-----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@xxxxxxxxxx>
> Cc: HAGIO KAZUHITO <k-hagio-ab@xxxxxxx>
> Cc: Lianbo Jiang <lijiang@xxxxxxxxxx>
> Cc: Bhupesh Sharma <bhupesh.sharma@xxxxxxxxxx>
> To: crash-utility@xxxxxxxxxx
> ---
> 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
--
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