Add support to libkvm for reading vmcores from other architectures.

- Add a kvaddr_type to represent kernel virtual addresses instead of
  unsigned long.
- Add a struct kvm_nlist which is a stripped down version of struct nlist
  that uses kvaddr_t for n_value.
- Add a kvm_native() routine that returns true if an open kvm descriptor
  is for a native kernel and memory image.
- Add a kvm_open2() function similar to kvm_openfiles().  It drops the
  unused 'swapfile' argument and adds a new function pointer argument for
  a symbol resolving function.  Native kernels still use _fdnlist() from
  libc to resolve symbols if a resolver function is not supplied, but cross
  kernels require a resolver.
- Add a kvm_nlist2() function similar to kvm_nlist() except that it uses
  struct kvm_nlist instead of struct nlist.
- Add a kvm_read2() function similar to kvm_read() except that it uses
  kvaddr_t instead of unsigned long for the kernel virtual address.
- Add a new kvm_arch switch of routines needed by a vmcore backend.
  Each backend is responsible for implementing kvm_read2() for a given
  vmcore format.
- Use libelf to read headers from ELF kernels and cores (except for
  powerpc cores).
- Add internal helper routines for the common page offset hash table used
  by the minidump backends.
- Port all of the existing kvm backends to implement a kvm_arch switch and
  to be cross-friendly by using private constants instead of ones that
  vary by platform (e.g. PAGE_SIZE).  Static assertions are present when
  a given backend is compiled natively to ensure the private constants
  match the real ones.
- Enable all of the existing vmcore backends on all platforms.  This means
  that libkvm on any platform should be able to perform KVA translation
  and read data from a vmcore of any platform.

Tested on:	amd64, i386, sparc64 (marius)
Differential Revision:	https://reviews.freebsd.org/D3341

3 files changed, 17 insertions, 29 deletions

diff --git a/gnu/usr.bin/gdb/kgdb/Makefile b/gnu/usr.bin/gdb/kgdb/Makefile
index 8af2e18..39f4cd5 100644
--- a/gnu/usr.bin/gdb/kgdb/Makefile
+++ b/gnu/usr.bin/gdb/kgdb/Makefile
@@ -9,11 +9,7 @@ BULIBS= ${OBJ_BU}/libbfd/libbfd.a ${OBJ_BU}/libopcodes/libopcodes.a \
 GDBLIBS= ${OBJ_GDB}/libgdb/libgdb.a
 
 DPADD=	${GDBLIBS} ${BULIBS} ${LIBKVM}
-LDADD=	${GDBLIBS} ${BULIBS} -lkvm${GDB_SUFFIX}
+LDADD=	${GDBLIBS} ${BULIBS} -lkvm
 LIBADD+=	m readline ncursesw gnuregex
 
-.if defined(GDB_CROSS_DEBUGGER)
-CFLAGS+= -Wl,-export-dynamic
-.endif
-
 .include <bsd.prog.mk>
diff --git a/gnu/usr.bin/gdb/kgdb/main.c b/gnu/usr.bin/gdb/kgdb/main.c
index 19246c0..aa062a2 100644
--- a/gnu/usr.bin/gdb/kgdb/main.c
+++ b/gnu/usr.bin/gdb/kgdb/main.c
@@ -41,9 +41,6 @@ __FBSDID("$FreeBSD$");
 #include <kvm.h>
 #include <limits.h>
 #include <paths.h>
-#ifdef CROSS_DEBUGGER
-#include <proc_service.h>
-#endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -81,24 +78,6 @@ static struct ui_file *parse_gdberr;
 
 static void (*kgdb_new_objfile_chain)(struct objfile * objfile);
 
-#ifdef CROSS_DEBUGGER
-ps_err_e
-ps_pglobal_lookup(struct ps_prochandle *ph, const char *obj, const char *name,
-    psaddr_t *sym_addr)
-{
-	struct minimal_symbol *ms;
-	CORE_ADDR addr;
-
-	ms = lookup_minimal_symbol (name, NULL, NULL);
-	if (ms == NULL)
-		return PS_NOSYM;
-
-	addr = SYMBOL_VALUE_ADDRESS (ms);
-	store_typed_address(sym_addr, builtin_type_void_data_ptr, addr);
-	return PS_OK;
-}
-#endif
-
 static void
 usage(void)
 {
diff --git a/gnu/usr.bin/gdb/kgdb/trgt.c b/gnu/usr.bin/gdb/kgdb/trgt.c
index c75edf0..0e29b7a 100644
--- a/gnu/usr.bin/gdb/kgdb/trgt.c
+++ b/gnu/usr.bin/gdb/kgdb/trgt.c
@@ -78,6 +78,19 @@ static char kvm_err[_POSIX2_LINE_MAX];
 #define	KERNOFF		(kgdb_kernbase ())
 #define	PINKERNEL(x)	((x) >= KERNOFF)
 
+static int
+kgdb_resolve_symbol(const char *name, kvaddr_t *kva)
+{
+	struct minimal_symbol *ms;
+
+	ms = lookup_minimal_symbol (name, NULL, NULL);
+	if (ms == NULL)
+		return (1);
+
+	*kva = SYMBOL_VALUE_ADDRESS (ms);
+	return (0);;
+}
+
 static CORE_ADDR
 kgdb_kernbase (void)
 {
@@ -120,8 +133,8 @@ kgdb_trgt_open(char *filename, int from_tty)
 
 	old_chain = make_cleanup (xfree, filename);
 
-	nkvm = kvm_openfiles(bfd_get_filename(exec_bfd), filename, NULL,
-	    write_files ? O_RDWR : O_RDONLY, kvm_err);
+	nkvm = kvm_open2(bfd_get_filename(exec_bfd), filename,
+	    write_files ? O_RDWR : O_RDONLY, kvm_err, kgdb_resolve_symbol);
 	if (nkvm == NULL)
 		error ("Failed to open vmcore: %s", kvm_err);
 
@@ -254,7 +267,7 @@ kgdb_trgt_xfer_memory(CORE_ADDR memaddr, char *myaddr, int len, int write,
 		if (len == 0)
 			return (0);
 		if (!write)
-			return (kvm_read(kvm, memaddr, myaddr, len));
+			return (kvm_read2(kvm, memaddr, myaddr, len));
 		else
 			return (kvm_write(kvm, memaddr, myaddr, len));
 	}