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 --- .../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->line ) );
diff --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(); #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(); - } + 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(); #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(); - } + 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 + } + + 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)