kernel.git/arch/mips/kernel/entry.S, branch linux-3.7.y

MIPS: Fix endless loop when processing signals for kernel tasks

2012-12-05T18:59:00Z

The problem occurs [1] when a kernel-mode task returns from a system call with a pending signal. A real-life scenario is a child of 'khelper' returning from a failed kernel_execve() in ____call_usermodehelper() [ kernel/kmod.c ]. kernel_execve() fails due to a pending SIGKILL, which is the result of "kill -9 -1" (at least, busybox's init does it upon reboot). The loop is as follows: * syscall_exit_work: - work_pending: // start_of_the_loop - work_notifysig: - do_notify_resume() - do_signal() - if (!user_mode(regs)) return; - resume_userspace // TIF_SIGPENDING is still set - work_pending // so we call work_pending => goto // start_of_the_loop More information can be found in another LKML thread: http://www.serverphorums.com/read.php?12,457826 [1] The problem was also reproduced on !CONFIG_VM86 x86, and the following fix was accepted. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=29a2e2836ff9ea65a603c89df217f4198973a74f Signed-off-by: Dmitry Adamushko Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/3571/ Signed-off-by: Ralf Baechle

MIPS: Merge the identical "return from syscall" per-ABI code

2012-09-22T13:47:31Z

No need to keep 4 copies of that stuff; merged and taken to entry.S, unused public symbols there killed off. Signed-off-by: Al Viro Signed-off-by: Ralf Baechle

MIPS: Prevent hitting do_notify_resume() with !user_mode(regs).

2012-09-22T13:47:11Z

Too late to do anything there... Signed-off-by: Al Viro Signed-off-by: Ralf Baechle

MIPS: Split do_syscall_trace into two functions.

2011-05-19T08:55:44Z

Signed-off-by: Ralf Baechle

MIPS: Use single define for pending work on syscall exit

2011-05-19T08:55:44Z

Signed-off-by: Ralf Baechle

[MIPS] SMTC: Close tiny holes in the SMTC IPI replay system.

2008-10-03T16:58:58Z

Signed-off-by: Kevin D. Kissell Signed-off-by: Ralf Baechle

[MIPS] SMTC: Interrupt mask backstop hack

2007-07-12T16:41:17Z

To support multiple TC microthreads acting as "CPUs" within a VPE, VPE-wide interrupt mask bits must be specially manipulated during interrupt handling. To support legacy drivers and interrupt controller management code, SMTC has a "backstop" to track and if necessary restore the interrupt mask. This has some performance impact on interrupt service overhead. Disable it only if you know what you are doing. Signed-off-by: Ralf Baechle

[MIPS] lockdep: Handle interrupts in R3000 style c0_status register.

2007-03-29T22:46:35Z

Check the IEP bit for R3000 style processors when checking to see if interrupts will be reenabled in restore_all. Signed-off-by: Chris Dearman Signed-off-by: Ralf Baechle

[MIPS] Make entry.S a little more readable.

2007-02-13T22:40:51Z

When CONFIG_PREEMPT is not set, it also moves one branch instruction from ret_from_irq() to ret_from_exception(). Therefore we favour the return from irq case which should be more common than the other one. Signed-off-by: Franck Bui-Huu Acked-by: Atsushi Nemoto Signed-off-by: Ralf Baechle

[MIPS] SMTC: Fix crash if # of TC's > # of VPE's after pt_regs irq cleanup.

2006-11-01T17:46:09Z

Signed-off-by: Ralf Baechle