target/linux/mediatek/patches-6.1/350-18-cpufreq-mediatek-fix-KP-caused-by-handler-usage-afte.patch

   1 From fced531b7c7e18192e7982637c8e8f20c29aad64 Mon Sep 17 00:00:00 2001
   2 From: Jia-Wei Chang <jia-wei.chang@mediatek.com>
   3 Date: Fri, 24 Mar 2023 18:11:28 +0800
   4 Subject: [PATCH 18/21] cpufreq: mediatek: fix KP caused by handler usage after
   5  regulator_put/clk_put
   6
   7 Any kind of failure in mtk_cpu_dvfs_info_init() will lead to calling
   8 regulator_put() or clk_put() and the KP will occur since the regulator/clk
   9 handlers are used after released in mtk_cpu_dvfs_info_release().
  10
  11 To prevent the usage after regulator_put()/clk_put(), the regulator/clk
  12 handlers are addressed in a way of "Free the Last Thing Style".
  13
  14 Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>
  15 Fixes: 4b9ceb757bbb ("cpufreq: mediatek: Enable clocks and regulators")
  16 Suggested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
  17 Suggested-by: Dan Carpenter <error27@gmail.com>
  18 Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
  19 ---
  20  drivers/cpufreq/mediatek-cpufreq.c | 62 +++++++++++++++---------------
  21  1 file changed, 30 insertions(+), 32 deletions(-)
  22
  23 --- a/drivers/cpufreq/mediatek-cpufreq.c
  24 +++ b/drivers/cpufreq/mediatek-cpufreq.c
  25 @@ -420,7 +420,7 @@ static int mtk_cpu_dvfs_info_init(struct
  26                 ret = PTR_ERR(info->inter_clk);
  27                 dev_err_probe(cpu_dev, ret,
  28                               "cpu%d: failed to get intermediate clk\n", cpu);
  29 -               goto out_free_resources;
  30 +               goto out_free_mux_clock;
  31         }
  32
  33         info->proc_reg = regulator_get_optional(cpu_dev, "proc");
  34 @@ -428,13 +428,13 @@ static int mtk_cpu_dvfs_info_init(struct
  35                 ret = PTR_ERR(info->proc_reg);
  36                 dev_err_probe(cpu_dev, ret,
  37                               "cpu%d: failed to get proc regulator\n", cpu);
  38 -               goto out_free_resources;
  39 +               goto out_free_inter_clock;
  40         }
  41
  42         ret = regulator_enable(info->proc_reg);
  43         if (ret) {
  44                 dev_warn(cpu_dev, "cpu%d: failed to enable vproc\n", cpu);
  45 -               goto out_free_resources;
  46 +               goto out_free_proc_reg;
  47         }
  48
  49         /* Both presence and absence of sram regulator are valid cases. */
  50 @@ -442,14 +442,14 @@ static int mtk_cpu_dvfs_info_init(struct
  51         if (IS_ERR(info->sram_reg)) {
  52                 ret = PTR_ERR(info->sram_reg);
  53                 if (ret == -EPROBE_DEFER)
  54 -                       goto out_free_resources;
  55 +                       goto out_disable_proc_reg;
  56
  57                 info->sram_reg = NULL;
  58         } else {
  59                 ret = regulator_enable(info->sram_reg);
  60                 if (ret) {
  61                         dev_warn(cpu_dev, "cpu%d: failed to enable vsram\n", cpu);
  62 -                       goto out_free_resources;
  63 +                       goto out_free_sram_reg;
  64                 }
  65         }
  66
  67 @@ -458,13 +458,13 @@ static int mtk_cpu_dvfs_info_init(struct
  68         if (ret) {
  69                 dev_err(cpu_dev,
  70                         "cpu%d: failed to get OPP-sharing information\n", cpu);
  71 -               goto out_free_resources;
  72 +               goto out_disable_sram_reg;
  73         }
  74
  75         ret = dev_pm_opp_of_cpumask_add_table(&info->cpus);
  76         if (ret) {
  77                 dev_warn(cpu_dev, "cpu%d: no OPP table\n", cpu);
  78 -               goto out_free_resources;
  79 +               goto out_disable_sram_reg;
  80         }
  81
  82         ret = clk_prepare_enable(info->cpu_clk);
  83 @@ -533,43 +533,41 @@ out_disable_mux_clock:
  84  out_free_opp_table:
  85         dev_pm_opp_of_cpumask_remove_table(&info->cpus);
  86
  87 -out_free_resources:
  88 -       if (regulator_is_enabled(info->proc_reg))
  89 -               regulator_disable(info->proc_reg);
  90 -       if (info->sram_reg && regulator_is_enabled(info->sram_reg))
  91 +out_disable_sram_reg:
  92 +       if (info->sram_reg)
  93                 regulator_disable(info->sram_reg);
  94
  95 -       if (!IS_ERR(info->proc_reg))
  96 -               regulator_put(info->proc_reg);
  97 -       if (!IS_ERR(info->sram_reg))
  98 +out_free_sram_reg:
  99 +       if (info->sram_reg)
 100                 regulator_put(info->sram_reg);
 101 -       if (!IS_ERR(info->cpu_clk))
 102 -               clk_put(info->cpu_clk);
 103 -       if (!IS_ERR(info->inter_clk))
 104 -               clk_put(info->inter_clk);
 105 +
 106 +out_disable_proc_reg:
 107 +       regulator_disable(info->proc_reg);
 108 +
 109 +out_free_proc_reg:
 110 +       regulator_put(info->proc_reg);
 111 +
 112 +out_free_inter_clock:
 113 +       clk_put(info->inter_clk);
 114 +
 115 +out_free_mux_clock:
 116 +       clk_put(info->cpu_clk);
 117
 118         return ret;
 119  }
 120
 121  static void mtk_cpu_dvfs_info_release(struct mtk_cpu_dvfs_info *info)
 122  {
 123 -       if (!IS_ERR(info->proc_reg)) {
 124 -               regulator_disable(info->proc_reg);
 125 -               regulator_put(info->proc_reg);
 126 -       }
 127 -       if (!IS_ERR(info->sram_reg)) {
 128 +       regulator_disable(info->proc_reg);
 129 +       regulator_put(info->proc_reg);
 130 +       if (info->sram_reg) {
 131                 regulator_disable(info->sram_reg);
 132                 regulator_put(info->sram_reg);
 133         }
 134 -       if (!IS_ERR(info->cpu_clk)) {
 135 -               clk_disable_unprepare(info->cpu_clk);
 136 -               clk_put(info->cpu_clk);
 137 -       }
 138 -       if (!IS_ERR(info->inter_clk)) {
 139 -               clk_disable_unprepare(info->inter_clk);
 140 -               clk_put(info->inter_clk);
 141 -       }
 142 -
 143 +       clk_disable_unprepare(info->cpu_clk);
 144 +       clk_put(info->cpu_clk);
 145 +       clk_disable_unprepare(info->inter_clk);
 146 +       clk_put(info->inter_clk);
 147         dev_pm_opp_of_cpumask_remove_table(&info->cpus);
 148         dev_pm_opp_unregister_notifier(info->cpu_dev, &info->opp_nb);
 149  }