These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

1 files changed, 65 insertions, 208 deletions

diff --git a/kernel/arch/x86/kernel/traps.c b/kernel/arch/x86/kernel/traps.c
index ebae11893..ade185a46 100644
--- a/kernel/arch/x86/kernel/traps.c
+++ b/kernel/arch/x86/kernel/traps.c
@@ -54,13 +54,15 @@
 #include <asm/ftrace.h>
 #include <asm/traps.h>
 #include <asm/desc.h>
-#include <asm/i387.h>
-#include <asm/fpu-internal.h>
+#include <asm/fpu/internal.h>
 #include <asm/mce.h>
 #include <asm/fixmap.h>
 #include <asm/mach_traps.h>
 #include <asm/alternative.h>
+#include <asm/fpu/xstate.h>
+#include <asm/trace/mpx.h>
 #include <asm/mpx.h>
+#include <asm/vm86.h>
 
 #ifdef CONFIG_X86_64
 #include <asm/x86_init.h>
@@ -72,8 +74,7 @@ gate_desc debug_idt_table[NR_VECTORS] __page_aligned_bss;
 #else
 #include <asm/processor-flags.h>
 #include <asm/setup.h>
-
-asmlinkage int system_call(void);
+#include <asm/proto.h>
 #endif
 
 /* Must be page-aligned because the real IDT is used in a fixmap. */
@@ -88,21 +89,9 @@ static inline void conditional_sti(struct pt_regs *regs)
 		local_irq_enable();
 }
 
-static inline void conditional_sti_ist(struct pt_regs *regs)
+static inline void preempt_conditional_sti(struct pt_regs *regs)
 {
-#ifdef CONFIG_X86_64
-	/*
-	 * X86_64 uses a per CPU stack on the IST for certain traps
-	 * like int3. The task can not be preempted when using one
-	 * of these stacks, thus preemption must be disabled, otherwise
-	 * the stack can be corrupted if the task is scheduled out,
-	 * and another task comes in and uses this stack.
-	 *
-	 * On x86_32 the task keeps its own stack and it is OK if the
-	 * task schedules out.
-	 */
 	preempt_count_inc();
-#endif
 	if (regs->flags & X86_EFLAGS_IF)
 		local_irq_enable();
 }
@@ -113,22 +102,17 @@ static inline void conditional_cli(struct pt_regs *regs)
 		local_irq_disable();
 }
 
-static inline void conditional_cli_ist(struct pt_regs *regs)
+static inline void preempt_conditional_cli(struct pt_regs *regs)
 {
 	if (regs->flags & X86_EFLAGS_IF)
 		local_irq_disable();
-#ifdef CONFIG_X86_64
 	preempt_count_dec();
-#endif
 }
 
-enum ctx_state ist_enter(struct pt_regs *regs)
+void ist_enter(struct pt_regs *regs)
 {
-	enum ctx_state prev_state;
-
 	if (user_mode(regs)) {
-		/* Other than that, we're just an exception. */
-		prev_state = exception_enter();
+		RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 	} else {
 		/*
 		 * We might have interrupted pretty much anything.  In
@@ -137,32 +121,25 @@ enum ctx_state ist_enter(struct pt_regs *regs)
 		 * but we need to notify RCU.
 		 */
 		rcu_nmi_enter();
-		prev_state = CONTEXT_KERNEL;  /* the value is irrelevant. */
 	}
 
 	/*
-	 * We are atomic because we're on the IST stack (or we're on x86_32,
-	 * in which case we still shouldn't schedule).
-	 *
-	 * This must be after exception_enter(), because exception_enter()
-	 * won't do anything if in_interrupt() returns true.
+	 * We are atomic because we're on the IST stack; or we're on
+	 * x86_32, in which case we still shouldn't schedule; or we're
+	 * on x86_64 and entered from user mode, in which case we're
+	 * still atomic unless ist_begin_non_atomic is called.
 	 */
 	preempt_count_add(HARDIRQ_OFFSET);
 
 	/* This code is a bit fragile.  Test it. */
-	rcu_lockdep_assert(rcu_is_watching(), "ist_enter didn't work");
-
-	return prev_state;
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "ist_enter didn't work");
 }
 
-void ist_exit(struct pt_regs *regs, enum ctx_state prev_state)
+void ist_exit(struct pt_regs *regs)
 {
-	/* Must be before exception_exit. */
 	preempt_count_sub(HARDIRQ_OFFSET);
 
-	if (user_mode(regs))
-		return exception_exit(prev_state);
-	else
+	if (!user_mode(regs))
 		rcu_nmi_exit();
 }
 
@@ -176,7 +153,7 @@ void ist_exit(struct pt_regs *regs, enum ctx_state prev_state)
  * a double fault, it can be safe to schedule.  ist_begin_non_atomic()
  * begins a non-atomic section within an ist_enter()/ist_exit() region.
  * Callers are responsible for enabling interrupts themselves inside
- * the non-atomic section, and callers must call is_end_non_atomic()
+ * the non-atomic section, and callers must call ist_end_non_atomic()
  * before ist_exit().
  */
 void ist_begin_non_atomic(struct pt_regs *regs)
@@ -303,17 +280,16 @@ NOKPROBE_SYMBOL(do_trap);
 static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
 			  unsigned long trapnr, int signr)
 {
-	enum ctx_state prev_state = exception_enter();
 	siginfo_t info;
 
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
+
 	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
 			NOTIFY_STOP) {
 		conditional_sti(regs);
 		do_trap(trapnr, signr, str, regs, error_code,
 			fill_trap_info(regs, signr, trapnr, &info));
 	}
-
-	exception_exit(prev_state);
 }
 
 #define DO_ERROR(trapnr, signr, str, name)				\
@@ -365,7 +341,7 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 	}
 #endif
 
-	ist_enter(regs);  /* Discard prev_state because we won't return. */
+	ist_enter(regs);
 	notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
 
 	tsk->thread.error_code = error_code;
@@ -385,16 +361,13 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 
 dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 {
-	struct task_struct *tsk = current;
-	struct xsave_struct *xsave_buf;
-	enum ctx_state prev_state;
-	struct bndcsr *bndcsr;
+	const struct mpx_bndcsr *bndcsr;
 	siginfo_t *info;
 
-	prev_state = exception_enter();
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 	if (notify_die(DIE_TRAP, "bounds", regs, error_code,
 			X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP)
-		goto exit;
+		return;
 	conditional_sti(regs);
 
 	if (!user_mode(regs))
@@ -407,15 +380,15 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 
 	/*
 	 * We need to look at BNDSTATUS to resolve this exception.
-	 * It is not directly accessible, though, so we need to
-	 * do an xsave and then pull it out of the xsave buffer.
+	 * A NULL here might mean that it is in its 'init state',
+	 * which is all zeros which indicates MPX was not
+	 * responsible for the exception.
 	 */
-	fpu_save_init(&tsk->thread.fpu);
-	xsave_buf = &(tsk->thread.fpu.state->xsave);
-	bndcsr = get_xsave_addr(xsave_buf, XSTATE_BNDCSR);
+	bndcsr = get_xsave_field_ptr(XFEATURE_MASK_BNDCSR);
 	if (!bndcsr)
 		goto exit_trap;
 
+	trace_bounds_exception_mpx(bndcsr);
 	/*
 	 * The error code field of the BNDSTATUS register communicates status
 	 * information of a bound range exception #BR or operation involving
@@ -423,11 +396,11 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 	 */
 	switch (bndcsr->bndstatus & MPX_BNDSTA_ERROR_CODE) {
 	case 2:	/* Bound directory has invalid entry. */
-		if (mpx_handle_bd_fault(xsave_buf))
+		if (mpx_handle_bd_fault())
 			goto exit_trap;
 		break; /* Success, it was handled */
 	case 1: /* Bound violation. */
-		info = mpx_generate_siginfo(regs, xsave_buf);
+		info = mpx_generate_siginfo(regs);
 		if (IS_ERR(info)) {
 			/*
 			 * We failed to decode the MPX instruction.  Act as if
@@ -451,9 +424,8 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 		die("bounds", regs, error_code);
 	}
 
-exit:
-	exception_exit(prev_state);
 	return;
+
 exit_trap:
 	/*
 	 * This path out is for all the cases where we could not
@@ -463,35 +435,33 @@ exit_trap:
 	 * time..
 	 */
 	do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, NULL);
-	exception_exit(prev_state);
 }
 
 dotraplinkage void
 do_general_protection(struct pt_regs *regs, long error_code)
 {
 	struct task_struct *tsk;
-	enum ctx_state prev_state;
 
-	prev_state = exception_enter();
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 	conditional_sti(regs);
 
 	if (v8086_mode(regs)) {
 		local_irq_enable();
 		handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
-		goto exit;
+		return;
 	}
 
 	tsk = current;
 	if (!user_mode(regs)) {
 		if (fixup_exception(regs))
-			goto exit;
+			return;
 
 		tsk->thread.error_code = error_code;
 		tsk->thread.trap_nr = X86_TRAP_GP;
 		if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
 			       X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP)
 			die("general protection fault", regs, error_code);
-		goto exit;
+		return;
 	}
 
 	tsk->thread.error_code = error_code;
@@ -507,16 +477,12 @@ do_general_protection(struct pt_regs *regs, long error_code)
 	}
 
 	force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
-exit:
-	exception_exit(prev_state);
 }
 NOKPROBE_SYMBOL(do_general_protection);
 
 /* May run on IST stack. */
 dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
-
 #ifdef CONFIG_DYNAMIC_FTRACE
 	/*
 	 * ftrace must be first, everything else may cause a recursive crash.
@@ -529,7 +495,8 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
 	if (poke_int3_handler(regs))
 		return;
 
-	prev_state = ist_enter(regs);
+	ist_enter(regs);
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
 	if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
 				SIGTRAP) == NOTIFY_STOP)
@@ -550,12 +517,12 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
 	 * as we may switch to the interrupt stack.
 	 */
 	debug_stack_usage_inc();
-	conditional_sti_ist(regs);
+	preempt_conditional_sti(regs);
 	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
-	conditional_cli_ist(regs);
+	preempt_conditional_cli(regs);
 	debug_stack_usage_dec();
 exit:
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 NOKPROBE_SYMBOL(do_int3);
 
@@ -631,12 +598,11 @@ NOKPROBE_SYMBOL(fixup_bad_iret);
 dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 {
 	struct task_struct *tsk = current;
-	enum ctx_state prev_state;
 	int user_icebp = 0;
 	unsigned long dr6;
 	int si_code;
 
-	prev_state = ist_enter(regs);
+	ist_enter(regs);
 
 	get_debugreg(dr6, 6);
 
@@ -682,12 +648,12 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 	debug_stack_usage_inc();
 
 	/* It's safe to allow irq's after DR6 has been saved */
-	conditional_sti_ist(regs);
+	preempt_conditional_sti(regs);
 
 	if (v8086_mode(regs)) {
 		handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
 					X86_TRAP_DB);
-		conditional_cli_ist(regs);
+		preempt_conditional_cli(regs);
 		debug_stack_usage_dec();
 		goto exit;
 	}
@@ -707,11 +673,11 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 	si_code = get_si_code(tsk->thread.debugreg6);
 	if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
 		send_sigtrap(tsk, regs, error_code, si_code);
-	conditional_cli_ist(regs);
+	preempt_conditional_cli(regs);
 	debug_stack_usage_dec();
 
 exit:
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 NOKPROBE_SYMBOL(do_debug);
 
@@ -723,8 +689,8 @@ NOKPROBE_SYMBOL(do_debug);
 static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 {
 	struct task_struct *task = current;
+	struct fpu *fpu = &task->thread.fpu;
 	siginfo_t info;
-	unsigned short err;
 	char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
 						"simd exception";
 
@@ -732,8 +698,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 		return;
 	conditional_sti(regs);
 
-	if (!user_mode(regs))
-	{
+	if (!user_mode(regs)) {
 		if (!fixup_exception(regs)) {
 			task->thread.error_code = error_code;
 			task->thread.trap_nr = trapnr;
@@ -745,150 +710,46 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 	/*
 	 * Save the info for the exception handler and clear the error.
 	 */
-	unlazy_fpu(task);
-	task->thread.trap_nr = trapnr;
+	fpu__save(fpu);
+
+	task->thread.trap_nr	= trapnr;
 	task->thread.error_code = error_code;
-	info.si_signo = SIGFPE;
-	info.si_errno = 0;
-	info.si_addr = (void __user *)uprobe_get_trap_addr(regs);
-	if (trapnr == X86_TRAP_MF) {
-		unsigned short cwd, swd;
-		/*
-		 * (~cwd & swd) will mask out exceptions that are not set to unmasked
-		 * status.  0x3f is the exception bits in these regs, 0x200 is the
-		 * C1 reg you need in case of a stack fault, 0x040 is the stack
-		 * fault bit.  We should only be taking one exception at a time,
-		 * so if this combination doesn't produce any single exception,
-		 * then we have a bad program that isn't synchronizing its FPU usage
-		 * and it will suffer the consequences since we won't be able to
-		 * fully reproduce the context of the exception
-		 */
-		cwd = get_fpu_cwd(task);
-		swd = get_fpu_swd(task);
+	info.si_signo		= SIGFPE;
+	info.si_errno		= 0;
+	info.si_addr		= (void __user *)uprobe_get_trap_addr(regs);
 
-		err = swd & ~cwd;
-	} else {
-		/*
-		 * The SIMD FPU exceptions are handled a little differently, as there
-		 * is only a single status/control register.  Thus, to determine which
-		 * unmasked exception was caught we must mask the exception mask bits
-		 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
-		 */
-		unsigned short mxcsr = get_fpu_mxcsr(task);
-		err = ~(mxcsr >> 7) & mxcsr;
-	}
+	info.si_code = fpu__exception_code(fpu, trapnr);
 
-	if (err & 0x001) {	/* Invalid op */
-		/*
-		 * swd & 0x240 == 0x040: Stack Underflow
-		 * swd & 0x240 == 0x240: Stack Overflow
-		 * User must clear the SF bit (0x40) if set
-		 */
-		info.si_code = FPE_FLTINV;
-	} else if (err & 0x004) { /* Divide by Zero */
-		info.si_code = FPE_FLTDIV;
-	} else if (err & 0x008) { /* Overflow */
-		info.si_code = FPE_FLTOVF;
-	} else if (err & 0x012) { /* Denormal, Underflow */
-		info.si_code = FPE_FLTUND;
-	} else if (err & 0x020) { /* Precision */
-		info.si_code = FPE_FLTRES;
-	} else {
-		/*
-		 * If we're using IRQ 13, or supposedly even some trap
-		 * X86_TRAP_MF implementations, it's possible
-		 * we get a spurious trap, which is not an error.
-		 */
+	/* Retry when we get spurious exceptions: */
+	if (!info.si_code)
 		return;
-	}
+
 	force_sig_info(SIGFPE, &info, task);
 }
 
 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
-
-	prev_state = exception_enter();
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 	math_error(regs, error_code, X86_TRAP_MF);
-	exception_exit(prev_state);
 }
 
 dotraplinkage void
 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
-
-	prev_state = exception_enter();
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 	math_error(regs, error_code, X86_TRAP_XF);
-	exception_exit(prev_state);
 }
 
 dotraplinkage void
 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
 {
 	conditional_sti(regs);
-#if 0
-	/* No need to warn about this any longer. */
-	pr_info("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
-#endif
-}
-
-asmlinkage __visible void __attribute__((weak)) smp_thermal_interrupt(void)
-{
-}
-
-asmlinkage __visible void __attribute__((weak)) smp_threshold_interrupt(void)
-{
-}
-
-/*
- * 'math_state_restore()' saves the current math information in the
- * old math state array, and gets the new ones from the current task
- *
- * Careful.. There are problems with IBM-designed IRQ13 behaviour.
- * Don't touch unless you *really* know how it works.
- *
- * Must be called with kernel preemption disabled (eg with local
- * local interrupts as in the case of do_device_not_available).
- */
-void math_state_restore(void)
-{
-	struct task_struct *tsk = current;
-
-	if (!tsk_used_math(tsk)) {
-		local_irq_enable();
-		/*
-		 * does a slab alloc which can sleep
-		 */
-		if (init_fpu(tsk)) {
-			/*
-			 * ran out of memory!
-			 */
-			do_group_exit(SIGKILL);
-			return;
-		}
-		local_irq_disable();
-	}
-
-	/* Avoid __kernel_fpu_begin() right after __thread_fpu_begin() */
-	kernel_fpu_disable();
-	__thread_fpu_begin(tsk);
-	if (unlikely(restore_fpu_checking(tsk))) {
-		fpu_reset_state(tsk);
-		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
-	} else {
-		tsk->thread.fpu_counter++;
-	}
-	kernel_fpu_enable();
 }
-EXPORT_SYMBOL_GPL(math_state_restore);
 
 dotraplinkage void
 do_device_not_available(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
-
-	prev_state = exception_enter();
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 	BUG_ON(use_eager_fpu());
 
 #ifdef CONFIG_MATH_EMULATION
@@ -899,15 +760,13 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 
 		info.regs = regs;
 		math_emulate(&info);
-		exception_exit(prev_state);
 		return;
 	}
 #endif
-	math_state_restore(); /* interrupts still off */
+	fpu__restore(&current->thread.fpu); /* interrupts still off */
 #ifdef CONFIG_X86_32
 	conditional_sti(regs);
 #endif
-	exception_exit(prev_state);
 }
 NOKPROBE_SYMBOL(do_device_not_available);
 
@@ -915,9 +774,8 @@ NOKPROBE_SYMBOL(do_device_not_available);
 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 {
 	siginfo_t info;
-	enum ctx_state prev_state;
 
-	prev_state = exception_enter();
+	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 	local_irq_enable();
 
 	info.si_signo = SIGILL;
@@ -929,7 +787,6 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 		do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
 			&info);
 	}
-	exception_exit(prev_state);
 }
 #endif
 
@@ -1006,13 +863,13 @@ void __init trap_init(void)
 		set_bit(i, used_vectors);
 
 #ifdef CONFIG_IA32_EMULATION
-	set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
+	set_system_intr_gate(IA32_SYSCALL_VECTOR, entry_INT80_compat);
 	set_bit(IA32_SYSCALL_VECTOR, used_vectors);
 #endif
 
 #ifdef CONFIG_X86_32
-	set_system_trap_gate(SYSCALL_VECTOR, &system_call);
-	set_bit(SYSCALL_VECTOR, used_vectors);
+	set_system_trap_gate(IA32_SYSCALL_VECTOR, entry_INT80_32);
+	set_bit(IA32_SYSCALL_VECTOR, used_vectors);
 #endif
 
 	/*