diff options
| author | Shyam Sundar S K <Shyam-sundar.S-k@amd.com> | 2023-10-10 20:20:02 +0530 |
|---|---|---|
| committer | Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> | 2023-10-12 16:55:31 +0300 |
| commit | b136225746a9793bdff9c78b215eac4f64bf21f2 (patch) | |
| tree | 39958d52fbbe113db07d097179e7984751b5c5c6 /drivers/platform | |
| parent | d9f421da6b9287000f8253628d54cf89b0c14da5 (diff) | |
platform/x86/amd/pmc: Handle overflow cases where the num_samples range is higher
In amd_pmc_stb_debugfs_open_v2(), the stb buffer is created based on the
num_samples and the read/write pointer offset. This holds good when the
num_samples reported by PMFW is less than S2D_TELEMETRY_BYTES_MAX; where
the stb buffer gets filled from 0th position until
S2D_TELEMETRY_BYTES_MAX - 1 based on the read/write pointer offset.
But when the num_samples exceeds the S2D_TELEMETRY_BYTES_MAX, the current
code does not handle it well as it does not account for the cases where
the stb buffer has to filled up as a circular buffer.
Handle this scenario into two cases, where first memcpy will have the
samples from location:
(num_samples % S2D_TELEMETRY_BYTES_MAX) - (S2D_TELEMETRY_BYTES_MAX - 1)
and next memcpy will have the newest ones i.e.
0 - (num_samples % S2D_TELEMETRY_BYTES_MAX - 1)
Suggested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sanket Goswami <Sanket.Goswami@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20231010145003.139932-2-Shyam-sundar.S-k@amd.com
[ij: renamed flex_arr -> stb_data_arr]
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Diffstat (limited to 'drivers/platform')
| -rw-r--r-- | drivers/platform/x86/amd/pmc/pmc.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/drivers/platform/x86/amd/pmc/pmc.c b/drivers/platform/x86/amd/pmc/pmc.c index 77dca9a1f00f..bc254e1fa71a 100644 --- a/drivers/platform/x86/amd/pmc/pmc.c +++ b/drivers/platform/x86/amd/pmc/pmc.c @@ -276,16 +276,23 @@ static int amd_pmc_stb_debugfs_open_v2(struct inode *inode, struct file *filp) stb_data_arr->size = fsize; - /* Start capturing data from the last push location */ + /* + * Start capturing data from the last push location. + * This is for general cases, where the stb limits + * are meant for standard usage. + */ if (num_samples > S2D_TELEMETRY_BYTES_MAX) { - fsize = S2D_TELEMETRY_BYTES_MAX; - stb_rdptr_offset = num_samples - fsize; + /* First read oldest data starting 1 behind last write till end of ringbuffer */ + stb_rdptr_offset = num_samples % S2D_TELEMETRY_BYTES_MAX; + fsize = S2D_TELEMETRY_BYTES_MAX - stb_rdptr_offset; + + memcpy_fromio(stb_data_arr->data, dev->stb_virt_addr + stb_rdptr_offset, fsize); + /* Second copy the newer samples from offset 0 - last write */ + memcpy_fromio(stb_data_arr->data + fsize, dev->stb_virt_addr, stb_rdptr_offset); } else { - fsize = num_samples; - stb_rdptr_offset = 0; + memcpy_fromio(stb_data_arr->data, dev->stb_virt_addr, fsize); } - memcpy_fromio(stb_data_arr->data, dev->stb_virt_addr + stb_rdptr_offset, fsize); filp->private_data = stb_data_arr; return 0; |