[PATCH] powerpc: workaround clang codegen bug in dcbz
segher at kernel.crashing.org
Wed Jul 31 03:07:28 AEST 2019
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?
More information about the Linuxppc-dev