[RFC PATCH 1/2] powerpc/signal: Clean up pt_regs access

[Nicholas Piggin]

There are places in signal code that are made more readable by using a
'regs' local variable instead of finding it from the task.

Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
 arch/powerpc/kernel/signal.c    | 11 ++++++-----
 arch/powerpc/kernel/signal_64.c |  5 +++--
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index aa17e62f3754..193211b04805 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -242,6 +242,7 @@ static void check_syscall_restart(struct pt_regs *regs, 
struct k_sigaction *ka,
 
 static void do_signal(struct task_struct *tsk)
 {
+       struct pt_regs *regs = tsk->thread.regs;
        sigset_t *oldset = sigmask_to_save();
        struct ksignal ksig = { .sig = 0 };
        int ret;
@@ -251,12 +252,12 @@ static void do_signal(struct task_struct *tsk)
        get_signal(&ksig);
 
        /* Is there any syscall restart business here ? */
-       check_syscall_restart(tsk->thread.regs, &ksig.ka, ksig.sig > 0);
+       check_syscall_restart(regs, &ksig.ka, ksig.sig > 0);
 
        if (ksig.sig <= 0) {
                /* No signal to deliver -- put the saved sigmask back */
                restore_saved_sigmask();
-               set_trap_norestart(tsk->thread.regs);
+               set_trap_norestart(regs);
                return;               /* no signals delivered */
        }
 
@@ -275,9 +276,9 @@ static void do_signal(struct task_struct *tsk)
        }
 
        /* Re-enable the breakpoints for the signal stack */
-       thread_change_pc(tsk, tsk->thread.regs);
+       thread_change_pc(tsk, regs);
 
-       rseq_signal_deliver(&ksig, tsk->thread.regs);
+       rseq_signal_deliver(&ksig, regs);
 
        if (is_32bit_task()) {
                if (ksig.ka.sa.sa_flags & SA_SIGINFO)
@@ -288,7 +289,7 @@ static void do_signal(struct task_struct *tsk)
                ret = handle_rt_signal64(&ksig, oldset, tsk);
        }
 
-       set_trap_norestart(tsk->thread.regs);
+       set_trap_norestart(regs);
        signal_setup_done(ret, &ksig, test_thread_flag(TIF_SINGLESTEP));
 }
 
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 86bb5bb4c143..1f0c43baeff2 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -748,6 +748,8 @@ SYSCALL_DEFINE0(rt_sigreturn)
        sigset_t set;
        unsigned long msr;
 
+       BUG_ON(regs != current->thread.regs);
+
        /* Always make any pending restarted system calls return -EINTR */
        current->restart_block.fn = do_no_restart_syscall;
 
@@ -827,8 +829,7 @@ SYSCALL_DEFINE0(rt_sigreturn)
                 * MSR[TS] set, but without CPU in the proper state,
                 * causing a TM bad thing.
                 */
-               regs_set_return_msr(current->thread.regs,
-                               current->thread.regs->msr & ~MSR_TS_MASK);
+               regs_set_return_msr(regs, regs->msr & ~MSR_TS_MASK);
                if (!user_read_access_begin(&uc->uc_mcontext, 
sizeof(uc->uc_mcontext)))
                        goto badframe;
 
-- 
2.47.1