From a1a541d86f50a9957beeedb122a035870d602647 Mon Sep 17 00:00:00 2001 From: Zhang Rui Date: Wed, 2 Dec 2009 13:31:00 +0800 Subject: ACPI: support customizing ACPI control methods at runtime Introduce a new debugfs I/F (/sys/kernel/debug/acpi/custom_method) for ACPI, which can be used to customize the ACPI control methods at runtime. We can use this to debug the AML code level bugs instead of overriding the whole DSDT table, without rebuilding/rebooting kernel any more. Detailed description about how to use this debugfs I/F is stated in Documentation/acpi/method-customizing.txt Signed-off-by: Zhang Rui Signed-off-by: Len Brown --- drivers/acpi/debug.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 82 insertions(+), 1 deletion(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/debug.c b/drivers/acpi/debug.c index 8a690c3b8e2..0bedd1554f2 100644 --- a/drivers/acpi/debug.c +++ b/drivers/acpi/debug.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -195,6 +196,79 @@ static int param_get_trace_state(char *buffer, struct kernel_param *kp) module_param_call(trace_state, param_set_trace_state, param_get_trace_state, NULL, 0644); +/* -------------------------------------------------------------------------- + DebugFS Interface + -------------------------------------------------------------------------- */ + +static ssize_t cm_write(struct file *file, const char __user *user_buf, + size_t count, loff_t *ppos) +{ + static char *buf; + static int uncopied_bytes; + struct acpi_table_header table; + acpi_status status; + + if (!(*ppos)) { + /* parse the table header to get the table length */ + if (count <= sizeof(struct acpi_table_header)) + return -EINVAL; + if (copy_from_user(&table, user_buf, + sizeof(struct acpi_table_header))) + return -EFAULT; + uncopied_bytes = table.length; + buf = kzalloc(uncopied_bytes, GFP_KERNEL); + if (!buf) + return -ENOMEM; + } + + if (uncopied_bytes < count) { + kfree(buf); + return -EINVAL; + } + + if (copy_from_user(buf + (*ppos), user_buf, count)) { + kfree(buf); + return -EFAULT; + } + + uncopied_bytes -= count; + *ppos += count; + + if (!uncopied_bytes) { + status = acpi_install_method(buf); + kfree(buf); + if (ACPI_FAILURE(status)) + return -EINVAL; + } + + return count; +} + +static const struct file_operations cm_fops = { + .write = cm_write, +}; + +static int acpi_debugfs_init(void) +{ + struct dentry *acpi_dir, *cm_dentry; + + acpi_dir = debugfs_create_dir("acpi", NULL); + if (!acpi_dir) + goto err; + + cm_dentry = debugfs_create_file("custom_method", S_IWUGO, + acpi_dir, NULL, &cm_fops); + if (!cm_dentry) + goto err; + + return 0; + +err: + if (acpi_dir) + debugfs_remove(acpi_dir); + return -EINVAL; +} + /* -------------------------------------------------------------------------- FS Interface (/proc) -------------------------------------------------------------------------- */ @@ -286,7 +360,7 @@ static const struct file_operations acpi_system_debug_proc_fops = { }; #endif -int __init acpi_debug_init(void) +int __init acpi_procfs_init(void) { #ifdef CONFIG_ACPI_PROCFS struct proc_dir_entry *entry; @@ -321,3 +395,10 @@ int __init acpi_debug_init(void) return 0; #endif } + +int __init acpi_debug_init(void) +{ + acpi_debugfs_init(); + acpi_procfs_init(); + return 0; +} -- cgit v1.2.3-70-g09d2 From 4bab30a041a2f27807b0b2a7fd36c8c8695c90c8 Mon Sep 17 00:00:00 2001 From: Zhang Rui Date: Mon, 14 Dec 2009 11:24:18 +0800 Subject: ACPI: add kernel tainting after overriding an ACPI control method Add kernel tainting after overriding an ACPI control method successfully. Signed-off-by: Zhang Rui Signed-off-by: Len Brown --- drivers/acpi/debug.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/acpi') diff --git a/drivers/acpi/debug.c b/drivers/acpi/debug.c index 0bedd1554f2..cc421b7ae16 100644 --- a/drivers/acpi/debug.c +++ b/drivers/acpi/debug.c @@ -239,6 +239,7 @@ static ssize_t cm_write(struct file *file, const char __user *user_buf, kfree(buf); if (ACPI_FAILURE(status)) return -EINVAL; + add_taint(TAINT_OVERRIDDEN_ACPI_TABLE); } return count; -- cgit v1.2.3-70-g09d2