Re: [Crash-utility] [PATCHv7 1/4] crash-utility/arm64: introduce a dedicated field to record the mem layout changes

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&gt; Cc: HAGIO KAZUHITO <k-hagio-ab(a)nec.com&gt; Cc: Lianbo Jiang <lijiang(a)redhat.com&gt; Cc: Bhupesh Sharma <bhupesh.sharma(a)linaro.org&gt; To: crash-utility(a)redhat.com --- 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