Add support for PowerPC kernel core files. This commit only adds

support for virtual core files (aka minidumps). physical core
files are not supported.

The implementation is cross-tool ready and can be used in a non-
powerpc hosted debugger to analyze PowerPC core files. It also
accepts core files that still have the dump header, as can be
the case within Juniper where TFTP-based kernel core files are
supported and savecore is not used to "extract" the core file
from some dump device.

Obtained from:	Juniper Networks, Inc.

lib/libkvm/kvm_powerpc.c

@@ -1,8 +1,5 @@
-/*	$NetBSD: kvm_powerpc.c,v 1.4 1998/02/03 06:50:07 mycroft Exp $	*/
-
 /*-
- * Copyright (C) 1996 Wolfgang Solfrank.
+ * Copyright (c) 2008, Juniper Networks, Inc.
- * Copyright (C) 1996 TooLs GmbH.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -13,91 +10,209 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
+ * 3. Neither the name of the author nor the names of any co-contributors
- *    must display the following acknowledgement:
+ *    may be used to endorse or promote products derived from this software
- *	This product includes software developed by TooLs GmbH.
+ *    without specific prior written permission.
- * 4. The name of TooLs GmbH may not be used to endorse or promote products
- *    derived from this software without specific prior written permission.
  *
- * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-/*
- * PowerPC machine dependent routines for kvm.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/endian.h>
+#include <sys/kerneldump.h>
+#include <sys/mman.h>
 
 #include <vm/vm.h>
 
 #include <db.h>
+#include <elf.h>
 #include <limits.h>
 #include <kvm.h>
 #include <stdlib.h>
 
 #include "kvm_private.h"
 
-void
+struct vmstate {
-_kvm_freevtop(kd)
+	void		*map;
-	kvm_t *kd;
+	size_t		mapsz;
+	size_t		dmphdrsz;
+	Elf32_Ehdr	*eh;
+	Elf32_Phdr	*ph;
+};
+
+static int
+valid_elf_header(Elf32_Ehdr *eh)
 {
-	if (kd->vmst != 0)
+
-		free(kd->vmst);
+	if (!IS_ELF(*eh))
+		return (0);
+	if (eh->e_ident[EI_CLASS] != ELFCLASS32)
+		return (0);
+	if (eh->e_ident[EI_DATA] != ELFDATA2MSB)
+		return (0);
+	if (eh->e_ident[EI_VERSION] != EV_CURRENT)
+		return (0);
+	if (eh->e_ident[EI_OSABI] != ELFOSABI_STANDALONE)
+		return (0);
+	if (be16toh(eh->e_type) != ET_CORE)
+		return (0);
+	if (be16toh(eh->e_machine) != EM_PPC)
+		return (0);
+	/* Can't think of anything else to check... */
+	return (1);
 }
 
-int
+static size_t
-_kvm_initvtop(kd)
+dump_header_size(struct kerneldumpheader *dh)
-	kvm_t *kd;
 {
-	return 0;
-}
 
-int
+	if (strcmp(dh->magic, KERNELDUMPMAGIC) != 0)
-_kvm_kvatop(kd, va, pa)
+		return (0);
-	kvm_t *kd;
+	if (strcmp(dh->architecture, "powerpc") != 0)
-	u_long va;
+		return (0);
-	off_t *pa;
+	/* That should do it... */
-{
+	return (sizeof(*dh));
-	_kvm_err(kd, 0, "vatop not yet implemented!");
-	return 0;
-}
-
-off_t
-_kvm_pa2off(kd, pa)
-	kvm_t *kd;
-	u_long pa;
-{
-	_kvm_err(kd, 0, "pa2off not yet implemented!");
-	return 0;
 }
 
 /*
- * Machine-dependent initialization for ALL open kvm descriptors,
+ * Map the ELF headers into the process' address space. We do this in two
- * not just those for a kernel crash dump.  Some architectures
+ * steps: first the ELF header itself and using that information the whole
- * have to deal with these NOT being constants!  (i.e. m68k)
+ * set of headers.
  */
+static int
+powerpc_maphdrs(kvm_t *kd)
+{
+	struct vmstate *vm;
+	size_t mapsz;
+
+	vm = kd->vmst;
+
+	vm->mapsz = PAGE_SIZE;
+	vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
+	if (vm->map == MAP_FAILED) {
+		_kvm_err(kd, kd->program, "cannot map corefile");
+		return (-1);
+	}
+	vm->dmphdrsz = 0;
+	vm->eh = vm->map;
+	if (!valid_elf_header(vm->eh)) {
+		/*
+		 * Hmmm, no ELF header. Maybe we still have a dump header.
+		 * This is normal when the core file wasn't created by
+		 * savecore(8), but instead was dumped over TFTP. We can
+		 * easily skip the dump header...
+		 */
+		vm->dmphdrsz = dump_header_size(vm->map);
+		if (vm->dmphdrsz == 0)
+			goto inval;
+		vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
+		if (!valid_elf_header(vm->eh))
+			goto inval;
+	}
+	mapsz = be16toh(vm->eh->e_phentsize) * be16toh(vm->eh->e_phnum) +
+	    be32toh(vm->eh->e_phoff);
+	munmap(vm->map, vm->mapsz);
+
+	/* Map all headers. */
+	vm->mapsz = vm->dmphdrsz + mapsz;
+	vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
+	if (vm->map == MAP_FAILED) {
+		_kvm_err(kd, kd->program, "cannot map corefle headers");
+		return (-1);
+	}
+	vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
+	vm->ph = (void *)((uintptr_t)vm->eh + be32toh(vm->eh->e_phoff));
+	return (0);
+
+ inval:
+	munmap(vm->map, vm->mapsz);
+	vm->map = MAP_FAILED;
+	_kvm_err(kd, kd->program, "invalid corefile");
+	return (-1);
+}
+
+/*
+ * Determine the offset within the corefile corresponding the virtual
+ * address. Return the number of contiguous bytes in the corefile or
+ * 0 when the virtual address is invalid.
+ */
+static size_t
+powerpc_va2off(kvm_t *kd, u_long va, off_t *ofs)
+{
+	struct vmstate *vm = kd->vmst;
+	Elf32_Phdr *ph;
+	int nph;
+
+	ph = vm->ph;
+	nph = be16toh(vm->eh->e_phnum);
+	while (nph && (va < be32toh(ph->p_vaddr) ||
+	    va >= be32toh(ph->p_vaddr) + be32toh(ph->p_memsz))) {
+		nph--;
+		ph = (void *)((uintptr_t)ph + be16toh(vm->eh->e_phentsize));
+	}
+	if (nph == 0)
+		return (0);
+
+	/* Segment found. Return file offset and range. */
+	*ofs = vm->dmphdrsz + be32toh(ph->p_offset) +
+	    (va - be32toh(ph->p_vaddr));
+	return (be32toh(ph->p_memsz) - (va - be32toh(ph->p_vaddr)));
+}
+
+void
+_kvm_freevtop(kvm_t *kd)
+{
+	struct vmstate *vm = kd->vmst;
+
+	if (vm == NULL)
+		return;
+
+	if (vm->eh != MAP_FAILED) {
+		munmap(vm->eh, vm->mapsz);
+		vm->eh = MAP_FAILED;
+	}
+	free(vm);
+	kd->vmst = NULL;
+}
+
 int
-_kvm_mdopen(kd)
+_kvm_initvtop(kvm_t *kd)
-	kvm_t	*kd;
 {
 
-#ifdef FBSD_NOT_YET
+	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
-	kd->usrstack = USRSTACK;
+	if (kd->vmst == NULL) {
-	kd->min_uva = VM_MIN_ADDRESS;
+		_kvm_err(kd, kd->program, "out of virtual memory");
-	kd->max_uva = VM_MAXUSER_ADDRESS;
+		return (-1);
-#endif
+	}
-
+	if (powerpc_maphdrs(kd) == -1) {
+		free(kd->vmst);
+		kd->vmst = NULL;
+		return (-1);
+	}
+	return (0);
+}
+
+int
+_kvm_kvatop(kvm_t *kd, u_long va, off_t *ofs)
+{
+	struct vmstate *vm;
+
+	vm = kd->vmst;
+	if (vm->ph->p_paddr == ~0U)
+		return ((int)powerpc_va2off(kd, va, ofs));
+
+	_kvm_err(kd, kd->program, "Raw corefile not supported");
 	return (0);
 }