diff options
author | Chris Metcalf <cmetcalf@ezchip.com> | 2015-03-23 21:23:58 +0300 |
---|---|---|
committer | Chris Metcalf <cmetcalf@ezchip.com> | 2015-04-17 21:01:10 +0300 |
commit | 49e4e15619cd7cd9fc275d460fae2a95c1337fcc (patch) | |
tree | 700e24bb8f72a7662e7d4ae26d847e908d08de92 /arch/tile/kernel/ptrace.c | |
parent | b340c656af6317e28b466996a72cca019d97b42d (diff) | |
download | linux-49e4e15619cd7cd9fc275d460fae2a95c1337fcc.tar.xz |
tile: support CONTEXT_TRACKING and thus NOHZ_FULL
Add the TIF_NOHZ flag appropriately.
Add call to user_exit() on entry to do_work_pending() and on entry
to syscalls via do_syscall_trace_enter(), and also the top of
do_syscall_trace_exit() just because it's done in x86.
Add call to user_enter() at the bottom of do_work_pending() once we
have no more work to do before returning to userspace.
Wrap all the trap code in exception_enter() / exception_exit().
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'arch/tile/kernel/ptrace.c')
-rw-r--r-- | arch/tile/kernel/ptrace.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/arch/tile/kernel/ptrace.c b/arch/tile/kernel/ptrace.c index de98c6ddf136..f84eed8243da 100644 --- a/arch/tile/kernel/ptrace.c +++ b/arch/tile/kernel/ptrace.c @@ -22,6 +22,7 @@ #include <linux/regset.h> #include <linux/elf.h> #include <linux/tracehook.h> +#include <linux/context_tracking.h> #include <asm/traps.h> #include <arch/chip.h> @@ -252,12 +253,21 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, int do_syscall_trace_enter(struct pt_regs *regs) { - if (test_thread_flag(TIF_SYSCALL_TRACE)) { + u32 work = ACCESS_ONCE(current_thread_info()->flags); + + /* + * If TIF_NOHZ is set, we are required to call user_exit() before + * doing anything that could touch RCU. + */ + if (work & _TIF_NOHZ) + user_exit(); + + if (work & _TIF_SYSCALL_TRACE) { if (tracehook_report_syscall_entry(regs)) regs->regs[TREG_SYSCALL_NR] = -1; } - if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) + if (work & _TIF_SYSCALL_TRACEPOINT) trace_sys_enter(regs, regs->regs[TREG_SYSCALL_NR]); return regs->regs[TREG_SYSCALL_NR]; @@ -268,6 +278,12 @@ void do_syscall_trace_exit(struct pt_regs *regs) long errno; /* + * We may come here right after calling schedule_user() + * in which case we can be in RCU user mode. + */ + user_exit(); + + /* * The standard tile calling convention returns the value (or negative * errno) in r0, and zero (or positive errno) in r1. * It saves a couple of cycles on the hot path to do this work in @@ -303,5 +319,7 @@ void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs) /* Handle synthetic interrupt delivered only by the simulator. */ void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num) { + enum ctx_state prev_state = exception_enter(); send_sigtrap(current, regs); + exception_exit(prev_state); } |