On 12/5/2025 12:20 PM, Yo-Jung Leo Lin (AMD) wrote:
Add a uma/ directory containing two sysfs files as interfaces to
inspect or change UMA carveout size. These files are:
- uma/carveout_options: a read-only file listing all the available
UMA allocation options and their index.
- uma/carveout: a file that is both readable and writable. On read,
it shows the index of the current setting. Writing a valid index
into this file allows users to change the UMA carveout size to that
option on the next boot.
Co-developed-by: Mario Limonciello (AMD) <[email protected]>
Signed-off-by: Mario Limonciello (AMD) <[email protected]>
Reviewed-by: Alex Deucher <[email protected]>
Signed-off-by: Yo-Jung Leo Lin (AMD) <[email protected]>
---
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 4 +
drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 7 ++
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 138 +++++++++++++++++++++++++++++
3 files changed, 149 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 6bf626a51dfc..177376ff5811 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1846,4 +1846,8 @@ void amdgpu_device_set_uid(struct amdgpu_uid *uid_info,
uint64_t uid);
uint64_t amdgpu_device_get_uid(struct amdgpu_uid *uid_info,
enum amdgpu_uid_type type, uint8_t inst);
+
+int amdgpu_acpi_uma_option_init(struct amdgpu_device *adev);
+void amdgpu_acpi_uma_option_fini(struct amdgpu_device *adev);
+
#endif
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
index bdafcde51107..b2779fc2f712 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
@@ -1288,6 +1288,12 @@ static int amdgpu_acpi_event(struct notifier_block *nb,
int amdgpu_acpi_init(struct amdgpu_device *adev)
{
struct amdgpu_atif *atif = &amdgpu_acpi_priv.atif;
+ int rc;
+
+ rc = amdgpu_acpi_uma_option_init(adev);
+
+ if (rc)
+ drm_dbg(adev_to_drm(adev), "Not creating uma carveout interfaces:
%d", rc);
if (atif->notifications.brightness_change) {
if (adev->dc_enabled) {
@@ -1340,6 +1346,7 @@ void amdgpu_acpi_get_backlight_caps(struct
amdgpu_dm_backlight_caps *caps)
void amdgpu_acpi_fini(struct amdgpu_device *adev)
{
unregister_acpi_notifier(&adev->acpi_nb);
+ amdgpu_acpi_uma_option_fini(adev);
}
/**
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index a7594ae44b20..979298d9c213 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -36,6 +36,7 @@
#include <linux/pci.h>
#include <linux/pci-p2pdma.h>
#include <linux/apple-gmux.h>
+#include <linux/nospec.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_client_event.h>
@@ -7835,3 +7836,140 @@ u64 amdgpu_device_get_uid(struct amdgpu_uid *uid_info,
return uid_info->uid[type][inst];
}
+
+static ssize_t carveout_options_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct drm_device *ddev = dev_get_drvdata(dev);
+ struct amdgpu_device *adev = drm_to_adev(ddev);
+ struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
+ uint32_t memory_carved;
+ ssize_t size = 0;
+
+ if (!uma_info || !uma_info->num_entries)
+ return -ENODEV;
+
+ for (int i = 0; i < uma_info->num_entries; i++) {
+ memory_carved = uma_info->entries[i].memory_carved_mb;
+ if (memory_carved >= SZ_1G/SZ_1M) {
+ size += sysfs_emit_at(buf, size, "%d: %s (%u GB)\n",
+ i,
+ uma_info->entries[i].name,
+ memory_carved >> 10);
+ } else {
+ size += sysfs_emit_at(buf, size, "%d: %s (%u MB)\n",
+ i,
+ uma_info->entries[i].name,
+ memory_carved);
+ }
+ }
+
+ return size;
+}
+static DEVICE_ATTR_RO(carveout_options);
+
+static ssize_t carveout_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct drm_device *ddev = dev_get_drvdata(dev);
+ struct amdgpu_device *adev = drm_to_adev(ddev);
+
+ return sysfs_emit(buf, "%u\n", adev->uma_info.uma_option_index);
+}
+
+static ssize_t carveout_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct drm_device *ddev = dev_get_drvdata(dev);
+ struct amdgpu_device *adev = drm_to_adev(ddev);
+ struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
+ struct amdgpu_uma_carveout_option *opt;
+ unsigned long val;
+ uint8_t flags;
+ int r;
+
+ r = kstrtoul(buf, 10, &val);
+ if (r)
+ return r;
+
+ if (val >= uma_info->num_entries)
+ return -EINVAL;
+
+ val = array_index_nospec(val, uma_info->num_entries);
+ opt = &uma_info->entries[val];
+
+ if (!(opt->flags & AMDGPU_UMA_FLAG_AUTO) &&
+ !(opt->flags & AMDGPU_UMA_FLAG_CUSTOM)) {
+ drm_err_once(ddev, "Option %lu not supported due to lack of
Custom/Auto flag", val);
+ return -EINVAL;
+ }
+
+ flags = opt->flags;
+ flags &= ~((flags & AMDGPU_UMA_FLAG_AUTO) >> 1);
+
+ guard(mutex)(&uma_info->update_lock);
+
+ r = amdgpu_acpi_set_uma_allocation_size(adev, val, flags);
+ if (r)
+ return r;
+
+ uma_info->uma_option_index = val;
+
+ return count;
+}
+static DEVICE_ATTR_RW(carveout);
+
+static struct attribute *amdgpu_uma_attrs[] = {
+ &dev_attr_carveout.attr,
+ &dev_attr_carveout_options.attr,
+ NULL
+};
+
+const struct attribute_group amdgpu_uma_attr_group = {
+ .name = "uma",
+ .attrs = amdgpu_uma_attrs
+};
+
+int amdgpu_acpi_uma_option_init(struct amdgpu_device *adev)
+{
To clarify on the comment about moving this to amdgpu_device -
UMA option is a device specific option which could be set through acpi.
Options are retrieved through atom tables.
So the function names remain amdgpu_device_uma_option_init/fini() and
init/fini are called within amdgpu_device.c
Thanks,
Lijo
+ int rc;
+
+ if (!amdgpu_acpi_is_set_uma_allocation_size_supported())
+ return -ENODEV;
+
+ rc = amdgpu_atomfirmware_get_uma_carveout_info(adev, &adev->uma_info);
+ if (rc) {
+ drm_dbg(adev_to_drm(adev),
+ "Failed to parse UMA carveout info from VBIOS: %d\n",
rc);
+ goto out_info;
+ }
+
+ mutex_init(&adev->uma_info.update_lock);
+
+ rc = devm_device_add_group(adev->dev, &amdgpu_uma_attr_group);
+ if (rc) {
+ drm_dbg(adev_to_drm(adev), "Failed to add UMA carveout sysfs
interfaces %d\n", rc);
+ goto out_attr;
+ }
+
+ return 0;
+
+out_attr:
+ mutex_destroy(&adev->uma_info.update_lock);
+out_info:
+ return rc;
+}
+
+void amdgpu_acpi_uma_option_fini(struct amdgpu_device *adev)
+{
+ struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info;
+
+ if (!amdgpu_acpi_is_set_uma_allocation_size_supported())
+ return;
+
+ mutex_destroy(&uma_info->update_lock);
+ uma_info->num_entries = 0;
+}
