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>
diff --git a/arch/x86/kernel/mmiotrace/mmio-mod.c b/arch/x86/kernel/mmiotrace/mmio-mod.c
index c7a67d7..62abc281 100644
--- a/arch/x86/kernel/mmiotrace/mmio-mod.c
+++ b/arch/x86/kernel/mmiotrace/mmio-mod.c
@@ -37,11 +37,6 @@
#define NAME "mmiotrace: "
-/* This app's relay channel files will appear in /debug/mmio-trace */
-static const char APP_DIR[] = "mmio-trace";
-/* the marker injection file in /debug/APP_DIR */
-static const char MARKER_FILE[] = "mmio-marker";
-
struct trap_reason {
unsigned long addr;
unsigned long ip;
@@ -56,18 +51,15 @@
unsigned long id;
};
-static const size_t subbuf_size = 256*1024;
-
/* Accessed per-cpu. */
static DEFINE_PER_CPU(struct trap_reason, pf_reason);
-static DEFINE_PER_CPU(struct mm_io_header_rw, cpu_trace);
+static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
#if 0 /* XXX: no way gather this info anymore */
/* Access to this is not per-cpu. */
static DEFINE_PER_CPU(atomic_t, dropped);
#endif
-static struct dentry *dir;
static struct dentry *marker_file;
static DEFINE_MUTEX(mmiotrace_mutex);
@@ -82,24 +74,21 @@
* and trace_lock.
* - Routines depending on is_enabled() must take trace_lock.
* - trace_list users must hold trace_lock.
- * - is_enabled() guarantees that chan is valid.
+ * - is_enabled() guarantees that mmio_trace_record is allowed.
* - pre/post callbacks assume the effect of is_enabled() being true.
*/
/* module parameters */
-static unsigned int n_subbufs = 32*4;
static unsigned long filter_offset;
static int nommiotrace;
static int ISA_trace;
static int trace_pc;
-module_param(n_subbufs, uint, 0);
module_param(filter_offset, ulong, 0);
module_param(nommiotrace, bool, 0);
module_param(ISA_trace, bool, 0);
module_param(trace_pc, bool, 0);
-MODULE_PARM_DESC(n_subbufs, "Number of 256kB buffers, default 128.");
MODULE_PARM_DESC(filter_offset, "Start address of traced mappings.");
MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing.");
MODULE_PARM_DESC(ISA_trace, "Do not exclude the low ISA range.");
@@ -110,6 +99,7 @@
return atomic_read(&mmiotrace_enabled);
}
+#if 0 /* XXX: needs rewrite */
/*
* Write callback for the debugfs entry:
* Read a marker and write it to the mmio trace log
@@ -145,6 +135,7 @@
kfree(event);
return len;
}
+#endif
static void print_pte(unsigned long address)
{
@@ -198,9 +189,10 @@
unsigned long addr)
{
struct trap_reason *my_reason = &get_cpu_var(pf_reason);
- struct mm_io_header_rw *my_trace = &get_cpu_var(cpu_trace);
+ struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
const unsigned long instptr = instruction_pointer(regs);
const enum reason_type type = get_ins_type(instptr);
+ struct remap_trace *trace = p->user_data;
/* it doesn't make sense to have more than one active trace per cpu */
if (my_reason->active_traces)
@@ -212,23 +204,17 @@
my_reason->addr = addr;
my_reason->ip = instptr;
- my_trace->header.type = MMIO_MAGIC;
- my_trace->header.pid = 0;
- my_trace->header.data_len = sizeof(struct mm_io_rw);
- my_trace->rw.address = addr;
- /*
- * struct remap_trace *trace = p->user_data;
- * phys = addr - trace->probe.addr + trace->phys;
- */
+ my_trace->phys = addr - trace->probe.addr + trace->phys;
+ my_trace->map_id = trace->id;
/*
* Only record the program counter when requested.
* It may taint clean-room reverse engineering.
*/
if (trace_pc)
- my_trace->rw.pc = instptr;
+ my_trace->pc = instptr;
else
- my_trace->rw.pc = 0;
+ my_trace->pc = 0;
/*
* XXX: the timestamp recorded will be *after* the tracing has been
@@ -238,28 +224,25 @@
switch (type) {
case REG_READ:
- my_trace->header.type |=
- (MMIO_READ << MMIO_OPCODE_SHIFT) |
- (get_ins_mem_width(instptr) << MMIO_WIDTH_SHIFT);
+ my_trace->opcode = MMIO_READ;
+ my_trace->width = get_ins_mem_width(instptr);
break;
case REG_WRITE:
- my_trace->header.type |=
- (MMIO_WRITE << MMIO_OPCODE_SHIFT) |
- (get_ins_mem_width(instptr) << MMIO_WIDTH_SHIFT);
- my_trace->rw.value = get_ins_reg_val(instptr, regs);
+ my_trace->opcode = MMIO_WRITE;
+ my_trace->width = get_ins_mem_width(instptr);
+ my_trace->value = get_ins_reg_val(instptr, regs);
break;
case IMM_WRITE:
- my_trace->header.type |=
- (MMIO_WRITE << MMIO_OPCODE_SHIFT) |
- (get_ins_mem_width(instptr) << MMIO_WIDTH_SHIFT);
- my_trace->rw.value = get_ins_imm_val(instptr);
+ my_trace->opcode = MMIO_WRITE;
+ my_trace->width = get_ins_mem_width(instptr);
+ my_trace->value = get_ins_imm_val(instptr);
break;
default:
{
unsigned char *ip = (unsigned char *)instptr;
- my_trace->header.type |=
- (MMIO_UNKNOWN_OP << MMIO_OPCODE_SHIFT);
- my_trace->rw.value = (*ip) << 16 | *(ip + 1) << 8 |
+ my_trace->opcode = MMIO_UNKNOWN_OP;
+ my_trace->width = 0;
+ my_trace->value = (*ip) << 16 | *(ip + 1) << 8 |
*(ip + 2);
}
}
@@ -271,7 +254,7 @@
struct pt_regs *regs)
{
struct trap_reason *my_reason = &get_cpu_var(pf_reason);
- struct mm_io_header_rw *my_trace = &get_cpu_var(cpu_trace);
+ struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
/* this should always return the active_trace count to 0 */
my_reason->active_traces--;
@@ -282,20 +265,13 @@
switch (my_reason->type) {
case REG_READ:
- my_trace->rw.value = get_ins_reg_val(my_reason->ip, regs);
+ my_trace->value = get_ins_reg_val(my_reason->ip, regs);
break;
default:
break;
}
- /*
- * XXX: Several required values are ignored:
- * - mapping id
- * - program counter
- * Also the address should be physical, not virtual.
- */
- mmio_trace_record(my_trace->header.type, my_trace->rw.address,
- my_trace->rw.value);
+ mmio_trace_rw(my_trace);
put_cpu_var(cpu_trace);
put_cpu_var(pf_reason);
}
@@ -305,21 +281,11 @@
{
static atomic_t next_id;
struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
- struct mm_io_header_map event = {
- .header = {
- .type = MMIO_MAGIC |
- (MMIO_PROBE << MMIO_OPCODE_SHIFT),
- .sec = 0,
- .nsec = 0,
- .pid = 0,
- .data_len = sizeof(struct mm_io_map)
- },
- .map = {
- .phys = offset,
- .addr = (unsigned long)addr,
- .len = size,
- .pc = 0
- }
+ struct mmiotrace_map map = {
+ .phys = offset,
+ .virt = (unsigned long)addr,
+ .len = size,
+ .opcode = MMIO_PROBE
};
if (!trace) {
@@ -338,15 +304,13 @@
.phys = offset,
.id = atomic_inc_return(&next_id)
};
+ map.map_id = trace->id;
spin_lock_irq(&trace_lock);
if (!is_enabled())
goto not_enabled;
- /*
- * XXX: Insufficient data recorded!
- */
- mmio_trace_record(event.header.type, event.map.addr, event.map.len);
+ mmio_trace_mapping(&map);
list_add_tail(&trace->list, &trace_list);
if (!nommiotrace)
register_kmmio_probe(&trace->probe);
@@ -369,21 +333,11 @@
static void iounmap_trace_core(volatile void __iomem *addr)
{
- struct mm_io_header_map event = {
- .header = {
- .type = MMIO_MAGIC |
- (MMIO_UNPROBE << MMIO_OPCODE_SHIFT),
- .sec = 0,
- .nsec = 0,
- .pid = 0,
- .data_len = sizeof(struct mm_io_map)
- },
- .map = {
- .phys = 0,
- .addr = (unsigned long)addr,
- .len = 0,
- .pc = 0
- }
+ struct mmiotrace_map map = {
+ .phys = 0,
+ .virt = (unsigned long)addr,
+ .len = 0,
+ .opcode = MMIO_UNPROBE
};
struct remap_trace *trace;
struct remap_trace *tmp;
@@ -404,8 +358,8 @@
break;
}
}
- mmio_trace_record(event.header.type, event.map.addr,
- found_trace ? found_trace->id : -1);
+ map.map_id = (found_trace) ? found_trace->id : -1;
+ mmio_trace_mapping(&map);
not_enabled:
spin_unlock_irq(&trace_lock);
@@ -448,10 +402,12 @@
}
}
+#if 0 /* XXX: out of order */
static struct file_operations fops_marker = {
.owner = THIS_MODULE,
.write = write_marker
};
+#endif
void enable_mmiotrace(void)
{
@@ -464,9 +420,9 @@
#if 0 /* XXX: tracing does not support text entries */
marker_file = debugfs_create_file("marker", 0660, dir, NULL,
&fops_marker);
-#endif
if (!marker_file)
pr_err(NAME "marker file creation failed.\n");
+#endif
if (nommiotrace)
pr_info(NAME "MMIO tracing disabled.\n");
@@ -502,17 +458,3 @@
out:
mutex_unlock(&mmiotrace_mutex);
}
-
-int __init init_mmiotrace(void)
-{
- pr_debug(NAME "load...\n");
- if (n_subbufs < 2)
- return -EINVAL;
-
- dir = debugfs_create_dir(APP_DIR, NULL);
- if (!dir) {
- pr_err(NAME "Couldn't create relay app directory.\n");
- return -ENOMEM;
- }
- return 0;
-}