From: Jason Baron <jba...@redhat.com>
Add core support to event tracing for compat syscalls. The basic idea is that we
check if we have a compat task via 'is_compat_task()'. If so, we lookup in the
new compat_syscalls_metadata table, the corresponding struct syscall_metadata,
to
check syscall arguments and whether or not we are enabled.
Signed-off-by: Jason Baron <jba...@redhat.com>
Signed-off-by: Ian Munsie <imun...@au1.ibm.com>
---
include/linux/compat.h | 2 +
include/trace/syscall.h | 4 ++
kernel/trace/trace.h | 2 +
kernel/trace/trace_syscalls.c | 86 +++++++++++++++++++++++++++++++++++++----
4 files changed, 86 insertions(+), 8 deletions(-)
diff --git a/include/linux/compat.h b/include/linux/compat.h
index ab638e9..a94f13d 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -363,6 +363,8 @@ extern ssize_t compat_rw_copy_check_uvector(int type,
#else /* CONFIG_COMPAT */
+#define NR_syscalls_compat 0
+
static inline int is_compat_task(void)
{
return 0;
diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index 75f3dce..67d4e64 100644
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -22,6 +22,7 @@
struct syscall_metadata {
const char *name;
int syscall_nr;
+ int compat_syscall_nr;
int nb_args;
const char **types;
const char **args;
@@ -38,6 +39,9 @@ struct syscall_metadata {
#ifdef CONFIG_FTRACE_SYSCALLS
extern unsigned long arch_syscall_addr(int nr);
+#ifdef CONFIG_COMPAT
+extern unsigned long arch_compat_syscall_addr(int nr);
+#endif
extern int init_syscall_trace(struct ftrace_event_call *call);
extern int reg_event_syscall_enter(struct ftrace_event_call *call);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 01ce088..53ace4b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -79,12 +79,14 @@ enum trace_type {
struct syscall_trace_enter {
struct trace_entry ent;
int nr;
+ int compat;
unsigned long args[];
};
struct syscall_trace_exit {
struct trace_entry ent;
int nr;
+ int compat;
long ret;
};
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index f5ddb9c..d910cba 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -4,6 +4,7 @@
#include <linux/kernel.h>
#include <linux/ftrace.h>
#include <linux/perf_event.h>
+#include <linux/compat.h>
#include <asm/syscall.h>
#include "trace_output.h"
@@ -65,6 +66,7 @@ extern unsigned long __start_syscalls_metadata[];
extern unsigned long __stop_syscalls_metadata[];
static struct syscall_metadata **syscalls_metadata;
+static struct syscall_metadata **compat_syscalls_metadata;
static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
{
@@ -84,8 +86,14 @@ static struct syscall_metadata *find_syscall_meta(unsigned
long syscall)
return NULL;
}
-static struct syscall_metadata *syscall_nr_to_meta(int nr)
+static struct syscall_metadata *syscall_nr_to_meta(int nr, int compat)
{
+ if (compat) {
+ if (!compat_syscalls_metadata || nr >= NR_syscalls_compat ||
+ nr < 0)
+ return NULL;
+ return compat_syscalls_metadata[nr];
+ }
if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
return NULL;
@@ -104,7 +112,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
trace = (typeof(trace))ent;
syscall = trace->nr;
- entry = syscall_nr_to_meta(syscall);
+ entry = syscall_nr_to_meta(syscall, trace->compat);
if (!entry)
goto end;
@@ -158,7 +166,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
trace = (typeof(trace))ent;
syscall = trace->nr;
- entry = syscall_nr_to_meta(syscall);
+ entry = syscall_nr_to_meta(syscall, trace->compat);
if (!entry) {
trace_seq_printf(s, "\n");
@@ -293,12 +301,16 @@ void ftrace_syscall_enter(void *ignore, struct pt_regs
*regs, long id)
struct ring_buffer *buffer;
int size;
int syscall_nr;
+ int compat = 0;
syscall_nr = syscall_get_nr(current, regs);
if (syscall_nr < 0)
return;
- sys_data = syscall_nr_to_meta(syscall_nr);
+ if (is_compat_task())
+ compat = 1;
+
+ sys_data = syscall_nr_to_meta(syscall_nr, compat);
if (!sys_data)
return;
@@ -314,6 +326,7 @@ void ftrace_syscall_enter(void *ignore, struct pt_regs
*regs, long id)
entry = ring_buffer_event_data(event);
entry->nr = syscall_nr;
+ entry->compat = compat;
syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
if (!filter_current_check_discard(buffer, sys_data->enter_event,
@@ -328,12 +341,16 @@ void ftrace_syscall_exit(void *ignore, struct pt_regs
*regs, long ret)
struct ring_buffer_event *event;
struct ring_buffer *buffer;
int syscall_nr;
+ int compat = 0;
syscall_nr = syscall_get_nr(current, regs);
if (syscall_nr < 0)
return;
- sys_data = syscall_nr_to_meta(syscall_nr);
+ if (is_compat_task())
+ compat = 1;
+
+ sys_data = syscall_nr_to_meta(syscall_nr, compat);
if (!sys_data)
return;
@@ -347,6 +364,7 @@ void ftrace_syscall_exit(void *ignore, struct pt_regs
*regs, long ret)
entry = ring_buffer_event_data(event);
entry->nr = syscall_nr;
+ entry->compat = compat;
entry->ret = syscall_get_return_value(current, regs);
if (!filter_current_check_discard(buffer, sys_data->exit_event,
@@ -485,7 +503,49 @@ int __init init_ftrace_syscalls(void)
meta->syscall_nr = i;
syscalls_metadata[i] = meta;
}
-
+#ifdef __HAVE_ARCH_FTRACE_COMPAT_SYSCALLS
+ if (NR_syscalls_compat) {
+ int match;
+ struct ftrace_event_call *ftrace_event;
+
+ compat_syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
+ NR_syscalls_compat, GFP_KERNEL);
+ if (!compat_syscalls_metadata) {
+ WARN_ON(1);
+ kfree(syscalls_metadata);
+ return -ENOMEM;
+ }
+ for (i = 0; i < NR_syscalls_compat; i++) {
+ addr = arch_compat_syscall_addr(i);
+ meta = find_syscall_meta(addr);
+ if (!meta)
+ continue;
+
+ meta->compat_syscall_nr = i;
+ compat_syscalls_metadata[i] = meta;
+ }
+ /* now check if any compat_syscalls are not referenced */
+ for (ftrace_event = __start_ftrace_events;
+ (unsigned long)ftrace_event <
+ (unsigned long)__stop_ftrace_events; ftrace_event++) {
+
+ match = 0;
+ if (!ftrace_event->name)
+ continue;
+ if (strcmp(ftrace_event->class->system,
"compat_syscalls"))
+ continue;
+ for (i = 0; i < NR_syscalls_compat; i++) {
+ if (ftrace_event->data ==
+ compat_syscalls_metadata[i]) {
+ match = 1;
+ break;
+ }
+ }
+ if (!match)
+ ftrace_event->name = NULL;
+ }
+ }
+#endif
return 0;
}
core_initcall(init_ftrace_syscalls);
@@ -503,9 +563,13 @@ static void perf_syscall_enter(void *ignore, struct
pt_regs *regs, long id)
int syscall_nr;
int rctx;
int size;
+ int compat = 0;
syscall_nr = syscall_get_nr(current, regs);
- sys_data = syscall_nr_to_meta(syscall_nr);
+ if (is_compat_task())
+ compat = 1;
+
+ sys_data = syscall_nr_to_meta(syscall_nr, compat);
if (!sys_data)
return;
@@ -527,6 +591,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs
*regs, long id)
return;
rec->nr = syscall_nr;
+ rec->compat = compat;
syscall_get_arguments(current, regs, 0, sys_data->nb_args,
(unsigned long *)&rec->args);
@@ -577,9 +642,13 @@ static void perf_syscall_exit(void *ignore, struct pt_regs
*regs, long ret)
int syscall_nr;
int rctx;
int size;
+ int compat = 0;
syscall_nr = syscall_get_nr(current, regs);
- sys_data = syscall_nr_to_meta(syscall_nr);
+ if (is_compat_task())
+ compat = 1;
+
+ sys_data = syscall_nr_to_meta(syscall_nr, compat);
if (!sys_data)
return;
@@ -604,6 +673,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs
*regs, long ret)
return;
rec->nr = syscall_nr;
+ rec->compat = compat;
rec->ret = syscall_get_return_value(current, regs);
head = this_cpu_ptr(sys_data->exit_event->perf_events);
--
1.7.1
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