ARM: ipipe: route traps to co-kernel

arch/arm/include/asm/ipipe_base.h

@@ -74,6 +74,18 @@ unsigned __ipipe_processor_id(void);
 
 #define IPIPE_TRAP_MAYDAY        0	/* Internal recovery trap */
 
+/* ARM traps */
+#define IPIPE_TRAP_ACCESS	 1	/* Data or instruction access exception */
+#define IPIPE_TRAP_SECTION	 2	/* Section fault */
+#define IPIPE_TRAP_DABT		 3	/* Generic data abort */
+#define IPIPE_TRAP_UNKNOWN	 4	/* Unknown exception */
+#define IPIPE_TRAP_BREAK	 5	/* Instruction breakpoint */
+#define IPIPE_TRAP_FPU		 6	/* Floating point exception */
+#define IPIPE_TRAP_VFP		 7	/* VFP floating point exception */
+#define IPIPE_TRAP_UNDEFINSTR	 8	/* Undefined instruction */
+#define IPIPE_TRAP_ALIGNMENT	 9	/* Unaligned access exception */
+#define IPIPE_NR_FAULTS         10
+
 #endif /* CONFIG_IPIPE */
 
 #endif /* __ASM_ARM_IPIPE_BASE_H */

arch/arm/kernel/entry-armv.S

@@ -286,6 +286,13 @@ __und_svc:
 	svc_entry
 #endif
 
+#ifdef CONFIG_IPIPE
+	mov	r0, #7				@ r0 = IPIPE_TRAP_UNDEFINSTR
+	mov	r1, sp				@ r1 = &regs
+	bl	__ipipe_notify_trap		@ branch to trap handler
+	cmp	r0, #0
+	bne	__und_svc_finish
+#endif /* CONFIG_IPIPE */
 	@
 	@ call emulation code, which returns using r9 if it has emulated
 	@ the instruction, or the more conventional lr if we are to treat
@@ -507,6 +514,15 @@ ENDPROC(__irq_usr)
 __und_usr:
 	usr_entry uaccess=0
 
+#ifdef CONFIG_IPIPE
+	mov	r0, #7				@ r0 = IPIPE_TRAP_UNDEFINSTR
+	mov	r1, sp				@ r1 = &regs
+	bl	__ipipe_notify_trap		@ branch to trap handler
+	cmp	r0, #0
+	bne	ret_from_exception
+	uaccess_enable ip
+#endif /* CONFIG_IPIPE */
+
 	mov	r2, r4
 	mov	r3, r5
 

arch/arm/kernel/ptrace.c

@@ -216,6 +216,10 @@ void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
 
 static int break_trap(struct pt_regs *regs, unsigned int instr)
 {
+
+	if (__ipipe_report_trap(IPIPE_TRAP_BREAK,regs))
+		return 0;
+
 	ptrace_break(current, regs);
 	return 0;
 }

arch/arm/kernel/traps.c

@@ -528,6 +528,9 @@ asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
  */
 asmlinkage void bad_mode(struct pt_regs *regs, int reason)
 {
+	if (__ipipe_report_trap(IPIPE_TRAP_UNKNOWN,regs))
+		return;
+
 	console_verbose();
 
 	pr_crit("Bad mode in %s handler detected\n", handler[reason]);

arch/arm/mm/alignment.c

@@ -14,6 +14,7 @@
 #include <linux/moduleparam.h>
 #include <linux/compiler.h>
 #include <linux/kernel.h>
+#include <linux/ipipe.h>
 #include <linux/sched/debug.h>
 #include <linux/errno.h>
 #include <linux/string.h>
@@ -781,7 +782,10 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	int thumb2_32b = 0;
 
 	if (interrupts_enabled(regs))
-		local_irq_enable();
+		hard_local_irq_enable();
+
+	if (__ipipe_report_trap(IPIPE_TRAP_ALIGNMENT,regs))
+		return 0;
 
 	instrptr = instruction_pointer(regs);
 
@@ -970,7 +974,7 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 		 * entry-common.S) and disable the alignment trap only if
 		 * there is no work pending for this thread.
 		 */
-		raw_local_irq_disable();
+		hard_local_irq_disable();
 		if (!(current_thread_info()->flags & _TIF_WORK_MASK))
 			set_cr(cr_no_alignment);
 	}

arch/arm/mm/fault.c

@@ -30,6 +30,39 @@
 
 #ifdef CONFIG_MMU
 
+#ifdef CONFIG_IPIPE
+
+static inline unsigned long ipipe_fault_entry(void)
+{
+	unsigned long flags;
+	int s;
+
+	flags = hard_local_irq_save();
+	s = __test_and_set_bit(IPIPE_STALL_FLAG, &__ipipe_root_status);
+	hard_local_irq_enable();
+
+	return arch_mangle_irq_bits(s, flags);
+}
+
+static inline void ipipe_fault_exit(unsigned long x)
+{
+	if (!arch_demangle_irq_bits(&x))
+		local_irq_enable();
+	else
+		hard_local_irq_restore(x);
+}
+
+#else
+
+static inline unsigned long ipipe_fault_entry(void)
+{
+	return 0;
+}
+
+static inline void ipipe_fault_exit(unsigned long x) { }
+
+#endif
+
 #ifdef CONFIG_KPROBES
 static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
 {
@@ -267,10 +300,16 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	int sig, code;
 	vm_fault_t fault;
 	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+	unsigned long irqflags;
 
-	if (notify_page_fault(regs, fsr))
+	if (__ipipe_report_trap(IPIPE_TRAP_ACCESS, regs))
 		return 0;
 
+	irqflags = ipipe_fault_entry();
+
+	if (notify_page_fault(regs, fsr))
+		goto out;
+
 	tsk = current;
 	mm  = tsk->mm;
 
@@ -323,7 +362,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) {
 		if (!user_mode(regs))
 			goto no_context;
-		return 0;
+		goto out;
 	}
 
 	/*
@@ -358,7 +397,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	 * Handle the "normal" case first - VM_FAULT_MAJOR
 	 */
 	if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
-		return 0;
+		goto out;
 
 	/*
 	 * If we are in kernel mode at this point, we
@@ -374,7 +413,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 		 * got oom-killed)
 		 */
 		pagefault_out_of_memory();
-		return 0;
+		goto out;
 	}
 
 	if (fault & VM_FAULT_SIGBUS) {
@@ -395,10 +434,13 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	}
 
 	__do_user_fault(tsk, addr, fsr, sig, code, regs);
-	return 0;
+	goto out;
 
 no_context:
 	__do_kernel_fault(mm, addr, fsr, regs);
+out:
+	ipipe_fault_exit(irqflags);
+
 	return 0;
 }
 #else					/* CONFIG_MMU */
@@ -431,11 +473,14 @@ static int __kprobes
 do_translation_fault(unsigned long addr, unsigned int fsr,
 		     struct pt_regs *regs)
 {
+	unsigned long irqflags;
 	unsigned int index;
 	pgd_t *pgd, *pgd_k;
 	pud_t *pud, *pud_k;
 	pmd_t *pmd, *pmd_k;
 
+	IPIPE_BUG_ON(!hard_irqs_disabled());
+
 	if (addr < TASK_SIZE)
 		return do_page_fault(addr, fsr, regs);
 
@@ -483,10 +528,19 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
 		goto bad_area;
 
 	copy_pmd(pmd, pmd_k);
+
 	return 0;
 
 bad_area:
+	if (__ipipe_report_trap(IPIPE_TRAP_ACCESS, regs))
+		return 0;
+
+	irqflags = ipipe_fault_entry();
+
 	do_bad_area(addr, fsr, regs);
+
+	ipipe_fault_exit(irqflags);
+
 	return 0;
 }
 #else					/* CONFIG_MMU */
@@ -506,7 +560,17 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
 static int
 do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 {
+	unsigned long irqflags;
+
+	if (__ipipe_report_trap(IPIPE_TRAP_SECTION, regs))
+		return 0;
+
+	irqflags = ipipe_fault_entry();
+
 	do_bad_area(addr, fsr, regs);
+
+	ipipe_fault_exit(irqflags);
+
 	return 0;
 }
 #endif /* CONFIG_ARM_LPAE */
@@ -517,6 +581,9 @@ do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 static int
 do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 {
+	if (__ipipe_report_trap(IPIPE_TRAP_DABT,regs))
+		return 0;
+
 	return 1;
 }
 
@@ -554,11 +621,17 @@ asmlinkage void
 do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 {
 	const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
+	unsigned long irqflags;
 	struct siginfo info;
 
 	if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
 		return;
 
+	if (__ipipe_report_trap(IPIPE_TRAP_UNKNOWN, regs))
+		return;
+
+	irqflags = ipipe_fault_entry();
+
 	pr_alert("Unhandled fault: %s (0x%03x) at 0x%08lx\n",
 		inf->name, fsr, addr);
 	show_pte(current->mm, addr);
@@ -569,6 +642,8 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	info.si_code  = inf->code;
 	info.si_addr  = (void __user *)addr;
 	arm_notify_die("", regs, &info, fsr, 0);
+
+	ipipe_fault_exit(irqflags);
 }
 
 void __init
@@ -588,11 +663,17 @@ asmlinkage void
 do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
 {
 	const struct fsr_info *inf = ifsr_info + fsr_fs(ifsr);
+	unsigned long irqflags;
 	struct siginfo info;
 
 	if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
 		return;
 
+	if (__ipipe_report_trap(IPIPE_TRAP_UNKNOWN, regs))
+		return;
+
+	irqflags = ipipe_fault_entry();
+
 	pr_alert("Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
 		inf->name, ifsr, addr);
 
@@ -602,6 +683,8 @@ do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
 	info.si_code  = inf->code;
 	info.si_addr  = (void __user *)addr;
 	arm_notify_die("", regs, &info, ifsr, 0);
+
+	ipipe_fault_exit(irqflags);
 }
 
 /*