Revert "powerpc/tm: Unset MSR[TS] if not recheckpointing"

This reverts commit a9935a12768851762089fda8e5a9daaf0231808e which is
commit 6f5b9f018f4c7686fd944d920209d1382d320e4e upstream.

It breaks the powerpc build, so drop it from the tree until a fix goes
upstream.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: Breno Leitao <leitao@debian.org>
Cc: Michal Suchánek <msuchanek@suse.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 6327fd7..e6474a4 100644 (file)
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -1140,11 +1140,11 @@ SYSCALL_DEFINE0(rt_sigreturn)
 {
        struct rt_sigframe __user *rt_sf;
        struct pt_regs *regs = current_pt_regs();
-       int tm_restore = 0;
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
        struct ucontext __user *uc_transact;
        unsigned long msr_hi;
        unsigned long tmp;
+       int tm_restore = 0;
 #endif
        /* Always make any pending restarted system calls return -EINTR */
        current->restart_block.fn = do_no_restart_syscall;
@@ -1192,19 +1192,11 @@ SYSCALL_DEFINE0(rt_sigreturn)
                                goto bad;
                }
        }
-       if (!tm_restore) {
-               /*
-                * Unset regs->msr because ucontext MSR TS is not
-                * set, and recheckpoint was not called. This avoid
-                * hitting a TM Bad thing at RFID
-                */
-               regs->msr &= ~MSR_TS_MASK;
-       }
-       /* Fall through, for non-TM restore */
-#endif
        if (!tm_restore)
-               if (do_setcontext(&rt_sf->uc, regs, 1))
-                       goto bad;
+               /* Fall through, for non-TM restore */
+#endif
+       if (do_setcontext(&rt_sf->uc, regs, 1))
+               goto bad;
 
        /*
         * It's not clear whether or why it is desirable to save the

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index daa28cb..83d51bf 100644 (file)
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -740,23 +740,11 @@ SYSCALL_DEFINE0(rt_sigreturn)
                                           &uc_transact->uc_mcontext))
                        goto badframe;
        }
-#endif
+       else
        /* Fall through, for non-TM restore */
-       if (!MSR_TM_ACTIVE(msr)) {
-               /*
-                * Unset MSR[TS] on the thread regs since MSR from user
-                * context does not have MSR active, and recheckpoint was
-                * not called since restore_tm_sigcontexts() was not called
-                * also.
-                *
-                * If not unsetting it, the code can RFID to userspace with
-                * MSR[TS] set, but without CPU in the proper state,
-                * causing a TM bad thing.
-                */
-               current->thread.regs->msr &= ~MSR_TS_MASK;
-               if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext))
-                       goto badframe;
-       }
+#endif
+       if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext))
+               goto badframe;
 
        if (restore_altstack(&uc->uc_stack))
                goto badframe;