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&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 | 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; }