Re: [PATCH v7 06/27] x86, 64bit: early #PF handler set page table

From: H. Peter Anvin
Date: Mon Dec 24 2012 - 19:22:15 EST


On 12/20/2012 08:56 AM, Yinghai Lu wrote:

So in that case, kgdb is broken and will need to be fixed up. That
happens all the time with debugging tools.

If there is a way that we can make all parties happy, we really should
not break KGDB.

Please reconsider to stop #PF handler in x86_64_start_kernel. in that case
1. microcode update still can use #PF handler to find microcode in
ramdisk and use it.
2. kernel that is loaded above 4G, could set mapping in C instead of
set that in head_64.S
and use ioremap to access zero_page
3. KGDB still can call early_trap_init early before init_mem_mapping.


Yinghai, this is total and utter bullshit.

We should *fix* kgdb, not pave around it. I refuse to have kgdb be yet another Xen turning random kernel internals into ABIs.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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