Nick Desaulniers writes:
> On Thu, Jun 11, 2020 at 4:53 PM Segher Boessenkool
> wrote:
>>
>> On Thu, Jun 11, 2020 at 03:43:55PM -0700, Nick Desaulniers wrote:
>> > Segher, Cristophe, I suspect Clang is missing support for the %L and %U
>> > output templates [1].
...
>
> IIUC the bug report
On 06/12/2020 09:33 PM, Nick Desaulniers wrote:
IIUC the bug report correctly, it looks like LLVM is failing for the
__put_user_asm2_goto case for -m32. A simple reproducer:
https://godbolt.org/z/jBBF9b
void foo(long long in, long long* out) {
asm volatile(
"stw%X1 %0, %1\n\t"
Hi!
On Fri, Jun 12, 2020 at 02:33:09PM -0700, Nick Desaulniers wrote:
> On Thu, Jun 11, 2020 at 4:53 PM Segher Boessenkool
> wrote:
> > The PowerPC part of
> > https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html#Machine-Constraints
> > (sorry, no anchor) documents %U.
>
> I thought
On Thu, Jun 11, 2020 at 4:53 PM Segher Boessenkool
wrote:
>
> On Thu, Jun 11, 2020 at 03:43:55PM -0700, Nick Desaulniers wrote:
> > Segher, Cristophe, I suspect Clang is missing support for the %L and %U
> > output templates [1].
>
> The arch/powerpc kernel first used the %U output modifier in
On Thu, Jun 11, 2020 at 03:43:55PM -0700, Nick Desaulniers wrote:
> Segher, Cristophe, I suspect Clang is missing support for the %L and %U
> output templates [1].
The arch/powerpc kernel first used the %U output modifier in 0c176fa80fdf
(from 2016), and %L in b8b572e1015f (2008).
Hello! It seems this patch broke our ppc32 builds, and we had to
disable them [0]. :(
>From what I can tell, though Michael mentioned this was merged on May
29, but our CI of -next was green for ppc32 until June 4, then mainline
went red June 6. So this patch only got 2 days of soak time before
On Fri, 2020-04-17 at 17:08:51 UTC, Christophe Leroy wrote:
> unsafe_put_user() is designed to take benefit of 'asm goto'.
>
> Instead of using the standard __put_user() approach and branch
> based on the returned error, use 'asm goto' and make the
> exception code branch directly to the error
On Wed, May 06, 2020 at 08:10:57PM +0200, Christophe Leroy wrote:
> Le 06/05/2020 à 19:58, Segher Boessenkool a écrit :
> >> #define __put_user_asm_goto(x, addr, label, op) \
> >>asm volatile goto( \
> >>- "1: " op "%U1%X1
Le 06/05/2020 à 19:58, Segher Boessenkool a écrit :
On Wed, May 06, 2020 at 10:58:55AM +1000, Michael Ellerman wrote:
The "m<>" here is breaking GCC 4.6.3, which we allegedly still support.
[ You shouldn't use 4.6.3, there has been 4.6.4 since a while. And 4.6
is nine years old now.
On Wed, May 06, 2020 at 11:36:00AM +1000, Michael Ellerman wrote:
> >> As far as I understood that's mandatory on recent gcc to get the
> >> pre-update form of the instruction. With older versions "m" was doing
> >> the same, but not anymore.
> >
> > Yes. How much that matters depends on the
On Wed, May 06, 2020 at 10:58:55AM +1000, Michael Ellerman wrote:
> >> The "m<>" here is breaking GCC 4.6.3, which we allegedly still support.
> >
> > [ You shouldn't use 4.6.3, there has been 4.6.4 since a while. And 4.6
> > is nine years old now. Most projects do not support < 4.8 anymore,
Segher Boessenkool writes:
> On Tue, May 05, 2020 at 05:40:21PM +0200, Christophe Leroy wrote:
>> >>+#define __put_user_asm_goto(x, addr, label, op) \
>> >>+ asm volatile goto( \
>> >>+ "1: " op "%U1%X1 %0,%1 # put_user\n"
Segher Boessenkool writes:
> Hi!
>
> On Wed, May 06, 2020 at 12:27:58AM +1000, Michael Ellerman wrote:
>> Christophe Leroy writes:
>> > unsafe_put_user() is designed to take benefit of 'asm goto'.
>> >
>> > Instead of using the standard __put_user() approach and branch
>> > based on the returned
On Tue, May 05, 2020 at 05:40:21PM +0200, Christophe Leroy wrote:
> >>+#define __put_user_asm_goto(x, addr, label, op)\
> >>+ asm volatile goto( \
> >>+ "1: " op "%U1%X1 %0,%1 # put_user\n" \
> >>+
Hi,
Le 05/05/2020 à 16:27, Michael Ellerman a écrit :
Christophe Leroy writes:
unsafe_put_user() is designed to take benefit of 'asm goto'.
Instead of using the standard __put_user() approach and branch
based on the returned error, use 'asm goto' and make the
exception code branch directly
Hi!
On Wed, May 06, 2020 at 12:27:58AM +1000, Michael Ellerman wrote:
> Christophe Leroy writes:
> > unsafe_put_user() is designed to take benefit of 'asm goto'.
> >
> > Instead of using the standard __put_user() approach and branch
> > based on the returned error, use 'asm goto' and make the
>
Christophe Leroy writes:
> unsafe_put_user() is designed to take benefit of 'asm goto'.
>
> Instead of using the standard __put_user() approach and branch
> based on the returned error, use 'asm goto' and make the
> exception code branch directly to the error label. There is
> no code anymore in
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