Messages in this thread | | | From | Arnd Bergmann <> | Date | Tue, 30 Jul 2019 20:24:58 +0200 | Subject | Re: [PATCH] powerpc: workaround clang codegen bug in dcbz |
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On Tue, Jul 30, 2019 at 7:07 PM Segher Boessenkool <segher@kernel.crashing.org> wrote: > > On Tue, Jul 30, 2019 at 11:16:37AM -0500, Segher Boessenkool wrote: > > in_le32 and friends? Yeah, huh. If LLVM copies that to the stack as > > well, its (not byte reversing) read will be atomic just fine, so things > > will still work correctly. > > > > The things defined with DEF_MMIO_IN_D (instead of DEF_MMIO_IN_X) do not > > look like they will work correctly if an update form address is chosen, > > but that won't happen because the constraint is "m" instead of "m<>", > > making the %Un pretty useless (it will always be the empty string). > > Btw, this is true since GCC 4.8; before 4.8, plain "m" *could* have an > automodify (autoinc, autodec, etc.) side effect. What is the minimum > GCC version required, these days?
gcc-4.6, but an architecture can require a higher version.
Arnd
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