From 8a7643b09856f4f661403dcedbe0455b3cbeeea9 Mon Sep 17 00:00:00 2001
From: Steven Newbury <s_j_newbury@yahoo.co.uk>
Date: Fri, 22 May 2009 14:25:40 +0200
Subject: [PATCH] implement TIF_RESTORE_SIGMASK support and enable the related
syscalls:
pselect6
ppoll
epoll_pwait
Based on http://www.spinics.net/lists/arm-kernel/msg38114.html
---
arch/arm/include/asm/thread_info.h | 2 +
arch/arm/include/asm/unistd.h | 7 ++-
arch/arm/kernel/calls.S | 6 +-
arch/arm/kernel/signal.c | 90 +++++++++++++++---------------------
4 files changed, 46 insertions(+), 59 deletions(-)
@@ -136,6 +136,7 @@ extern void vfp_sync_state(struct thread_info *thread);
#define TIF_SIGPENDING 0
#define TIF_NEED_RESCHED 1
#define TIF_SYSCALL_TRACE 8
+#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal */
#define TIF_POLLING_NRFLAG 16
#define TIF_USING_IWMMXT 17
#define TIF_MEMDIE 18
@@ -144,6 +145,7 @@ extern void vfp_sync_state(struct thread_info *thread);
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
+#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
#define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT)
#define _TIF_FREEZE (1 << TIF_FREEZE)
@@ -360,8 +360,8 @@
#define __NR_readlinkat (__NR_SYSCALL_BASE+332)
#define __NR_fchmodat (__NR_SYSCALL_BASE+333)
#define __NR_faccessat (__NR_SYSCALL_BASE+334)
- /* 335 for pselect6 */
- /* 336 for ppoll */
+#define __NR_pselect6 (__NR_SYSCALL_BASE+335)
+#define __NR_ppoll (__NR_SYSCALL_BASE+336)
#define __NR_unshare (__NR_SYSCALL_BASE+337)
#define __NR_set_robust_list (__NR_SYSCALL_BASE+338)
#define __NR_get_robust_list (__NR_SYSCALL_BASE+339)
@@ -372,7 +372,7 @@
#define __NR_vmsplice (__NR_SYSCALL_BASE+343)
#define __NR_move_pages (__NR_SYSCALL_BASE+344)
#define __NR_getcpu (__NR_SYSCALL_BASE+345)
- /* 346 for epoll_pwait */
+#define __NR_epoll_pwait (__NR_SYSCALL_BASE+346)
#define __NR_kexec_load (__NR_SYSCALL_BASE+347)
#define __NR_utimensat (__NR_SYSCALL_BASE+348)
#define __NR_signalfd (__NR_SYSCALL_BASE+349)
@@ -430,6 +430,7 @@
#define __ARCH_WANT_SYS_SIGPENDING
#define __ARCH_WANT_SYS_SIGPROCMASK
#define __ARCH_WANT_SYS_RT_SIGACTION
+#define __ARCH_WANT_SYS_RT_SIGSUSPEND
#if !defined(CONFIG_AEABI) || defined(CONFIG_OABI_COMPAT)
#define __ARCH_WANT_SYS_TIME
@@ -344,8 +344,8 @@
CALL(sys_readlinkat)
CALL(sys_fchmodat)
CALL(sys_faccessat)
-/* 335 */ CALL(sys_ni_syscall) /* eventually pselect6 */
- CALL(sys_ni_syscall) /* eventually ppoll */
+/* 335 */ CALL(sys_pselect6)
+ CALL(sys_ppoll)
CALL(sys_unshare)
CALL(sys_set_robust_list)
CALL(sys_get_robust_list)
@@ -355,7 +355,7 @@
CALL(sys_vmsplice)
CALL(sys_move_pages)
/* 345 */ CALL(sys_getcpu)
- CALL(sys_ni_syscall) /* eventually epoll_pwait */
+ CALL(sys_epoll_pwait)
CALL(sys_kexec_load)
CALL(sys_utimensat)
CALL(sys_signalfd)
@@ -47,57 +47,23 @@ const unsigned long sigreturn_codes[7] = {
MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
};
-static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
+static void do_signal(struct pt_regs * regs, int syscall);
/*
* atomically swap in the new signal mask, and wait for a signal.
*/
-asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs)
+asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
{
- sigset_t saveset;
-
mask &= _BLOCKABLE;
spin_lock_irq(¤t->sighand->siglock);
- saveset = current->blocked;
+ current->saved_sigmask = current->blocked;
siginitset(¤t->blocked, mask);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
- regs->ARM_r0 = -EINTR;
-
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (do_signal(&saveset, regs, 0))
- return regs->ARM_r0;
- }
-}
-
-asmlinkage int
-sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs)
-{
- sigset_t saveset, newset;
-
- /* XXX: Don't preclude handling different sized sigset_t's. */
- if (sigsetsize != sizeof(sigset_t))
- return -EINVAL;
-
- if (copy_from_user(&newset, unewset, sizeof(newset)))
- return -EFAULT;
- sigdelsetmask(&newset, ~_BLOCKABLE);
-
- spin_lock_irq(¤t->sighand->siglock);
- saveset = current->blocked;
- current->blocked = newset;
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
- regs->ARM_r0 = -EINTR;
-
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (do_signal(&saveset, regs, 0))
- return regs->ARM_r0;
- }
+ current->state = TASK_INTERRUPTIBLE;
+ schedule();
+ set_thread_flag(TIF_RESTORE_SIGMASK);
+ return -ERESTARTNOHAND;
}
asmlinkage int
@@ -290,7 +256,7 @@ asmlinkage int sys_sigreturn(struct pt_regs *regs)
badframe:
force_sig(SIGSEGV, current);
- return 0;
+ return -EFAULT;
}
asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
@@ -325,7 +291,7 @@ asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
badframe:
force_sig(SIGSEGV, current);
- return 0;
+ return -EFAULT;
}
static int
@@ -541,7 +507,7 @@ static inline void restart_syscall(struct pt_regs *regs)
/*
* OK, we're invoking a handler
*/
-static void
+static int
handle_signal(unsigned long sig, struct k_sigaction *ka,
siginfo_t *info, sigset_t *oldset,
struct pt_regs * regs, int syscall)
@@ -592,7 +558,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
if (ret != 0) {
force_sigsegv(sig, tsk);
- return;
+ return ret;
}
/*
@@ -606,6 +572,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
recalc_sigpending();
spin_unlock_irq(&tsk->sighand->siglock);
+ return ret;
}
/*
@@ -617,11 +584,12 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*/
-static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
+static void do_signal(struct pt_regs *regs, int syscall)
{
struct k_sigaction ka;
siginfo_t info;
int signr;
+ sigset_t *oldset;
/*
* We want the common case to go fast, which
@@ -630,18 +598,29 @@ static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
* if so.
*/
if (!user_mode(regs))
- return 0;
+ return;
if (try_to_freeze())
goto no_signal;
single_step_clear(current);
+ if (test_thread_flag(TIF_RESTORE_SIGMASK))
+ oldset = ¤t->saved_sigmask;
+ else
+ oldset = ¤t->blocked;
+
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
- handle_signal(signr, &ka, &info, oldset, regs, syscall);
+ if (handle_signal(signr, &ka, &info, oldset, regs, syscall) == 0) {
+ /* a signal was successfully delivered; the saved
+ * sigmask will have been stored in the signal frame,
+ * and will be restored by sigreturn, so we can simply
+ * clear the TIF_RESTORE_SIGMASK flag */
+ clear_thread_flag(TIF_RESTORE_SIGMASK);
+ }
single_step_set(current);
- return 1;
+ return;
}
no_signal:
@@ -665,7 +644,7 @@ static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
usp = (u32 __user *)regs->ARM_sp;
/*
- * Either we supports OABI only, or we have
+ * Either we support OABI only, or we have
* EABI with the OABI compat layer enabled.
* In the later case we don't know if user
* space is EABI or not, and if not we must
@@ -695,12 +674,17 @@ static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
}
}
single_step_set(current);
- return 0;
+ /* if there's no signal to deliver, we just put the saved sigmask
+ back. */
+ if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
+ clear_thread_flag(TIF_RESTORE_SIGMASK);
+ sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
+ }
}
asmlinkage void
do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
{
- if (thread_flags & _TIF_SIGPENDING)
- do_signal(¤t->blocked, regs, syscall);
+ if (thread_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK))
+ do_signal(regs, syscall);
}
--
1.6.2.4