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author | Al Viro <viro@zeniv.linux.org.uk> | 2012-07-19 16:48:21 (GMT) |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-07-28 10:11:52 (GMT) |
commit | 81783786d5cf4aa0d3e15bb0fac856aa8ebf1a76 (patch) | |
tree | ea1266df42b055ef03df4f3937f6c6b4326bafc7 /arch/arm/kernel/signal.c | |
parent | 0a267fa6a15d41c4061358bf2e67c633fdbffc90 (diff) | |
download | linux-81783786d5cf4aa0d3e15bb0fac856aa8ebf1a76.tar.xz |
ARM: 7473/1: deal with handlerless restarts without leaving the kernel
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/signal.c')
-rw-r--r-- | arch/arm/kernel/signal.c | 50 |
1 files changed, 29 insertions, 21 deletions
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 8756e5d..99851cb 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -569,12 +569,13 @@ 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 void do_signal(struct pt_regs *regs, int syscall) +static int do_signal(struct pt_regs *regs, int syscall) { unsigned int retval = 0, continue_addr = 0, restart_addr = 0; struct k_sigaction ka; siginfo_t info; int signr; + int restart = 0; /* * If we were from a system call, check for system call restarting... @@ -589,10 +590,12 @@ static void do_signal(struct pt_regs *regs, int syscall) * debugger will see the already changed PSW. */ switch (retval) { + case -ERESTART_RESTARTBLOCK: + restart++; case -ERESTARTNOHAND: case -ERESTARTSYS: case -ERESTARTNOINTR: - case -ERESTART_RESTARTBLOCK: + restart++; regs->ARM_r0 = regs->ARM_ORIG_r0; regs->ARM_pc = restart_addr; break; @@ -604,13 +607,15 @@ static void do_signal(struct pt_regs *regs, int syscall) * point the debugger may change all our registers ... */ signr = get_signal_to_deliver(&info, &ka, regs, NULL); + /* + * Depending on the signal settings we may need to revert the + * decision to restart the system call. But skip this if a + * debugger has chosen to restart at a different PC. + */ + if (regs->ARM_pc != restart_addr) + restart = 0; if (signr > 0) { - /* - * Depending on the signal settings we may need to revert the - * decision to restart the system call. But skip this if a - * debugger has chosen to restart at a different PC. - */ - if (regs->ARM_pc == restart_addr) { + if (unlikely(restart)) { if (retval == -ERESTARTNOHAND || retval == -ERESTART_RESTARTBLOCK || (retval == -ERESTARTSYS @@ -618,28 +623,23 @@ static void do_signal(struct pt_regs *regs, int syscall) regs->ARM_r0 = -EINTR; regs->ARM_pc = continue_addr; } - clear_thread_flag(TIF_SYSCALL_RESTARTSYS); } handle_signal(signr, &ka, &info, regs); - return; + return 0; } - if (syscall) { - /* - * Handle restarting a different system call. As above, - * if a debugger has chosen to restart at a different PC, - * ignore the restart. - */ - if (retval == -ERESTART_RESTARTBLOCK - && regs->ARM_pc == restart_addr) + if (unlikely(restart)) { + if (restart > 1) set_thread_flag(TIF_SYSCALL_RESTARTSYS); + regs->ARM_pc = continue_addr; } restore_saved_sigmask(); + return restart; } -asmlinkage void +asmlinkage int do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) { do { @@ -647,10 +647,17 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) schedule(); } else { if (unlikely(!user_mode(regs))) - return; + return 0; local_irq_enable(); if (thread_flags & _TIF_SIGPENDING) { - do_signal(regs, syscall); + if (unlikely(do_signal(regs, syscall))) { + /* + * Restart without handlers. + * Deal with it without leaving + * the kernel space. + */ + return 1; + } syscall = 0; } else { clear_thread_flag(TIF_NOTIFY_RESUME); @@ -660,4 +667,5 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) local_irq_disable(); thread_flags = current_thread_info()->flags; } while (thread_flags & _TIF_WORK_MASK); + return 0; } |