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Commit f086f674 authored by Sudeep Holla's avatar Sudeep Holla Committed by Catalin Marinas
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arm64: ptrace: add support for syscall emulation 



Add PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP support on arm64.
We don't need any special handling for PTRACE_SYSEMU_SINGLESTEP.

It's quite difficult to generalize handling PTRACE_SYSEMU cross
architectures and avoid calls to tracehook_report_syscall_entry twice.
Different architecture have different mechanism to indicate NO_SYSCALL
and trying to generalise adds more code for no gain.

Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent fd386638

arch/arm64/include/asm/thread_info.h

+4 −1
Original line number Diff line number Diff line
@@ -75,6 +75,7 @@ void arch_release_task_struct(struct task_struct *tsk); 
 *  TIF_SYSCALL_TRACE	- syscall trace active

 *  TIF_SYSCALL_TRACEPOINT - syscall tracepoint for ftrace

 *  TIF_SYSCALL_AUDIT	- syscall auditing

 *  TIF_SYSCALL_EMU     - syscall emulation active

 *  TIF_SECOMP		- syscall secure computing

 *  TIF_SIGPENDING	- signal pending

 *  TIF_NEED_RESCHED	- rescheduling necessary
@@ -91,6 +92,7 @@ void arch_release_task_struct(struct task_struct *tsk); 
#define TIF_SYSCALL_AUDIT	9

#define TIF_SYSCALL_TRACEPOINT	10

#define TIF_SECCOMP		11

#define TIF_SYSCALL_EMU		12

#define TIF_MEMDIE		18	/* is terminating due to OOM killer */

#define TIF_FREEZE		19

#define TIF_RESTORE_SIGMASK	20
@@ -109,6 +111,7 @@ void arch_release_task_struct(struct task_struct *tsk); 
#define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)

#define _TIF_SYSCALL_TRACEPOINT	(1 << TIF_SYSCALL_TRACEPOINT)

#define _TIF_SECCOMP		(1 << TIF_SECCOMP)

#define _TIF_SYSCALL_EMU	(1 << TIF_SYSCALL_EMU)

#define _TIF_UPROBE		(1 << TIF_UPROBE)

#define _TIF_FSCHECK		(1 << TIF_FSCHECK)

#define _TIF_32BIT		(1 << TIF_32BIT)
@@ -120,7 +123,7 @@ void arch_release_task_struct(struct task_struct *tsk); 


#define _TIF_SYSCALL_WORK	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \

				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \

				 _TIF_NOHZ)

				 _TIF_NOHZ | _TIF_SYSCALL_EMU)



#define INIT_THREAD_INFO(tsk)						\

{									\

arch/arm64/kernel/ptrace.c

+5 −1
Original line number Diff line number Diff line
@@ -1819,8 +1819,12 @@ static void tracehook_report_syscall(struct pt_regs *regs, 


int syscall_trace_enter(struct pt_regs *regs)

{

	if (test_thread_flag(TIF_SYSCALL_TRACE))

	if (test_thread_flag(TIF_SYSCALL_TRACE) ||

		test_thread_flag(TIF_SYSCALL_EMU)) {

		tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);

		if (!in_syscall(regs) || test_thread_flag(TIF_SYSCALL_EMU))

			return -1;

	}



	/* Do the secure computing after ptrace; failures should be fast. */

	if (secure_computing(NULL) == -1)