Based on confirmation from Christian, it seems my understanding of the
design was not correct, and user must add a list of registers to dump.
That resolves most of my comments automatically, @Amar, please fix a max
register condition in the loop, to handle the negative testing case and
the uint32_t stuff. With those two changes in place, feel free to use
for this patch:
Reviewed-by: Shashank Sharma <shashank.sharma@xxxxxxx>
- Shashank
On 2/8/2022 3:31 PM, Sharma, Shashank wrote:
>> User only update the list of reg offsets on init, there is no
>> predefined reg offset from kernel code.
I missed this comment in the last patch, and this makes me a bit
confused. During the design phase, did we agree to have this whole list
loaded from user ? which means that if user doesn't define the list at
init, we will not send the trace_event().
Or was it kernel has a list, and user can modify if he wants to, and we
will dump the values as per the register list.
@Christian ?
Regards
Shashank
On 2/8/2022 3:18 PM, Sharma, Shashank wrote:
On 2/8/2022 2:39 PM, Somalapuram, Amaranath wrote:
On 2/8/2022 4:43 PM, Sharma, Shashank wrote:
I thought we spoke and agreed about:
- Not doing dynamic memory allocation during a reset call,
as there is a redesign debugfs call will happen during the
application initialization and not during reset.
- Not doing string operations, but just dumping register values by
index.
I think your referring to the second patch which happens during reset
and no string operation in second patch.
Pls see my comment in the end.
NACK !
- Shashank
Amar,
Apart from the long comment,there are a few more bugs in the patch,
which I have mentioned here inline. Please check them out.
- Shashank
On 2/8/2022 9:18 AM, Christian König wrote:
Am 08.02.22 um 09:16 schrieb Somalapuram Amaranath:
List of register to be populated for dump collection during the
GPU reset.
Signed-off-by: Somalapuram Amaranath <Amaranath.Somalapuram@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 3 ++
drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 60
+++++++++++++++++++++
2 files changed, 63 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index b85b67a88a3d..78fa46f959c5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1097,6 +1097,9 @@ struct amdgpu_device {
struct amdgpu_reset_control *reset_cntl;
uint32_t ip_versions[HW_ID_MAX][HWIP_MAX_INSTANCE];
+
+ /* reset dump register */
+ long reset_dump_reg_list[128];
I don't have time for a full review, but using long here certainly
makes no sense.
long is either 32bit or 64bit depending on the CPU architecture.
Regards,
Christian.
will change uint32_t.
};
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..dad268e8a81a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
@@ -1609,6 +1609,64 @@ 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;
+ int i, r, len;
+
+ reg_offset = kmalloc(2048, GFP_KERNEL);
We also want to understand how does the value 2048 came into picture,
probably a macro which calculates the size preprocessing time will
work better.
#define #define N_REGS_DUMP_GPU_RESET 10
#define BUFFER_SZ(N_REGS_DUMP_GPU_RESET * (sizeof uint64_t) + 1)
This first macro can be used later for the loop count for registers as
well.
+ memset(reg_offset, 0, 2048);
+ for (i = 0; adev->reset_dump_reg_list[i] != 0; i++)
This loop termination condition is incorrect, why are we running the
loop until adev->reset_dump_reg_list[i] != 0 ?
What if I have 10 registers to dump, but my 4th register value is 0
? It will break the loop at 4 and we will not get all values.
agreed, i try to avoid one more variable in adev
Not by the cost of logic of course :).
Now you can run this loop here.
for (i = 0; i < N_REGS...; i++) {
register_value_copy_here;
}
+ sprintf(reg_offset + strlen(reg_offset), "0x%lx ",
adev->reset_dump_reg_list[i]);
+
+ sprintf(reg_offset + strlen(reg_offset), "\n");
+ len = strlen(reg_offset);
+
+ if (*pos >= len)
+ return 0;
+
+ r = copy_to_user(buf, reg_offset, len);
+ *pos += len - r;
+ kfree(reg_offset);
Also, why are we doing a dynamic memory allocation for reg_offest ?
We can simply use adev->reset_dump_reg_list[i] isnt't it ?
simply
for (i=0; i<num_of_regs;i++) {
copy_to_user(buf, adev->reg_list[i], sizeof(uint64_t));
}
Or without even a loop, simply:
copy_to_user(buf, &adev->reg_list, num_regs * sizeof(uint64_t));
- Shashank
it will not be in user readable format for debugfs, (if non readable
is acceptable I will change this)
We are just adding 0x in front of the reg value, so honestly I don't
see a huge improvement in the user readability, but if you still want
to do the dynamic allocation of memory, add the register offset or
name as well, I mean then it should read like:
0x1234 = 0xABCD
0x1238 = 0xFFFF
- Shashank
+
+ return len - r;
+}
+
+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;
+ int ret, i = 0;
+
+ reg_offset = kmalloc(size, GFP_KERNEL);
+ memset(reg_offset, 0, size);
+ ret = copy_from_user(reg_offset, buf, size);
+
We are not allowing user to write into the list, so this whole
function can just be a NOOP.
- Shashank
User only update the list of reg offsets on init, there is no
predefined reg offset from kernel code.
+ if (ret)
+ return -EFAULT;
+
+ while ((reg = strsep(®_offset, " ")) != NULL) {
+ ret = kstrtol(reg, 16, &adev->reset_dump_reg_list[i]);
+ if (ret)
+ return -EINVAL;
+ i++;
+ }
+
+ kfree(reg_offset);
+
+ 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 +1730,8 @@ 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;
