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authorRoland McGrath <roland@gnu.org>2013-08-26 19:27:25 +0000
committerRoland McGrath <roland@gnu.org>2013-08-26 19:27:25 +0000
commit887badb310f11f59df2f6833a6bd0b219ba225a0 (patch)
treef196415a00ae9ff7f2e6a97c4eecc4bb6a4d687d /bfd
parent779bd270818aeb064c2d218ad8f80a3b608f95c9 (diff)
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bfd/
* elf-nacl.c (nacl_modify_segment_map): Fix logic reordering the elf_segment_map list. If an executable segment is page-aligned but does not end with a full page, then append a fake section into the segment map entry that pads out the page. (nacl_final_write_processing): New function. Write the code fill laid out in nacl_modify_segment_map. * elf-nacl.h: Declare it. * elf32-arm.c (elf32_arm_nacl_final_write_processing): New function. (elf_backend_final_write_processing): Define it for NaCl backend. * elf32-i386.c (elf_backend_final_write_processing): Likewise. * elf64-x86-64.c (elf_backend_final_write_processing): Likewise. * elf-nacl.c (segment_eligible_for_headers): Rename MAXPAGESIZE parameter to MINPAGESIZE. (nacl_modify_segment_map): Use minpagesize instead of maxpagesize. * elf32-arm.c (ELF_MINPAGESIZE, ELF_COMMONPAGESIZE): Set to 0x10000 for NaCl targets. ld/testsuite/ * ld-x86-64/ilp32-4-nacl.d: Loosen .shstrtab line regexp to match any file offset. * ld-x86-64/tlsbin-nacl.rd: Update expected code segment PT_LOAD. * ld-x86-64/tlsbindesc-nacl.rd: Likewise. * ld-scripts/rgn-at3.d: XFAIL for *-*-nacl* targets. * ld-scripts/rgn-over8-ok.d: Likewise.
Diffstat (limited to 'bfd')
-rw-r--r--bfd/ChangeLog20
-rw-r--r--bfd/elf-nacl.c285
-rw-r--r--bfd/elf-nacl.h3
-rw-r--r--bfd/elf32-arm.c20
-rw-r--r--bfd/elf32-i386.c3
-rw-r--r--bfd/elf64-x86-64.c3
6 files changed, 251 insertions, 83 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index cc4d7fd..ebae60d 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,23 @@
+2013-08-26 Roland McGrath <mcgrathr@google.com>
+
+ * elf-nacl.c (nacl_modify_segment_map): Fix logic reordering the
+ elf_segment_map list. If an executable segment is page-aligned
+ but does not end with a full page, then append a fake section into
+ the segment map entry that pads out the page.
+ (nacl_final_write_processing): New function. Write the code fill
+ laid out in nacl_modify_segment_map.
+ * elf-nacl.h: Declare it.
+ * elf32-arm.c (elf32_arm_nacl_final_write_processing): New function.
+ (elf_backend_final_write_processing): Define it for NaCl backend.
+ * elf32-i386.c (elf_backend_final_write_processing): Likewise.
+ * elf64-x86-64.c (elf_backend_final_write_processing): Likewise.
+
+ * elf-nacl.c (segment_eligible_for_headers): Rename MAXPAGESIZE
+ parameter to MINPAGESIZE.
+ (nacl_modify_segment_map): Use minpagesize instead of maxpagesize.
+
+ * elf32-arm.c (ELF_MINPAGESIZE, ELF_COMMONPAGESIZE): #undef for NaCl.
+
2013-08-24 Maciej W. Rozycki <macro@linux-mips.org>
* elf32-tilepro.c (tilepro_elf_finish_dynamic_sections): Don't
diff --git a/bfd/elf-nacl.c b/bfd/elf-nacl.c
index 39ffb5d..5ec1161 100644
--- a/bfd/elf-nacl.c
+++ b/bfd/elf-nacl.c
@@ -1,5 +1,5 @@
/* Native Client support for ELF
- Copyright 2012 Free Software Foundation, Inc.
+ Copyright 2012, 2013 Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
@@ -20,6 +20,7 @@
#include "sysdep.h"
#include "bfd.h"
+#include "libbfd.h"
#include "elf-bfd.h"
#include "elf-nacl.h"
#include "elf/common.h"
@@ -33,11 +34,11 @@ segment_executable (struct elf_segment_map *seg)
else
{
/* The p_flags value has not been computed yet,
- so we have to look through the sections. */
+ so we have to look through the sections. */
unsigned int i;
for (i = 0; i < seg->count; ++i)
- if (seg->sections[i]->flags & SEC_CODE)
- return TRUE;
+ if (seg->sections[i]->flags & SEC_CODE)
+ return TRUE;
}
return FALSE;
}
@@ -48,18 +49,18 @@ segment_executable (struct elf_segment_map *seg)
allow space for the headers. */
static bfd_boolean
segment_eligible_for_headers (struct elf_segment_map *seg,
- bfd_vma maxpagesize, bfd_vma sizeof_headers)
+ bfd_vma minpagesize, bfd_vma sizeof_headers)
{
bfd_boolean any_contents = FALSE;
unsigned int i;
- if (seg->count == 0 || seg->sections[0]->lma % maxpagesize < sizeof_headers)
+ if (seg->count == 0 || seg->sections[0]->lma % minpagesize < sizeof_headers)
return FALSE;
for (i = 0; i < seg->count; ++i)
{
if ((seg->sections[i]->flags & (SEC_CODE|SEC_READONLY)) != SEC_READONLY)
- return FALSE;
+ return FALSE;
if (seg->sections[i]->flags & SEC_HAS_CONTENTS)
- any_contents = TRUE;
+ any_contents = TRUE;
}
return any_contents;
}
@@ -76,7 +77,7 @@ nacl_modify_segment_map (bfd *abfd, struct bfd_link_info *info)
struct elf_segment_map **last_load = NULL;
bfd_boolean moved_headers = FALSE;
int sizeof_headers = info == NULL ? 0 : bfd_sizeof_headers (abfd, info);
- bfd_vma maxpagesize = get_elf_backend_data (abfd)->maxpagesize;
+ bfd_vma minpagesize = get_elf_backend_data (abfd)->minpagesize;
if (info != NULL && info->user_phdrs)
/* The linker script used PHDRS explicitly, so don't change what the
@@ -88,52 +89,124 @@ nacl_modify_segment_map (bfd *abfd, struct bfd_link_info *info)
struct elf_segment_map *seg = *m;
if (seg->p_type == PT_LOAD)
- {
- /* First, we're just finding the earliest PT_LOAD.
- By the normal rules, this will be the lowest-addressed one.
- We only have anything interesting to do if it's executable. */
- last_load = m;
- if (first_load == NULL)
- {
- if (!segment_executable (*m))
- return TRUE;
- first_load = m;
- }
- /* Now that we've noted the first PT_LOAD, we're looking for
- the first non-executable PT_LOAD with a nonempty p_filesz. */
- else if (!moved_headers
- && segment_eligible_for_headers (seg, maxpagesize,
- sizeof_headers))
- {
- /* This is the one we were looking for!
-
- First, clear the flags on previous segments that
- say they include the file header and phdrs. */
- struct elf_segment_map *prevseg;
- for (prevseg = *first_load;
- prevseg != seg;
- prevseg = prevseg->next)
- if (prevseg->p_type == PT_LOAD)
- {
- prevseg->includes_filehdr = 0;
- prevseg->includes_phdrs = 0;
- }
-
- /* This segment will include those headers instead. */
- seg->includes_filehdr = 1;
- seg->includes_phdrs = 1;
-
- moved_headers = TRUE;
- }
- }
-
+ {
+ bfd_boolean executable = segment_executable (seg);
+
+ if (executable
+ && seg->count > 0
+ && seg->sections[0]->vma % minpagesize == 0)
+ {
+ asection *lastsec = seg->sections[seg->count - 1];
+ bfd_vma end = lastsec->vma + lastsec->size;
+ if (end % minpagesize != 0)
+ {
+ /* This is an executable segment that starts on a page
+ boundary but does not end on a page boundary. Fill
+ it out to a whole page with code fill (the tail of
+ the segment will not be within any section). Thus
+ the entire code segment can be mapped from the file
+ as whole pages and that mapping will contain only
+ valid instructions.
+
+ To accomplish this, we must fake out the code in
+ assign_file_positions_for_load_sections (elf.c) so
+ that it advances past the rest of the final page,
+ rather than trying to put the next (unaligned, or
+ unallocated) section. We do this by appending a
+ dummy section record to this element in the segment
+ map. No such output section ever actually exists,
+ but this gets the layout logic to advance the file
+ positions past this partial page. Since we are
+ lying to BFD like this, nothing will ever know to
+ write the section contents. So we do that by hand
+ after the fact, in nacl_final_write_processing, below. */
+
+ struct elf_segment_map *newseg;
+ asection *sec;
+ struct bfd_elf_section_data *secdata;
+
+ BFD_ASSERT (!seg->p_size_valid);
+
+ secdata = bfd_zalloc (abfd, sizeof *secdata);
+ if (secdata == NULL)
+ return FALSE;
+
+ sec = bfd_zalloc (abfd, sizeof *sec);
+ if (sec == NULL)
+ return FALSE;
+
+ /* Fill in only the fields that actually affect the logic
+ in assign_file_positions_for_load_sections. */
+ sec->vma = end;
+ sec->lma = lastsec->lma + lastsec->size;
+ sec->size = minpagesize - (end % minpagesize);
+ sec->flags = (SEC_ALLOC | SEC_LOAD
+ | SEC_READONLY | SEC_CODE | SEC_LINKER_CREATED);
+ sec->used_by_bfd = secdata;
+
+ secdata->this_hdr.sh_type = SHT_PROGBITS;
+ secdata->this_hdr.sh_flags = SHF_ALLOC | SHF_EXECINSTR;
+ secdata->this_hdr.sh_addr = sec->vma;
+ secdata->this_hdr.sh_size = sec->size;
+
+ newseg = bfd_alloc (abfd,
+ sizeof *newseg + ((seg->count + 1)
+ * sizeof (asection *)));
+ if (newseg == NULL)
+ return FALSE;
+ memcpy (newseg, seg,
+ sizeof *newseg + (seg->count * sizeof (asection *)));
+ newseg->sections[newseg->count++] = sec;
+ *m = seg = newseg;
+ }
+ }
+
+ /* First, we're just finding the earliest PT_LOAD.
+ By the normal rules, this will be the lowest-addressed one.
+ We only have anything interesting to do if it's executable. */
+ last_load = m;
+ if (first_load == NULL)
+ {
+ if (!executable)
+ goto next;
+ first_load = m;
+ }
+ /* Now that we've noted the first PT_LOAD, we're looking for
+ the first non-executable PT_LOAD with a nonempty p_filesz. */
+ else if (!moved_headers
+ && segment_eligible_for_headers (seg, minpagesize,
+ sizeof_headers))
+ {
+ /* This is the one we were looking for!
+
+ First, clear the flags on previous segments that
+ say they include the file header and phdrs. */
+ struct elf_segment_map *prevseg;
+ for (prevseg = *first_load;
+ prevseg != seg;
+ prevseg = prevseg->next)
+ if (prevseg->p_type == PT_LOAD)
+ {
+ prevseg->includes_filehdr = 0;
+ prevseg->includes_phdrs = 0;
+ }
+
+ /* This segment will include those headers instead. */
+ seg->includes_filehdr = 1;
+ seg->includes_phdrs = 1;
+
+ moved_headers = TRUE;
+ }
+ }
+
+ next:
m = &seg->next;
}
if (first_load != last_load && moved_headers)
{
/* Now swap the first and last PT_LOAD segments'
- positions in segment_map. */
+ positions in segment_map. */
struct elf_segment_map *first = *first_load;
struct elf_segment_map *last = *last_load;
*first_load = first->next;
@@ -164,7 +237,7 @@ nacl_modify_program_headers (bfd *abfd, struct bfd_link_info *info)
while (*m != NULL)
{
if ((*m)->p_type == PT_LOAD && (*m)->includes_filehdr)
- break;
+ break;
m = &(*m)->next;
++p;
@@ -178,47 +251,95 @@ nacl_modify_program_headers (bfd *abfd, struct bfd_link_info *info)
Elf_Internal_Phdr *next_load_phdr = NULL;
/* Now move past that first one and find the PT_LOAD that should be
- before it by address order. */
+ before it by address order. */
m = &(*m)->next;
++p;
- while ((*m) != NULL)
- {
- if (p->p_type == PT_LOAD && p->p_vaddr < first_load_phdr->p_vaddr)
- {
- next_load_seg = m;
- next_load_phdr = p;
- break;
- }
+ while (*m != NULL)
+ {
+ if (p->p_type == PT_LOAD && p->p_vaddr < first_load_phdr->p_vaddr)
+ {
+ next_load_seg = m;
+ next_load_phdr = p;
+ break;
+ }
- m = &(*m)->next;
- ++p;
- }
+ m = &(*m)->next;
+ ++p;
+ }
/* Swap their positions in the segment_map back to how they used to be.
- The phdrs have already been set up by now, so we have to slide up
- the earlier ones to insert the one that should be first. */
+ The phdrs have already been set up by now, so we have to slide up
+ the earlier ones to insert the one that should be first. */
if (next_load_seg != NULL)
- {
- Elf_Internal_Phdr move_phdr;
- struct elf_segment_map *first_seg = *first_load_seg;
- struct elf_segment_map *next_seg = *next_load_seg;
- struct elf_segment_map *first_next = first_seg->next;
- struct elf_segment_map *next_next = next_seg->next;
-
- first_seg->next = next_next;
- *first_load_seg = next_seg;
-
- next_seg->next = first_next;
- *next_load_seg = first_seg;
-
- move_phdr = *next_load_phdr;
- memmove (first_load_phdr + 1, first_load_phdr,
- (next_load_phdr - first_load_phdr) * sizeof move_phdr);
- *first_load_phdr = move_phdr;
- }
+ {
+ Elf_Internal_Phdr move_phdr;
+ struct elf_segment_map *first_seg = *first_load_seg;
+ struct elf_segment_map *next_seg = *next_load_seg;
+ struct elf_segment_map *first_next = first_seg->next;
+ struct elf_segment_map *next_next = next_seg->next;
+
+ if (next_load_seg == &first_seg->next)
+ {
+ *first_load_seg = next_seg;
+ next_seg->next = first_seg;
+ first_seg->next = next_next;
+ }
+ else
+ {
+ *first_load_seg = first_next;
+ *next_load_seg = next_next;
+
+ first_seg->next = *next_load_seg;
+ *next_load_seg = first_seg;
+
+ next_seg->next = *first_load_seg;
+ *first_load_seg = next_seg;
+ }
+
+ move_phdr = *next_load_phdr;
+ memmove (first_load_phdr + 1, first_load_phdr,
+ (next_load_phdr - first_load_phdr) * sizeof move_phdr);
+ *first_load_phdr = move_phdr;
+ }
}
return TRUE;
}
+
+void
+nacl_final_write_processing (bfd *abfd, bfd_boolean linker ATTRIBUTE_UNUSED)
+{
+ struct elf_segment_map *seg;
+ for (seg = elf_seg_map (abfd); seg != NULL; seg = seg->next)
+ if (seg->p_type == PT_LOAD
+ && seg->count > 1
+ && seg->sections[seg->count - 1]->owner == NULL)
+ {
+ /* This is a fake section added in nacl_modify_segment_map, above.
+ It's not a real BFD section, so nothing wrote its contents.
+ Now write out its contents. */
+
+ asection *sec = seg->sections[seg->count - 1];
+ char *fill;
+
+ BFD_ASSERT (sec->flags & SEC_LINKER_CREATED);
+ BFD_ASSERT (sec->flags & SEC_CODE);
+ BFD_ASSERT (sec->size > 0);
+
+ fill = abfd->arch_info->fill (sec->size, bfd_big_endian (abfd), TRUE);
+
+ if (fill == NULL
+ || bfd_seek (abfd, sec->filepos, SEEK_SET) != 0
+ || bfd_bwrite (fill, sec->size, abfd) != sec->size)
+ {
+ /* We don't have a proper way to report an error here. So
+ instead fudge things so that elf_write_shdrs_and_ehdr will
+ fail. */
+ elf_elfheader (abfd)->e_shoff = (file_ptr) -1;
+ }
+
+ free (fill);
+ }
+}
diff --git a/bfd/elf-nacl.h b/bfd/elf-nacl.h
index 417c7e3..87719ef 100644
--- a/bfd/elf-nacl.h
+++ b/bfd/elf-nacl.h
@@ -1,5 +1,5 @@
/* Native Client support for ELF
- Copyright 2012 Free Software Foundation, Inc.
+ Copyright 2012, 2013 Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
@@ -22,3 +22,4 @@
bfd_boolean nacl_modify_segment_map (bfd *, struct bfd_link_info *);
bfd_boolean nacl_modify_program_headers (bfd *, struct bfd_link_info *);
+void nacl_final_write_processing (bfd *, bfd_boolean linker);
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 6d2d553..5af1643 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -15860,6 +15860,14 @@ elf32_arm_nacl_modify_segment_map (bfd *abfd, struct bfd_link_info *info)
&& nacl_modify_segment_map (abfd, info));
}
+static void
+elf32_arm_nacl_final_write_processing (bfd *abfd, bfd_boolean linker)
+{
+ elf32_arm_final_write_processing (abfd, linker);
+ nacl_final_write_processing (abfd, linker);
+}
+
+
#undef elf32_bed
#define elf32_bed elf32_arm_nacl_bed
#undef bfd_elf32_bfd_link_hash_table_create
@@ -15871,9 +15879,14 @@ elf32_arm_nacl_modify_segment_map (bfd *abfd, struct bfd_link_info *info)
#define elf_backend_modify_segment_map elf32_arm_nacl_modify_segment_map
#undef elf_backend_modify_program_headers
#define elf_backend_modify_program_headers nacl_modify_program_headers
+#undef elf_backend_final_write_processing
+#define elf_backend_final_write_processing elf32_arm_nacl_final_write_processing
#undef ELF_MAXPAGESIZE
#define ELF_MAXPAGESIZE 0x10000
+#undef ELF_MINPAGESIZE
+#undef ELF_COMMONPAGESIZE
+
#include "elf32-target.h"
@@ -15882,6 +15895,13 @@ elf32_arm_nacl_modify_segment_map (bfd *abfd, struct bfd_link_info *info)
#undef elf_backend_modify_segment_map
#define elf_backend_modify_segment_map elf32_arm_modify_segment_map
#undef elf_backend_modify_program_headers
+#undef elf_backend_final_write_processing
+#define elf_backend_final_write_processing elf32_arm_final_write_processing
+#undef ELF_MINPAGESIZE
+#define ELF_MINPAGESIZE 0x1000
+#undef ELF_COMMONPAGESIZE
+#define ELF_COMMONPAGESIZE 0x1000
+
/* VxWorks Targets. */
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index cc8b48e..560e05c 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -5302,12 +5302,15 @@ static const struct elf_i386_backend_data elf_i386_nacl_arch_bed =
#define elf_backend_modify_segment_map nacl_modify_segment_map
#undef elf_backend_modify_program_headers
#define elf_backend_modify_program_headers nacl_modify_program_headers
+#undef elf_backend_final_write_processing
+#define elf_backend_final_write_processing nacl_final_write_processing
#include "elf32-target.h"
/* Restore defaults. */
#undef elf_backend_modify_segment_map
#undef elf_backend_modify_program_headers
+#undef elf_backend_final_write_processing
/* VxWorks support. */
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 3352d05..0da839a 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -5399,6 +5399,8 @@ static const struct elf_x86_64_backend_data elf_x86_64_nacl_arch_bed =
#define elf_backend_modify_segment_map nacl_modify_segment_map
#undef elf_backend_modify_program_headers
#define elf_backend_modify_program_headers nacl_modify_program_headers
+#undef elf_backend_final_write_processing
+#define elf_backend_final_write_processing nacl_final_write_processing
#include "elf64-target.h"
@@ -5443,6 +5445,7 @@ static const struct elf_x86_64_backend_data elf_x86_64_nacl_arch_bed =
#undef elf_backend_size_info
#undef elf_backend_modify_segment_map
#undef elf_backend_modify_program_headers
+#undef elf_backend_final_write_processing
/* Intel L1OM support. */