Received: from mail.onstor.com ([66.201.51.107]) by onstor-exch02.onstor.net with Microsoft SMTPSVC(6.0.3790.1830);
	 Fri, 9 Mar 2007 08:06:08 -0800
Received: from ftp.linux-mips.org ([194.74.144.162]) by mail.onstor.com with Microsoft SMTPSVC(6.0.3790.1830);
	 Fri, 9 Mar 2007 08:06:07 -0800
Received: from localhost.localdomain ([127.0.0.1]:50899 "EHLO
	ftp.linux-mips.org") by ftp.linux-mips.org with ESMTP
	id S20021492AbXCIQFk (ORCPT <rfc822;dan.stein@onstor.com> + 1 other);
	Fri, 9 Mar 2007 16:05:40 +0000
Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 09 Mar 2007 16:05:16 +0000 (GMT)
Received: from mba.ocn.ne.jp ([122.1.175.29]:43462 "HELO smtp.mba.ocn.ne.jp")
	by ftp.linux-mips.org with SMTP id S20021471AbXCIQFL (ORCPT
	<rfc822;linux-mips@linux-mips.org>); Fri, 9 Mar 2007 16:05:11 +0000
Received: from localhost (p4160-ipad211funabasi.chiba.ocn.ne.jp [58.91.160.160])
	by smtp.mba.ocn.ne.jp (Postfix) with ESMTP
	id E4BA0BB70; Sat, 10 Mar 2007 01:03:48 +0900 (JST)
Date:	Sat, 10 Mar 2007 01:03:48 +0900 (JST)
Message-Id: <20070310.010348.72708233.anemo@mba.ocn.ne.jp>
To:	linux-mips@linux-mips.org
Cc:	ralf@linux-mips.org, macro@linux-mips.org, vagabon.xyz@gmail.com
Subject: [PATCH] Check FCSR for pending interrupts, alternative version
From:	Atsushi Nemoto <anemo@mba.ocn.ne.jp>
X-Fingerprint: 6ACA 1623 39BD 9A94 9B1A  B746 CA77 FE94 2874 D52F
X-Pgp-Public-Key: http://wwwkeys.pgp.net/pks/lookup?op=get&search=0x2874D52F
X-Mailer: Mew version 3.3 on Emacs 21.4 / Mule 5.0 (SAKAKI)
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-archive-position: 14403
X-ecartis-version: Ecartis v1.0.0
Sender:	linux-mips-bounce@linux-mips.org
Errors-to: linux-mips-bounce@linux-mips.org
X-original-sender: anemo@mba.ocn.ne.jp
Precedence: bulk
X-list:	linux-mips
Return-Path: linux-mips-bounce@linux-mips.org
X-OriginalArrivalTime: 09 Mar 2007 16:06:07.0928 (UTC) FILETIME=[D8F11B80:01C76264]

The commit 6d6671066a311703bca1b91645bb1e04cc983387 is incomplete and
misses non-r4k CPUs.  This patch reverts the commit and fixes in other
way.

* Do FCSR checking in caller of restore_fp_context.
* Send SIGFPE if the signal handler set any FPU exception bits.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
---
This is an update of:
http://www.linux-mips.org/archives/linux-mips/2007-02/msg00215.html

 arch/mips/kernel/r4k_fpu.S       |   16 ------------
 arch/mips/kernel/signal-common.h |    3 ++
 arch/mips/kernel/signal.c        |   46 ++++++++++++++++++++++++++++++++++---
 arch/mips/kernel/signal32.c      |   27 +++++++++++++++++++--
 arch/mips/kernel/signal_n32.c    |    6 ++++
 5 files changed, 75 insertions(+), 23 deletions(-)

diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
index 59c1577..dbd42ad 100644
--- a/arch/mips/kernel/r4k_fpu.S
+++ b/arch/mips/kernel/r4k_fpu.S
@@ -114,14 +114,6 @@ LEAF(_save_fp_context32)
  */
 LEAF(_restore_fp_context)
 	EX	lw t0, SC_FPC_CSR(a0)
-
-	/* Fail if the CSR has exceptions pending */
-	srl	t1, t0, 5
-	and	t1, t0
-	andi	t1, 0x1f << 7
-	bnez	t1, fault
-	 nop
-
 #ifdef CONFIG_64BIT
 	EX	ldc1 $f1, SC_FPREGS+8(a0)
 	EX	ldc1 $f3, SC_FPREGS+24(a0)
@@ -165,14 +157,6 @@ LEAF(_restore_fp_context)
 LEAF(_restore_fp_context32)
 	/* Restore an o32 sigcontext.  */
 	EX	lw t0, SC32_FPC_CSR(a0)
-
-	/* Fail if the CSR has exceptions pending */
-	srl	t1, t0, 5
-	and	t1, t0
-	andi	t1, 0x1f << 7
-	bnez	t1, fault
-	 nop
-
 	EX	ldc1 $f0, SC32_FPREGS+0(a0)
 	EX	ldc1 $f2, SC32_FPREGS+16(a0)
 	EX	ldc1 $f4, SC32_FPREGS+32(a0)
diff --git a/arch/mips/kernel/signal-common.h b/arch/mips/kernel/signal-common.h
index fdbdbdc..297dfcb 100644
--- a/arch/mips/kernel/signal-common.h
+++ b/arch/mips/kernel/signal-common.h
@@ -31,4 +31,7 @@ extern void __user *get_sigframe(struct
  */
 extern int install_sigtramp(unsigned int __user *tramp, unsigned int syscall);
 
+/* Check and clear pending FPU exceptions in saved CSR */
+extern int fpcsr_pending(unsigned int __user *fpcsr);
+
 #endif	/* __SIGNAL_COMMON_H */
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index f091786..bf094fc 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -124,6 +124,37 @@ int setup_sigcontext(struct pt_regs *reg
 	return err;
 }
 
+int fpcsr_pending(unsigned int __user *fpcsr)
+{
+	int err, sig = 0;
+	unsigned int csr, enabled;
+
+	err = __get_user(csr, fpcsr);
+	enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
+	/*
+	 * If the signal handler set some FPU exceptions, clear it and
+	 * send SIGFPE.
+	 */
+	if (csr & enabled) {
+		csr &= ~enabled;
+		err |= __put_user(csr, fpcsr);
+		sig = SIGFPE;
+	}
+	return err ?: sig;
+}
+
+static int
+check_and_restore_fp_context(struct sigcontext __user *sc)
+{
+	int err, sig;
+
+	err = sig = fpcsr_pending(&sc->sc_fpc_csr);
+	if (err > 0)
+		err = 0;
+	err |= restore_fp_context(sc);
+	return err ?: sig;
+}
+
 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 {
 	unsigned int used_math;
@@ -162,7 +193,8 @@ int restore_sigcontext(struct pt_regs *r
 	if (used_math()) {
 		/* restore fpu context if we have used it before */
 		own_fpu();
-		err |= restore_fp_context(sc);
+		if (!err)
+			err = check_and_restore_fp_context(sc);
 	} else {
 		/* signal handler may have used FPU.  Give it up. */
 		lose_fpu();
@@ -332,6 +364,7 @@ asmlinkage void sys_sigreturn(nabi_no_re
 {
 	struct sigframe __user *frame;
 	sigset_t blocked;
+	int sig;
 
 	frame = (struct sigframe __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -345,8 +378,11 @@ asmlinkage void sys_sigreturn(nabi_no_re
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext(&regs, &frame->sf_sc))
+	sig = restore_sigcontext(&regs, &frame->sf_sc);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	/*
 	 * Don't let your children do this ...
@@ -368,6 +404,7 @@ asmlinkage void sys_rt_sigreturn(nabi_no
 	struct rt_sigframe __user *frame;
 	sigset_t set;
 	stack_t st;
+	int sig;
 
 	frame = (struct rt_sigframe __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -381,8 +418,11 @@ asmlinkage void sys_rt_sigreturn(nabi_no
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
+	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
 		goto badframe;
diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c
index 19bbef0..20013b6 100644
--- a/arch/mips/kernel/signal32.c
+++ b/arch/mips/kernel/signal32.c
@@ -220,6 +220,18 @@ static int setup_sigcontext32(struct pt_
 	return err;
 }
 
+static int
+check_and_restore_fp_context32(struct sigcontext32 __user *sc)
+{
+	int err, sig;
+
+	err = sig = fpcsr_pending(&sc->sc_fpc_csr);
+	if (err > 0)
+		err = 0;
+	err |= restore_fp_context32(sc);
+	return err ?: sig;
+}
+
 static int restore_sigcontext32(struct pt_regs *regs,
 				struct sigcontext32 __user *sc)
 {
@@ -255,7 +267,8 @@ static int restore_sigcontext32(struct p
 	if (used_math()) {
 		/* restore fpu context if we have used it before */
 		own_fpu();
-		err |= restore_fp_context32(sc);
+		if (!err)
+			err = check_and_restore_fp_context32(sc);
 	} else {
 		/* signal handler may have used FPU.  Give it up. */
 		lose_fpu();
@@ -508,6 +521,7 @@ asmlinkage void sys32_sigreturn(nabi_no_
 {
 	struct sigframe32 __user *frame;
 	sigset_t blocked;
+	int sig;
 
 	frame = (struct sigframe32 __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -521,8 +535,11 @@ asmlinkage void sys32_sigreturn(nabi_no_
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext32(&regs, &frame->sf_sc))
+	sig = restore_sigcontext32(&regs, &frame->sf_sc);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	/*
 	 * Don't let your children do this ...
@@ -545,6 +562,7 @@ asmlinkage void sys32_rt_sigreturn(nabi_
 	sigset_t set;
 	stack_t st;
 	s32 sp;
+	int sig;
 
 	frame = (struct rt_sigframe32 __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -558,8 +576,11 @@ asmlinkage void sys32_rt_sigreturn(nabi_
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext))
+	sig = restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	/* The ucontext contains a stack32_t, so we must convert!  */
 	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
diff --git a/arch/mips/kernel/signal_n32.c b/arch/mips/kernel/signal_n32.c
index ecf1f7e..a9202fa 100644
--- a/arch/mips/kernel/signal_n32.c
+++ b/arch/mips/kernel/signal_n32.c
@@ -127,6 +127,7 @@ asmlinkage void sysn32_rt_sigreturn(nabi
 	sigset_t set;
 	stack_t st;
 	s32 sp;
+	int sig;
 
 	frame = (struct rt_sigframe_n32 __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -140,8 +141,11 @@ asmlinkage void sysn32_rt_sigreturn(nabi
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
+	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	/* The ucontext contains a stack32_t, so we must convert!  */
 	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))

