sh: Add ftrace syscall tracing support

Now that I've added TIF_SYSCALL_FTRACE the thread flags do not fit into
a single byte any more. Code testing them now needs to be aware of the
upper and lower bytes.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

8 files changed, 100 insertions, 10 deletions

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 801a4a79ffe3..29e41ec6537d 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -32,6 +32,7 @@ config SUPERH32
         select HAVE_FTRACE_MCOUNT_RECORD
         select HAVE_DYNAMIC_FTRACE
         select HAVE_FUNCTION_TRACE_MCOUNT_TEST
+        select HAVE_FTRACE_SYSCALLS
         select HAVE_ARCH_KGDB
         select ARCH_HIBERNATION_POSSIBLE if MMU
 
diff --git a/arch/sh/include/asm/syscall_32.h b/arch/sh/include/asm/syscall_32.h
index 6f83f2cc45c1..7d80df4f09cb 100644
--- a/arch/sh/include/asm/syscall_32.h
+++ b/arch/sh/include/asm/syscall_32.h
@@ -65,6 +65,7 @@ static inline void syscall_get_arguments(struct task_struct *task,
         case 3: args[2] = regs->regs[6];
         case 2: args[1] = regs->regs[5];
         case 1: args[0] = regs->regs[4];
+        case 0:
                 break;
         default:
                 BUG();
diff --git a/arch/sh/include/asm/thread_info.h b/arch/sh/include/asm/thread_info.h
index f09ac4806294..499e315f4be2 100644
--- a/arch/sh/include/asm/thread_info.h
+++ b/arch/sh/include/asm/thread_info.h
@@ -97,7 +97,7 @@ static inline struct thread_info *current_thread_info(void)
 
 extern struct thread_info *alloc_thread_info(struct task_struct *tsk);
 extern void free_thread_info(struct thread_info *ti);
- 
+
 #endif /* THREAD_SHIFT < PAGE_SHIFT */
 
 #endif /* __ASSEMBLY__ */
@@ -116,6 +116,7 @@ extern void free_thread_info(struct thread_info *ti);
 #define TIF_SYSCALL_AUDIT       5       /* syscall auditing active */
 #define TIF_SECCOMP             6       /* secure computing */
 #define TIF_NOTIFY_RESUME       7       /* callback before returning to user */
+#define TIF_SYSCALL_FTRACE      8       /* for ftrace syscall instrumentation */
 #define TIF_USEDFPU             16      /* FPU was used by this task this quantum (SMP) */
 #define TIF_POLLING_NRFLAG      17      /* true if poll_idle() is polling TIF_NEED_RESCHED */
 #define TIF_MEMDIE              18
@@ -129,25 +130,27 @@ extern void free_thread_info(struct thread_info *ti);
 #define _TIF_SYSCALL_AUDIT      (1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP            (1 << TIF_SECCOMP)
 #define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
+#define _TIF_SYSCALL_FTRACE     (1 << TIF_SYSCALL_FTRACE)
 #define _TIF_USEDFPU            (1 << TIF_USEDFPU)
 #define _TIF_POLLING_NRFLAG     (1 << TIF_POLLING_NRFLAG)
 #define _TIF_FREEZE             (1 << TIF_FREEZE)
 
 /*
- * _TIF_ALLWORK_MASK and _TIF_WORK_MASK need to fit within a byte, or we
+ * _TIF_ALLWORK_MASK and _TIF_WORK_MASK need to fit within 2 bytes, or we
  * blow the tst immediate size constraints and need to fix up
  * arch/sh/kernel/entry-common.S.
  */
 
 /* work to do in syscall trace */
 #define _TIF_WORK_SYSCALL_MASK  (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
-                                 _TIF_SYSCALL_AUDIT | _TIF_SECCOMP)
+                                 _TIF_SYSCALL_AUDIT | _TIF_SECCOMP    | \
+                                 _TIF_SYSCALL_FTRACE)
 
 /* work to do on any return to u-space */
 #define _TIF_ALLWORK_MASK       (_TIF_SYSCALL_TRACE | _TIF_SIGPENDING      | \
                                  _TIF_NEED_RESCHED  | _TIF_SYSCALL_AUDIT   | \
                                  _TIF_SINGLESTEP    | _TIF_RESTORE_SIGMASK | \
-                                 _TIF_NOTIFY_RESUME)
+                                 _TIF_NOTIFY_RESUME | _TIF_SYSCALL_FTRACE)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK          (_TIF_ALLWORK_MASK & ~(_TIF_SYSCALL_TRACE | \
diff --git a/arch/sh/kernel/Makefile_32 b/arch/sh/kernel/Makefile_32
index 9411e3e31e68..fee924a9c46c 100644
--- a/arch/sh/kernel/Makefile_32
+++ b/arch/sh/kernel/Makefile_32
@@ -29,6 +29,7 @@ obj-$(CONFIG_IO_TRAPPED)	+= io_trapped.o
 obj-$(CONFIG_KPROBES)           += kprobes.o
 obj-$(CONFIG_GENERIC_GPIO)      += gpio.o
 obj-$(CONFIG_DYNAMIC_FTRACE)    += ftrace.o
+obj-$(CONFIG_FTRACE_SYSCALLS)   += ftrace.o
 obj-$(CONFIG_DUMP_CODE)         += disassemble.o
 obj-$(CONFIG_HIBERNATION)       += swsusp.o
 
diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
index d62359cfbbe2..d62175650c54 100644
--- a/arch/sh/kernel/entry-common.S
+++ b/arch/sh/kernel/entry-common.S
@@ -131,7 +131,7 @@ ENTRY(resume_userspace)
          nop
 #endif
         mov.l   @(TI_FLAGS,r8), r0              ! current_thread_info->flags
-        tst     #_TIF_WORK_MASK, r0
+        tst     #(_TIF_WORK_MASK & 0xff), r0
         bt/s    __restore_all
          tst    #_TIF_NEED_RESCHED, r0
 
@@ -163,7 +163,7 @@ work_resched:
 #endif
         !
         mov.l   @(TI_FLAGS,r8), r0              ! current_thread_info->flags
-        tst     #_TIF_WORK_MASK, r0
+        tst     #(_TIF_WORK_MASK & 0xff), r0
         bt      __restore_all
         bra     work_pending
          tst    #_TIF_NEED_RESCHED, r0
@@ -181,7 +181,7 @@ work_resched:
 syscall_exit_work:
         ! r0: current_thread_info->flags
         ! r8: current_thread_info
-        tst     #_TIF_WORK_SYSCALL_MASK, r0
+        tst     #(_TIF_WORK_SYSCALL_MASK & 0xff), r0
         bt/s    work_pending
          tst    #_TIF_NEED_RESCHED, r0
 #ifdef CONFIG_TRACE_IRQFLAGS
@@ -331,8 +331,12 @@ ENTRY(system_call)
         !
         get_current_thread_info r8, r10
         mov.l   @(TI_FLAGS,r8), r8
-        mov     #_TIF_WORK_SYSCALL_MASK, r10
+        mov     #(_TIF_WORK_SYSCALL_MASK & 0xff), r10
+        mov     #(_TIF_WORK_SYSCALL_MASK >> 8), r9
         tst     r10, r8
+        shll8   r9
+        bf      syscall_trace_entry
+        tst     r9, r8
         bf      syscall_trace_entry
         !
         mov.l   2f, r8                  ! Number of syscalls
@@ -359,7 +363,11 @@ syscall_exit:
         !
         get_current_thread_info r8, r0
         mov.l   @(TI_FLAGS,r8), r0              ! current_thread_info->flags
-        tst     #_TIF_ALLWORK_MASK, r0
+        tst     #(_TIF_ALLWORK_MASK & 0xff), r0
+        mov     #(_TIF_ALLWORK_MASK >> 8), r1
+        bf      syscall_exit_work
+        shlr8   r0
+        tst     r0, r1
         bf      syscall_exit_work
         bra     __restore_all
          nop
diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c
index 066f37dc32a9..4f62eced0aec 100644
--- a/arch/sh/kernel/ftrace.c
+++ b/arch/sh/kernel/ftrace.c
@@ -18,6 +18,8 @@
 #include <linux/io.h>
 #include <asm/ftrace.h>
 #include <asm/cacheflush.h>
+#include <asm/unistd.h>
+#include <trace/syscall.h>
 
 static unsigned char ftrace_replaced_code[MCOUNT_INSN_SIZE];
 
@@ -131,3 +133,69 @@ int __init ftrace_dyn_arch_init(void *data)
 
         return 0;
 }
+
+#ifdef CONFIG_FTRACE_SYSCALLS
+
+extern unsigned long __start_syscalls_metadata[];
+extern unsigned long __stop_syscalls_metadata[];
+extern unsigned long *sys_call_table;
+
+static struct syscall_metadata **syscalls_metadata;
+
+static struct syscall_metadata *find_syscall_meta(unsigned long *syscall)
+{
+        struct syscall_metadata *start;
+        struct syscall_metadata *stop;
+        char str[KSYM_SYMBOL_LEN];
+
+
+        start = (struct syscall_metadata *)__start_syscalls_metadata;
+        stop = (struct syscall_metadata *)__stop_syscalls_metadata;
+        kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str);
+
+        for ( ; start < stop; start++) {
+                if (start->name && !strcmp(start->name, str))
+                        return start;
+        }
+
+        return NULL;
+}
+
+#define FTRACE_SYSCALL_MAX      (NR_syscalls - 1)
+
+struct syscall_metadata *syscall_nr_to_meta(int nr)
+{
+        if (!syscalls_metadata || nr >= FTRACE_SYSCALL_MAX || nr < 0)
+                return NULL;
+
+        return syscalls_metadata[nr];
+}
+
+void arch_init_ftrace_syscalls(void)
+{
+        int i;
+        struct syscall_metadata *meta;
+        unsigned long **psys_syscall_table = &sys_call_table;
+        static atomic_t refs;
+
+        if (atomic_inc_return(&refs) != 1)
+                goto end;
+
+        syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
+                                        FTRACE_SYSCALL_MAX, GFP_KERNEL);
+        if (!syscalls_metadata) {
+                WARN_ON(1);
+                return;
+        }
+
+        for (i = 0; i < FTRACE_SYSCALL_MAX; i++) {
+                meta = find_syscall_meta(psys_syscall_table[i]);
+                syscalls_metadata[i] = meta;
+        }
+        return;
+
+        /* Paranoid: avoid overflow */
+end:
+        atomic_dec(&refs);
+}
+#endif /* CONFIG_FTRACE_SYSCALLS */
diff --git a/arch/sh/kernel/ptrace_32.c b/arch/sh/kernel/ptrace_32.c
index 3392e835a374..c198eceaee94 100644
--- a/arch/sh/kernel/ptrace_32.c
+++ b/arch/sh/kernel/ptrace_32.c
@@ -34,6 +34,8 @@
 #include <asm/syscalls.h>
 #include <asm/fpu.h>
 
+#include <trace/syscall.h>
+
 /*
  * This routine will get a word off of the process kernel stack.
  */
@@ -459,6 +461,9 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
                  */
                 ret = -1L;
 
+        if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))
+                ftrace_syscall_enter(regs);
+
         if (unlikely(current->audit_context))
                 audit_syscall_entry(audit_arch(), regs->regs[3],
                                     regs->regs[4], regs->regs[5],
@@ -475,6 +480,9 @@ asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[0]),
                                    regs->regs[0]);
 
+        if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))
+                ftrace_syscall_exit(regs);
+
         step = test_thread_flag(TIF_SINGLESTEP);
         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
                 tracehook_report_syscall_exit(regs, step);
diff --git a/arch/sh/lib/mcount.S b/arch/sh/lib/mcount.S
index cb87ef580b31..71e87f9b4fda 100644
--- a/arch/sh/lib/mcount.S
+++ b/arch/sh/lib/mcount.S
@@ -72,7 +72,7 @@ ftrace_caller:
         mov.l   @r0, r0
         tst     r0, r0
         bf      ftrace_stub
-        
+
         MCOUNT_ENTER()
 
         .globl ftrace_call