powerpc: Fix 32-bit frames for signals delivered when transactional

Commit d31626f70b61 ("powerpc: Don't corrupt transactional state when
using FP/VMX in kernel") introduced a bug where the uc_link and uc_regs
fields of the ucontext_t that is created to hold the transactional
values of the registers in a 32-bit signal frame didn't get set
correctly.  The reason is that we now clear the MSR_TS bits in the MSR
in save_tm_user_regs(), before the code that sets uc_link and uc_regs.
To fix this, we move the setting of uc_link and uc_regs into the same
if statement that selects whether to call save_tm_user_regs() or
save_user_regs().

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 7 insertions, 12 deletions

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 6ce69e6f1fcb..a67e00aa3caa 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -1022,29 +1022,24 @@ int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
         tm_frame = &rt_sf->uc_transact.uc_mcontext;
         if (MSR_TM_ACTIVE(regs->msr)) {
+                if (__put_user((unsigned long)&rt_sf->uc_transact,
+                               &rt_sf->uc.uc_link) ||
+                    __put_user((unsigned long)tm_frame,
+                               &rt_sf->uc_transact.uc_regs))
+                        goto badframe;
                 if (save_tm_user_regs(regs, frame, tm_frame, sigret))
                         goto badframe;
         }
         else
 #endif
         {
+                if (__put_user(0, &rt_sf->uc.uc_link))
+                        goto badframe;
                 if (save_user_regs(regs, frame, tm_frame, sigret, 1))
                         goto badframe;
         }
         regs->link = tramp;
 
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-        if (MSR_TM_ACTIVE(regs->msr)) {
-                if (__put_user((unsigned long)&rt_sf->uc_transact,
-                               &rt_sf->uc.uc_link)
-                    || __put_user((unsigned long)tm_frame, &rt_sf->uc_transact.uc_regs))
-                        goto badframe;
-        }
-        else
-#endif
-                if (__put_user(0, &rt_sf->uc.uc_link))
-                        goto badframe;
-
         current->thread.fp_state.fpscr = 0;     /* turn off all fp exceptions */
 
         /* create a stack frame for the caller of the handler */