Line data    Source code

       1             : // SPDX-License-Identifier: MIT
       2             : /*
       3             :  * Copyright 2021 Advanced Micro Devices, Inc.
       4             :  *
       5             :  * Permission is hereby granted, free of charge, to any person obtaining a
       6             :  * copy of this software and associated documentation files (the "Software"),
       7             :  * to deal in the Software without restriction, including without limitation
       8             :  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
       9             :  * and/or sell copies of the Software, and to permit persons to whom the
      10             :  * Software is furnished to do so, subject to the following conditions:
      11             :  *
      12             :  * The above copyright notice and this permission notice shall be included in
      13             :  * all copies or substantial portions of the Software.
      14             :  *
      15             :  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
      16             :  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
      17             :  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
      18             :  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
      19             :  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
      20             :  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
      21             :  * OTHER DEALINGS IN THE SOFTWARE.
      22             :  *
      23             :  * Authors: AMD
      24             :  *
      25             :  */
      26             : 
      27             : #include "dc_trace.h"
      28             : 
      29             : #if defined(CONFIG_X86)
      30             : #include <asm/fpu/api.h>
      31             : #elif defined(CONFIG_PPC64)
      32             : #include <asm/switch_to.h>
      33             : #include <asm/cputable.h>
      34             : #endif
      35             : 
      36             : /**
      37             :  * DOC: DC FPU manipulation overview
      38             :  *
      39             :  * DC core uses FPU operations in multiple parts of the code, which requires a
      40             :  * more specialized way to manage these areas' entrance. To fulfill this
      41             :  * requirement, we created some wrapper functions that encapsulate
      42             :  * kernel_fpu_begin/end to better fit our need in the display component. In
      43             :  * summary, in this file, you can find functions related to FPU operation
      44             :  * management.
      45             :  */
      46             : 
      47             : static DEFINE_PER_CPU(int, fpu_recursion_depth);
      48             : 
      49             : /**
      50             :  * dc_assert_fp_enabled - Check if FPU protection is enabled
      51             :  *
      52             :  * This function tells if the code is already under FPU protection or not. A
      53             :  * function that works as an API for a set of FPU operations can use this
      54             :  * function for checking if the caller invoked it after DC_FP_START(). For
      55             :  * example, take a look at dcn20_fpu.c file.
      56             :  */
      57           4 : inline void dc_assert_fp_enabled(void)
      58             : {
      59           4 :         int *pcpu, depth = 0;
      60             : 
      61           4 :         pcpu = get_cpu_ptr(&fpu_recursion_depth);
      62           4 :         depth = *pcpu;
      63           4 :         put_cpu_ptr(&fpu_recursion_depth);
      64             : 
      65           4 :         ASSERT(depth >= 1);
      66           4 : }
      67             : 
      68             : /**
      69             :  * dc_fpu_begin - Enables FPU protection
      70             :  * @function_name: A string containing the function name for debug purposes
      71             :  *   (usually __func__)
      72             :  *
      73             :  * @line: A line number where DC_FP_START was invoked for debug purpose
      74             :  *   (usually __LINE__)
      75             :  *
      76             :  * This function is responsible for managing the use of kernel_fpu_begin() with
      77             :  * the advantage of providing an event trace for debugging.
      78             :  *
      79             :  * Note: Do not call this function directly; always use DC_FP_START().
      80             :  */
      81          45 : void dc_fpu_begin(const char *function_name, const int line)
      82             : {
      83             :         int *pcpu;
      84             : 
      85          45 :         pcpu = get_cpu_ptr(&fpu_recursion_depth);
      86          45 :         *pcpu += 1;
      87             : 
      88             :         if (*pcpu == 1) {
      89             : #if defined(CONFIG_X86)
      90             :                 kernel_fpu_begin();
      91             : #elif defined(CONFIG_PPC64)
      92             :                 if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
      93             :                         preempt_disable();
      94             :                         enable_kernel_vsx();
      95             :                 } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
      96             :                         preempt_disable();
      97             :                         enable_kernel_altivec();
      98             :                 } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
      99             :                         preempt_disable();
     100             :                         enable_kernel_fp();
     101             :                 }
     102             : #endif
     103             :         }
     104             : 
     105          45 :         TRACE_DCN_FPU(true, function_name, line, *pcpu);
     106          45 :         put_cpu_ptr(&fpu_recursion_depth);
     107          45 : }
     108             : 
     109             : /**
     110             :  * dc_fpu_end - Disable FPU protection
     111             :  * @function_name: A string containing the function name for debug purposes
     112             :  * @line: A-line number where DC_FP_END was invoked for debug purpose
     113             :  *
     114             :  * This function is responsible for managing the use of kernel_fpu_end() with
     115             :  * the advantage of providing an event trace for debugging.
     116             :  *
     117             :  * Note: Do not call this function directly; always use DC_FP_END().
     118             :  */
     119          45 : void dc_fpu_end(const char *function_name, const int line)
     120             : {
     121             :         int *pcpu;
     122             : 
     123          45 :         pcpu = get_cpu_ptr(&fpu_recursion_depth);
     124          45 :         *pcpu -= 1;
     125             :         if (*pcpu <= 0) {
     126             : #if defined(CONFIG_X86)
     127             :                 kernel_fpu_end();
     128             : #elif defined(CONFIG_PPC64)
     129             :                 if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
     130             :                         disable_kernel_vsx();
     131             :                         preempt_enable();
     132             :                 } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
     133             :                         disable_kernel_altivec();
     134             :                         preempt_enable();
     135             :                 } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
     136             :                         disable_kernel_fp();
     137             :                         preempt_enable();
     138             :                 }
     139             : #endif
     140             :         }
     141             : 
     142          45 :         TRACE_DCN_FPU(false, function_name, line, *pcpu);
     143          45 :         put_cpu_ptr(&fpu_recursion_depth);
     144          45 : }