1SZ), those also should have flipped VM.
So we can simply add the following at the beginning or the end of the
"if vabits_actual exists" block like this?
--- a/arm64.c
+++ b/arm64.c
@@ -3960,6 +3960,7 @@ arm64_calc_VA_BITS(void)
error(FATAL, "cannot determine
VA_BITS_ACTUAL\n");
}
+ machdep->flags |= FLIPPED_VM;
return;
}
Thanks,
Kazu
machdep->machspec->VA_BITS =
machdep->machspec->VA_BITS_ACTUAL;
machdep->machspec->VA_START =
_VA_START(machdep->machspec->VA_BITS_ACTUAL);
diff --git a/defs.h b/defs.h
index 396d61a..24d41e7 100644
--- a/defs.h
+++ b/defs.h
@@ -3208,6 +3208,8 @@ 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
@@ -3290,6 +3292,7 @@ struct arm64_pt_regs {
struct machine_specific {
ulong flags;
ulong userspace_top;
+ ulong mmlayout_flags;
ulong page_offset;
ulong vmalloc_start_addr;
ulong vmalloc_end;
--
2.29.2