Add support for ptrace() and gdb breakpoints.

svn path=/head/; revision=140001

sys/arm/arm/machdep.c

@@ -64,8 +64,10 @@ __FBSDID("$FreeBSD$");
 #include <sys/buf.h>
 #include <sys/exec.h>
 #include <sys/sysent.h>
+#include <sys/uio.h>
 #include <machine/reg.h>
 #include <machine/cpu.h>
+#include <machine/trap.h>
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
@@ -289,17 +291,68 @@ set_dbregs(struct thread *td, struct dbreg *regs)
 	return (0);
 }
 
+
+static int
+ptrace_read_int(struct thread *td, vm_offset_t addr, u_int32_t *v)
+{
+	struct iovec iov;
+	struct uio uio;
+	iov.iov_base = (caddr_t) v;
+	iov.iov_len = sizeof(u_int32_t);
+	uio.uio_iov = &iov;
+	uio.uio_iovcnt = 1;
+	uio.uio_offset = (off_t)addr;
+	uio.uio_resid = sizeof(u_int32_t);
+	uio.uio_segflg = UIO_SYSSPACE;
+	uio.uio_rw = UIO_READ;
+	uio.uio_td = td;
+	return proc_rwmem(td->td_proc, &uio);
+}
+
+static int
+ptrace_write_int(struct thread *td, vm_offset_t addr, u_int32_t v)
+{
+	struct iovec iov;
+	struct uio uio;
+	iov.iov_base = (caddr_t) &v;
+	iov.iov_len = sizeof(u_int32_t);
+	uio.uio_iov = &iov;
+	uio.uio_iovcnt = 1;
+	uio.uio_offset = (off_t)addr;
+	uio.uio_resid = sizeof(u_int32_t);
+	uio.uio_segflg = UIO_SYSSPACE;
+	uio.uio_rw = UIO_WRITE;
+	uio.uio_td = td;
+	return proc_rwmem(td->td_proc, &uio);
+}
+
 int
 ptrace_single_step(struct thread *td)
 {
-	/* XXX */
-	return (0);
+	int error;
+	
+	KASSERT(td->td_md.md_ptrace_instr == 0,
+	 ("Didn't clear single step"));
+	error = ptrace_read_int(td, td->td_frame->tf_pc + 4, 
+	    &td->td_md.md_ptrace_instr);
+	if (error)
+		return (error);
+	error = ptrace_write_int(td, td->td_frame->tf_pc + 4,
+	    PTRACE_BREAKPOINT);
+	if (error)
+		td->td_md.md_ptrace_instr = 0;
+	td->td_md.md_ptrace_addr = td->td_frame->tf_pc + 4;
+	return (error);
 }
 
 int
 ptrace_clear_single_step(struct thread *td)
 {
-	/* XXX */
+	if (td->td_md.md_ptrace_instr) {
+		ptrace_write_int(td, td->td_md.md_ptrace_addr,
+		    td->td_md.md_ptrace_instr);
+		td->td_md.md_ptrace_instr = 0;
+	}
 	return (0);
 }
 

sys/arm/arm/trap.c

@@ -100,6 +100,8 @@ __FBSDID("$FreeBSD$");
 #include <sys/uio.h>
 #include <sys/ktrace.h>
 #endif
+#include <sys/ptrace.h>
+#include <sys/pioctl.h>
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
@@ -919,6 +921,8 @@ syscall(struct thread *td, trapframe_t *frame, u_int32_t insn)
 	if (error == 0) {
 		td->td_retval[0] = 0;
 		td->td_retval[1] = 0;
+		STOPEVENT(p, S_SCE, (callp->sy_narg & SYF_ARGMASK));
+		PTRACESTOP_SC(p, td, S_PT_SCE);
 		error = (*callp->sy_call)(td, args);
 	}
 	switch (error) {
@@ -952,6 +956,8 @@ syscall(struct thread *td, trapframe_t *frame, u_int32_t insn)
 	CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td,
 	    td->td_proc->p_pid, td->td_proc->p_comm, code);
 	
+	STOPEVENT(p, S_SCX, code);
+	PTRACESTOP_SC(p, td, S_PT_SCX);
 #ifdef KTRACE
       	if (KTRPOINT(td, KTR_SYSRET))
 		ktrsysret(code, error, td->td_retval[0]);

sys/arm/arm/undefined.c

@@ -62,6 +62,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/signalvar.h>
+#include <sys/ptrace.h>
 #ifdef KDB
 #include <sys/kdb.h>
 #endif
@@ -135,26 +136,17 @@ gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
 	struct thread *td;
 	td = (curthread == NULL) ? &thread0 : curthread;
 
-#if 0
 	if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
 		if (code == FAULT_USER) {
-			ksiginfo_t ksi;
-
-			KSI_INIT_TRAP(&ksi);
-			ksi.ksi_signo = SIGTRAP;
-			ksi.ksi_code = TRAP_BRKPT;
-			ksi.ksi_addr = (u_int32_t *)addr;
-			ksi.ksi_trap = 0;
-			PROC_LOCK(td->td_proc);
-			trapsignal(td, &ksi);
-			PROC_UNLOCK(td->td_proc);
+			trapsignal(td, SIGTRAP, 0);
 			return 0;
 		}
+#if 0
 #ifdef KGDB
 		return !kgdb_trap(T_BREAKPOINT, frame);
 #endif
-	}
 #endif
+	}
 	return 1;
 }
 
@@ -257,6 +249,11 @@ undefinedinstruction(trapframe_t *frame)
 			       fault_code) == 0)
 		    break;
 
+	if (fault_code & FAULT_USER && fault_instruction == PTRACE_BREAKPOINT) {
+		ptrace_clear_single_step(td);
+		return;
+	}
+
 	if (uh == NULL && (fault_code & FAULT_USER)) {
 		/* Fault has not been handled */
 		trapsignal(td, SIGILL, 0);
@@ -272,7 +269,7 @@ undefinedinstruction(trapframe_t *frame)
 		return;
 		} else
 			panic("Undefined instruction in kernel.\n");
-	}		
+	}
 
 #ifdef FAST_FPE
 	/* Optimised exit code */

sys/arm/include/proc.h

@@ -47,6 +47,8 @@ struct md_utrap {
 
 struct mdthread {
 	register_t md_savecrit;
+	int md_ptrace_instr;
+	int md_ptrace_addr;
 };
 
 struct mdproc {

sys/arm/include/trap.h

@@ -1,4 +1,10 @@
 /*	$NetBSD: trap.h,v 1.1 2001/02/23 03:48:19 ichiro Exp $	*/
 /* $FreeBSD$ */
 
+#ifndef _MACHINE_TRAP_H_
+#define _MACHINE_TRAP_H_
+#define GDB_BREAKPOINT		0xe6000011
+#define GDB5_BREAKPOINT		0xe7ffdefe
+#define PTRACE_BREAKPOINT	0xe7fffff0
 #define KERNEL_BREAKPOINT	0xe7ffffff
+#endif /* _MACHINE_TRAP_H_ */