c637e4861c
Introduce module parameter acpi.aml_debug_output. With acpi.aml_debug_output set, we can get AML debug object output (Store (AAA, Debug)), even with CONFIG_ACPI_DEBUG cleared. Together with the runtime custom method mechanism, we can debug AML code problems without rebuilding the kernel. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
94 lines
1.9 KiB
C
94 lines
1.9 KiB
C
/*
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* debugfs.c - ACPI debugfs interface to userspace.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/uaccess.h>
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#include <linux/debugfs.h>
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#include <acpi/acpi_drivers.h>
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#define _COMPONENT ACPI_SYSTEM_COMPONENT
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ACPI_MODULE_NAME("debugfs");
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/* /sys/modules/acpi/parameters/aml_debug_output */
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module_param_named(aml_debug_output, acpi_gbl_enable_aml_debug_object,
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bool, 0644);
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MODULE_PARM_DESC(aml_debug_output,
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"To enable/disable the ACPI Debug Object output.");
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/* /sys/kernel/debug/acpi/custom_method */
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static ssize_t cm_write(struct file *file, const char __user * user_buf,
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size_t count, loff_t *ppos)
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{
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static char *buf;
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static int uncopied_bytes;
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struct acpi_table_header table;
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acpi_status status;
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if (!(*ppos)) {
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/* parse the table header to get the table length */
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if (count <= sizeof(struct acpi_table_header))
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return -EINVAL;
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if (copy_from_user(&table, user_buf,
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sizeof(struct acpi_table_header)))
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return -EFAULT;
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uncopied_bytes = table.length;
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buf = kzalloc(uncopied_bytes, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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}
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if (uncopied_bytes < count) {
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kfree(buf);
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return -EINVAL;
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}
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if (copy_from_user(buf + (*ppos), user_buf, count)) {
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kfree(buf);
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return -EFAULT;
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}
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uncopied_bytes -= count;
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*ppos += count;
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if (!uncopied_bytes) {
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status = acpi_install_method(buf);
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kfree(buf);
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if (ACPI_FAILURE(status))
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return -EINVAL;
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add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
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}
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return count;
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}
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static const struct file_operations cm_fops = {
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.write = cm_write,
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};
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int __init acpi_debugfs_init(void)
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{
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struct dentry *acpi_dir, *cm_dentry;
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acpi_dir = debugfs_create_dir("acpi", NULL);
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if (!acpi_dir)
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goto err;
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cm_dentry = debugfs_create_file("custom_method", S_IWUGO,
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acpi_dir, NULL, &cm_fops);
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if (!cm_dentry)
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goto err;
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return 0;
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err:
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if (acpi_dir)
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debugfs_remove(acpi_dir);
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return -EINVAL;
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}
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