Re: [PATCH V2 2/2] Documentation: kdump: describe VMCOREINFO export for RISCV64

From: Conor Dooley <conor.dooley@microchip.com>
To: Xianting Tian <xianting.tian@linux.alibaba.com>
Cc: Conor Dooley <conor@kernel.org>, <paul.walmsley@sifive.com>,
	<palmer@dabbelt.com>, <aou@eecs.berkeley.edu>,
	<anup@brainfault.org>, <heiko@sntech.de>, <guoren@kernel.org>,
	<mick@ics.forth.gr>, <alexandre.ghiti@canonical.com>,
	<bhe@redhat.com>, <vgoyal@redhat.com>, <dyoung@redhat.com>,
	<corbet@lwn.net>, <bagasdotme@gmail.com>,
	<kexec@lists.infradead.org>, <linux-doc@vger.kernel.org>,
	<linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
	<crash-utility@redhat.com>, <heinrich.schuchardt@canonical.com>,
	<k-hagio-ab@nec.com>, <hschauhan@nulltrace.org>,
	<yixun.lan@gmail.com>
Subject: Re: [PATCH V2 2/2] Documentation: kdump: describe VMCOREINFO export for RISCV64
Date: Tue, 18 Oct 2022 08:13:01 +0100	[thread overview]
Message-ID: <Y05R/WK3cSEmwmYx@wendy> (raw)
In-Reply-To: <a4d2dc7e-7f45-00b7-6c31-cc934ba9c1f5@linux.alibaba.com>

On Tue, Oct 18, 2022 at 10:41:50AM +0800, Xianting Tian wrote:
> 
> 在 2022/10/18 上午3:40, Conor Dooley 写道:
> > On Fri, Oct 14, 2022 at 09:41:39PM +0800, Xianting Tian wrote:
> > > The following interrelated definitions and ranges are needed by the kdump
> > > crash tool, they are exported by "arch/riscv/kernel/crash_core.c":
> > >      VA_BITS,
> > >      PAGE_OFFSET,
> > >      phys_ram_base,
> > >      MODULES_VADDR ~ MODULES_END,
> > >      VMALLOC_START ~ VMALLOC_END,
> > >      VMEMMAP_START ~ VMEMMAP_END,
> > >      KASAN_SHADOW_START ~ KASAN_SHADOW_END,
> > >      KERNEL_LINK_ADDR ~ ADDRESS_SPACE_END
> > > 
> > > Document these RISCV64 exports above.
> > > 
> > > Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
> > > ---
> > >   .../admin-guide/kdump/vmcoreinfo.rst          | 30 +++++++++++++++++++
> > >   1 file changed, 30 insertions(+)
> > > 
> > > diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
> > > index 6726f439958c..8e2e164cf3db 100644
> > > --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
> > > +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
> > > @@ -595,3 +595,33 @@ X2TLB
> > >   -----
> > >   Indicates whether the crashed kernel enabled SH extended mode.
> > > +
> > > +RISCV64
> > > +=======
> > > +
> > > +VA_BITS
> > > +-------
> > > +
> > > +The maximum number of bits for virtual addresses. Used to compute the
> > > +virtual memory ranges.
> > > +
> > > +PAGE_OFFSET
> > > +-----------
> > > +
> > > +Indicates the virtual kernel start address of direct-mapped RAM region.
> > Apologies for not seeing this sooner, but should there not be a "the"
> > prior to "direct-mapped"?
> will fix in v3
> > 
> > > +
> > > +phys_ram_base
> > > +-------------
> > > +
> > > +Indicates the start physical RAM address.
> > > +
> > > +MODULES_VADDR|MODULES_END|VMALLOC_START|VMALLOC_END|VMEMMAP_START|VMEMMAP_END|KASAN_SHADOW_START|KASAN_SHADOW_END|KERNEL_LINK_ADDR|ADDRESS_SPACE_END
> > > +----------------------------------------------------------------------------------------------------------------------------------------------------
> > > +
> > > +Used to get the correct ranges:
> > > +
> > > +  * MODULES_VADDR ~ MODULES_END : Kernel module space.
> > > +  * VMALLOC_START ~ VMALLOC_END : vmalloc() / ioremap() space.
> > > +  * VMEMMAP_START ~ VMEMMAP_END : vmemmap region, used for struct page array.
> > Since I'm in pedant mode, it does look a little odd that you're using
> > region for vmemmap but space for the others but idc that much.
> 
> Sorry, I didn't get your point :(
> 
> it contains vmemmap area with reference wth arch/arm64/kernel/crash_core.c.

The wording is different, vmemmap uses space and the others use region.
Not a big deal.

> 
> > 
> > Thanks,
> > Conor.
> > 
> > > +  * KASAN_SHADOW_START ~ KASAN_SHADOW_END : kasan shadow space.
> > > +  * KERNEL_LINK_ADDR ~ ADDRESS_SPACE_END : Kernel link and BPF space.
> > > -- 
> > > 2.17.1
> > > 
> > > 
> 
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