Re: PATCH: Add AVX support to x86-64 _dl_runtime_profile

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Tue, Jul 7, 2009 at 6:27 PM, H.J. Lu<hjl.tools@gmail.com> wrote:
> On Mon, Jul 6, 2009 at 10:16 PM, Ulrich Drepper<drepper@redhat.com> wrote:
>> H.J. Lu wrote:
>>> Since SSE registers are aliases of the lower 128bits of AVX register,
>>> we only need to restore AVX register if it is available.
>>
>> No. ?This would only work if we would have had the AVX registers in the
>> data structure from day one. ?The current ABI allows audit modules to
>> modify the lr_xmm array and see the changes being reflected in the
>> program run. ?You cannot after that fact require that the lr_ymm
>> registers have to be modified.
>>
>> This is why this two-step process is needed.
>
> Here is the updated patch with 2 testcases. They are passed under
> AVX emulator.
>
>>
>>> Since AVX register is just SSE register extended to 256bit, we only
>>> use the first 8 AVX/SSE registers for passing parameters.
>>
>> This makes no sense. ?There are 16 of them and if a function needs more
>> than 8 it should be able to use it. ?Someone should fix gcc.
>>
>
> The current psABI only uses the first 8 vector registers to pass
> function parameters. We only ?eed to save/restore the first 8
> vector registers
>
>>> Here is the updated patch tested under AVX emulator.
>>
>> As said above, the restoring issue has to be addressed.
>
> Done. ?tst-audit5 changes xmm fields. ?It worked under
> AVX emulator.
>
>>
>>> It defines
>>> La_x86_64_vector as 64byte since we will extend 256bit AVX register
>>> to 512bit in the future.
>>
>> OK I guess.
>
>

Here is the updated patch. We should only build tst-auditmod3a
tst-auditmod3b tst-auditmod4a 	tst-auditmod4b tst-auditmod5a
tst-auditmod5b for x86_64 only.  Tested on Linux/ia32 and Linux/Intel64.

Thanks.


-- 
H.J.
--
2009-07-10  H.J. Lu  <hongjiu.lu@intel.com>

	* config.h.in (HAVE_AVX_SUPPORT): New.

	* config.make.in (config-cflags-avx): New.

	* configure.in: Substitute libc_cv_cc_avx.
	* configure: Regenerated.

	* elf/Makefile (distribute): Add tst-audit4.c tst-auditmod4a.c
	tst-auditmod4b.c tst-audit5.c tst-auditmod5a.c
	tst-auditmod5b.c.
	(tests): Add tst-audit4 tst-audit5 for x86_64.
	(modules-names): Add tst-auditmod3a tst-auditmod3b tst-auditmod4a
	tst-auditmod4b tst-auditmod5a tst-auditmod5b for x86_64 only.
	($(objpfx)tst-audit4): New.
	($(objpfx)tst-audit4.out): Likewise.
	(tst-audit4-ENV): Likewise.
	($(objpfx)tst-audit5): Likewise.
	($(objpfx)tst-audit5.out): Likewise.
	(tst-audit5-ENV): Likewise.
	(CFLAGS-tst-audit4.c): Likewise.
	(CFLAGS-tst-auditmod4a.c): Likewise.
	(CFLAGS-tst-auditmod4b.c): Likewise.

	* elf/tst-audit4.c: New.
	* elf/tst-audit5.c: Likewise.
	* elf/tst-auditmod4a.c: Likewise.
	* elf/tst-auditmod4b.c: Likewise.
	* elf/tst-auditmod5a.c: Likewise.
	* elf/tst-auditmod5b.c: Likewise.

	* sysdeps/x86_64/Makefile (gen-as-const-headers): Add
	link-defines.sym.

	* sysdeps/x86_64/bits/link.h (La_x86_64_ymm): New.
	(La_x86_64_vector): Likewise.
	(La_x86_64_regs): Append lr_vector.
	(La_x86_64_retval): Append lr_vector0/lrv_vector1.

	* sysdeps/x86_64/dl-trampoline.S (_dl_runtime_profile): Move
	saving and restoring SSE registers to ...
	* sysdeps/x86_64/dl-trampoline.h: This.  New.

	* sysdeps/x86_64/dl-trampoline.S: Include <config.h> and
	<link-defines.h>.
	(_dl_runtime_profile): Use LR_SIZE to allocate space for
	La_x86_64_regs.  Allocate extra space and jump to memory at
	save_and_restore_vector if HAVE_AVX_SUPPORT is defined.
	(save_and_restore_vector_sse): New.
	(save_and_restore_vector_avx): Likewise.
	(check_avx): Likewise.
	(save_and_restore_vector): Likewise.

	* sysdeps/x86_64/elf/configure.in: Set libc_cv_cc_avx and
	HAVE_AVX_SUPPORT.
	* sysdeps/x86_64/elf/configure: Regenerated.

	* sysdeps/x86_64/link-defines.sym: New.

Attachment: libc-avx-5.patch
Description: Text document