drivers/gpu/drm/i915/i915_mitigations.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/i915/i915_mitigations.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/i915/i915_mitigations.c
Extension
.c
Size
3135 bytes
Lines
148
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (first) {
			first = false;

			if (!strcmp(tok, "auto"))
				continue;

			new = 0;
			if (!strcmp(tok, "off"))
				continue;
		}

		if (*tok == '!') {
			enable = !enable;
			tok++;
		}

		if (!strncmp(tok, "no", 2)) {
			enable = !enable;
			tok += 2;
		}

		if (*tok == '\0')
			continue;

		for (i = 0; i < ARRAY_SIZE(names); i++) {
			if (!strcmp(tok, names[i])) {
				if (enable)
					new |= BIT(i);
				else
					new &= ~BIT(i);
				break;
			}
		}
		if (i == ARRAY_SIZE(names)) {
			pr_err("Bad \"%s.mitigations=%s\", '%s' is unknown\n",
			       DRIVER_NAME, val, tok);
			err = -EINVAL;
			break;
		}
	}
	kfree(str);
	if (err)
		return err;

	WRITE_ONCE(mitigations, new);
	return 0;
}

static int mitigations_get(char *buffer, const struct kernel_param *kp)
{
	unsigned long local = READ_ONCE(mitigations);
	int count, i;
	bool enable;

	if (!local)
		return scnprintf(buffer, PAGE_SIZE, "%s\n", "off");

	if (local & BIT(BITS_PER_LONG - 1)) {
		count = scnprintf(buffer, PAGE_SIZE, "%s,", "auto");
		enable = false;
	} else {
		enable = true;
		count = 0;
	}

	for (i = 0; i < ARRAY_SIZE(names); i++) {
		if ((local & BIT(i)) != enable)
			continue;

		count += scnprintf(buffer + count, PAGE_SIZE - count,
				   "%s%s,", enable ? "" : "!", names[i]);
	}

	buffer[count - 1] = '\n';
	return count;
}

static const struct kernel_param_ops ops = {
	.set = mitigations_set,
	.get = mitigations_get,
};

module_param_cb_unsafe(mitigations, &ops, NULL, 0600);
MODULE_PARM_DESC(mitigations,
"Selectively enable security mitigations for all Intel® GPUs in the system.\n"
"\n"
"  auto -- enables all mitigations required for the platform [default]\n"
"  off  -- disables all mitigations\n"
"\n"
"Individual mitigations can be enabled by passing a comma-separated string,\n"

Annotation

Implementation Notes