Re: [PATCH 02/28] drm/amd/display: Rework dsc to isolate FPU operations
Am 08.06.20 um 06:59 schrieb Qingqing Zhuo:
From: Rodrigo Siqueira
When we want to use float point operation on Linux
we need to use within special kernel protection
(`kernel_fpu_{begin,end}()`.), otherwise the kernel
can clobber userspace FPU register state. For detecting
these issues we use a tool named objtool (with -Ffa
flags) to highlight the FPU problems, all warnings can
be summed up as follows:
./tools/objtool/objtool check -Ffa
drivers/gpu/drm/amd/display/dc/dml/dml_common_defs.o
[..] dc/dsc/rc_calc.o: warning: objtool: get_qp_set()+0x2f8:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: dsc_roundf()+0x5:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: dsc_ceil()+0x5:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: get_ofs_set()+0x3eb:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: calc_rc_params()+0x3c:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/dc_dsc.o: warning: objtool:
get_dsc_bandwidth_range.isra.0()+0x8d:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/dc_dsc.o: warning: objtool: setup_dsc_config()+0x2ef:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc_dpi.o: warning: objtool:copy_pps_fields()+0xbb:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc_dpi.o: warning: objtool:
dscc_compute_dsc_parameters()+0x7b:
FPU instruction outside of kernel_fpu_{begin,end}()
This commit fixes the above issues by rework DSC as described:
1. Isolate all FPU operations in a single file;
2. Use FPU flags only in the file that handles FPU operations;
3. Isolate all functions that require float point operation in static
functions;
4. Add a mid-layer function that does not use any float point operation,
and that could be safely invoked in other parts of the code.
5. Keep float point operation under DC_FP_{START/END} macro.
CC: Christian König
CC: Alexander Deucher
CC: Peter Zijlstra
CC: Tony Cheng
CC: Harry Wentland
Signed-off-by: Rodrigo Siqueira
Reviewed-by: Mikita Lipski
Acked-by: Qingqing Zhuo
---
drivers/gpu/drm/amd/display/dc/dsc/Makefile | 2 -
drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c | 18 +--
drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c | 151 +-
drivers/gpu/drm/amd/display/dc/dsc/rc_calc.h | 5 +-
.../gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c | 27 +---
5 files changed, 153 insertions(+), 50 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/Makefile
b/drivers/gpu/drm/amd/display/dc/dsc/Makefile
index 3f66868df171..ea29cf95d470 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dsc/Makefile
@@ -28,8 +28,6 @@ endif
endif
CFLAGS_$(AMDDALPATH)/dc/dsc/rc_calc.o := $(dsc_ccflags)
-CFLAGS_$(AMDDALPATH)/dc/dsc/rc_calc_dpi.o := $(dsc_ccflags)
-CFLAGS_$(AMDDALPATH)/dc/dsc/dc_dsc.o := $(dsc_ccflags)
DSC = dc_dsc.o rc_calc.o rc_calc_dpi.o
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
index 0ea6662a1563..0c7f247bb7de 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
@@ -22,10 +22,12 @@
* Author: AMD
*/
+#include
#include "dc_hw_types.h"
#include "dsc.h"
#include
#include "dc.h"
+#include "rc_calc.h"
/* This module's internal functions */
@@ -304,22 +306,6 @@ static inline uint32_t dsc_div_by_10_round_up(uint32_t value)
return (value + 9) / 10;
}
-static inline uint32_t calc_dsc_bpp_x16(uint32_t stream_bandwidth_kbps, uint32_t pix_clk_100hz, uint32_t bpp_increment_div)
-{
- uint32_t dsc_target_bpp_x16;
- float f_dsc_target_bpp;
- float f_stream_bandwidth_100bps = stream_bandwidth_kbps * 10.0f;
- uint32_t precision = bpp_increment_div; // bpp_increment_div is
actually precision
-
- f_dsc_target_bpp = f_stream_bandwidth_100bps / pix_clk_100hz;
-
- // Round down to the nearest precision stop to bring it into DSC spec
range
- dsc_target_bpp_x16 = (uint32_t)(f_dsc_target_bpp * precision);
- dsc_target_bpp_x16 = (dsc_target_bpp_x16 * 16) / precision;
-
- return dsc_target_bpp_x16;
-}
-
/* Get DSC bandwidth range based on [min_bpp, max_bpp] target bitrate range,
and timing's pixel clock
* and uncompressed bandwidth.
*/
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
index 03ae15946c6d..667afbc260f9 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
@@ -23,6 +23,7 @@
* Authors: AMD
*
*/
+#include
#include "os_types.h"
#include "rc_calc.h"
@@ -40,7 +41,8 @@
break
-void get_qp_set(qp_set qps, enum colour_mode cm, enum bits_per_comp bpc, enum max_min max_min, float bpp)
[PATCH 02/28] drm/amd/display: Rework dsc to isolate FPU operations
From: Rodrigo Siqueira
When we want to use float point operation on Linux
we need to use within special kernel protection
(`kernel_fpu_{begin,end}()`.), otherwise the kernel
can clobber userspace FPU register state. For detecting
these issues we use a tool named objtool (with -Ffa
flags) to highlight the FPU problems, all warnings can
be summed up as follows:
./tools/objtool/objtool check -Ffa
drivers/gpu/drm/amd/display/dc/dml/dml_common_defs.o
[..] dc/dsc/rc_calc.o: warning: objtool: get_qp_set()+0x2f8:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: dsc_roundf()+0x5:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: dsc_ceil()+0x5:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: get_ofs_set()+0x3eb:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: calc_rc_params()+0x3c:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/dc_dsc.o: warning: objtool:
get_dsc_bandwidth_range.isra.0()+0x8d:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/dc_dsc.o: warning: objtool: setup_dsc_config()+0x2ef:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc_dpi.o: warning: objtool:copy_pps_fields()+0xbb:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc_dpi.o: warning: objtool:
dscc_compute_dsc_parameters()+0x7b:
FPU instruction outside of kernel_fpu_{begin,end}()
This commit fixes the above issues by rework DSC as described:
1. Isolate all FPU operations in a single file;
2. Use FPU flags only in the file that handles FPU operations;
3. Isolate all functions that require float point operation in static
functions;
4. Add a mid-layer function that does not use any float point operation,
and that could be safely invoked in other parts of the code.
5. Keep float point operation under DC_FP_{START/END} macro.
CC: Christian König
CC: Alexander Deucher
CC: Peter Zijlstra
CC: Tony Cheng
CC: Harry Wentland
Signed-off-by: Rodrigo Siqueira
Reviewed-by: Mikita Lipski
Acked-by: Qingqing Zhuo
---
drivers/gpu/drm/amd/display/dc/dsc/Makefile | 2 -
drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c | 18 +--
drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c | 151 +-
drivers/gpu/drm/amd/display/dc/dsc/rc_calc.h | 5 +-
.../gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c | 27 +---
5 files changed, 153 insertions(+), 50 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/Makefile
b/drivers/gpu/drm/amd/display/dc/dsc/Makefile
index 3f66868df171..ea29cf95d470 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dsc/Makefile
@@ -28,8 +28,6 @@ endif
endif
CFLAGS_$(AMDDALPATH)/dc/dsc/rc_calc.o := $(dsc_ccflags)
-CFLAGS_$(AMDDALPATH)/dc/dsc/rc_calc_dpi.o := $(dsc_ccflags)
-CFLAGS_$(AMDDALPATH)/dc/dsc/dc_dsc.o := $(dsc_ccflags)
DSC = dc_dsc.o rc_calc.o rc_calc_dpi.o
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
index 0ea6662a1563..0c7f247bb7de 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
@@ -22,10 +22,12 @@
* Author: AMD
*/
+#include
#include "dc_hw_types.h"
#include "dsc.h"
#include
#include "dc.h"
+#include "rc_calc.h"
/* This module's internal functions */
@@ -304,22 +306,6 @@ static inline uint32_t dsc_div_by_10_round_up(uint32_t
value)
return (value + 9) / 10;
}
-static inline uint32_t calc_dsc_bpp_x16(uint32_t stream_bandwidth_kbps,
uint32_t pix_clk_100hz, uint32_t bpp_increment_div)
-{
- uint32_t dsc_target_bpp_x16;
- float f_dsc_target_bpp;
- float f_stream_bandwidth_100bps = stream_bandwidth_kbps * 10.0f;
- uint32_t precision = bpp_increment_div; // bpp_increment_div is
actually precision
-
- f_dsc_target_bpp = f_stream_bandwidth_100bps / pix_clk_100hz;
-
- // Round down to the nearest precision stop to bring it into DSC spec
range
- dsc_target_bpp_x16 = (uint32_t)(f_dsc_target_bpp * precision);
- dsc_target_bpp_x16 = (dsc_target_bpp_x16 * 16) / precision;
-
- return dsc_target_bpp_x16;
-}
-
/* Get DSC bandwidth range based on [min_bpp, max_bpp] target bitrate range,
and timing's pixel clock
* and uncompressed bandwidth.
*/
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
index 03ae15946c6d..667afbc260f9 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
@@ -23,6 +23,7 @@
* Authors: AMD
*
*/
+#include
#include "os_types.h"
#include "rc_calc.h"
@@ -40,7 +41,8 @@
break
-void get_qp_set(qp_set qps, enum colour_mode cm, enum bits_per_comp bpc, enum
max_min max_min, float bpp)
+static void get_qp_set(qp_set qps, enum colour_mode cm, enum bits_per_comp bpc,
+
