arch/x86/Makefile disables SSE and SSE2 for the whole kernel. The
AMDGPU drivers modified in this patch re-enable SSE but not SSE2. Turn
on SSE2 to support emitting double precision floating point instructions
rather than calls to non-existent (usually available from gcc_s or
compiler_rt) floating point helper routines.
Link: https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html
Link: https://github.com/ClangBuiltLinux/linux/issues/327
Cc: [email protected] # 4.19
Reported-by: S, Shirish <[email protected]>
Reported-by: Matthias Kaehlcke <[email protected]>
Suggested-by: James Y Knight <[email protected]>
Suggested-by: Nathan Chancellor <[email protected]>
Signed-off-by: Nick Desaulniers <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
---
drivers/gpu/drm/amd/display/dc/calcs/Makefile | 2 +-
drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
index 95f332ee3e7e..dc85a3c088af 100644
--- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
@@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
cc_stack_align := -mstack-alignment=16
endif
-calcs_ccflags := -mhard-float -msse $(cc_stack_align)
+calcs_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
CFLAGS_dcn_calcs.o := $(calcs_ccflags)
CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
index d97ca6528f9d..33c7d7588712 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
@@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
cc_stack_align := -mstack-alignment=16
endif
-dml_ccflags := -mhard-float -msse $(cc_stack_align)
+dml_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
CFLAGS_display_mode_lib.o := $(dml_ccflags)
CFLAGS_display_pipe_clocks.o := $(dml_ccflags)
--
2.20.1.321.g9e740568ce-goog
On Thu, Jan 24, 2019 at 04:52:59PM -0800, [email protected] wrote:
> arch/x86/Makefile disables SSE and SSE2 for the whole kernel. The
> AMDGPU drivers modified in this patch re-enable SSE but not SSE2. Turn
> on SSE2 to support emitting double precision floating point instructions
> rather than calls to non-existent (usually available from gcc_s or
> compiler_rt) floating point helper routines.
>
> Link: https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html
> Link: https://github.com/ClangBuiltLinux/linux/issues/327
> Cc: [email protected] # 4.19
> Reported-by: S, Shirish <[email protected]>
> Reported-by: Matthias Kaehlcke <[email protected]>
> Suggested-by: James Y Knight <[email protected]>
> Suggested-by: Nathan Chancellor <[email protected]>
> Signed-off-by: Nick Desaulniers <[email protected]>
> Tested-by: Guenter Roeck <[email protected]>
> ---
> drivers/gpu/drm/amd/display/dc/calcs/Makefile | 2 +-
> drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> index 95f332ee3e7e..dc85a3c088af 100644
> --- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> cc_stack_align := -mstack-alignment=16
> endif
>
> -calcs_ccflags := -mhard-float -msse $(cc_stack_align)
> +calcs_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
>
> CFLAGS_dcn_calcs.o := $(calcs_ccflags)
> CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
> diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> index d97ca6528f9d..33c7d7588712 100644
> --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> cc_stack_align := -mstack-alignment=16
> endif
>
> -dml_ccflags := -mhard-float -msse $(cc_stack_align)
> +dml_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
>
> CFLAGS_display_mode_lib.o := $(dml_ccflags)
> CFLAGS_display_pipe_clocks.o := $(dml_ccflags)
Tested-by: Matthias Kaehlcke <[email protected]>
On Thu, Jan 24, 2019 at 04:52:59PM -0800, [email protected] wrote:
> arch/x86/Makefile disables SSE and SSE2 for the whole kernel. The
> AMDGPU drivers modified in this patch re-enable SSE but not SSE2. Turn
> on SSE2 to support emitting double precision floating point instructions
> rather than calls to non-existent (usually available from gcc_s or
> compiler_rt) floating point helper routines.
>
> Link: https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html
> Link: https://github.com/ClangBuiltLinux/linux/issues/327
> Cc: [email protected] # 4.19
> Reported-by: S, Shirish <[email protected]>
> Reported-by: Matthias Kaehlcke <[email protected]>
> Suggested-by: James Y Knight <[email protected]>
> Suggested-by: Nathan Chancellor <[email protected]>
> Signed-off-by: Nick Desaulniers <[email protected]>
> Tested-by: Guenter Roeck <[email protected]>
Tested-by: Nathan Chancellor <[email protected]>
> ---
> drivers/gpu/drm/amd/display/dc/calcs/Makefile | 2 +-
> drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> index 95f332ee3e7e..dc85a3c088af 100644
> --- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> cc_stack_align := -mstack-alignment=16
> endif
>
> -calcs_ccflags := -mhard-float -msse $(cc_stack_align)
> +calcs_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
>
> CFLAGS_dcn_calcs.o := $(calcs_ccflags)
> CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
> diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> index d97ca6528f9d..33c7d7588712 100644
> --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> cc_stack_align := -mstack-alignment=16
> endif
>
> -dml_ccflags := -mhard-float -msse $(cc_stack_align)
> +dml_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
>
> CFLAGS_display_mode_lib.o := $(dml_ccflags)
> CFLAGS_display_pipe_clocks.o := $(dml_ccflags)
> --
> 2.20.1.321.g9e740568ce-goog
>
On 2019-01-24 7:52 p.m., [email protected] wrote:
> arch/x86/Makefile disables SSE and SSE2 for the whole kernel. The
> AMDGPU drivers modified in this patch re-enable SSE but not SSE2. Turn
> on SSE2 to support emitting double precision floating point instructions
> rather than calls to non-existent (usually available from gcc_s or
> compiler_rt) floating point helper routines.
>
> Link: https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html
> Link: https://github.com/ClangBuiltLinux/linux/issues/327
> Cc: [email protected] # 4.19
> Reported-by: S, Shirish <[email protected]>
> Reported-by: Matthias Kaehlcke <[email protected]>
> Suggested-by: James Y Knight <[email protected]>
> Suggested-by: Nathan Chancellor <[email protected]>
> Signed-off-by: Nick Desaulniers <[email protected]>
> Tested-by: Guenter Roeck <[email protected]>
Reviewed-by: Harry Wentland <[email protected]>
and applied.
Harry
> ---
> drivers/gpu/drm/amd/display/dc/calcs/Makefile | 2 +-
> drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> index 95f332ee3e7e..dc85a3c088af 100644
> --- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> cc_stack_align := -mstack-alignment=16
> endif
>
> -calcs_ccflags := -mhard-float -msse $(cc_stack_align)
> +calcs_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
>
> CFLAGS_dcn_calcs.o := $(calcs_ccflags)
> CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
> diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> index d97ca6528f9d..33c7d7588712 100644
> --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> cc_stack_align := -mstack-alignment=16
> endif
>
> -dml_ccflags := -mhard-float -msse $(cc_stack_align)
> +dml_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
>
> CFLAGS_display_mode_lib.o := $(dml_ccflags)
> CFLAGS_display_pipe_clocks.o := $(dml_ccflags)
>
On Fri, Jan 25, 2019 at 10:29 AM Wentland, Harry <[email protected]> wrote:
>
> On 2019-01-24 7:52 p.m., [email protected] wrote:
> > arch/x86/Makefile disables SSE and SSE2 for the whole kernel. The
> > AMDGPU drivers modified in this patch re-enable SSE but not SSE2. Turn
> > on SSE2 to support emitting double precision floating point instructions
> > rather than calls to non-existent (usually available from gcc_s or
> > compiler_rt) floating point helper routines.
> >
> > Link: https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html
> > Link: https://github.com/ClangBuiltLinux/linux/issues/327
> > Cc: [email protected] # 4.19
> > Reported-by: S, Shirish <[email protected]>
> > Reported-by: Matthias Kaehlcke <[email protected]>
> > Suggested-by: James Y Knight <[email protected]>
> > Suggested-by: Nathan Chancellor <[email protected]>
> > Signed-off-by: Nick Desaulniers <[email protected]>
> > Tested-by: Guenter Roeck <[email protected]>
>
> Reviewed-by: Harry Wentland <[email protected]>
>
> and applied.
>
This patch causes a segfault:
https://bugs.freedesktop.org/show_bug.cgi?id=109487
Any ideas?
Alex
> Harry
>
> > ---
> > drivers/gpu/drm/amd/display/dc/calcs/Makefile | 2 +-
> > drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
> > 2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> > index 95f332ee3e7e..dc85a3c088af 100644
> > --- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> > +++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> > @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> > cc_stack_align := -mstack-alignment=16
> > endif
> >
> > -calcs_ccflags := -mhard-float -msse $(cc_stack_align)
> > +calcs_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
> >
> > CFLAGS_dcn_calcs.o := $(calcs_ccflags)
> > CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
> > diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> > index d97ca6528f9d..33c7d7588712 100644
> > --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
> > +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> > @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> > cc_stack_align := -mstack-alignment=16
> > endif
> >
> > -dml_ccflags := -mhard-float -msse $(cc_stack_align)
> > +dml_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
> >
> > CFLAGS_display_mode_lib.o := $(dml_ccflags)
> > CFLAGS_display_pipe_clocks.o := $(dml_ccflags)
> >
> _______________________________________________
> amd-gfx mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
On Tue, Jan 29, 2019 at 10:30:31AM -0500, Alex Deucher wrote:
> On Fri, Jan 25, 2019 at 10:29 AM Wentland, Harry <[email protected]> wrote:
> >
> > On 2019-01-24 7:52 p.m., [email protected] wrote:
> > > arch/x86/Makefile disables SSE and SSE2 for the whole kernel. The
> > > AMDGPU drivers modified in this patch re-enable SSE but not SSE2. Turn
> > > on SSE2 to support emitting double precision floating point instructions
> > > rather than calls to non-existent (usually available from gcc_s or
> > > compiler_rt) floating point helper routines.
> > >
> > > Link: https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html
> > > Link: https://github.com/ClangBuiltLinux/linux/issues/327
> > > Cc: [email protected] # 4.19
> > > Reported-by: S, Shirish <[email protected]>
> > > Reported-by: Matthias Kaehlcke <[email protected]>
> > > Suggested-by: James Y Knight <[email protected]>
> > > Suggested-by: Nathan Chancellor <[email protected]>
> > > Signed-off-by: Nick Desaulniers <[email protected]>
> > > Tested-by: Guenter Roeck <[email protected]>
> >
> > Reviewed-by: Harry Wentland <[email protected]>
> >
> > and applied.
> >
>
> This patch causes a segfault:
> https://bugs.freedesktop.org/show_bug.cgi?id=109487
>
> Any ideas?
>
Set -msse2 only for clang ? I suspect, though, that this might only
solve the compile problem. If I understand correctly, the first
warning in the log is due to BREAK_TO_DEBUGGER(), suggesting that
something is seriously wrong. Maybe enabling sse2 results in different
results from floating point operations.
Unfortunately I don't have a system with the affected GPU,
so I can't run any tests on real hardware. Unless someone can test
with real hardware, I think we have no choice but to revert the
patch.
Guenter
> Alex
>
> > Harry
> >
> > > ---
> > > drivers/gpu/drm/amd/display/dc/calcs/Makefile | 2 +-
> > > drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
> > > 2 files changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> > > index 95f332ee3e7e..dc85a3c088af 100644
> > > --- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> > > +++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> > > @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> > > cc_stack_align := -mstack-alignment=16
> > > endif
> > >
> > > -calcs_ccflags := -mhard-float -msse $(cc_stack_align)
> > > +calcs_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
> > >
> > > CFLAGS_dcn_calcs.o := $(calcs_ccflags)
> > > CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
> > > diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> > > index d97ca6528f9d..33c7d7588712 100644
> > > --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
> > > +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> > > @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> > > cc_stack_align := -mstack-alignment=16
> > > endif
> > >
> > > -dml_ccflags := -mhard-float -msse $(cc_stack_align)
> > > +dml_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
> > >
> > > CFLAGS_display_mode_lib.o := $(dml_ccflags)
> > > CFLAGS_display_pipe_clocks.o := $(dml_ccflags)
> > >
> > _______________________________________________
> > amd-gfx mailing list
> > [email protected]
> > https://lists.freedesktop.org/mailman/listinfo/amd-gfx
On 2019-01-29 1:56 p.m., Guenter Roeck wrote:
> On Tue, Jan 29, 2019 at 10:30:31AM -0500, Alex Deucher wrote:
>> On Fri, Jan 25, 2019 at 10:29 AM Wentland, Harry <[email protected]> wrote:
>>>
>>> On 2019-01-24 7:52 p.m., [email protected] wrote:
>>>> arch/x86/Makefile disables SSE and SSE2 for the whole kernel. The
>>>> AMDGPU drivers modified in this patch re-enable SSE but not SSE2. Turn
>>>> on SSE2 to support emitting double precision floating point instructions
>>>> rather than calls to non-existent (usually available from gcc_s or
>>>> compiler_rt) floating point helper routines.
>>>>
>>>> Link: https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html
>>>> Link: https://github.com/ClangBuiltLinux/linux/issues/327
>>>> Cc: [email protected] # 4.19
>>>> Reported-by: S, Shirish <[email protected]>
>>>> Reported-by: Matthias Kaehlcke <[email protected]>
>>>> Suggested-by: James Y Knight <[email protected]>
>>>> Suggested-by: Nathan Chancellor <[email protected]>
>>>> Signed-off-by: Nick Desaulniers <[email protected]>
>>>> Tested-by: Guenter Roeck <[email protected]>
>>>
>>> Reviewed-by: Harry Wentland <[email protected]>
>>>
>>> and applied.
>>>
>>
>> This patch causes a segfault:
>> https://bugs.freedesktop.org/show_bug.cgi?id=109487
>>
>> Any ideas?
>>
>
> Set -msse2 only for clang ? I suspect, though, that this might only
> solve the compile problem. If I understand correctly, the first
> warning in the log is due to BREAK_TO_DEBUGGER(), suggesting that
> something is seriously wrong. Maybe enabling sse2 results in different
> results from floating point operations.
>
> Unfortunately I don't have a system with the affected GPU,
> so I can't run any tests on real hardware. Unless someone can test
> with real hardware, I think we have no choice but to revert the
> patch.
>
Might be a good idea. Even though, best to revert for now until we understand what's going on.
It seems like people at AMD building with gcc 5.4 are fine, but those using gcc 7.3 or 8.2 experience the crash.
Harry
> Guenter
>
>> Alex
>>
>>> Harry
>>>
>>>> ---
>>>> drivers/gpu/drm/amd/display/dc/calcs/Makefile | 2 +-
>>>> drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
>>>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
>>>> index 95f332ee3e7e..dc85a3c088af 100644
>>>> --- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile
>>>> +++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
>>>> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
>>>> cc_stack_align := -mstack-alignment=16
>>>> endif
>>>>
>>>> -calcs_ccflags := -mhard-float -msse $(cc_stack_align)
>>>> +calcs_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
>>>>
>>>> CFLAGS_dcn_calcs.o := $(calcs_ccflags)
>>>> CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
>>>> diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
>>>> index d97ca6528f9d..33c7d7588712 100644
>>>> --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
>>>> +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
>>>> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
>>>> cc_stack_align := -mstack-alignment=16
>>>> endif
>>>>
>>>> -dml_ccflags := -mhard-float -msse $(cc_stack_align)
>>>> +dml_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
>>>>
>>>> CFLAGS_display_mode_lib.o := $(dml_ccflags)
>>>> CFLAGS_display_pipe_clocks.o := $(dml_ccflags)
>>>>
>>> _______________________________________________
>>> amd-gfx mailing list
>>> [email protected]
>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
Suggestions:
1. revert patch
2. get me the disassembly from gcc of the translation unit in question.
3. land patch that adds clang guards or something different based on 2.
Revert first; ask questions later.
On Tue, Jan 29, 2019 at 11:01 AM Wentland, Harry <[email protected]> wrote:
>
> On 2019-01-29 1:56 p.m., Guenter Roeck wrote:
> > On Tue, Jan 29, 2019 at 10:30:31AM -0500, Alex Deucher wrote:
> >> On Fri, Jan 25, 2019 at 10:29 AM Wentland, Harry <[email protected]> wrote:
> >>>
> >>> On 2019-01-24 7:52 p.m., [email protected] wrote:
> >>>> arch/x86/Makefile disables SSE and SSE2 for the whole kernel. The
> >>>> AMDGPU drivers modified in this patch re-enable SSE but not SSE2. Turn
> >>>> on SSE2 to support emitting double precision floating point instructions
> >>>> rather than calls to non-existent (usually available from gcc_s or
> >>>> compiler_rt) floating point helper routines.
> >>>>
> >>>> Link: https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html
> >>>> Link: https://github.com/ClangBuiltLinux/linux/issues/327
> >>>> Cc: [email protected] # 4.19
> >>>> Reported-by: S, Shirish <[email protected]>
> >>>> Reported-by: Matthias Kaehlcke <[email protected]>
> >>>> Suggested-by: James Y Knight <[email protected]>
> >>>> Suggested-by: Nathan Chancellor <[email protected]>
> >>>> Signed-off-by: Nick Desaulniers <[email protected]>
> >>>> Tested-by: Guenter Roeck <[email protected]>
> >>>
> >>> Reviewed-by: Harry Wentland <[email protected]>
> >>>
> >>> and applied.
> >>>
> >>
> >> This patch causes a segfault:
> >> https://bugs.freedesktop.org/show_bug.cgi?id=109487
> >>
> >> Any ideas?
> >>
> >
> > Set -msse2 only for clang ? I suspect, though, that this might only
> > solve the compile problem. If I understand correctly, the first
> > warning in the log is due to BREAK_TO_DEBUGGER(), suggesting that
> > something is seriously wrong. Maybe enabling sse2 results in different
> > results from floating point operations.
> >
> > Unfortunately I don't have a system with the affected GPU,
> > so I can't run any tests on real hardware. Unless someone can test
> > with real hardware, I think we have no choice but to revert the
> > patch.
> >
>
> Might be a good idea. Even though, best to revert for now until we understand what's going on.
>
> It seems like people at AMD building with gcc 5.4 are fine, but those using gcc 7.3 or 8.2 experience the crash.
>
> Harry
>
> > Guenter
> >
> >> Alex
> >>
> >>> Harry
> >>>
> >>>> ---
> >>>> drivers/gpu/drm/amd/display/dc/calcs/Makefile | 2 +-
> >>>> drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
> >>>> 2 files changed, 2 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> >>>> index 95f332ee3e7e..dc85a3c088af 100644
> >>>> --- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> >>>> +++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile
> >>>> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> >>>> cc_stack_align := -mstack-alignment=16
> >>>> endif
> >>>>
> >>>> -calcs_ccflags := -mhard-float -msse $(cc_stack_align)
> >>>> +calcs_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
> >>>>
> >>>> CFLAGS_dcn_calcs.o := $(calcs_ccflags)
> >>>> CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
> >>>> diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> >>>> index d97ca6528f9d..33c7d7588712 100644
> >>>> --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
> >>>> +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> >>>> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
> >>>> cc_stack_align := -mstack-alignment=16
> >>>> endif
> >>>>
> >>>> -dml_ccflags := -mhard-float -msse $(cc_stack_align)
> >>>> +dml_ccflags := -mhard-float -msse -msse2 $(cc_stack_align)
> >>>>
> >>>> CFLAGS_display_mode_lib.o := $(dml_ccflags)
> >>>> CFLAGS_display_pipe_clocks.o := $(dml_ccflags)
> >>>>
> >>> _______________________________________________
> >>> amd-gfx mailing list
> >>> [email protected]
> >>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
--
Thanks,
~Nick Desaulniers