linux-kernel - [ 006/103] powerpc/tm: Fix 32 bit non-rt signals

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Date:	Tue, 23 Jul 2013 15:25:17 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Michael Neuling <mikey@...ling.org>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>
Subject: [ 006/103] powerpc/tm: Fix 32 bit non-rt signals

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michael Neuling <mikey@...ling.org>

commit fee55450710dff32a13ae30b4129ec7b5a4b44d0 upstream.

Currently sys_sigreturn() is TM unaware.  Therefore, if we take a 32 bit signal
without SIGINFO (non RT) inside a transaction, on signal return we don't
restore the signal frame correctly.

This checks if the signal frame being restoring is an active transaction, and
if so, it copies the additional state to ptregs so it can be restored.

Signed-off-by: Michael Neuling <mikey@...ling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/powerpc/kernel/signal_32.c |   30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -1494,16 +1494,22 @@ badframe:
 long sys_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
 		       struct pt_regs *regs)
 {
+	struct sigframe __user *sf;
 	struct sigcontext __user *sc;
 	struct sigcontext sigctx;
 	struct mcontext __user *sr;
 	void __user *addr;
 	sigset_t set;
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	struct mcontext __user *mcp, *tm_mcp;
+	unsigned long msr_hi;
+#endif
 
 	/* Always make any pending restarted system calls return -EINTR */
 	current_thread_info()->restart_block.fn = do_no_restart_syscall;
 
-	sc = (struct sigcontext __user *)(regs->gpr[1] + __SIGNAL_FRAMESIZE);
+	sf = (struct sigframe __user *)(regs->gpr[1] + __SIGNAL_FRAMESIZE);
+	sc = &sf->sctx;
 	addr = sc;
 	if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
 		goto badframe;
@@ -1520,11 +1526,25 @@ long sys_sigreturn(int r3, int r4, int r
 #endif
 	set_current_blocked(&set);
 
-	sr = (struct mcontext __user *)from_user_ptr(sigctx.regs);
-	addr = sr;
-	if (!access_ok(VERIFY_READ, sr, sizeof(*sr))
-	    || restore_user_regs(regs, sr, 1))
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	mcp = (struct mcontext __user *)&sf->mctx;
+	tm_mcp = (struct mcontext __user *)&sf->mctx_transact;
+	if (__get_user(msr_hi, &tm_mcp->mc_gregs[PT_MSR]))
 		goto badframe;
+	if (MSR_TM_ACTIVE(msr_hi<<32)) {
+		if (!cpu_has_feature(CPU_FTR_TM))
+			goto badframe;
+		if (restore_tm_user_regs(regs, mcp, tm_mcp))
+			goto badframe;
+	} else
+#endif
+	{
+		sr = (struct mcontext __user *)from_user_ptr(sigctx.regs);
+		addr = sr;
+		if (!access_ok(VERIFY_READ, sr, sizeof(*sr))
+		    || restore_user_regs(regs, sr, 1))
+			goto badframe;
+	}
 
 	set_thread_flag(TIF_RESTOREALL);
 	return 0;


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