Am 17.02.22 um 15:29 schrieb Somalapuram Amaranath:
List of register populated for dump collection during the GPU reset.

Signed-off-by: Somalapuram Amaranath <amaranath.somalapu...@amd.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu.h         |   4 +
  drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 112 ++++++++++++++++++++
  2 files changed, 116 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index b85b67a88a3d..6e35f2c4c869 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1097,6 +1097,10 @@ struct amdgpu_device {
struct amdgpu_reset_control *reset_cntl;
        uint32_t                        
ip_versions[HW_ID_MAX][HWIP_MAX_INSTANCE];
+
+       /* reset dump register */
+       uint32_t                        *reset_dump_reg_list;
+       int                             num_regs;
  };
static inline struct amdgpu_device *drm_to_adev(struct drm_device *ddev)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
index 164d6a9e9fbb..ad807350d13e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
@@ -1609,6 +1609,116 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_ib_preempt, NULL,
  DEFINE_DEBUGFS_ATTRIBUTE(fops_sclk_set, NULL,
                        amdgpu_debugfs_sclk_set, "%llu\n");
+static ssize_t amdgpu_reset_dump_register_list_read(struct file *f,
+                               char __user *buf, size_t size, loff_t *pos)
+{
+       struct amdgpu_device *adev = (struct amdgpu_device 
*)file_inode(f)->i_private;
+       char reg_offset[11];
+       int i, ret, len = 0;
+
+       if (*pos)
+               return 0;
+
+       ret = down_read_killable(&adev->reset_sem);

Using the _killable() variant is a really good idea here.

+
+       if (ret)
+               return ret;
+
+       if (adev->num_regs == 0)
+               return 0;
+
+       for (i = 0; i < adev->num_regs; i++) {
+               sprintf(reg_offset, "0x%x ", adev->reset_dump_reg_list[i]);
+               ret = copy_to_user(buf + len, reg_offset, strlen(reg_offset));

Uff, I'm not 100% sure if we can do copy_to_user without dropping the lock.

+
+               if (ret)
+                       return -EFAULT;

But returning here without dropping the lock is certainly incorrect.

+
+               len += strlen(reg_offset);
+       }
+
+       up_read(&adev->reset_sem);
+
+       ret = copy_to_user(buf + len, "\n", 1);
+
+       if (ret)
+               return -EFAULT;
+
+       len++;
+       *pos += len;
+
+       return len;
+}
+
+static ssize_t amdgpu_reset_dump_register_list_write(struct file *f,
+                       const char __user *buf, size_t size, loff_t *pos)
+{
+       struct amdgpu_device *adev = (struct amdgpu_device 
*)file_inode(f)->i_private;
+       char *reg_offset, *reg, reg_temp[11];
+       uint32_t reg_list[128];
+       int ret, i = 0, len = 0;
+
+       do {
+               reg_offset = reg_temp;
+               memset(reg_offset,  0, 11);
+               ret = copy_from_user(reg_offset, buf + len, min(11, 
((int)size-len)));
+
+               if (ret)
+                       return -EFAULT;
+
+               if (strncmp(reg_offset, "clear", 5) == 0) {

Please completely drop the idea with the clear here, that should be unnecessary.

+
+                       ret = down_read_killable(&adev->reset_sem);
+
+                       if (ret)
+                               return ret;
+
+                       kfree(adev->reset_dump_reg_list);
+                       adev->reset_dump_reg_list = NULL;
+                       adev->num_regs = 0;
+
+                       up_read(&adev->reset_sem);
+
+                       return size;
+               }
+
+               reg = strsep(&reg_offset, " ");
+               ret = kstrtouint(reg, 16, &reg_list[i]);
+
+               if (ret)
+                       return -EFAULT;
+
+               len += strlen(reg) + 1;
+               i++;
+
+       } while (len < size);
+
+       adev->reset_dump_reg_list =  krealloc_array(adev->reset_dump_reg_list,
+                                               i, sizeof(uint32_t), 
GFP_KERNEL);

Well that still doesn't looks like what we need.

Here is once more the roughly what the code should do:

unsigned int i;
uint32_t *tmp;

i = 0;
do {
    tmp = krealloc_array(tmp, i, sizeof(uint32_t), GFP_KERNEL);
    copy_from_user().....
    i++;
} while (len < size);

down_write_killable();
...

swap(adev->reset_dump_reg_list, tmp);
adev->num_regs = i;
up_write();

Regards,
Christian.

+
+       ret = down_read_killable(&adev->reset_sem);
+
+       if (ret)
+               return ret;
+
+       adev->num_regs = i;
+       memcpy(adev->reset_dump_reg_list, reg_list,
+                       sizeof(uint32_t) * adev->num_regs);
+
+       up_read(&adev->reset_sem);
+
+       return size;
+}
+
+
+
+static const struct file_operations amdgpu_reset_dump_register_list = {
+       .owner = THIS_MODULE,
+       .read = amdgpu_reset_dump_register_list_read,
+       .write = amdgpu_reset_dump_register_list_write,
+       .llseek = default_llseek
+};
+
  int amdgpu_debugfs_init(struct amdgpu_device *adev)
  {
        struct dentry *root = adev_to_drm(adev)->primary->debugfs_root;
@@ -1672,6 +1782,8 @@ int amdgpu_debugfs_init(struct amdgpu_device *adev)
                            &amdgpu_debugfs_test_ib_fops);
        debugfs_create_file("amdgpu_vm_info", 0444, root, adev,
                            &amdgpu_debugfs_vm_info_fops);
+       debugfs_create_file("amdgpu_reset_dump_register_list", 0644, root, adev,
+                           &amdgpu_reset_dump_register_list);
adev->debugfs_vbios_blob.data = adev->bios;
        adev->debugfs_vbios_blob.size = adev->bios_size;

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