From 5323180db75d562a287cb2020b07c9422df13df6 Mon Sep 17 00:00:00 2001 From: Atsushi Nemoto Date: Sat, 14 Apr 2007 02:37:26 +0900 Subject: [MIPS] Disallow CpU exception in kernel again. The commit 4d40bff7110e9e1a97ff8c01bdd6350e9867cc10 ("Allow CpU exception in kernel partially") was broken. The commit was to fix theoretical problem but broke usual case. Revert it for now. Signed-off-by: Atsushi Nemoto Signed-off-by: Ralf Baechle --- arch/mips/kernel/r2300_switch.S | 10 ++++------ arch/mips/kernel/r4k_switch.S | 10 ++++------ arch/mips/kernel/signal.c | 10 +++++----- arch/mips/kernel/signal32.c | 10 +++++----- arch/mips/kernel/traps.c | 21 +++------------------ 5 files changed, 21 insertions(+), 40 deletions(-) (limited to 'arch/mips') diff --git a/arch/mips/kernel/r2300_switch.S b/arch/mips/kernel/r2300_switch.S index 28c2e2e6af73..656bde2e11b1 100644 --- a/arch/mips/kernel/r2300_switch.S +++ b/arch/mips/kernel/r2300_switch.S @@ -49,7 +49,8 @@ LEAF(resume) #ifndef CONFIG_CPU_HAS_LLSC sw zero, ll_bit #endif - mfc0 t2, CP0_STATUS + mfc0 t1, CP0_STATUS + sw t1, THREAD_STATUS(a0) cpu_save_nonscratch a0 sw ra, THREAD_REG31(a0) @@ -59,8 +60,8 @@ LEAF(resume) lw t3, TASK_THREAD_INFO(a0) lw t0, TI_FLAGS(t3) li t1, _TIF_USEDFPU - and t1, t0 - beqz t1, 1f + and t2, t0, t1 + beqz t2, 1f nor t1, zero, t1 and t0, t0, t1 @@ -73,13 +74,10 @@ LEAF(resume) li t1, ~ST0_CU1 and t0, t0, t1 sw t0, ST_OFF(t3) - /* clear thread_struct CU1 bit */ - and t2, t1 fpu_save_single a0, t0 # clobbers t0 1: - sw t2, THREAD_STATUS(a0) /* * The order of restoring the registers takes care of the race * updating $28, $29 and kernelsp without disabling ints. diff --git a/arch/mips/kernel/r4k_switch.S b/arch/mips/kernel/r4k_switch.S index c7698fd9955c..cc566cf12246 100644 --- a/arch/mips/kernel/r4k_switch.S +++ b/arch/mips/kernel/r4k_switch.S @@ -48,7 +48,8 @@ #ifndef CONFIG_CPU_HAS_LLSC sw zero, ll_bit #endif - mfc0 t2, CP0_STATUS + mfc0 t1, CP0_STATUS + LONG_S t1, THREAD_STATUS(a0) cpu_save_nonscratch a0 LONG_S ra, THREAD_REG31(a0) @@ -58,8 +59,8 @@ PTR_L t3, TASK_THREAD_INFO(a0) LONG_L t0, TI_FLAGS(t3) li t1, _TIF_USEDFPU - and t1, t0 - beqz t1, 1f + and t2, t0, t1 + beqz t2, 1f nor t1, zero, t1 and t0, t0, t1 @@ -72,13 +73,10 @@ li t1, ~ST0_CU1 and t0, t0, t1 LONG_S t0, ST_OFF(t3) - /* clear thread_struct CU1 bit */ - and t2, t1 fpu_save_double a0 t0 t1 # c0_status passed in t0 # clobbers t1 1: - LONG_S t2, THREAD_STATUS(a0) /* * The order of restoring the registers takes care of the race diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c index 8c3c5a5789b0..fa581192de21 100644 --- a/arch/mips/kernel/signal.c +++ b/arch/mips/kernel/signal.c @@ -113,10 +113,10 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) * Save FPU state to signal context. Signal handler * will "inherit" current FPU state. */ + preempt_disable(); own_fpu(1); - enable_fp_in_kernel(); err |= save_fp_context(sc); - disable_fp_in_kernel(); + preempt_enable(); } return err; } @@ -148,7 +148,10 @@ check_and_restore_fp_context(struct sigcontext __user *sc) err = sig = fpcsr_pending(&sc->sc_fpc_csr); if (err > 0) err = 0; + preempt_disable(); + own_fpu(0); err |= restore_fp_context(sc); + preempt_enable(); return err ?: sig; } @@ -187,11 +190,8 @@ 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(0); - enable_fp_in_kernel(); if (!err) err = check_and_restore_fp_context(sc); - disable_fp_in_kernel(); } else { /* signal handler may have used FPU. Give it up. */ lose_fpu(0); diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c index 151fd2f0893a..53a337cfeb66 100644 --- a/arch/mips/kernel/signal32.c +++ b/arch/mips/kernel/signal32.c @@ -209,10 +209,10 @@ static int setup_sigcontext32(struct pt_regs *regs, * Save FPU state to signal context. Signal handler * will "inherit" current FPU state. */ + preempt_disable(); own_fpu(1); - enable_fp_in_kernel(); err |= save_fp_context32(sc); - disable_fp_in_kernel(); + preempt_enable(); } return err; } @@ -225,7 +225,10 @@ check_and_restore_fp_context32(struct sigcontext32 __user *sc) err = sig = fpcsr_pending(&sc->sc_fpc_csr); if (err > 0) err = 0; + preempt_disable(); + own_fpu(0); err |= restore_fp_context32(sc); + preempt_enable(); return err ?: sig; } @@ -261,11 +264,8 @@ static int restore_sigcontext32(struct pt_regs *regs, if (used_math) { /* restore fpu context if we have used it before */ - own_fpu(0); - enable_fp_in_kernel(); if (!err) err = check_and_restore_fp_context32(sc); - disable_fp_in_kernel(); } else { /* signal handler may have used FPU. Give it up. */ lose_fpu(0); diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 7d76a85422b2..6b356f62289e 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -757,11 +757,12 @@ asmlinkage void do_cpu(struct pt_regs *regs) { unsigned int cpid; + die_if_kernel("do_cpu invoked from kernel context!", regs); + cpid = (regs->cp0_cause >> CAUSEB_CE) & 3; switch (cpid) { case 0: - die_if_kernel("do_cpu invoked from kernel context!", regs); if (!cpu_has_llsc) if (!simulate_llsc(regs)) return; @@ -772,9 +773,6 @@ asmlinkage void do_cpu(struct pt_regs *regs) break; case 1: - if (!test_thread_flag(TIF_ALLOW_FP_IN_KERNEL)) - die_if_kernel("do_cpu invoked from kernel context!", - regs); if (used_math()) /* Using the FPU again. */ own_fpu(1); else { /* First time FPU user. */ @@ -782,19 +780,7 @@ asmlinkage void do_cpu(struct pt_regs *regs) set_used_math(); } - if (raw_cpu_has_fpu) { - if (test_thread_flag(TIF_ALLOW_FP_IN_KERNEL)) { - local_irq_disable(); - if (cpu_has_fpu) - regs->cp0_status |= ST0_CU1; - /* - * We must return without enabling - * interrupts to ensure keep FPU - * ownership until resume. - */ - return; - } - } else { + if (!raw_cpu_has_fpu) { int sig; sig = fpu_emulator_cop1Handler(regs, ¤t->thread.fpu, 0); @@ -836,7 +822,6 @@ asmlinkage void do_cpu(struct pt_regs *regs) case 2: case 3: - die_if_kernel("do_cpu invoked from kernel context!", regs); break; } -- cgit v1.2.2