Messages in this thread | | | Date | Tue, 15 Jun 2010 11:44:40 -0400 | From | Mathieu Desnoyers <> | Subject | Re: [PATCH 00/13] jump label v9 |
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* Jason Baron (jbaron@redhat.com) wrote: > On Mon, Jun 14, 2010 at 08:47:59PM -0700, David Miller wrote: > > Jason, I'm really at wits end about this patch set. To say > > that trying to test our your patches is frustrating for me > > so far would be an understatement. > > > > Nothing you ever post builds for me, not one patch set has > > built properly. > > > > I can also tell that you're just blindly making changes to the > > sparc bits and not trying to build test them at all: > > > > 1) Even though you created the jump_label_t, and made it properly > > a u32 on sparc, you left the assembler using ".xword" to > > record the entries. > > > > 2) The sparc "struct jump_label" still calls it's third member "name", > > it needs to be "key" or else the build breaks. > > > > 3) Eventhough the sparc JUMP_LABEL macro was fixed to have two args, > > the first arg was left as "tag" instead of being renamed to "key" > > and that name change propaged into the asm in the macro expansion. > > > > I took care of that locally to try and test this, but then I hit the > > current major problem which is that you're using things like > > text_poke_early() unconditionally, but that is an X86-only facility > > implemented by x86's alternative mechanism. > > > > Also, kernel/jump_label.c only gets the ERR_PTR() definitions > > indirectly on the x86 platform, it needs to include linux/err.h > > directly to make sure those things are available on every platform. > > > > You gave me the impression a few iterations ago that you were doing > > build testing on sparc64 using cross-compilers, or that you would > > start to do so. You're obviously not, could you please start doing so > > and let me know when you've at least build tested your jump-label > > patch series on sparc64 and at least one architecture that lacks > > jump-label support? > > > > Thanks. > > Hi David, > > Yes, I've tried to help re-write the sparc bits to the current api. > However, I did not test the sparc enabled jump-label bits, b/c I need an > updated cross compiler to do so (that has jump label support). However, I > certainly did build test the patches on powerpc, which lacks jump-label support, > so I know it builds on at least one architecture that lacks jump-label support > as you've mentioned. And I did this specifically, since you requested this > testing. > > I guess I was hoping we could work more collaboratively on the sparc > bits. A couple lines of code have fixed the issues that you've brought up. > Sorry, if i mislead you. I really just want to do what is best for the linux > kernel, if that's going off and figuring out how to compile a new sparc > enabled jump label compiler for sparc, I will do it.
Hi Jason,
It makes me wonder if anyone had success building a gcc 4.5 Intel-to-sparc64 cross-compiler ? Usually, the crosstool-like suites are a few versions behind. I'm aware that this is not trivial, as cross-compilers have a tendency to refuse to get built in certain occasions (such as being a recent less tested version). I'd recommend you focus on this as a first step before resubmitting.
> And I do agree, > that leaving text_poke_early() is my mistake. However, maybe we can > discuss this issue? For example, the reason I have it in the code is b/c > x86 determines the best no-op at run-time. Are other architectures going > to have to require this kind of functionality. Or like sparc, are we > going to be able to generally hard-code the nops on non-x86 at > compile-time?
You might want to create "dumb" text_poke() and text_poke_early() implementations on other architectures that wraps kernel text updates pretty simply. The implementation is trivial if the architecture does not write-protect the text pages, but becomes more evolved when it does.
Thanks,
Mathieu
> > thanks. And again I apologize for any wasted cycles that I've caused. > > -Jason > >
-- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com
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