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 <[email protected]>
Cc: HAGIO KAZUHITO <[email protected]>
Cc: Lianbo Jiang <[email protected]>
Cc: Bhupesh Sharma <[email protected]>
To: [email protected]
---
arm64.c | 11 +++++++++++
defs.h | 1 +
2 files changed, 12 insertions(+)
diff --git a/arm64.c b/arm64.c
index 8934961..eb88ced 100644
--- a/arm64.c
+++ b/arm64.c
@@ -88,6 +88,10 @@ static int arm64_is_uvaddr(ulong, struct task_context *);
static void arm64_calc_KERNELPACMASK(void);
+/* arm64 kernel layout experiences changes, using these flags to distinguish
them */
+#define MMLAYOUT_FLAGS_FLIP 0x1
+#define MMLAYOUT_FLAGS_HAS_PHYSVIRT_OFFSET 0x2
+
/*
* Do all necessary machine-specific setup here. This is called several times
* during initialization.
@@ -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->machspec->mmlayout_flags |=
MMLAYOUT_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->machspec->mmlayout_flags |=
MMLAYOUT_FLAGS_FLIP;
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->machspec->mmlayout_flags |=
MMLAYOUT_FLAGS_FLIP;
} else if (machdep->machspec->VA_BITS_ACTUAL) {
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..22b3cbd 100644
--- a/defs.h
+++ b/defs.h
@@ -3290,6 +3290,7 @@ 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
--
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