3 files changed, 28 insertions, 23 deletions

diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index fd83b69207f5..a1dc6457016c 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -302,7 +302,8 @@ static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
 
         regs32.psw.mask = psw32_user_bits |
                 ((__u32)(regs->psw.mask >> 32) & PSW32_MASK_USER);
-        regs32.psw.addr = PSW32_ADDR_AMODE | (__u32) regs->psw.addr;
+        regs32.psw.addr = (__u32) regs->psw.addr |
+                (__u32)(regs->psw.mask & PSW_MASK_BA);
         for (i = 0; i < NUM_GPRS; i++)
                 regs32.gprs[i] = (__u32) regs->gprs[i];
         save_access_regs(current->thread.acrs);
@@ -328,7 +329,8 @@ static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
         if (err)
                 return err;
         regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
-                (__u64)(regs32.psw.mask & PSW32_MASK_USER) << 32;
+                (__u64)(regs32.psw.mask & PSW32_MASK_USER) << 32 |
+                (__u64)(regs32.psw.addr & PSW32_ADDR_AMODE);
         regs->psw.addr = (__u64)(regs32.psw.addr & PSW32_ADDR_INSN);
         for (i = 0; i < NUM_GPRS; i++)
                 regs->gprs[i] = (__u64) regs32.gprs[i];
@@ -496,9 +498,9 @@ static int setup_frame32(int sig, struct k_sigaction *ka,
         /* Set up to return from userspace.  If provided, use a stub
            already in userspace.  */
         if (ka->sa.sa_flags & SA_RESTORER) {
-                regs->gprs[14] = (__u64) ka->sa.sa_restorer;
+                regs->gprs[14] = (__u64) ka->sa.sa_restorer | PSW32_ADDR_AMODE;
         } else {
-                regs->gprs[14] = (__u64) frame->retcode;
+                regs->gprs[14] = (__u64) frame->retcode | PSW32_ADDR_AMODE;
                 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
                                (u16 __user *)(frame->retcode)))
                         goto give_sigsegv;
@@ -510,6 +512,7 @@ static int setup_frame32(int sig, struct k_sigaction *ka,
 
         /* Set up registers for signal handler */
         regs->gprs[15] = (__u64) frame;
+        regs->psw.mask |= PSW_MASK_BA;          /* force amode 31 */
         regs->psw.addr = (__u64) ka->sa.sa_handler;
 
         regs->gprs[2] = map_signal(sig);
@@ -573,6 +576,7 @@ static int setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,
 
         /* Set up registers for signal handler */
         regs->gprs[15] = (__u64) frame;
+        regs->psw.mask |= PSW_MASK_BA;          /* force amode 31 */
         regs->psw.addr = (__u64) ka->sa.sa_handler;
 
         regs->gprs[2] = map_signal(sig);
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 41e20763886e..450931a45b68 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -170,8 +170,7 @@ static unsigned long __peek_user(struct task_struct *child, addr_t addr)
                 tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
                 if (addr == (addr_t) &dummy->regs.psw.mask)
                         /* Return a clean psw mask. */
-                        tmp = psw_user_bits | (tmp & PSW_MASK_USER) |
-                                PSW_MASK_EA | PSW_MASK_BA;
+                        tmp = psw_user_bits | (tmp & PSW_MASK_USER);
 
         } else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
                 /*
@@ -286,26 +285,17 @@ static inline void __poke_user_per(struct task_struct *child,
 static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
 {
         struct user *dummy = NULL;
-        addr_t offset, tmp;
+        addr_t offset;
 
         if (addr < (addr_t) &dummy->regs.acrs) {
                 /*
                  * psw and gprs are stored on the stack
                  */
-                tmp = (data & ~PSW_MASK_USER) ^ psw_user_bits;
                 if (addr == (addr_t) &dummy->regs.psw.mask &&
-#ifdef CONFIG_COMPAT
-                    tmp != PSW_MASK_BA &&
-#endif
-                    tmp != (PSW_MASK_EA | PSW_MASK_BA))
+                    ((data & ~PSW_MASK_USER) != psw_user_bits ||
+                     ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))))
                         /* Invalid psw mask. */
                         return -EINVAL;
-#ifndef CONFIG_64BIT
-                if (addr == (addr_t) &dummy->regs.psw.addr)
-                        /* I'd like to reject addresses without the
-                           high order bit but older gdb's rely on it */
-                        data |= PSW_ADDR_AMODE;
-#endif
                 if (addr == (addr_t) &dummy->regs.psw.addr)
                         /*
                          * The debugger changed the instruction address,
@@ -517,7 +507,8 @@ static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
                         tmp = psw32_user_bits | (tmp & PSW32_MASK_USER);
                 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
                         /* Fake a 31 bit psw address. */
-                        tmp = (__u32) regs->psw.addr | PSW32_ADDR_AMODE;
+                        tmp = (__u32) regs->psw.addr |
+                                (__u32)(regs->psw.mask & PSW_MASK_BA);
                 } else {
                         /* gpr 0-15 */
                         tmp = *(__u32 *)((addr_t) &regs->psw + addr*2 + 4);
@@ -615,10 +606,14 @@ static int __poke_user_compat(struct task_struct *child,
                                 /* Invalid psw mask. */
                                 return -EINVAL;
                         regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
+                                (regs->psw.mask & PSW_MASK_BA) |
                                 (__u64)(tmp & PSW32_MASK_USER) << 32;
                 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
                         /* Build a 64 bit psw address from 31 bit address. */
                         regs->psw.addr = (__u64) tmp & PSW32_ADDR_INSN;
+                        /* Transfer 31 bit amode bit to psw mask. */
+                        regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
+                                (__u64)(tmp & PSW32_ADDR_AMODE);
                         /*
                          * The debugger changed the instruction address,
                          * reset system call restart, see signal.c:do_signal
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index c19755815e53..05a85bc14c98 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -117,8 +117,8 @@ static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 
         /* Copy a 'clean' PSW mask to the user to avoid leaking
            information about whether PER is currently on.  */
-        user_sregs.regs.psw.mask = psw_user_bits | PSW_MASK_EA | PSW_MASK_BA |
-                                   (regs->psw.mask & PSW_MASK_USER);
+        user_sregs.regs.psw.mask = psw_user_bits |
+                (regs->psw.mask & PSW_MASK_USER);
         user_sregs.regs.psw.addr = regs->psw.addr;
         memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
         memcpy(&user_sregs.regs.acrs, current->thread.acrs,
@@ -145,9 +145,13 @@ static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
         err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
         if (err)
                 return err;
+        /* Use regs->psw.mask instead of psw_user_bits to preserve PER bit. */
         regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
-                         (user_sregs.regs.psw.mask & PSW_MASK_USER);
-        regs->psw.addr = PSW_ADDR_AMODE | user_sregs.regs.psw.addr;
+                (user_sregs.regs.psw.mask & PSW_MASK_USER);
+        /* Check for invalid amode */
+        if (regs->psw.mask & PSW_MASK_EA)
+                regs->psw.mask |= PSW_MASK_BA;
+        regs->psw.addr = user_sregs.regs.psw.addr;
         memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
         memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
                sizeof(sregs->regs.acrs));
@@ -290,6 +294,7 @@ static int setup_frame(int sig, struct k_sigaction *ka,
 
         /* Set up registers for signal handler */
         regs->gprs[15] = (unsigned long) frame;
+        regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA;    /* 64 bit amode */
         regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
 
         regs->gprs[2] = map_signal(sig);
@@ -358,6 +363,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 
         /* Set up registers for signal handler */
         regs->gprs[15] = (unsigned long) frame;
+        regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA;    /* 64 bit amode */
         regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
 
         regs->gprs[2] = map_signal(sig);