ftrace: mmiotrace, updates

here is a patch that makes mmiotrace work almost well within the tracing
framework. The patch applies on top of my previous patch. I have my own
output formatting in place now.

Summary of changes:
- fix the NULL dereference that was due to not calling tracing_reset()
- add print_line() callback into struct tracer
- implement print_line() for mmiotrace, producing up-to-spec text
- add my output header, but that is not really called in the right place
- rewrote the main structs in mmiotrace
- added two new trace entry types: TRACE_MMIO_RW and TRACE_MMIO_MAP
- made some functions in trace.c non-static
- check current==NULL in tracing_generic_entry_update()
- fix(?) comparison in trace_seq_printf()

Things seem to work fine except a few issues. Markers (text lines injected
into mmiotrace log) are missing, I did not feel hacking them in before we
have variable length entries. My output header is printed only for 'trace'
file, but not 'trace_pipe'. For some reason, despite my quick fix,
iter->trace is NULL in print_trace_line() when called from 'trace_pipe'
file, which means I don't get proper output formatting.

I only tried by loading nouveau.ko, which just detects the card, and that
is traced fine. I didn't try further. Map, two reads and unmap. Works
perfectly.

I am missing the information about overflows, I'd prefer to have a
counter for lost events. I didn't try, but I guess currently there is no
way of knowning when it overflows?

So, not too far from being fully operational, it seems :-)
And looking at the diffstat, there also is some 700-900 lines of user space
code that just became obsolete.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 25 insertions, 60 deletions

diff --git a/include/linux/mmiotrace.h b/include/linux/mmiotrace.h
index 579b3b06..c88a9c1 100644
--- a/include/linux/mmiotrace.h
+++ b/include/linux/mmiotrace.h
@@ -54,73 +54,38 @@ static inline void mmiotrace_iounmap(volatile void __iomem *addr)
 }
 #endif /* CONFIG_MMIOTRACE_HOOKS */
 
-/* in kernel/trace/trace_mmiotrace.c */
-extern int __init init_mmiotrace(void);
-extern void enable_mmiotrace(void);
-extern void disable_mmiotrace(void);
-extern void mmio_trace_record(u32 type, unsigned long addr, unsigned long arg);
-
-#endif /* __KERNEL__ */
-
-
-/*
- * If you change anything here, you must bump MMIO_VERSION.
- * This is the relay data format for user space.
- */
-#define MMIO_VERSION 0x04
-
-/* mm_io_header.type */
-#define MMIO_OPCODE_MASK 0xff
-#define MMIO_OPCODE_SHIFT 0
-#define MMIO_WIDTH_MASK 0xff00
-#define MMIO_WIDTH_SHIFT 8
-#define MMIO_MAGIC (0x6f000000 | (MMIO_VERSION<<16))
-#define MMIO_MAGIC_MASK 0xffff0000
-
-enum mm_io_opcode {          /* payload type: */
-	MMIO_READ = 0x1,     /* struct mm_io_rw */
-	MMIO_WRITE = 0x2,    /* struct mm_io_rw */
-	MMIO_PROBE = 0x3,    /* struct mm_io_map */
-	MMIO_UNPROBE = 0x4,  /* struct mm_io_map */
+enum mm_io_opcode {
+	MMIO_READ = 0x1,     /* struct mmiotrace_rw */
+	MMIO_WRITE = 0x2,    /* struct mmiotrace_rw */
+	MMIO_PROBE = 0x3,    /* struct mmiotrace_map */
+	MMIO_UNPROBE = 0x4,  /* struct mmiotrace_map */
 	MMIO_MARKER = 0x5,   /* raw char data */
-	MMIO_UNKNOWN_OP = 0x6, /* struct mm_io_rw */
+	MMIO_UNKNOWN_OP = 0x6, /* struct mmiotrace_rw */
 };
 
-struct mm_io_header {
-	__u32 type;     /* see MMIO_* macros above */
-	__u32 sec;      /* timestamp */
-	__u32 nsec;
-	__u32 pid;      /* PID of the process, or 0 for kernel core */
-	__u16 data_len; /* length of the following payload */
+struct mmiotrace_rw {
+	unsigned long phys;	/* PCI address of register */
+	unsigned long value;
+	unsigned long pc;	/* optional program counter */
+	int map_id;
+	unsigned char opcode;	/* one of MMIO_{READ,WRITE,UNKNOWN_OP} */
+	unsigned char width;	/* size of register access in bytes */
 };
 
-struct mm_io_rw {
-	__u64 address; /* virtual address of register */
-	__u64 value;
-	__u64 pc;      /* optional program counter */
+struct mmiotrace_map {
+	unsigned long phys;	/* base address in PCI space */
+	unsigned long virt;	/* base virtual address */
+	unsigned long len;	/* mapping size */
+	int map_id;
+	unsigned char opcode;	/* MMIO_PROBE or MMIO_UNPROBE */
 };
 
-struct mm_io_map {
-	__u64 phys;  /* base address in PCI space */
-	__u64 addr;  /* base virtual address */
-	__u64 len;   /* mapping size */
-	__u64 pc;    /* optional program counter */
-};
-
-
-/*
- * These structures are used to allow a single relay_write()
- * call to write a full packet.
- */
-
-struct mm_io_header_rw {
-	struct mm_io_header header;
-	struct mm_io_rw rw;
-} __attribute__((packed));
+/* in kernel/trace/trace_mmiotrace.c */
+extern void enable_mmiotrace(void);
+extern void disable_mmiotrace(void);
+extern void mmio_trace_rw(struct mmiotrace_rw *rw);
+extern void mmio_trace_mapping(struct mmiotrace_map *map);
 
-struct mm_io_header_map {
-	struct mm_io_header header;
-	struct mm_io_map map;
-} __attribute__((packed));
+#endif /* __KERNEL__ */
 
 #endif /* MMIOTRACE_H */