Module Name: src
Committed By: maxv
Date: Fri Jan 6 09:14:36 UTC 2017
Modified Files:
src/sys/lib/libsa: loadfile_elf32.c
Log Message:
Explain how all that mess works, without actually fixing it yet.
To generate a diff of this commit:
cvs rdiff -u -r1.33 -r1.34 src/sys/lib/libsa/loadfile_elf32.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/lib/libsa/loadfile_elf32.c
diff -u src/sys/lib/libsa/loadfile_elf32.c:1.33 src/sys/lib/libsa/loadfile_elf32.c:1.34
--- src/sys/lib/libsa/loadfile_elf32.c:1.33 Sat Dec 3 09:20:55 2016
+++ src/sys/lib/libsa/loadfile_elf32.c Fri Jan 6 09:14:36 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: loadfile_elf32.c,v 1.33 2016/12/03 09:20:55 maxv Exp $ */
+/* $NetBSD: loadfile_elf32.c,v 1.34 2017/01/06 09:14:36 maxv Exp $ */
/*
* Copyright (c) 1997, 2008 The NetBSD Foundation, Inc.
@@ -259,6 +259,21 @@ externalize_shdr(Elf_Byte bo, Elf_Shdr *
#define IS_DATA(p) (p.p_flags & PF_W)
#define IS_BSS(p) (p.p_filesz < p.p_memsz)
+/*
+ * Load the ELF binary into memory. Layout of the memory:
+ * +-----------------+------------+-----------------+-----------------+
+ * | KERNEL SEGMENTS | ELF HEADER | SECTION HEADERS | SYMBOL SECTIONS |
+ * +-----------------+------------+-----------------+-----------------+
+ * The KERNEL SEGMENTS start address is fixed by the segments themselves. We
+ * then map the rest by increasing maxp.
+ *
+ * The offsets of the SYMBOL SECTIONS are relative to the start address of the
+ * ELF HEADER. The shdr offset of ELF HEADER points to SECTION HEADERS.
+ *
+ * We just give the kernel a pointer to the ELF HEADER, which is enough for it
+ * to find the location and number of symbols by itself later.
+ */
+
int
ELFNAMEEND(loadfile)(int fd, Elf_Ehdr *elf, u_long *marks, int flags)
{
