From 369842658a36bcea28ecb643ba4bdb53919330dd Mon Sep 17 00:00:00 2001 From: Mikael Pettersson Date: Sat, 15 Aug 2009 12:58:11 +0100 Subject: ARM: 5677/1: ARM support for TIF_RESTORE_SIGMASK/pselect6/ppoll/epoll_pwait This patch adds support for TIF_RESTORE_SIGMASK to ARM's signal handling, which allows to hook up the pselect6, ppoll, and epoll_pwait syscalls on ARM. Tested here with eabi userspace and a test program with a deliberate race between a child's exit and the parent's sigprocmask/select sequence. Using sys_pselect6() instead of sigprocmask/select reliably prevents the race. The other arch's support for TIF_RESTORE_SIGMASK has evolved over time: In 2.6.16: - add TIF_RESTORE_SIGMASK which parallels TIF_SIGPENDING - test both when checking for pending signal [changed later] - reimplement sys_sigsuspend() to use current->saved_sigmask, TIF_RESTORE_SIGMASK [changed later], and -ERESTARTNOHAND; ditto for sys_rt_sigsuspend(), but drop private code and use common code via __ARCH_WANT_SYS_RT_SIGSUSPEND; - there are now no "extra" calls to do_signal() so its oldset parameter is always ¤t->blocked so need not be passed, also its return value is changed to void - change handle_signal() to return 0/-errno - change do_signal() to honor TIF_RESTORE_SIGMASK: + get oldset from current->saved_sigmask if TIF_RESTORE_SIGMASK is set + if handle_signal() was successful then clear TIF_RESTORE_SIGMASK + if no signal was delivered and TIF_RESTORE_SIGMASK is set then clear it and restore the sigmask - hook up sys_pselect6() and sys_ppoll() In 2.6.19: - hook up sys_epoll_pwait() In 2.6.26: - allow archs to override how TIF_RESTORE_SIGMASK is implemented; default set_restore_sigmask() sets both TIF_RESTORE_SIGMASK and TIF_SIGPENDING; archs need now just test TIF_SIGPENDING again when checking for pending signal work; some archs now implement TIF_RESTORE_SIGMASK as a secondary/non-atomic thread flag bit - call set_restore_sigmask() in sys_sigsuspend() instead of setting TIF_RESTORE_SIGMASK In 2.6.29-rc: - kill sys_pselect7() which no arch wanted So for 2.6.31-rc6/ARM this patch does the following: - Add TIF_RESTORE_SIGMASK. Use the generic set_restore_sigmask() which sets both TIF_SIGPENDING and TIF_RESTORE_SIGMASK, so TIF_RESTORE_SIGMASK need not claim one of the scarce low thread flags, and existing TIF_SIGPENDING and _TIF_WORK_MASK tests need not be extended for TIF_RESTORE_SIGMASK. - sys_sigsuspend() is reimplemented to use current->saved_sigmask and set_restore_sigmask(), making it identical to most other archs - The private code for sys_rt_sigsuspend() is removed, instead generic code supplies it via __ARCH_WANT_SYS_RT_SIGSUSPEND. - sys_sigsuspend() and sys_rt_sigsuspend() no longer need a pt_regs parameter, so their assembly code wrappers are removed. - handle_signal() is changed to return 0 on success or -errno. - The oldset parameter to do_signal() is now redundant and removed, and the return value is now also redundant and changed to void. - do_signal() is changed to honor TIF_RESTORE_SIGMASK: + get oldset from current->saved_sigmask if TIF_RESTORE_SIGMASK is set + if handle_signal() was successful then clear TIF_RESTORE_SIGMASK + if no signal was delivered and TIF_RESTORE_SIGMASK is set then clear it and restore the sigmask - Hook up sys_pselect6, sys_ppoll, and sys_epoll_pwait. Signed-off-by: Mikael Pettersson Signed-off-by: Russell King --- arch/arm/kernel/calls.S | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'arch/arm/kernel/calls.S') diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S index f776e72a4cb8..ecfa98954d1d 100644 --- a/arch/arm/kernel/calls.S +++ b/arch/arm/kernel/calls.S @@ -81,7 +81,7 @@ CALL(sys_ni_syscall) /* was sys_ssetmask */ /* 70 */ CALL(sys_setreuid16) CALL(sys_setregid16) - CALL(sys_sigsuspend_wrapper) + CALL(sys_sigsuspend) CALL(sys_sigpending) CALL(sys_sethostname) /* 75 */ CALL(sys_setrlimit) @@ -188,7 +188,7 @@ CALL(sys_rt_sigpending) CALL(sys_rt_sigtimedwait) CALL(sys_rt_sigqueueinfo) - CALL(sys_rt_sigsuspend_wrapper) + CALL(sys_rt_sigsuspend) /* 180 */ CALL(ABI(sys_pread64, sys_oabi_pread64)) CALL(ABI(sys_pwrite64, sys_oabi_pwrite64)) CALL(sys_chown16) @@ -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) -- cgit v1.2.3-55-g7522