From 1bd79336a426c5e4f3bab142407059ceb12cadf9 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Wed, 8 Mar 2006 13:24:22 +1100 Subject: powerpc: Fix various syscall/signal/swapcontext bugs A careful reading of the recent changes to the system call entry/exit paths revealed several problems, plus some things that could be simplified and improved: * 32-bit wasn't testing the _TIF_NOERROR bit in the syscall fast exit path, so it was only doing anything with it once it saw some other bit being set. In other words, the noerror behaviour would apply to the next system call where we had to reschedule or deliver a signal, which is not necessarily the current system call. * 32-bit wasn't doing the call to ptrace_notify in the syscall exit path when the _TIF_SINGLESTEP bit was set. * _TIF_RESTOREALL was in both _TIF_USER_WORK_MASK and _TIF_PERSYSCALL_MASK, which is odd since _TIF_RESTOREALL is only set by system calls. I took it out of _TIF_USER_WORK_MASK. * On 64-bit, _TIF_RESTOREALL wasn't causing the non-volatile registers to be restored (unless perhaps a signal was delivered or the syscall was traced or single-stepped). Thus the non-volatile registers weren't restored on exit from a signal handler. We probably got away with it mostly because signal handlers written in C wouldn't alter the non-volatile registers. * On 32-bit I simplified the code and made it more like 64-bit by making the syscall exit path jump to ret_from_except to handle preemption and signal delivery. * 32-bit was calling do_signal unnecessarily when _TIF_RESTOREALL was set - but I think because of that 32-bit was actually restoring the non-volatile registers on exit from a signal handler. * I changed the order of enabling interrupts and saving the non-volatile registers before calling do_syscall_trace_leave; now we enable interrupts first. Signed-off-by: Paul Mackerras --- arch/ppc/kernel/asm-offsets.c | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/ppc/kernel/asm-offsets.c') diff --git a/arch/ppc/kernel/asm-offsets.c b/arch/ppc/kernel/asm-offsets.c index 7964bf660e92..77e4dc780f8c 100644 --- a/arch/ppc/kernel/asm-offsets.c +++ b/arch/ppc/kernel/asm-offsets.c @@ -131,7 +131,6 @@ main(void) DEFINE(CPU_SPEC_FEATURES, offsetof(struct cpu_spec, cpu_features)); DEFINE(CPU_SPEC_SETUP, offsetof(struct cpu_spec, cpu_setup)); - DEFINE(TI_SIGFRAME, offsetof(struct thread_info, nvgprs_frame)); DEFINE(TI_TASK, offsetof(struct thread_info, task)); DEFINE(TI_EXECDOMAIN, offsetof(struct thread_info, exec_domain)); DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); -- cgit v1.2.2