| Message ID | 1575057559-25496-6-git-send-email-bhsharma@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Append new variables to vmcoreinfo (TCR_EL1.T1SZ for arm64 and MAX_PHYSMEM_BITS for all archs) | expand |
Hi Bhupesh, On 29/11/2019 19:59, Bhupesh Sharma wrote: > Add documentation for TCR_EL1.T1SZ variable being added to > vmcoreinfo. > > It indicates the size offset of the memory region addressed by TTBR1_EL1 > and hence can be used for determining the vabits_actual value. used for determining random-internal-kernel-variable, that might not exist tomorrow. Could you describe how this is useful/necessary if a debugger wants to walk the page tables from the core file? I think this is a better argument. Wouldn't the documentation be better as part of the patch that adds the export? (... unless these have to go via different trees? ..) > diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst > index 447b64314f56..f9349f9d3345 100644 > --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst > +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst > @@ -398,6 +398,12 @@ KERNELOFFSET > The kernel randomization offset. Used to compute the page offset. If > KASLR is disabled, this value is zero. > > +TCR_EL1.T1SZ > +------------ > + > +Indicates the size offset of the memory region addressed by TTBR1_EL1 > +and hence can be used for determining the vabits_actual value. 'vabits_actual' may not exist when the next person comes to read this documentation (its going to rot really quickly). I think the first half of this text is enough to say what this is for. You should include words to the effect that its the hardware value that goes with swapper_pg_dir. You may want to point readers to the arm-arm for more details on what the value means. Thanks, James
Hi James, On 12/12/2019 04:02 PM, James Morse wrote: > Hi Bhupesh, I am sorry this review mail skipped my attention due to holidays and focus on other urgent issues. > On 29/11/2019 19:59, Bhupesh Sharma wrote: >> Add documentation for TCR_EL1.T1SZ variable being added to >> vmcoreinfo. >> >> It indicates the size offset of the memory region addressed by TTBR1_EL1 > >> and hence can be used for determining the vabits_actual value. > > used for determining random-internal-kernel-variable, that might not exist tomorrow. > > Could you describe how this is useful/necessary if a debugger wants to walk the page > tables from the core file? I think this is a better argument. > > Wouldn't the documentation be better as part of the patch that adds the export? > (... unless these have to go via different trees? ..) Ok, will fix the same in v6 version. >> diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst >> index 447b64314f56..f9349f9d3345 100644 >> --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst >> +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst >> @@ -398,6 +398,12 @@ KERNELOFFSET >> The kernel randomization offset. Used to compute the page offset. If >> KASLR is disabled, this value is zero. >> >> +TCR_EL1.T1SZ >> +------------ >> + >> +Indicates the size offset of the memory region addressed by TTBR1_EL1 > >> +and hence can be used for determining the vabits_actual value. > > 'vabits_actual' may not exist when the next person comes to read this documentation (its > going to rot really quickly). > > I think the first half of this text is enough to say what this is for. You should include > words to the effect that its the hardware value that goes with swapper_pg_dir. You may > want to point readers to the arm-arm for more details on what the value means. Ok, got it. Fixed this in v6, which should be on its way shortly. Thanks, Bhupesh
Hi Bhupesh, Would be great to get this patch series upstreamed? On 2019-12-25 10:49 a.m., Bhupesh Sharma wrote: > Hi James, > > On 12/12/2019 04:02 PM, James Morse wrote: >> Hi Bhupesh, > > I am sorry this review mail skipped my attention due to holidays and > focus on other urgent issues. > >> On 29/11/2019 19:59, Bhupesh Sharma wrote: >>> Add documentation for TCR_EL1.T1SZ variable being added to >>> vmcoreinfo. >>> >>> It indicates the size offset of the memory region addressed by >>> TTBR1_EL1 >> >>> and hence can be used for determining the vabits_actual value. >> >> used for determining random-internal-kernel-variable, that might not >> exist tomorrow. >> >> Could you describe how this is useful/necessary if a debugger wants >> to walk the page >> tables from the core file? I think this is a better argument. >> >> Wouldn't the documentation be better as part of the patch that adds >> the export? >> (... unless these have to go via different trees? ..) > > Ok, will fix the same in v6 version. > >>> diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst >>> b/Documentation/admin-guide/kdump/vmcoreinfo.rst >>> index 447b64314f56..f9349f9d3345 100644 >>> --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst >>> +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst >>> @@ -398,6 +398,12 @@ KERNELOFFSET >>> The kernel randomization offset. Used to compute the page offset. If >>> KASLR is disabled, this value is zero. >>> +TCR_EL1.T1SZ >>> +------------ >>> + >>> +Indicates the size offset of the memory region addressed by TTBR1_EL1 >> >>> +and hence can be used for determining the vabits_actual value. >> >> 'vabits_actual' may not exist when the next person comes to read this >> documentation (its >> going to rot really quickly). >> >> I think the first half of this text is enough to say what this is >> for. You should include >> words to the effect that its the hardware value that goes with >> swapper_pg_dir. You may >> want to point readers to the arm-arm for more details on what the >> value means. > > Ok, got it. Fixed this in v6, which should be on its way shortly. I can't seem to find v6? > > Thanks, > Bhupesh > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
Hello Scott, On Thu, Jun 4, 2020 at 12:17 AM Scott Branden <scott.branden@broadcom.com> wrote: > > Hi Bhupesh, > > Would be great to get this patch series upstreamed? > > On 2019-12-25 10:49 a.m., Bhupesh Sharma wrote: > > Hi James, > > > > On 12/12/2019 04:02 PM, James Morse wrote: > >> Hi Bhupesh, > > > > I am sorry this review mail skipped my attention due to holidays and > > focus on other urgent issues. > > > >> On 29/11/2019 19:59, Bhupesh Sharma wrote: > >>> Add documentation for TCR_EL1.T1SZ variable being added to > >>> vmcoreinfo. > >>> > >>> It indicates the size offset of the memory region addressed by > >>> TTBR1_EL1 > >> > >>> and hence can be used for determining the vabits_actual value. > >> > >> used for determining random-internal-kernel-variable, that might not > >> exist tomorrow. > >> > >> Could you describe how this is useful/necessary if a debugger wants > >> to walk the page > >> tables from the core file? I think this is a better argument. > >> > >> Wouldn't the documentation be better as part of the patch that adds > >> the export? > >> (... unless these have to go via different trees? ..) > > > > Ok, will fix the same in v6 version. > > > >>> diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst > >>> b/Documentation/admin-guide/kdump/vmcoreinfo.rst > >>> index 447b64314f56..f9349f9d3345 100644 > >>> --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst > >>> +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst > >>> @@ -398,6 +398,12 @@ KERNELOFFSET > >>> The kernel randomization offset. Used to compute the page offset. If > >>> KASLR is disabled, this value is zero. > >>> +TCR_EL1.T1SZ > >>> +------------ > >>> + > >>> +Indicates the size offset of the memory region addressed by TTBR1_EL1 > >> > >>> +and hence can be used for determining the vabits_actual value. > >> > >> 'vabits_actual' may not exist when the next person comes to read this > >> documentation (its > >> going to rot really quickly). > >> > >> I think the first half of this text is enough to say what this is > >> for. You should include > >> words to the effect that its the hardware value that goes with > >> swapper_pg_dir. You may > >> want to point readers to the arm-arm for more details on what the > >> value means. > > > > Ok, got it. Fixed this in v6, which should be on its way shortly. > I can't seem to find v6? Oops. I remember Cc'ing you to the v6 patchset (may be my email client messed up), anyways here is the v6 patchset for your reference: <http://lists.infradead.org/pipermail/kexec/2020-May/025095.html> Do share your review/test comments on the same. Thanks, Bhupesh
diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst index 447b64314f56..f9349f9d3345 100644 --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst @@ -398,6 +398,12 @@ KERNELOFFSET The kernel randomization offset. Used to compute the page offset. If KASLR is disabled, this value is zero. +TCR_EL1.T1SZ +------------ + +Indicates the size offset of the memory region addressed by TTBR1_EL1 +and hence can be used for determining the vabits_actual value. + arm ===
Add documentation for TCR_EL1.T1SZ variable being added to vmcoreinfo. It indicates the size offset of the memory region addressed by TTBR1_EL1 and hence can be used for determining the vabits_actual value. Cc: James Morse <james.morse@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Steve Capper <steve.capper@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Dave Anderson <anderson@redhat.com> Cc: Kazuhito Hagio <k-hagio@ab.jp.nec.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org Signed-off-by: Bhupesh Sharma <bhsharma@redhat.com> --- Documentation/admin-guide/kdump/vmcoreinfo.rst | 6 ++++++ 1 file changed, 6 insertions(+)