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switch back to using a file mapping for the initial mapping of a new object. 

this allows the kernel to use PMAP_PREFER() to give us better alignment on
platforms that care.
This commit is contained in:
chs 2000-02-13 04:28:09 +00:00
parent 9671588a30
commit 871e0c1533
1 changed files with 29 additions and 25 deletions
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54
libexec/ld.elf_so/map_object.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: map_object.c,v 1.10 1999/11/07 00:21:13 mycroft Exp $ */
/* $NetBSD: map_object.c,v 1.11 2000/02/13 04:28:09 chs Exp $ */
/*
* Copyright 1996 John D. Polstra.
@ -178,47 +178,38 @@ _rtld_map_object(path, fd, sb)
#endif
/*
* Map the entire address space of the object as an anonymous
* Map the entire address space of the object as a file
* region to stake out our contiguous region and establish a
* base for relocation.
* base for relocation. We use a file mapping so that
* the kernel will give us whatever alignment is appropriate
* for the platform we're running on.
*
* We map it using the data/BSS protection, then overlay bits
* of the file over the top, and unmap the gaps left by padding
* to alignment.
* We map it using the text protection, map the data segment
* into the right place, then map an anon segment for the bss
* and unmap the gaps left by padding to alignment.
*/
base_offset = round_down(segs[0]->p_offset);
base_vaddr = round_down(segs[0]->p_vaddr);
base_vlimit = round_up(segs[1]->p_vaddr + segs[1]->p_memsz);
text_vlimit = round_up(segs[0]->p_vaddr + segs[0]->p_memsz);
mapsize = base_vlimit - base_vaddr;
#ifdef RTLD_LOADER
base_addr = u.hdr.e_type == ET_EXEC ? (caddr_t) base_vaddr : NULL;
#else
base_addr = NULL;
#endif
mapbase = mmap(base_addr, mapsize, protflags(segs[1]->p_flags),
MAP_ANON | MAP_PRIVATE, -1, (off_t) 0);
mapbase = mmap(base_addr, mapsize, protflags(segs[0]->p_flags),
MAP_FILE | MAP_PRIVATE, fd, base_offset);
if (mapbase == MAP_FAILED) {
_rtld_error("mmap of entire address space failed: %s",
xstrerror(errno));
return NULL;
}
if (base_addr != NULL && mapbase != base_addr) {
_rtld_error("mmap returned wrong address: wanted %p, got %p",
base_addr, mapbase);
munmap(mapbase, mapsize);
return NULL;
}
base_addr = mapbase;
/* Overlay the text segment onto the proper region. */
text_vlimit = round_up(segs[0]->p_vaddr + segs[0]->p_memsz);
if (mmap(base_addr, text_vlimit - base_vaddr,
protflags(segs[0]->p_flags), MAP_FILE | MAP_PRIVATE | MAP_FIXED,
fd, base_offset) == MAP_FAILED) {
_rtld_error("mmap of text failed: %s", xstrerror(errno));
return NULL;
}
base_addr = mapbase;
/* Overlay the data segment onto the proper region. */
data_offset = round_down(segs[1]->p_offset);
@ -226,9 +217,21 @@ _rtld_map_object(path, fd, sb)
data_vlimit = round_up(segs[1]->p_vaddr + segs[1]->p_filesz);
data_addr = mapbase + (data_vaddr - base_vaddr);
if (mmap(data_addr, data_vlimit - data_vaddr,
protflags(segs[1]->p_flags), MAP_FILE | MAP_PRIVATE | MAP_FIXED,
fd, data_offset) == MAP_FAILED) {
protflags(segs[1]->p_flags),
MAP_FILE | MAP_PRIVATE | MAP_FIXED, fd, data_offset)
== MAP_FAILED) {
_rtld_error("mmap of data failed: %s", xstrerror(errno));
munmap(mapbase, mapsize);
return NULL;
}
/* Overlay the bss segment onto the proper region. */
if (mmap(mapbase + data_vlimit - base_vaddr, base_vlimit - data_vlimit,
protflags(segs[1]->p_flags),
MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0)
== MAP_FAILED) {
_rtld_error("mmap of bss failed: %s", xstrerror(errno));
munmap(mapbase, mapsize);
return NULL;
}
@ -238,6 +241,7 @@ _rtld_map_object(path, fd, sb)
if (gap_size != 0 && munmap(gap_addr, gap_size) == -1) {
_rtld_error("munmap of text -> data gap failed: %s",
xstrerror(errno));
munmap(mapbase, mapsize);
return NULL;
}