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From: Sudeep Holla <sudeep.holla@arm.com>
To: x86@kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: Sudeep Holla <sudeep.holla@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Richard Weinberger <richard@nod.at>,
	jdike@addtoit.com, Steve Capper <Steve.Capper@arm.com>,
	Haibo Xu <haibo.xu@arm.com>, Bin Lu <bin.lu@arm.com>
Subject: [PATCH v4 4/4] arm64: ptrace: add support for syscall emulation
Date: Thu, 23 May 2019 10:06:18 +0100	[thread overview]
Message-ID: <20190523090618.13410-5-sudeep.holla@arm.com> (raw)
In-Reply-To: <20190523090618.13410-1-sudeep.holla@arm.com>

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: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 arch/arm64/include/asm/thread_info.h | 5 ++++-
 arch/arm64/kernel/ptrace.c           | 6 +++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index eb3ef73e07cf..c285d1ce7186 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -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)						\
 {									\
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index b82e0a9b3da3..9353355cb91a 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -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)
-- 
2.17.1


  parent reply	other threads:[~2019-05-23  9:06 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-23  9:06 [PATCH v4 0/4] ptrace: cleanup PTRACE_SYSEMU handling and add support for arm64 Sudeep Holla
2019-05-23  9:06 ` [PATCH v4 1/4] ptrace: move clearing of TIF_SYSCALL_EMU flag to core Sudeep Holla
2019-05-23  9:06 ` [PATCH v4 2/4] x86: simplify _TIF_SYSCALL_EMU handling Sudeep Holla
2019-06-03 17:22   ` Catalin Marinas
2019-06-11 14:38   ` Thomas Gleixner
2019-06-11 14:56   ` [PATCH v5 2/4] x86/entry: Simplify " Sudeep Holla
2019-06-24 17:30     ` Catalin Marinas
2019-06-24 17:37       ` Thomas Gleixner
2019-06-26 18:45         ` Thomas Gleixner
2019-05-23  9:06 ` [PATCH v4 3/4] arm64: add PTRACE_SYSEMU{,SINGLESTEP} definations to uapi headers Sudeep Holla
2019-05-23  9:06 ` Sudeep Holla [this message]
2019-06-05 16:54 ` [PATCH v4 0/4] ptrace: cleanup PTRACE_SYSEMU handling and add support for arm64 Catalin Marinas

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