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author | Mikael Pettersson <mikpe@it.uu.se> | 2009-08-15 11:58:11 (GMT) |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-08-15 14:10:31 (GMT) |
commit | 369842658a36bcea28ecb643ba4bdb53919330dd (patch) | |
tree | 1a590eabceea85b974360eca2cfba54d86ae4933 /arch/arm/include/asm | |
parent | 4bf1fa5a34aa2dd0d2cc58f0fc213a2e22d007a4 (diff) | |
download | linux-fsl-qoriq-369842658a36bcea28ecb643ba4bdb53919330dd.tar.xz |
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 <mikpe@it.uu.se>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/include/asm')
-rw-r--r-- | arch/arm/include/asm/thread_info.h | 2 | ||||
-rw-r--r-- | arch/arm/include/asm/unistd.h | 7 |
2 files changed, 6 insertions, 3 deletions
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index 73394e5..e20d805 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -140,6 +140,7 @@ extern void vfp_sync_state(struct thread_info *thread); #define TIF_USING_IWMMXT 17 #define TIF_MEMDIE 18 #define TIF_FREEZE 19 +#define TIF_RESTORE_SIGMASK 20 #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) @@ -147,6 +148,7 @@ extern void vfp_sync_state(struct thread_info *thread); #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) #define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT) #define _TIF_FREEZE (1 << TIF_FREEZE) +#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK) /* * Change these and you break ASM code in entry-common.S diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h index 0e97b8c..9122c9e 100644 --- a/arch/arm/include/asm/unistd.h +++ b/arch/arm/include/asm/unistd.h @@ -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) @@ -432,6 +432,7 @@ #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 |