1 files changed, 44 insertions, 18 deletions

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index e6474a45cef5..ede4f04281ae 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -470,9 +470,9 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
 		return 1;
 
 	if (sigret) {
-		/* Set up the sigreturn trampoline: li r0,sigret; sc */
-		if (__put_user(0x38000000UL + sigret, &frame->tramp[0])
-		    || __put_user(0x44000002UL, &frame->tramp[1]))
+		/* Set up the sigreturn trampoline: li 0,sigret; sc */
+		if (__put_user(PPC_INST_ADDI + sigret, &frame->tramp[0])
+		    || __put_user(PPC_INST_SC, &frame->tramp[1]))
 			return 1;
 		flush_icache_range((unsigned long) &frame->tramp[0],
 				   (unsigned long) &frame->tramp[2]);
@@ -619,9 +619,9 @@ static int save_tm_user_regs(struct pt_regs *regs,
 	if (__put_user(msr, &frame->mc_gregs[PT_MSR]))
 		return 1;
 	if (sigret) {
-		/* Set up the sigreturn trampoline: li r0,sigret; sc */
-		if (__put_user(0x38000000UL + sigret, &frame->tramp[0])
-		    || __put_user(0x44000002UL, &frame->tramp[1]))
+		/* Set up the sigreturn trampoline: li 0,sigret; sc */
+		if (__put_user(PPC_INST_ADDI + sigret, &frame->tramp[0])
+		    || __put_user(PPC_INST_SC, &frame->tramp[1]))
 			return 1;
 		flush_icache_range((unsigned long) &frame->tramp[0],
 				   (unsigned long) &frame->tramp[2]);
@@ -848,7 +848,23 @@ static long restore_tm_user_regs(struct pt_regs *regs,
 	/* If TM bits are set to the reserved value, it's an invalid context */
 	if (MSR_TM_RESV(msr_hi))
 		return 1;
-	/* Pull in the MSR TM bits from the user context */
+
+	/*
+	 * Disabling preemption, since it is unsafe to be preempted
+	 * with MSR[TS] set without recheckpointing.
+	 */
+	preempt_disable();
+
+	/*
+	 * CAUTION:
+	 * After regs->MSR[TS] being updated, make sure that get_user(),
+	 * put_user() or similar functions are *not* called. These
+	 * functions can generate page faults which will cause the process
+	 * to be de-scheduled with MSR[TS] set but without calling
+	 * tm_recheckpoint(). This can cause a bug.
+	 *
+	 * Pull in the MSR TM bits from the user context
+	 */
 	regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr_hi & MSR_TS_MASK);
 	/* Now, recheckpoint.  This loads up all of the checkpointed (older)
 	 * registers, including FP and V[S]Rs.  After recheckpointing, the
@@ -873,6 +889,8 @@ static long restore_tm_user_regs(struct pt_regs *regs,
 	}
 #endif
 
+	preempt_enable();
+
 	return 0;
 }
 #endif
@@ -999,7 +1017,7 @@ static int do_setcontext(struct ucontext __user *ucp, struct pt_regs *regs, int
 #else
 	if (__get_user(mcp, &ucp->uc_regs))
 		return -EFAULT;
-	if (!access_ok(VERIFY_READ, mcp, sizeof(*mcp)))
+	if (!access_ok(mcp, sizeof(*mcp)))
 		return -EFAULT;
 #endif
 	set_current_blocked(&set);
@@ -1102,7 +1120,7 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
 		 */
 		mctx = (struct mcontext __user *)
 			((unsigned long) &old_ctx->uc_mcontext & ~0xfUL);
-		if (!access_ok(VERIFY_WRITE, old_ctx, ctx_size)
+		if (!access_ok(old_ctx, ctx_size)
 		    || save_user_regs(regs, mctx, NULL, 0, ctx_has_vsx_region)
 		    || put_sigset_t(&old_ctx->uc_sigmask, &current->blocked)
 		    || __put_user(to_user_ptr(mctx), &old_ctx->uc_regs))
@@ -1110,7 +1128,7 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
 	}
 	if (new_ctx == NULL)
 		return 0;
-	if (!access_ok(VERIFY_READ, new_ctx, ctx_size) ||
+	if (!access_ok(new_ctx, ctx_size) ||
 	    fault_in_pages_readable((u8 __user *)new_ctx, ctx_size))
 		return -EFAULT;
 
@@ -1140,18 +1158,18 @@ 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;
 
 	rt_sf = (struct rt_sigframe __user *)
 		(regs->gpr[1] + __SIGNAL_FRAMESIZE + 16);
-	if (!access_ok(VERIFY_READ, rt_sf, sizeof(*rt_sf)))
+	if (!access_ok(rt_sf, sizeof(*rt_sf)))
 		goto bad;
 
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
@@ -1192,11 +1210,19 @@ SYSCALL_DEFINE0(rt_sigreturn)
 				goto bad;
 		}
 	}
-	if (!tm_restore)
-		/* Fall through, for non-TM restore */
+	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 (do_setcontext(&rt_sf->uc, regs, 1))
-		goto bad;
+	if (!tm_restore)
+		if (do_setcontext(&rt_sf->uc, regs, 1))
+			goto bad;
 
 	/*
 	 * It's not clear whether or why it is desirable to save the
@@ -1289,7 +1315,7 @@ SYSCALL_DEFINE3(debug_setcontext, struct ucontext __user *, ctx,
 	current->thread.debug.dbcr0 = new_dbcr0;
 #endif
 
-	if (!access_ok(VERIFY_READ, ctx, sizeof(*ctx)) ||
+	if (!access_ok(ctx, sizeof(*ctx)) ||
 	    fault_in_pages_readable((u8 __user *)ctx, sizeof(*ctx)))
 		return -EFAULT;
 
@@ -1474,7 +1500,7 @@ SYSCALL_DEFINE0(sigreturn)
 	{
 		sr = (struct mcontext __user *)from_user_ptr(sigctx.regs);
 		addr = sr;
-		if (!access_ok(VERIFY_READ, sr, sizeof(*sr))
+		if (!access_ok(sr, sizeof(*sr))
 		    || restore_user_regs(regs, sr, 1))
 			goto badframe;
 	}