powerpc/xmon: add debugfs entry for xmon (de78ae6c) · Commits · 戴 / test

Currently the xmon debugger is set only via kernel boot command-line. It's disabled by default, and can be enabled with "xmon=on" on the command-line. Also, xmon may be accessed via sysrq mechanism. But we cannot enable/disable xmon in runtime, it needs kernel reload. This patch introduces a debugfs entry for xmon, allowing user to query its current state and change it if desired. Basically, the "xmon" file to read from/write to is under the debugfs mount point, on powerpc directory. It's a simple attribute, value 0 meaning xmon is disabled and value 1 the opposite. Writing these states to the file will take immediate effect in the debugger. Signed-off-by:

Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/xmon/xmon.c

+31 −0

Original line number	Diff line number	Diff line
		@@ -29,6 +29,10 @@
		#include <linux/nmi.h>
		#include <linux/ctype.h>

		#ifdef CONFIG_DEBUG_FS
		#include <linux/debugfs.h>
		#endif

		#include <asm/ptrace.h>
		#include <asm/string.h>
		#include <asm/prom.h>
		@@ -3316,6 +3320,33 @@ static int __init setup_xmon_sysrq(void)
		device_initcall(setup_xmon_sysrq);
		#endif /* CONFIG_MAGIC_SYSRQ */

		#ifdef CONFIG_DEBUG_FS
		static int xmon_dbgfs_set(void *data, u64 val)
		{
		xmon_on = !!val;
		xmon_init(xmon_on);

		return 0;
		}

		static int xmon_dbgfs_get(void data, u64 val)
		{
		*val = xmon_on;
		return 0;
		}

		DEFINE_SIMPLE_ATTRIBUTE(xmon_dbgfs_ops, xmon_dbgfs_get,
		xmon_dbgfs_set, "%llu\n");

		static int __init setup_xmon_dbgfs(void)
		{
		debugfs_create_file("xmon", 0600, powerpc_debugfs_root, NULL,
		&xmon_dbgfs_ops);
		return 0;
		}
		device_initcall(setup_xmon_dbgfs);
		#endif /* CONFIG_DEBUG_FS */

		static int xmon_early __initdata;

		static int __init early_parse_xmon(char *p)

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