- On Jul 9, 2020, at 4:46 PM, Segher Boessenkool seg...@kernel.crashing.org
wrote:
> On Thu, Jul 09, 2020 at 01:56:19PM -0400, Mathieu Desnoyers wrote:
>> > Just to make sure I understand your recommendation. So rather than
>> > hard coding r17 as the temporary registers, we could explicitly
On Thu, Jul 09, 2020 at 01:56:19PM -0400, Mathieu Desnoyers wrote:
> > Just to make sure I understand your recommendation. So rather than
> > hard coding r17 as the temporary registers, we could explicitly
> > declare the temporary register as a C variable, pass it as an
> > input operand to the
On Thu, Jul 09, 2020 at 01:42:56PM -0400, Mathieu Desnoyers wrote:
> > That works fine then, for a testcase. Using r17 is not a great idea for
> > performance (it increases the active register footprint, and causes more
> > registers to be saved in the prologue of the functions, esp. on older
> >
- On Jul 9, 2020, at 1:42 PM, Mathieu Desnoyers
mathieu.desnoy...@efficios.com wrote:
> - On Jul 9, 2020, at 1:37 PM, Segher Boessenkool
> seg...@kernel.crashing.org
> wrote:
>
>> On Thu, Jul 09, 2020 at 09:43:47AM -0400, Mathieu Desnoyers wrote:
>>> > What protects r17 *after* this
- On Jul 9, 2020, at 1:37 PM, Segher Boessenkool seg...@kernel.crashing.org
wrote:
> On Thu, Jul 09, 2020 at 09:43:47AM -0400, Mathieu Desnoyers wrote:
>> > What protects r17 *after* this asm statement?
>>
>> As discussed in the other leg of the thread (with the code example),
>> r17 is in
On Thu, Jul 09, 2020 at 09:43:47AM -0400, Mathieu Desnoyers wrote:
> > What protects r17 *after* this asm statement?
>
> As discussed in the other leg of the thread (with the code example),
> r17 is in the clobber list of all asm statements using this macro, and
> is used as a temporary register
On Thu, Jul 09, 2020 at 09:33:18AM -0400, Mathieu Desnoyers wrote:
> > The way this all uses r17 will likely not work reliably.
>
> r17 is only used as a temporary register within the inline assembler, and it
> is
> in the clobber list. In which scenario would it not work reliably ?
This isn't
- On Jul 8, 2020, at 8:18 PM, Segher Boessenkool seg...@kernel.crashing.org
wrote:
> On Wed, Jul 08, 2020 at 08:01:23PM -0400, Mathieu Desnoyers wrote:
>> > > #define RSEQ_ASM_OP_CMPEQ(var, expect, label)
>> > > \
>> > > LOAD_WORD "%%r17, %[" __rseq_str(var) "]\n\t"
- On Jul 8, 2020, at 8:10 PM, Segher Boessenkool seg...@kernel.crashing.org
wrote:
> Hi!
>
> On Wed, Jul 08, 2020 at 10:00:01AM -0400, Mathieu Desnoyers wrote:
[...]
>
>> -#define STORE_WORD "std "
>> -#define LOAD_WORD "ld "
>> -#define LOADX_WORD "ldx "
>> +#define
On Wed, Jul 08, 2020 at 08:01:23PM -0400, Mathieu Desnoyers wrote:
> > > #define RSEQ_ASM_OP_CMPEQ(var, expect, label)
> > > \
> > > LOAD_WORD "%%r17, %[" __rseq_str(var) "]\n\t"
> > > \
> >
> > The way this hardcodes r17
On Wed, Jul 08, 2020 at 10:32:20AM -0400, Mathieu Desnoyers wrote:
> > As far as I can see, %U is mentioned in
> > https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html in the
> > powerpc subpart, at the "m" constraint.
>
> Yep, I did notice it, but mistakenly thought it was only needed for
Hi!
On Wed, Jul 08, 2020 at 10:00:01AM -0400, Mathieu Desnoyers wrote:
> >> So perhaps you have code like
> >>
> >> int *p;
> >> int x;
> >> ...
> >> asm ("lwz %0,%1" : "=r"(x) : "m"(*p));
> >
> > We indeed have explicit "lwz" and "stw" instructions in there.
> >
> >>
> >> where that last
- Segher Boessenkool wrote:
> Hi!
>
> On Wed, Jul 08, 2020 at 10:27:27PM +1000, Michael Ellerman wrote:
> > Segher Boessenkool writes:
> > > You'll have to show the actual failing machine code, and with enough
> > > context that we can relate this to the source code.
> > >
> > >
Hi!
On Wed, Jul 08, 2020 at 10:27:27PM +1000, Michael Ellerman wrote:
> Segher Boessenkool writes:
> > You'll have to show the actual failing machine code, and with enough
> > context that we can relate this to the source code.
> >
> > -save-temps helps, or use -S instead of -c, etc.
>
>
Le 08/07/2020 à 16:32, Mathieu Desnoyers a écrit :
- On Jul 8, 2020, at 10:21 AM, Christophe Leroy christophe.le...@csgroup.eu
wrote:
Le 08/07/2020 à 16:00, Mathieu Desnoyers a écrit :
- On Jul 8, 2020, at 8:33 AM, Mathieu Desnoyers
mathieu.desnoy...@efficios.com wrote:
- On
- On Jul 8, 2020, at 10:21 AM, Christophe Leroy christophe.le...@csgroup.eu
wrote:
> Le 08/07/2020 à 16:00, Mathieu Desnoyers a écrit :
>> - On Jul 8, 2020, at 8:33 AM, Mathieu Desnoyers
>> mathieu.desnoy...@efficios.com wrote:
>>
>>> - On Jul 7, 2020, at 8:59 PM, Segher Boessenkool
Le 08/07/2020 à 16:00, Mathieu Desnoyers a écrit :
- On Jul 8, 2020, at 8:33 AM, Mathieu Desnoyers
mathieu.desnoy...@efficios.com wrote:
- On Jul 7, 2020, at 8:59 PM, Segher Boessenkool seg...@kernel.crashing.org
wrote:
[...]
So perhaps you have code like
int *p;
int x;
- On Jul 8, 2020, at 8:33 AM, Mathieu Desnoyers
mathieu.desnoy...@efficios.com wrote:
> - On Jul 7, 2020, at 8:59 PM, Segher Boessenkool
> seg...@kernel.crashing.org
> wrote:
[...]
>>
>> So perhaps you have code like
>>
>> int *p;
>> int x;
>> ...
>> asm ("lwz %0,%1" : "=r"(x) :
- On Jul 7, 2020, at 8:59 PM, Segher Boessenkool seg...@kernel.crashing.org
wrote:
> Hi!
>
> On Tue, Jul 07, 2020 at 03:17:10PM -0400, Mathieu Desnoyers wrote:
>> I'm trying to build librseq at:
>>
>> https://git.kernel.org/pub/scm/libs/librseq/librseq.git
>>
>> on powerpc, and I get
Segher Boessenkool writes:
> Hi!
>
> On Tue, Jul 07, 2020 at 03:17:10PM -0400, Mathieu Desnoyers wrote:
>> I'm trying to build librseq at:
>>
>> https://git.kernel.org/pub/scm/libs/librseq/librseq.git
>>
>> on powerpc, and I get these errors when building the rseq basic
>> test mirrored from
Hi!
On Tue, Jul 07, 2020 at 03:17:10PM -0400, Mathieu Desnoyers wrote:
> I'm trying to build librseq at:
>
> https://git.kernel.org/pub/scm/libs/librseq/librseq.git
>
> on powerpc, and I get these errors when building the rseq basic
> test mirrored from the kernel selftests code:
>
>
Hi Boqun,
I'm trying to build librseq at:
https://git.kernel.org/pub/scm/libs/librseq/librseq.git
on powerpc, and I get these errors when building the rseq basic
test mirrored from the kernel selftests code:
/tmp/ccieEWxU.s: Assembler messages:
/tmp/ccieEWxU.s:118: Error: syntax error; found
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