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xtensa: implement syscall tracepoints 

Add TIF_SYSCALL_TRACEPOINT flag definition; add _TIF_SYSCALL_TRACEPOINT
to _TIF_WORK_MASK. Call trace_sys_enter from do_syscall_trace_enter and
trace_sys_exit from do_syscall_trace_leave when TIF_SYSCALL_TRACEPOINT
flag is set.
Add declaration of sys_call_table to arch/xtensa/include/asm/syscall.h
Add definition of NR_syscalls to arch/xtensa/include/asm/unistd.h
Select HAVE_SYSCALL_TRACEPOINTS.

This change allows tracing each syscall entry and exit through the
ftrace mechanism.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov 2018-11-11 21:51:49 -08:00
parent 9f24f3c106
commit af5395c214
7 changed files with 23 additions and 3 deletions
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1
arch/xtensa/Kconfig
View File

@ -29,6 +29,7 @@ config XTENSA
select HAVE_OPROFILE
select HAVE_PERF_EVENTS
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select IRQ_DOMAIN
select MODULES_USE_ELF_RELA
select PERF_USE_VMALLOC

5
arch/xtensa/include/asm/ptrace.h
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@ -102,6 +102,11 @@ struct pt_regs {
#define user_stack_pointer(regs) ((regs)->areg[1])
static inline unsigned long regs_return_value(struct pt_regs *regs)
{
return regs->areg[2];
}
#else /* __ASSEMBLY__ */
# include <asm/asm-offsets.h>

3
arch/xtensa/include/asm/syscall.h
View File

@ -19,6 +19,9 @@ static inline int syscall_get_arch(void)
return AUDIT_ARCH_XTENSA;
}
typedef void (*syscall_t)(void);
extern syscall_t sys_call_table[];
static inline long syscall_get_nr(struct task_struct *task,
struct pt_regs *regs)
{

5
arch/xtensa/include/asm/thread_info.h
View File

@ -106,6 +106,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_SIGPENDING 1 /* signal pending */
#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
#define TIF_SINGLESTEP 3 /* restore singlestep on return to user mode */
#define TIF_SYSCALL_TRACEPOINT 4 /* syscall tracepoint instrumentation */
#define TIF_MEMDIE 5 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 6 /* restore signal mask in do_signal() */
#define TIF_NOTIFY_RESUME 7 /* callback before returning to user */
@ -115,8 +116,10 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
#define _TIF_WORK_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP)
#define _TIF_WORK_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
_TIF_SYSCALL_TRACEPOINT)
/*
* Thread-synchronous status.

2
arch/xtensa/include/asm/unistd.h
View File

@ -22,4 +22,6 @@
#define __IGNORE_vfork /* use clone */
#define __IGNORE_fadvise64 /* use fadvise64_64 */
#define NR_syscalls __NR_syscalls
#endif /* _XTENSA_UNISTD_H */

8
arch/xtensa/kernel/ptrace.c
View File

@ -27,6 +27,9 @@
#include <linux/tracehook.h>
#include <linux/uaccess.h>
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
#include <asm/coprocessor.h>
#include <asm/elf.h>
#include <asm/page.h>
@ -545,12 +548,17 @@ void do_syscall_trace_enter(struct pt_regs *regs)
tracehook_report_syscall_entry(regs))
regs->syscall = NO_SYSCALL;
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
trace_sys_enter(regs, syscall_get_nr(current, regs));
}
void do_syscall_trace_leave(struct pt_regs *regs)
{
int step;
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
trace_sys_exit(regs, regs_return_value(regs));
step = test_thread_flag(TIF_SINGLESTEP);
if (step || test_thread_flag(TIF_SYSCALL_TRACE))

2
arch/xtensa/kernel/syscall.c
View File

@ -28,8 +28,6 @@
#include <linux/sched/mm.h>
#include <linux/shm.h>
typedef void (*syscall_t)(void);
syscall_t sys_call_table[__NR_syscalls] /* FIXME __cacheline_aligned */= {
[0 ... __NR_syscalls - 1] = (syscall_t)&sys_ni_syscall,