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From: Nicholas Piggin <npiggin@gmail.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org,
	"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Subject: Re: [RFC PATCH 1/5] powerpc/64s/hash: convert SLB miss handlers to C
Date: Wed, 22 Aug 2018 13:17:10 +1000	[thread overview]
Message-ID: <20180822131710.5e2c45f5@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <87y3d0kyj9.fsf@concordia.ellerman.id.au>

On Tue, 21 Aug 2018 16:46:02 +1000
Michael Ellerman <mpe@ellerman.id.au> wrote:

> Nicholas Piggin <npiggin@gmail.com> writes:
> 
> > This patch moves SLB miss handlers completely to C, using the standard
> > exception handler macros to set up the stack and branch to C.
> >
> > This can be done because the segment containing the kernel stack is
> > always bolted, so accessing it with relocation on will not cause an
> > SLB exception.
> >
> > Arbitrary kernel memory may not be accessed when handling kernel space
> > SLB misses, so care should be taken there.  
> 
> We'll need to mark everything that's used in slb.c as notrace, otherwise
> 
> Probably we just need to mark the whole file as not traceable.

Yeah good point there. I'll do that. The whole file including things we
allow today? How do we do that, like this?

CFLAGS_REMOVE_slb.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)

Thanks,
Nick

  reply	other threads:[~2018-08-22  3:17 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-20  9:41 [RFC PATCH 0/5] rewriting SLB miss handler in C Nicholas Piggin
2018-08-20  9:41 ` [RFC PATCH 1/5] powerpc/64s/hash: convert SLB miss handlers to C Nicholas Piggin
2018-08-20 10:08   ` Nicholas Piggin
2018-08-21  6:46   ` Michael Ellerman
2018-08-22  3:17     ` Nicholas Piggin [this message]
2018-08-22 10:11       ` Michael Ellerman
2018-08-20  9:41 ` [RFC PATCH 2/5] powerpc/64s/hash: remove user SLB data from the paca Nicholas Piggin
2018-08-20  9:41 ` [RFC PATCH 3/5] powerpc/64s/hash: remove the first vmalloc segment from the bolted SLB Nicholas Piggin
2018-08-20  9:41 ` [RFC PATCH 4/5] powerpc/64s/hash: Add SLB allocation bitmaps Nicholas Piggin
2018-08-20  9:42 ` [RFC PATCH 5/5] powerpc/64s/hash: Add a SLB preload cache Nicholas Piggin

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