[IA64] Synchronize kernel RSE to user-space and back (3b2ce0b1) · Commits · 戴 / test

arch/ia64/kernel/process.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -163,6 +163,8 @@ void tsk_clear_notify_resume(struct task_struct *tsk)
		if (tsk->thread.pfm_needs_checking)
		return;
		#endif
		if (test_ti_thread_flag(task_thread_info(tsk), TIF_RESTORE_RSE))
		return;
		clear_ti_thread_flag(task_thread_info(tsk), TIF_NOTIFY_RESUME);
		}

		@@ -184,6 +186,10 @@ do_notify_resume_user (sigset_t unused, struct sigscratch scr, long in_syscall
		/* deal with pending signal delivery */
		if (test_thread_flag(TIF_SIGPENDING)\|\|test_thread_flag(TIF_RESTORE_SIGMASK))
		ia64_do_signal(scr, in_syscall);

		/* copy user rbs to kernel rbs */
		if (unlikely(test_thread_flag(TIF_RESTORE_RSE)))
		ia64_sync_krbs();
		}

		static int pal_halt = 1;

arch/ia64/kernel/ptrace.c

+82 −0

Original line number	Diff line number	Diff line
		@@ -547,6 +547,72 @@ ia64_sync_user_rbs (struct task_struct child, struct switch_stack sw,
		return 0;
		}

		static long
		ia64_sync_kernel_rbs (struct task_struct child, struct switch_stack sw,
		unsigned long user_rbs_start, unsigned long user_rbs_end)
		{
		unsigned long addr, val;
		long ret;

		/* now copy word for word from user rbs to kernel rbs: */
		for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) {
		if (access_process_vm(child, addr, &val, sizeof(val), 0)
		!= sizeof(val))
		return -EIO;

		ret = ia64_poke(child, sw, user_rbs_end, addr, val);
		if (ret < 0)
		return ret;
		}
		return 0;
		}

		typedef long (syncfunc_t)(struct task_struct , struct switch_stack *,
		unsigned long, unsigned long);

		static void do_sync_rbs(struct unw_frame_info info, void arg)
		{
		struct pt_regs *pt;
		unsigned long urbs_end;
		syncfunc_t fn = arg;

		if (unw_unwind_to_user(info) < 0)
		return;
		pt = task_pt_regs(info->task);
		urbs_end = ia64_get_user_rbs_end(info->task, pt, NULL);

		fn(info->task, info->sw, pt->ar_bspstore, urbs_end);
		}

		/*
		* when a thread is stopped (ptraced), debugger might change thread's user
		* stack (change memory directly), and we must avoid the RSE stored in kernel
		* to override user stack (user space's RSE is newer than kernel's in the
		* case). To workaround the issue, we copy kernel RSE to user RSE before the
		* task is stopped, so user RSE has updated data. we then copy user RSE to
		* kernel after the task is resummed from traced stop and kernel will use the
		* newer RSE to return to user. TIF_RESTORE_RSE is the flag to indicate we need
		* synchronize user RSE to kernel.
		*/
		void ia64_ptrace_stop(void)
		{
		if (test_and_set_tsk_thread_flag(current, TIF_RESTORE_RSE))
		return;
		tsk_set_notify_resume(current);
		unw_init_running(do_sync_rbs, ia64_sync_user_rbs);
		}

		/*
		* This is called to read back the register backing store.
		*/
		void ia64_sync_krbs(void)
		{
		clear_tsk_thread_flag(current, TIF_RESTORE_RSE);
		tsk_clear_notify_resume(current);

		unw_init_running(do_sync_rbs, ia64_sync_kernel_rbs);
		}

		static inline int
		thread_matches (struct task_struct *thread, unsigned long addr)
		{
		@@ -1422,6 +1488,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
		struct task_struct *child;
		struct switch_stack *sw;
		long ret;
		struct unw_frame_info info;

		lock_kernel();
		ret = -EPERM;
		@@ -1453,6 +1520,8 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)

		if (request == PTRACE_ATTACH) {
		ret = ptrace_attach(child);
		if (!ret)
		arch_ptrace_attach(child);
		goto out_tsk;
		}

		@@ -1481,6 +1550,11 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
		/* write the word at location addr */
		urbs_end = ia64_get_user_rbs_end(child, pt, NULL);
		ret = ia64_poke(child, sw, urbs_end, addr, data);

		/* Make sure user RBS has the latest data */
		unw_init_from_blocked_task(&info, child);
		do_sync_rbs(&info, ia64_sync_user_rbs);

		goto out_tsk;

		case PTRACE_PEEKUSR:
		@@ -1634,6 +1708,10 @@ syscall_trace_enter (long arg0, long arg1, long arg2, long arg3,
		&& (current->ptrace & PT_PTRACED))
		syscall_trace();

		/* copy user rbs to kernel rbs */
		if (test_thread_flag(TIF_RESTORE_RSE))
		ia64_sync_krbs();

		if (unlikely(current->audit_context)) {
		long syscall;
		int arch;
		@@ -1671,4 +1749,8 @@ syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
		\|\| test_thread_flag(TIF_SINGLESTEP))
		&& (current->ptrace & PT_PTRACED))
		syscall_trace();

		/* copy user rbs to kernel rbs */
		if (test_thread_flag(TIF_RESTORE_RSE))
		ia64_sync_krbs();
		}

include/asm-ia64/ptrace.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -292,6 +292,7 @@ struct switch_stack {
		unsigned long, long);
		extern void ia64_flush_fph (struct task_struct *);
		extern void ia64_sync_fph (struct task_struct *);
		extern void ia64_sync_krbs(void);
		extern long ia64_sync_user_rbs (struct task_struct , struct switch_stack ,
		unsigned long, unsigned long);

		@@ -303,6 +304,12 @@ struct switch_stack {
		extern void ia64_increment_ip (struct pt_regs *pt);
		extern void ia64_decrement_ip (struct pt_regs *pt);

		extern void ia64_ptrace_stop(void);
		#define arch_ptrace_stop(code, info) \
		ia64_ptrace_stop()
		#define arch_ptrace_stop_needed(code, info) \
		(!test_thread_flag(TIF_RESTORE_RSE))

		#endif /* !__KERNEL__ */

		/* pt_all_user_regs is used for PTRACE_GETREGS PTRACE_SETREGS */

include/asm-ia64/thread_info.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -94,6 +94,7 @@ extern void tsk_clear_notify_resume(struct task_struct *tsk);
		#define TIF_MCA_INIT 18 /* this task is processing MCA or INIT */
		#define TIF_DB_DISABLED 19 /* debug trap disabled for fsyscall */
		#define TIF_FREEZE 20 /* is freezing for suspend */
		#define TIF_RESTORE_RSE 21 /* user RBS is newer than kernel RBS */

		#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
		#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
		@@ -107,6 +108,7 @@ extern void tsk_clear_notify_resume(struct task_struct *tsk);
		#define _TIF_MCA_INIT (1 << TIF_MCA_INIT)
		#define _TIF_DB_DISABLED (1 << TIF_DB_DISABLED)
		#define _TIF_FREEZE (1 << TIF_FREEZE)
		#define _TIF_RESTORE_RSE (1 << TIF_RESTORE_RSE)

		/* "work to do on user-return" bits */
		#define TIF_ALLWORK_MASK (_TIF_SIGPENDING\|_TIF_NOTIFY_RESUME\|_TIF_SYSCALL_AUDIT\|\

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