Re: [Crash-utility] [PATCH] arm64 : assign page_offset and kvbase based on VA_BITS passed

On Thu, Oct 14, 2021 at 11:17 AM HAGIO KAZUHITO(萩尾　一仁) <k-hagio-ab(a)nec.com&gt; wrote: > > Hi Ankur, > > -----Original Message----- > > >> assign page_offset and kvbase based on VA_BITS passed > > >> > > > > >Thank you for the patch, Ankur. > > >Can you help to describe the reason in detail? And what happened? > > > > > > > > Hi Lianbo, Raw ramdump without vmcoreinfo doesn't work here. > > read_vmcoreinfo("NUMBER(BA_BITS)") will not work on raw ramdump. > > getting below error > > Thank you for the information, Ankur. > > crash_64: vmlinux and /var/tmp/ramdump_elf_XUtCMT do not match! > > Usage: > > crash [OPTION]... NAMELIST MEMORY-IMAGE[@address <https://github.com/address> ] (dumpfile form) > > crash [OPTION]... [NAMELIST] (live system form) > > Enter "crash_64 -h" for details. > > > > Recent change https://github.com/crash-utility/crash/commit/167d37e347fe35c6f7db826e853... is > > causing this issue, before this change VA_BITS_ACTUAL was used which is passed from cmd line. > > ok, I see, but I'm not sure why your patch uses the (pc->flags2 & SNAP) condition. This seems not very reasonable, the SNAP flag has a specific use. > The calculation used VA_BITS_ACTUAL (== VA_BITS for ramdump) before the change, > so how about the following patch? >./crash > diff --git a/arm64.c b/arm64.c > index 7069312671cf..da78acbb013f 100644 > --- a/arm64.c > +++ b/arm64.c > @@ -4031,6 +4031,9 @@ arm64_calc_VA_BITS(void) > error(FATAL, "cannot determine VA_BITS_ACTUAL\n"); > } > > + if (!machdep->machspec->CONFIG_ARM64_VA_BITS) /* guess */ > + machdep->machspec->CONFIG_ARM64_VA_BITS = machedp->machspec->VA_BITS; > + Looks good.

> /* > * The mm flip commit is introduced before 52-bits VA, which is before the > * commit to export NUMBER(TCR_EL1_T1SZ) > BTW: Can we also try to get its value from kernel config? But this relies on kernel config: CONFIG_IKCONFIG.

diff --git a/arm64.c b/arm64.c index 7069312..79f9929 100644 --- a/arm64.c +++ b/arm64.c @@ -3989,6 +3989,10 @@ arm64_calc_VA_BITS(void) value = atol(string); free(string); machdep->machspec->CONFIG_ARM64_VA_BITS = value; + } else if (kt->ikconfig_flags & IKCONFIG_AVAIL) { + if ((get_kernel_config("CONFIG_ARM64_VA_BITS", + &string)) == IKCONFIG_STR) + machdep->machspec->CONFIG_ARM64_VA_BITS = atol(string); } if (kernel_symbol_exists("vabits_actual")) { Thanks. Lianbo > > 3987 static void > > 3988 arm64_calc_VA_BITS(void) > > 3989 { > > 3990 int bitval; > > 3991 struct syment *sp; > > 3992 ulong vabits_actual, value; > > 3993 char *string; > > 3994 > > 3995 if ((string = pc->read_vmcoreinfo("NUMBER(VA_BITS)"))) { > > 3996 value = atol(string); > > 3997 free(string); > > 3998 machdep->machspec->CONFIG_ARM64_VA_BITS = value; > > 3999 } > > > > > > > > > > >Thanks. > > >Lianbo > > > > >> Change-Id: I525f3c7fd91e1f06e909c2f4c1749c44c068baea > > >> Signed-off-by: Ankur Bansal <er.ankurbansal(a)gmail.com <mailto:er.ankurbansal@gmail.com> > > > >> --- > > >> arm64.c | 15 +++++++++++---- > > >> 1 file changed, 11 insertions(+), 4 deletions(-) > > >> > > >> diff --git a/arm64.c b/arm64.c > > >> index 7069312..2dc77f7 100644 > > >> --- a/arm64.c > > >> +++ b/arm64.c > > >> @@ -220,10 +220,17 @@ arm64_init(int when) > > >> > > >> /* vabits_actual introduced after mm flip, so it should be flipped layout */ > > >> if (ms->VA_BITS_ACTUAL) { > > >> - ms->page_offset = ARM64_FLIP_PAGE_OFFSET; > > >> - /* useless on arm64 */ > > >> - machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET; > > >> - machdep->kvbase = ARM64_FLIP_PAGE_OFFSET; > > >> + if ((pc->flags2 & SNAP)) { > > >> + ms->page_offset = ARM64_FLIP_PAGE_OFFSET; > > >> + /* useless on arm64 */ > > >> + machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET; > > >> + machdep->kvbase = ARM64_FLIP_PAGE_OFFSET; > > >> + } > > >> + else{ > > >> + ms->page_offset = ARM64_FLIP_PAGE_OFFSET_ACTUAL; > > >> + machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET_ACTUAL; > > >> + machdep->kvbase = ARM64_FLIP_PAGE_OFFSET_ACTUAL; > > >> + } > > >> ms->userspace_top = ARM64_USERSPACE_TOP_ACTUAL; > > >> } else { > > >> ms->page_offset = ARM64_PAGE_OFFSET; > > >> -- > > >> 2.7.4 > > > > > > > > ------------------------------ > > > > -- > > Crash-utility mailing list > > Crash-utility(a)redhat.com <mailto:Crash-utility@redhat.com> > > https://listman.redhat.com/mailman/listinfo/crash-utility > > > > End of Crash-utility Digest, Vol 192, Issue 28 > > ********************************************** > > > > > > >