Re: [PATCH v4 2/4] drm/amd/display: Add control mechanism for FPU

Am 27.07.21 um 02:52 schrieb Rodrigo Siqueira:

DC invokes DC_FPU_START/END in multiple parts of the code; this can create a situation where we invoke this FPU operation in a nested way or exit too early. For avoiding this situation, this commit adds a mechanism where dc_fpu_begin/end manages the access to kernel_fpu_begin/end.

Change since V3:

• Christian: Move PPC64 code to dc_fpu_begin/end.

Change since V2:

• Christian: Do not use this_cpu_* between get/put_cpu_ptr().

Change since V1:

• Use a better variable names
• Use get_cpu_ptr and put_cpu_ptr to better balance preemption enable

and disable

Cc: Harry Wentland harry.wentland@amd.com Cc: Anson Jacob Anson.Jacob@amd.com Cc: Christian König christian.koenig@amd.com Cc: Hersen Wu hersenxs.wu@amd.com Cc: Aric Cyr aric.cyr@amd.com Cc: Jun Lei jun.lei@amd.com Cc: Dmytro Laktyushkin dmytro.laktyushkin@amd.com Cc: Qingqing Zhuo qingqing.zhuo@amd.com Signed-off-by: Rodrigo Siqueira Rodrigo.Siqueira@amd.com

Reviewed-by: Christian König christian.koenig@amd.com

---

.../gpu/drm/amd/display/amdgpu_dm/Makefile | 4 + .../amd/display/amdgpu_dm/amdgpu_dm_trace.h | 21 ++++ .../gpu/drm/amd/display/amdgpu_dm/dc_fpu.c | 96 +++++++++++++++++++ .../gpu/drm/amd/display/amdgpu_dm/dc_fpu.h | 33 +++++++ drivers/gpu/drm/amd/display/dc/dc_trace.h | 3 + drivers/gpu/drm/amd/display/dc/os_types.h | 35 +------ 6 files changed, 160 insertions(+), 32 deletions(-) create mode 100644 drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c create mode 100644 drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.h

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/Makefile b/drivers/gpu/drm/amd/display/amdgpu_dm/Makefile index 91fb72c96545..718e123a3230 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/Makefile +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/Makefile @@ -27,6 +27,10 @@

AMDGPUDM = amdgpu_dm.o amdgpu_dm_irq.o amdgpu_dm_mst_types.o amdgpu_dm_color.o

+ifdef CONFIG_DRM_AMD_DC_DCN +AMDGPUDM += dc_fpu.o +endif

• ifneq ($(CONFIG_DRM_AMD_DC),) AMDGPUDM += amdgpu_dm_services.o amdgpu_dm_helpers.o amdgpu_dm_pp_smu.o amdgpu_dm_psr.o endif

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_trace.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_trace.h index 46a33f64cf8e..230bb12c405e 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_trace.h +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_trace.h @@ -637,6 +637,27 @@ TRACE_EVENT(amdgpu_refresh_rate_track, __entry->refresh_rate_ns) );

+TRACE_EVENT(dcn_fpu,

•    TP_PROTO(bool begin, const char *function, const int line),
  

•    TP_ARGS(begin, function, line),
  

•    TP_STRUCT__entry(
  

• 	     __field(bool, begin)
  

• 	     __field(const char *, function)
  

• 	     __field(int, line)
  

•    ),
  

•    TP_fast_assign(
  

• 	   __entry->begin = begin;
  

• 	   __entry->function = function;
  

• 	   __entry->line = line;
  

•    ),
  

•    TP_printk("%s()+%d: %s",
  

•       __entry->function,
  

•       __entry->line,
  

•       __entry->begin ? "begin" : "end"
  

•    )
  

+);

• #endif /* _AMDGPU_DM_TRACE_H_ */

  #undef TRACE_INCLUDE_PATH

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c new file mode 100644 index 000000000000..d4ab27bf8d04 --- /dev/null +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: MIT +/*

• • Copyright 2021 Advanced Micro Devices, Inc.
• • Permission is hereby granted, free of charge, to any person obtaining a
• • copy of this software and associated documentation files (the "Software"),
• • to deal in the Software without restriction, including without limitation
• • the rights to use, copy, modify, merge, publish, distribute, sublicense,
• • and/or sell copies of the Software, and to permit persons to whom the
• • Software is furnished to do so, subject to the following conditions:
• • The above copyright notice and this permission notice shall be included in
• • all copies or substantial portions of the Software.
• • THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
• • IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
• • FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
• • THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
• • OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
• • ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
• • OTHER DEALINGS IN THE SOFTWARE.
• • Authors: AMD
• */

+#include "dc_trace.h"

+#if defined(CONFIG_X86) +#include <asm/fpu/api.h> +#elif defined(CONFIG_PPC64) +#include <asm/switch_to.h> +#include <asm/cputable.h> +#endif

+/**

• • dc_fpu_begin - Enables FPU protection
• • @function_name: A string containing the function name for debug purposes
• • (usually __func__)
• • @line: A line number where DC_FP_START was invoked for debug purpose
• • (usually __LINE__)
• • This function is responsible for managing the use of kernel_fpu_begin() with
• • the advantage of providing an event trace for debugging.
• • Note: Do not call this function directly; always use DC_FP_START().
• */

+void dc_fpu_begin(const char *function_name, const int line) +{

• TRACE_DCN_FPU(true, function_name, line);

+#if defined(CONFIG_X86)

• kernel_fpu_begin();

+#elif defined(CONFIG_PPC64)

• if (cpu_has_feature(CPU_FTR_VSX_COMP)) {

• preempt_disable();
  

• enable_kernel_vsx();
  

• } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {

• preempt_disable();
  

• enable_kernel_altivec();
  

• } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {

• preempt_disable();
  

• enable_kernel_fp();
  

• }

+#endif +}

+/**

• • dc_fpu_end - Disable FPU protection
• • @function_name: A string containing the function name for debug purposes
• • @line: A-line number where DC_FP_END was invoked for debug purpose
• • This function is responsible for managing the use of kernel_fpu_end() with
• • the advantage of providing an event trace for debugging.
• • Note: Do not call this function directly; always use DC_FP_END().
• */

+void dc_fpu_end(const char *function_name, const int line) +{

• TRACE_DCN_FPU(false, function_name, line);

+#if defined(CONFIG_X86)

• kernel_fpu_end();

+#elif defined(CONFIG_PPC64)

• if (cpu_has_feature(CPU_FTR_VSX_COMP)) {

• disable_kernel_vsx();
  

• preempt_enable();
  

• } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {

• disable_kernel_altivec();
  

• preempt_enable();
  

• } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {

• disable_kernel_fp();
  

• preempt_enable();
  

• }

+#endif +} diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.h b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.h new file mode 100644 index 000000000000..fb54983c5c60 --- /dev/null +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: MIT */ +/*

• • Copyright 2021 Advanced Micro Devices, Inc.
• • Permission is hereby granted, free of charge, to any person obtaining a
• • copy of this software and associated documentation files (the "Software"),
• • to deal in the Software without restriction, including without limitation
• • the rights to use, copy, modify, merge, publish, distribute, sublicense,
• • and/or sell copies of the Software, and to permit persons to whom the
• • Software is furnished to do so, subject to the following conditions:
• • The above copyright notice and this permission notice shall be included in
• • all copies or substantial portions of the Software.
• • THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
• • IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
• • FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
• • THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
• • OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
• • ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
• • OTHER DEALINGS IN THE SOFTWARE.
• • Authors: AMD
• */

+#ifndef __DC_FPU_H__ +#define __DC_FPU_H__

+void dc_fpu_begin(const char *function_name, const int line); +void dc_fpu_end(const char *function_name, const int line);

+#endif /* __DC_FPU_H__ */ diff --git a/drivers/gpu/drm/amd/display/dc/dc_trace.h b/drivers/gpu/drm/amd/display/dc/dc_trace.h index d2615357269b..d598ba697e45 100644 --- a/drivers/gpu/drm/amd/display/dc/dc_trace.h +++ b/drivers/gpu/drm/amd/display/dc/dc_trace.h @@ -37,3 +37,6 @@

#define TRACE_DCN_CLOCK_STATE(dcn_clocks) \ trace_amdgpu_dm_dc_clocks_state(dcn_clocks)

+#define TRACE_DCN_FPU(begin, function, line) \

• trace_dcn_fpu(begin, function, line)

diff --git a/drivers/gpu/drm/amd/display/dc/os_types.h b/drivers/gpu/drm/amd/display/dc/os_types.h index 126c2f3a4dd3..f50cae252de4 100644 --- a/drivers/gpu/drm/amd/display/dc/os_types.h +++ b/drivers/gpu/drm/amd/display/dc/os_types.h @@ -51,38 +51,9 @@ #define dm_error(fmt, ...) DRM_ERROR(fmt, ##__VA_ARGS__)

#if defined(CONFIG_DRM_AMD_DC_DCN) -#if defined(CONFIG_X86) -#include <asm/fpu/api.h> -#define DC_FP_START() kernel_fpu_begin() -#define DC_FP_END() kernel_fpu_end() -#elif defined(CONFIG_PPC64) -#include <asm/switch_to.h> -#include <asm/cputable.h> -#define DC_FP_START() { \

• if (cpu_has_feature(CPU_FTR_VSX_COMP)) { \

• preempt_disable(); \
  

• enable_kernel_vsx(); \
  

• } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) { \

• preempt_disable(); \
  

• enable_kernel_altivec(); \
  

• } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) { \

• preempt_disable(); \
  

• enable_kernel_fp(); \
  

• } \

-} -#define DC_FP_END() { \

• if (cpu_has_feature(CPU_FTR_VSX_COMP)) { \

• disable_kernel_vsx(); \
  

• preempt_enable(); \
  

• } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) { \

• disable_kernel_altivec(); \
  

• preempt_enable(); \
  

• } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) { \

• disable_kernel_fp(); \
  

• preempt_enable(); \
  

• } \

-} -#endif +#include "amdgpu_dm/dc_fpu.h" +#define DC_FP_START() dc_fpu_begin(__func__, __LINE__) +#define DC_FP_END() dc_fpu_end(__func__, __LINE__) #endif

/*