Revised again. Fix check_and_restore_fp_context32 and rediff against
current git.
Subject: Check FCSR for pending interrupts, alternative version
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@xxxxxxxxxxxxx>
---
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 k_sigaction *ka, struct pt_regs *regs,
*/
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 b2e9ab1..2420ed6 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -121,6 +121,37 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
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;
@@ -155,7 +186,8 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
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();
@@ -325,6 +357,7 @@ asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
{
struct sigframe __user *frame;
sigset_t blocked;
+ int sig;
frame = (struct sigframe __user *) regs.regs[29];
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -338,8 +371,11 @@ asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
- if (restore_sigcontext(®s, &frame->sf_sc))
+ sig = restore_sigcontext(®s, &frame->sf_sc);
+ if (sig < 0)
goto badframe;
+ else if (sig)
+ force_sig(sig, current);
/*
* Don't let your children do this ...
@@ -361,6 +397,7 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
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)))
@@ -374,8 +411,11 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
- if (restore_sigcontext(®s, &frame->rs_uc.uc_mcontext))
+ sig = restore_sigcontext(®s, &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 dd4e518..813279d 100644
--- a/arch/mips/kernel/signal32.c
+++ b/arch/mips/kernel/signal32.c
@@ -220,6 +220,18 @@ static int setup_sigcontext32(struct pt_regs *regs,
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 pt_regs *regs,
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_regargs struct pt_regs regs)
{
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_regargs struct pt_regs regs)
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
- if (restore_sigcontext32(®s, &frame->sf_sc))
+ sig = restore_sigcontext32(®s, &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_no_regargs struct pt_regs regs)
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_no_regargs struct pt_regs regs)
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
- if (restore_sigcontext32(®s, &frame->rs_uc.uc_mcontext))
+ sig = restore_sigcontext32(®s, &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 7ca2a07..26ca944 100644
--- a/arch/mips/kernel/signal_n32.c
+++ b/arch/mips/kernel/signal_n32.c
@@ -126,6 +126,7 @@ asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
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)))
@@ -139,8 +140,11 @@ asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
- if (restore_sigcontext(®s, &frame->rs_uc.uc_mcontext))
+ sig = restore_sigcontext(®s, &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))
