[binutils-gdb] elf/x86: Place code after read-only data for --rosegment
H.J. Lu
hjl@sourceware.org
Mon Mar 30 19:03:55 GMT 2026
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=99600a4787910d4b1994b243473a7386dbee641d
commit 99600a4787910d4b1994b243473a7386dbee641d
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Wed Mar 18 12:13:26 2026 -0700
elf/x86: Place code after read-only data for --rosegment
commit e8e10743f7b207b21a1efb0cc9e42487080db013
Author: Nick Clifton <nickc@redhat.com>
Date: Thu Jun 13 15:10:15 2024 +0100
Add --rosegment option to BFD linker to stop the '-z separate-code' from gen erating two read-only segments.
added --rosegment option to generate one read-only segment with
-z separate-code. But it puts the read-only data, which contains ELF
headers and .note.gnu.build-id section, in the executable segment:
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x000000 0x00000000 0x00000000 0x00185 0x00185 R E 0x1000
LOAD 0x001000 0x00001000 0x00001000 0x000d0 0x000d0 R 0x1000
LOAD 0x001f78 0x00002f78 0x00002f78 0x0008c 0x0008c RW 0x1000
DYNAMIC 0x001f78 0x00002f78 0x00002f78 0x00070 0x00070 RW 0x4
NOTE 0x000154 0x00000154 0x00000154 0x00024 0x00024 R 0x4
NOTE 0x00109c 0x0000109c 0x0000109c 0x00034 0x00034 R 0x4
GNU_PROPERTY 0x00109c 0x0000109c 0x0000109c 0x00034 0x00034 R 0x4
GNU_STACK 0x000000 0x00000000 0x00000000 0x00000 0x00000 RW 0x10
GNU_RELRO 0x001f78 0x00002f78 0x00002f78 0x00088 0x00088 R 0x1
Section to Segment mapping:
Segment Sections...
00 .note.gnu.build-id .text
01 .gnu.hash .dynsym .dynstr .rela.dyn .rodata .eh_frame .note.gnu.property
02 .dynamic .got.plt .data
03 .dynamic
04 .note.gnu.build-id
05 .note.gnu.property
06 .note.gnu.property
07
08 .dynamic .got.plt
which defeats the purpose of -z separate-code. Update --rosegment to
place code after read-only data:
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x000000 0x00000000 0x00000000 0x00248 0x00248 R 0x1000
LOAD 0x001000 0x00001000 0x00001000 0x00005 0x00005 R E 0x1000
LOAD 0x001f78 0x00002f78 0x00002f78 0x0008c 0x0008c RW 0x1000
DYNAMIC 0x001f78 0x00002f78 0x00002f78 0x00070 0x00070 RW 0x4
NOTE 0x000154 0x00000154 0x00000154 0x00024 0x00024 R 0x4
NOTE 0x000214 0x00000214 0x00000214 0x00034 0x00034 R 0x4
GNU_PROPERTY 0x000214 0x00000214 0x00000214 0x00034 0x00034 R 0x4
GNU_STACK 0x000000 0x00000000 0x00000000 0x00000 0x00000 RW 0x10
GNU_RELRO 0x001f78 0x00002f78 0x00002f78 0x00088 0x00088 R 0x1
Section to Segment mapping:
Segment Sections...
00 .note.gnu.build-id .gnu.hash .dynsym .dynstr .rela.dyn .rodata .eh_frame .note.gnu.property
01 .text
02 .dynamic .got.plt .data
03 .dynamic
04 .note.gnu.build-id
05 .note.gnu.property
06 .note.gnu.property
07
08 .dynamic .got.plt
PR ld/23704
PR ld/30907
PR ld/32191
PR ld/34003
* emulparams/elf32_x86_64.sh (ALL_TEXT_AFTER_RO): New.
* emulparams/elf_i386.sh (ALL_TEXT_AFTER_RO): Likewise.
* emulparams/elf_i386_be.sh (ALL_TEXT_AFTER_RO): Likewise.
* emulparams/elf_i386_vxworks.sh (ALL_TEXT_AFTER_RO): Likewise.
* emulparams/elf_iamcu.sh (ALL_TEXT_AFTER_RO): Likewise.
* emulparams/elf_x86_64.sh (ALL_TEXT_AFTER_RO): Likewise.
* scripttempl/elf.sc (ALL_TEXT_AFTER_RO): New. If set, place
code after read-only data for -z separate-code --rosegment.
* testsuite/ld-elf/pr30907-2.d: Skip x86 targets.
* testsuite/ld-elf/pr34003.d: New file.
* testsuite/ld-i386/pr32191.d: Updated.
* testsuite/ld-x86-64/pr32191-x32.d: Likewise.
* testsuite/ld-x86-64/pr32191.d: Likewise.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Diff:
---
ld/emulparams/elf32_x86_64.sh | 1 +
ld/emulparams/elf_i386.sh | 1 +
ld/emulparams/elf_i386_be.sh | 1 +
ld/emulparams/elf_i386_vxworks.sh | 1 +
ld/emulparams/elf_iamcu.sh | 1 +
ld/emulparams/elf_x86_64.sh | 1 +
ld/scripttempl/elf.sc | 39 ++++++++++++++++++++++--------------
ld/testsuite/ld-elf/pr30907-2.d | 1 +
ld/testsuite/ld-elf/pr34003.d | 13 ++++++++++++
ld/testsuite/ld-i386/pr32191.d | 4 +++-
ld/testsuite/ld-x86-64/pr32191-x32.d | 4 +++-
ld/testsuite/ld-x86-64/pr32191.d | 4 +++-
12 files changed, 53 insertions(+), 18 deletions(-)
diff --git a/ld/emulparams/elf32_x86_64.sh b/ld/emulparams/elf32_x86_64.sh
index 8a07f50e47f..256ae31ed24 100644
--- a/ld/emulparams/elf32_x86_64.sh
+++ b/ld/emulparams/elf32_x86_64.sh
@@ -35,6 +35,7 @@ OTHER_PLT_SECTIONS="
"
OTHER_GOT_RELOC_SECTIONS="
.rela.tls ${RELOCATING-0} : { *(.rela.tls) }"
+ALL_TEXT_AFTER_RO=yes
if [ "x${host}" = "x${target}" ]; then
case " $EMULATION_LIBPATH " in
diff --git a/ld/emulparams/elf_i386.sh b/ld/emulparams/elf_i386.sh
index 12d71f5ef9e..d093afb9fa3 100644
--- a/ld/emulparams/elf_i386.sh
+++ b/ld/emulparams/elf_i386.sh
@@ -30,6 +30,7 @@ OTHER_PLT_SECTIONS="
"
OTHER_GOT_RELOC_SECTIONS="
.rel.tls ${RELOCATING-0} : { *(.rel.tls) }"
+ALL_TEXT_AFTER_RO=yes
# Linux modify the default library search path to first include
# a 32-bit specific directory.
diff --git a/ld/emulparams/elf_i386_be.sh b/ld/emulparams/elf_i386_be.sh
index dbe68e99e63..e13d07dec23 100644
--- a/ld/emulparams/elf_i386_be.sh
+++ b/ld/emulparams/elf_i386_be.sh
@@ -13,3 +13,4 @@ TEMPLATE_NAME=elf
EXTRA_EM_FILE="elf-x86"
GENERATE_SHLIB_SCRIPT=yes
NO_SMALL_DATA=yes
+ALL_TEXT_AFTER_RO=yes
diff --git a/ld/emulparams/elf_i386_vxworks.sh b/ld/emulparams/elf_i386_vxworks.sh
index 40c809263d1..347842909aa 100644
--- a/ld/emulparams/elf_i386_vxworks.sh
+++ b/ld/emulparams/elf_i386_vxworks.sh
@@ -11,6 +11,7 @@ EXTRA_EM_FILE="elf-x86"
GENERATE_SHLIB_SCRIPT=yes
GENERATE_PIE_SCRIPT=yes
NO_SMALL_DATA=yes
+ALL_TEXT_AFTER_RO=yes
source_sh ${srcdir}/emulparams/vxworks.sh
source_sh ${srcdir}/emulparams/extern_protected_data.sh
source_sh ${srcdir}/emulparams/dynamic_undefined_weak.sh
diff --git a/ld/emulparams/elf_iamcu.sh b/ld/emulparams/elf_iamcu.sh
index c1582235eda..7377ddee350 100644
--- a/ld/emulparams/elf_iamcu.sh
+++ b/ld/emulparams/elf_iamcu.sh
@@ -21,6 +21,7 @@ IREL_IN_PLT=
OTHER_PLT_SECTIONS="
.plt.got ${RELOCATING-0} : { *(.plt.got) }
"
+ALL_TEXT_AFTER_RO=yes
# Linux modify the default library search path to first include
# a 32-bit specific directory.
diff --git a/ld/emulparams/elf_x86_64.sh b/ld/emulparams/elf_x86_64.sh
index 747114bc4b4..63e2419184c 100644
--- a/ld/emulparams/elf_x86_64.sh
+++ b/ld/emulparams/elf_x86_64.sh
@@ -37,6 +37,7 @@ OTHER_PLT_SECTIONS="
"
OTHER_GOT_RELOC_SECTIONS="
.rela.tls ${RELOCATING-0} : { *(.rela.tls) }"
+ALL_TEXT_AFTER_RO=yes
if [ "x${host}" = "x${target}" ]; then
case " $EMULATION_LIBPATH " in
diff --git a/ld/scripttempl/elf.sc b/ld/scripttempl/elf.sc
index 8a0efc02c86..2ded3fa3ddd 100644
--- a/ld/scripttempl/elf.sc
+++ b/ld/scripttempl/elf.sc
@@ -82,6 +82,8 @@
# applied to every symbol definition
# ALL_TEXT_BEFORE_RO - put all code sections before read-only
# sections
+# ALL_TEXT_AFTER_RO - put all code sections after read-only
+# sections
#
# When adding sections, do note that the names of some sections are used
# when specifying the start address of the next.
@@ -360,7 +362,11 @@ SHLIB_TEXT_START_ADDR="SEGMENT_START(\"text-segment\", ${SHLIB_TEXT_START_ADDR:-
if test -z "$TINY_READONLY_SECTION"; then
case "$LD_FLAG" in
*ro*textonly*)
- ALL_TEXT_BEFORE_RO=" "
+ if test -n "${ALL_TEXT_AFTER_RO}"; then
+ TEXT_AFTER_RO=" "
+ else
+ ALL_TEXT_BEFORE_RO=" "
+ fi
SEPARATE_TEXT=" "
TEXT_SEGMENT_ALIGN=". = ALIGN(${MAXPAGESIZE});"
;;
@@ -1021,7 +1027,7 @@ EOF
#------Early Read Only Data -----------------------------------------------
- if test -z "${ALL_TEXT_BEFORE_RO}"; then
+ if test -n "${TEXT_AFTER_RO}" || test -z "${ALL_TEXT_BEFORE_RO}"; then
# We are allowed to put R/O sections before code sections.
# Doing so either puts read only data into the code segment, if the data
# and code sections are contiguous, or creates a data segment followed by
@@ -1033,6 +1039,7 @@ EOF
test -n "${SEPARATE_CODE}" || emit_early_ro
test -n "${NON_ALLOC_DYN}${SEPARATE_CODE}" || emit_dyn
+ test -z "${TEXT_AFTER_RO}" || emit_rodata
# We only need the alignment if we have emitted some sections.
if test -z "${SEPARATE_CODE}"; then
@@ -1058,24 +1065,26 @@ EOF
align_text
- #------Read Only Data -----------------------------------------------------
+ if test -z "${TEXT_AFTER_RO}"; then
+ #------Read Only Data ------------------------------------------------
- align_rodata
+ align_rodata
- # If we have not already emitted the early read only data sections then do
- # so now. Also if the dynamic section has not already been emitted and we
- # can put it into the data segment, then do that here as well.
+ # If we have not already emitted the early read only data sections then do
+ # so now. Also if the dynamic section has not already been emitted and we
+ # can put it into the data segment, then do that here as well.
- if test -n "${ALL_TEXT_BEFORE_RO}"; then
- test -n "${SEPARATE_CODE}" || emit_early_ro
- test -n "${NON_ALLOC_DYN}${SEPARATE_CODE}" || emit_dyn
- fi
- test -z "${SEPARATE_CODE}" || emit_early_ro
- test -z "${SEPARATE_CODE}" || emit_dyn
+ if test -n "${ALL_TEXT_BEFORE_RO}"; then
+ test -n "${SEPARATE_CODE}" || emit_early_ro
+ test -n "${NON_ALLOC_DYN}${SEPARATE_CODE}" || emit_dyn
+ fi
+ test -z "${SEPARATE_CODE}" || emit_early_ro
+ test -z "${SEPARATE_CODE}" || emit_dyn
- # Now emit the rest of the read only data.
+ # Now emit the rest of the read only data.
- emit_rodata
+ emit_rodata
+ fi
#------Read Write Data ----------------------------------------------------
diff --git a/ld/testsuite/ld-elf/pr30907-2.d b/ld/testsuite/ld-elf/pr30907-2.d
index fed957e760e..f6254d3ab25 100644
--- a/ld/testsuite/ld-elf/pr30907-2.d
+++ b/ld/testsuite/ld-elf/pr30907-2.d
@@ -2,6 +2,7 @@
#source: pr22393-1.s
#ld: -shared -z separate-code -z relro --rosegment
#readelf: -l --wide
+#notarget: i?86-*-* x86_64-*-*
#target: *-*-linux-gnu *-*-gnu* arm*-*-uclinuxfdpiceabi
#xfail: ![check_shared_lib_support]
#xfail: ![check_relro_support]
diff --git a/ld/testsuite/ld-elf/pr34003.d b/ld/testsuite/ld-elf/pr34003.d
new file mode 100644
index 00000000000..9e04914e647
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr34003.d
@@ -0,0 +1,13 @@
+#name: --rosegment (has at least one R, one RX and one RW segments)
+#source: pr22393-1.s
+#ld: -shared -z separate-code -z relro --rosegment
+#readelf: -l --wide
+#target: i?86-*-* x86_64-*-*
+
+#...
+[ ]+LOAD[ ]+0x[0-9a-f x]+R[ ]+0x.*
+#...
+[ ]+LOAD[ ]+0x[0-9a-f x]+R E[ ]+0x.*
+#...
+[ ]+LOAD[ ]+0x[0-9a-f x]+RW[ ]+0x.*
+#...
diff --git a/ld/testsuite/ld-i386/pr32191.d b/ld/testsuite/ld-i386/pr32191.d
index 8d7838a1311..5558da1b0b8 100644
--- a/ld/testsuite/ld-i386/pr32191.d
+++ b/ld/testsuite/ld-i386/pr32191.d
@@ -4,6 +4,8 @@
#readelf: -lW
#...
- +[0-9]+ +\.note\.gnu\.build-id \.text
+ +[0-9]+ +\.note\.gnu\.build-id .*
+ +[0-9]+ +\.text
+#...
+[0-9]+ +\..* \.note\.gnu\.property .*
#pass
diff --git a/ld/testsuite/ld-x86-64/pr32191-x32.d b/ld/testsuite/ld-x86-64/pr32191-x32.d
index 19e06a26c11..b574e05f6c9 100644
--- a/ld/testsuite/ld-x86-64/pr32191-x32.d
+++ b/ld/testsuite/ld-x86-64/pr32191-x32.d
@@ -4,6 +4,8 @@
#readelf: -lW
#...
- +[0-9]+ +\.note\.gnu\.build-id \.text
+ +[0-9]+ +\.note\.gnu\.build-id .*
+ +[0-9]+ +\.text
+#...
+[0-9]+ +\..* \.note\.gnu\.property .*
#pass
diff --git a/ld/testsuite/ld-x86-64/pr32191.d b/ld/testsuite/ld-x86-64/pr32191.d
index 9038ccd9b35..2a0c0339165 100644
--- a/ld/testsuite/ld-x86-64/pr32191.d
+++ b/ld/testsuite/ld-x86-64/pr32191.d
@@ -4,6 +4,8 @@
#readelf: -lW
#...
- +[0-9]+ +\.note\.gnu\.build-id \.text
+ +[0-9]+ +\.note\.gnu\.build-id .*
+ +[0-9]+ +\.text
+#...
+[0-9]+ +\..* \.note\.gnu\.property .*
#pass
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