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From: guoren@kernel.org
To: arnd@arndb.de
Cc: linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org,
	Guo Ren <guoren@linux.alibaba.com>
Subject: [PATCH 03/11] csky: Add support for restartable sequence
Date: Fri,  3 Apr 2020 12:41:42 +0800	[thread overview]
Message-ID: <20200403044150.20562-3-guoren@kernel.org> (raw)
In-Reply-To: <20200403044150.20562-1-guoren@kernel.org>

From: Guo Ren <guoren@linux.alibaba.com>

Copied and adapted from vincent's patch, but modified for csky.

ref:
https://lore.kernel.org/linux-riscv/1572919114-3886-3-git-send-email-vincent.chen@sifive.com/raw

Add calls to rseq_signal_deliver(), rseq_handle_notify_resume() and
rseq_syscall() to introduce RSEQ support.

1. Call the rseq_handle_notify_resume() function on return to userspace
   if TIF_NOTIFY_RESUME thread flag is set.

2. Call the rseq_signal_deliver() function to fixup on the pre-signal
   frame when a signal is delivered on top of a restartable sequence
   critical section.

3. Check that system calls are not invoked from within rseq critical
   sections by invoking rseq_signal() from ret_from_syscall(). With
   CONFIG_DEBUG_RSEQ, such behavior results in termination of the
   process with SIGSEGV.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
---
 arch/csky/Kconfig         | 1 +
 arch/csky/kernel/entry.S  | 5 ++++-
 arch/csky/kernel/signal.c | 3 +++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 2dfd3fb07db9..0e9b14367fa8 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -49,6 +49,7 @@ config CSKY
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_DMA_CONTIGUOUS
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_RSEQ
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select MAY_HAVE_SPARSE_IRQ
diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index 007706328000..0bde1d9fd277 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -128,7 +128,10 @@ tlbop_end 1
 ENTRY(csky_systemcall)
 	SAVE_ALL TRAP0_SIZE
 	zero_fp
-
+#ifdef CONFIG_RSEQ_DEBUG
+	mov	a0, sp
+	jbsr	rseq_syscall
+#endif
 	psrset  ee, ie
 
 	lrw     r11, __NR_syscalls
diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
index 9b1b7c039ddf..3d6b728cbb72 100644
--- a/arch/csky/kernel/signal.c
+++ b/arch/csky/kernel/signal.c
@@ -175,6 +175,8 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 	sigset_t *oldset = sigmask_to_save();
 	int ret;
 
+	rseq_signal_deliver(ksig, regs);
+
 	/* Are we from a system call? */
 	if (in_syscall(regs)) {
 		/* Avoid additional syscall restarting via ret_from_exception */
@@ -258,5 +260,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 		clear_thread_flag(TIF_NOTIFY_RESUME);
 		tracehook_notify_resume(regs);
+		rseq_handle_notify_resume(NULL, regs);
 	}
 }
-- 
2.17.0


  parent reply	other threads:[~2020-04-03  4:42 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-03  4:41 [PATCH 01/11] csky: Fixup init_fpu compile warning with __init guoren
2020-04-03  4:41 ` [PATCH 02/11] csky: Implement ptrace regs and stack API guoren
2020-04-03  4:41 ` guoren [this message]
2020-04-03  4:41 ` [PATCH 04/11] csky: Implement ftrace with regs guoren
2020-04-03  4:41 ` [PATCH 05/11] csky/ftrace: Fixup ftrace_modify_code deadlock without CPU_HAS_ICACHE_INS guoren
2020-04-03  4:41 ` [PATCH 06/11] csky: Fixup get wrong psr value from phyical reg guoren
2020-04-03  4:41 ` [PATCH 07/11] csky: Enable the gcov function guoren
2020-04-03  4:41 ` [PATCH 08/11] csky: Enable LOCKDEP_SUPPORT guoren
2020-04-03  4:41 ` [PATCH 09/11] csky: Add kprobes supported guoren
2020-04-03  4:41 ` [PATCH 10/11] csky: Add uprobes support guoren
2020-04-03  4:41 ` [PATCH 11/11] csky: Fixup cpu speculative execution to IO area guoren

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