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Commit a0186bcf authored by Lv Zheng's avatar Lv Zheng Committed by Rafael J. Wysocki
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ACPI / sysfs: Add support to allow leading "\" missing in trace_method_name. 



Since _SB.PCI0 can be used as relative path from root and can be easily
converted into internal trace_method_name format, we allow users to specify
trace_method_name using relative paths from root.
Note this is useful for grub2 for which users failed to pass "\" from the
grub configuration file.

Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 7901a052

drivers/acpi/sysfs.c

+13 −15
Original line number Diff line number Diff line
@@ -164,14 +164,18 @@ static const struct kernel_param_ops param_ops_debug_level = { 
module_param_cb(debug_layer, &param_ops_debug_layer, &acpi_dbg_layer, 0644);

module_param_cb(debug_level, &param_ops_debug_level, &acpi_dbg_level, 0644);



static char* trace_method_name;

static bool trace_method_kmalloced;

static char trace_method_name[1024];



int param_set_trace_method_name(const char *val, const struct kernel_param *kp)

{

	u32 saved_flags = 0;

	bool is_abs_path = true;



	if (strlen(val) > 1024) {

	if (*val != '\\')

		is_abs_path = false;



	if ((is_abs_path && strlen(val) > 1023) ||

	    (!is_abs_path && strlen(val) > 1022)) {

		pr_err("%s: string parameter too long\n", kp->name);

		return -ENOSPC;

	}
@@ -187,19 +191,13 @@ int param_set_trace_method_name(const char *val, const struct kernel_param *kp) 
			       acpi_gbl_trace_dbg_layer,

			       0);



	if (trace_method_kmalloced)

		kfree(trace_method_name);

	trace_method_name = NULL;

	trace_method_kmalloced = false;



	/* This is a hack.  We can't kmalloc in early boot. */

	if (slab_is_available()) {

		trace_method_name = kstrdup(val, GFP_KERNEL);

		if (!trace_method_name)

			return -ENOMEM;

		trace_method_kmalloced = true;

	} else

		trace_method_name = (char *)val;

	if (is_abs_path)

		strcpy(trace_method_name, val);

	else {

		trace_method_name[0] = '\\';

		strcpy(trace_method_name+1, val);

	}



	/* Restore the original tracer state */

	(void)acpi_debug_trace(trace_method_name,