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:
- Rebase
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 Reported-by: kernel test robot lkp@intel.com Signed-off-by: Rodrigo Siqueira Rodrigo.Siqueira@amd.com
Reviewed-by: Christian König christian.koenig@amd.com
.../amd/display/amdgpu_dm/amdgpu_dm_trace.h | 13 ++-- .../gpu/drm/amd/display/amdgpu_dm/dc_fpu.c | 77 +++++++++++++------ drivers/gpu/drm/amd/display/dc/dc_trace.h | 4 +- 3 files changed, 63 insertions(+), 31 deletions(-)
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 230bb12c405e..fdcaea22b456 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 @@ -638,23 +638,26 @@ TRACE_EVENT(amdgpu_refresh_rate_track, );
TRACE_EVENT(dcn_fpu,
TP_PROTO(bool begin, const char *function, const int line),TP_ARGS(begin, function, line),
TP_PROTO(bool begin, const char *function, const int line, const int recursion_depth),TP_ARGS(begin, function, line, recursion_depth), TP_STRUCT__entry( __field(bool, begin) __field(const char *, function) __field(int, line)__field(int, recursion_depth)), TP_fast_assign( __entry->begin = begin; __entry->function = function; __entry->line = line;
__entry->recursion_depth = recursion_depth;),
TP_printk("%s()+%d: %s",
TP_printk("%s: recursion_depth: %d: %s()+%d:",__entry->begin ? "begin" : "end",__entry->recursion_depth, __entry->function,
__entry->line,__entry->begin ? "begin" : "end"
__entry->linediff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c index d4ab27bf8d04..33807d746e76 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c @@ -33,6 +33,19 @@ #include <asm/cputable.h> #endif
+/**
- DOC: DC FPU manipulation overview
- DC core uses FPU operations in multiple parts of the code, which requires a
- more specialized way to manage these areas' entrance. To fulfill this
- requirement, we created some wrapper functions that encapsulate
- kernel_fpu_begin/end to better fit our need in the display component. In
- summary, in this file, you can find functions related to FPU operation
- management.
- */
+static DEFINE_PER_CPU(int, fpu_recursion_depth);
- /**
- dc_fpu_begin - Enables FPU protection
- @function_name: A string containing the function name for debug purposes
@@ -48,22 +61,30 @@ */ void dc_fpu_begin(const char *function_name, const int line) {
- TRACE_DCN_FPU(true, function_name, line);
int *pcpu;
pcpu = get_cpu_ptr(&fpu_recursion_depth);
*pcpu += 1;
if (*pcpu == 1) { #if defined(CONFIG_X86)
- kernel_fpu_begin();
kernel_fpu_begin();
- 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();- }
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
}
TRACE_DCN_FPU(true, function_name, line, *pcpu);
put_cpu_ptr(&fpu_recursion_depth); }
/**
@@ -78,19 +99,27 @@ void dc_fpu_begin(const char *function_name, const int line) */ void dc_fpu_end(const char *function_name, const int line) {
- TRACE_DCN_FPU(false, function_name, line);
- int *pcpu;
- pcpu = get_cpu_ptr(&fpu_recursion_depth);
- *pcpu -= 1;
- if (*pcpu <= 0) { #if defined(CONFIG_X86)
- kernel_fpu_end();
kernel_fpu_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();- }
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();}- }
- TRACE_DCN_FPU(false, function_name, line, *pcpu);
- put_cpu_ptr(&fpu_recursion_depth); }
diff --git a/drivers/gpu/drm/amd/display/dc/dc_trace.h b/drivers/gpu/drm/amd/display/dc/dc_trace.h index d598ba697e45..c711797e5c9e 100644 --- a/drivers/gpu/drm/amd/display/dc/dc_trace.h +++ b/drivers/gpu/drm/amd/display/dc/dc_trace.h @@ -38,5 +38,5 @@ #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)
+#define TRACE_DCN_FPU(begin, function, line, ref_count) \
- trace_dcn_fpu(begin, function, line, ref_count)