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

Hi, Pingfan Thank you for the update. On Fri, Jun 4, 2021 at 10:39 AM Pingfan Liu <piliu(a)redhat.com&gt; wrote: > > 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); > > I tested this patchset with the old vmcore and the latest vmcore, and it passed. But I still have

some questions: > +/* arm64 kernel layout experiences changes, using these flags to distinguish them */ > +#define MMLAYOUT_FLAGS_FLIP 0x1 [1] For this micro, is it possible to check the "vabits_actual" and "TCR_EL1_T1SZ" in order to achieve a similar purpose? if (kernel_symbol_exists("vabits_actual") || ... read_vmcoreinfo("NUMBER(TCR_EL1_T1SZ)")) > +#define MMLAYOUT_FLAGS_HAS_PHYSVIRT_OFFSET 0x2 [2] For this one, can it be replaced with the following ways instead of adding a new micro definition? if (kernel_symbol_exists("physvirt_offset"))