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ELF: Support .noinit and .persistent sections

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The ".persistent" section is for data that should be initialized during
load, but not during application reset.

The ".noinit" section is for data that should not be initialized during
load or application reset.

Targets utilizing the elf.sc linker script template can define
HAVE_{NOINIT,PERSISTENT}=yes to include the .noinit or .persistent
output sections in the generated linker script.

Targets with existing support for .noinit did not handle unique
.noinit.* and .gnu.linkonce.n.* sections the .noinit output section,
this patch also fixes that.

bfd/ChangeLog:

	* elf.c (special_sections_g): Add .gnu.linkonce.n and .gnu.linkonce.p.
	(special_sections_n): Add .noinit.
	(special_sections_p): Add .persistent.

binutils/ChangeLog:

	* testsuite/lib/binutils-common.exp (supports_noinit_section): New.
	(supports_persistent_section): New.

gas/ChangeLog:

	* testsuite/gas/elf/elf.exp: Run new tests.
	* testsuite/gas/elf/section25.d: New test.
	* testsuite/gas/elf/section25.s: New test.
	* testsuite/gas/elf/section26.d: New test.
	* testsuite/gas/elf/section26.s: New test.

ld/ChangeLog:

	* emulparams/armelf.sh (OTHER_SECTIONS): Remove .noinit section
	definition.
	Define HAVE_{NOINIT,PERSISTENT}=yes.
	* scripttempl/avr.sc (.noinit): Add .noinit.* and .gnu.linkonce.n.*
	input section wildcard patterns.
	* scripttempl/elf.sc: Define .noinit and .persistent sections when
	HAVE_NOINIT or HAVE_PERSISTENT are defined to "yes".
	* scripttempl/elf32msp430.sc (.noinit): Add .noinit.* and
	.gnu.linkonce.n.*. input section wildcard patterns.
	(.persistent): Add .persistent.* and
	.gnu.linkonce.p.*. input section wildcard patterns.
	* scripttempl/elfarcv2.sc (.noinit): Add .noinit.* and
	.gnu.linkonce.n.*. input section wildcard patterns.
	* scripttempl/pru.sc: Likewise.
	* testsuite/ld-elf/noinit-sections-1.d: New test.
	* testsuite/ld-elf/noinit-sections-2.d: New test.
	* testsuite/ld-elf/noinit-sections-2.l: New test.
	* testsuite/ld-elf/noinit-sections.s: New test.
	* testsuite/ld-elf/persistent-sections-1.d: New test.
	* testsuite/ld-elf/persistent-sections-2.d: New test.
	* testsuite/ld-elf/persistent-sections-2.l: New test.
	* testsuite/ld-elf/persistent-sections.s: New test.
This commit is contained in:
Jozef Lawrynowicz 2020-11-27 10:45:35 +00:00
parent bab6ead85f
commit 2c6f3e56cb
25 changed files with 249 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
bfd/ChangeLog
View File

@ -1,3 +1,9 @@
2020-11-27 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* elf.c (special_sections_g): Add .gnu.linkonce.n and .gnu.linkonce.p.
(special_sections_n): Add .noinit.
(special_sections_p): Add .persistent.
2020-11-26 Nick Clifton <nickc@redhat.com>
PR 26946

4
bfd/elf.c
View File

@ -2705,6 +2705,8 @@ static const struct bfd_elf_special_section special_sections_f[] =
static const struct bfd_elf_special_section special_sections_g[] =
{
{ STRING_COMMA_LEN (".gnu.linkonce.b"), -2, SHT_NOBITS, SHF_ALLOC + SHF_WRITE },
{ STRING_COMMA_LEN (".gnu.linkonce.n"), -2, SHT_NOBITS, SHF_ALLOC + SHF_WRITE },
{ STRING_COMMA_LEN (".gnu.linkonce.p"), -2, SHT_PROGBITS, SHF_ALLOC + SHF_WRITE },
{ STRING_COMMA_LEN (".gnu.lto_"), -1, SHT_PROGBITS, SHF_EXCLUDE },
{ STRING_COMMA_LEN (".got"), 0, SHT_PROGBITS, SHF_ALLOC + SHF_WRITE },
{ STRING_COMMA_LEN (".gnu.version"), 0, SHT_GNU_versym, 0 },
@ -2738,6 +2740,7 @@ static const struct bfd_elf_special_section special_sections_l[] =
static const struct bfd_elf_special_section special_sections_n[] =
{
{ STRING_COMMA_LEN (".noinit"), -2, SHT_NOBITS, SHF_ALLOC + SHF_WRITE },
{ STRING_COMMA_LEN (".note.GNU-stack"), 0, SHT_PROGBITS, 0 },
{ STRING_COMMA_LEN (".note"), -1, SHT_NOTE, 0 },
{ NULL, 0, 0, 0, 0 }
@ -2745,6 +2748,7 @@ static const struct bfd_elf_special_section special_sections_n[] =
static const struct bfd_elf_special_section special_sections_p[] =
{
{ STRING_COMMA_LEN (".persistent"), -2, SHT_PROGBITS, SHF_ALLOC + SHF_WRITE },
{ STRING_COMMA_LEN (".preinit_array"), -2, SHT_PREINIT_ARRAY, SHF_ALLOC + SHF_WRITE },
{ STRING_COMMA_LEN (".plt"), 0, SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR },
{ NULL, 0, 0, 0, 0 }

5
binutils/ChangeLog
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@ -1,3 +1,8 @@
2020-11-27 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* testsuite/lib/binutils-common.exp (supports_noinit_section): New.
(supports_persistent_section): New.
2020-11-23 Nick Alcock <nick.alcock@oracle.com>
* readelf.c (dump_section_as_ctf): Call ctf_arc_symsect_endianness.

39
binutils/testsuite/lib/binutils-common.exp
View File

@ -345,6 +345,45 @@ proc check_relro_support { } {
return $relro_available_saved
}
# Check for support of the .noinit section, used for data that is not
# initialized at load, or during the application's initialization sequence.
proc supports_noinit_section {} {
# .noinit is only supported by ELF targets.
if { ![is_elf_format] } {
return 0;
}
# Targets that set HAVE_NOINIT=yes in their emulparams script utilizing
# elf.sc, or explicitly define a .noinit section in their linker script.
#
# arc-*-* is not included here, since it only supports .noinit with the
# non-default arcv2elf emulation.
if {[istarget "arm-*-*"]
|| [istarget "avr-*-*"]
|| [istarget "msp430-*-*"]
|| [istarget "pru-*-*"] } {
return 1;
}
return 0;
}
# Check for support of the .persistent section, used for data that is
# initialized at load, but not during the application's initialization sequence.
proc supports_persistent_section {} {
# .persistent is only supported by ELF targets.
if { ![is_elf_format] } {
return 0;
}
# Targets that set HAVE_PERSISTENT=yes in their emulparams script utilizing
# elf.sc, or explicitly define a .persistent section in their linker script.
if { [istarget "arm-*-*"]
|| [istarget "msp430-*-*"] } {
return 1;
}
return 0;
}
# Compare two files line-by-line. FILE_1 is the actual output and FILE_2
# is the expected output. Ignore blank lines in either file.
#

8
gas/ChangeLog
View File

@ -1,3 +1,11 @@
2020-11-27 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* testsuite/gas/elf/elf.exp: Run new tests.
* testsuite/gas/elf/section25.d: New test.
* testsuite/gas/elf/section25.s: New test.
* testsuite/gas/elf/section26.d: New test.
* testsuite/gas/elf/section26.s: New test.
2020-11-25 Alan Modra <amodra@gmail.com>
* output-file.c (output_file_close): Remove "can't close" from

2
gas/testsuite/gas/elf/elf.exp
View File

@ -266,6 +266,8 @@ if { [is_elf_format] } then {
run_dump_test "section23b"
run_dump_test "section24a"
run_dump_test "section24b"
run_dump_test "section25"
run_dump_test "section26"
run_dump_test "sh-link-zero"
run_dump_test "dwarf2-1" $dump_opts
run_dump_test "dwarf2-2" $dump_opts

12
gas/testsuite/gas/elf/section25.d Normal file
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@ -0,0 +1,12 @@
#name: sections 25 (.noinit)
#target: [supports_noinit_section]
#source: section25.s
#readelf: -S --wide
#...
\[..\] .noinit[ ]+NOBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA .*
#...
\[..\] .noinit.foo[ ]+NOBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA .*
#...
\[..\] .gnu.linkonce.n.bar[ ]+NOBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA .*
#pass

8
gas/testsuite/gas/elf/section25.s Normal file
View File

@ -0,0 +1,8 @@
.section .noinit
.word 0
.section .noinit.foo
.word 0
.section .gnu.linkonce.n.bar
.word 0

12
gas/testsuite/gas/elf/section26.d Normal file
View File

@ -0,0 +1,12 @@
#name: sections 26 (.persistent)
#target: [supports_persistent_section]
#source: section26.s
#readelf: -S --wide
#...
\[..\] .persistent[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA .*
#...
\[..\] .persistent.foo[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA .*
#...
\[..\] .gnu.linkonce.p.bar[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA .*
#pass

8
gas/testsuite/gas/elf/section26.s Normal file
View File

@ -0,0 +1,8 @@
.section .persistent
.word 0
.section .persistent.foo
.word 0
.section .gnu.linkonce.p.bar
.word 0

25
ld/ChangeLog
View File

@ -1,3 +1,28 @@
2020-11-27 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* emulparams/armelf.sh (OTHER_SECTIONS): Remove .noinit section
definition.
Define HAVE_{NOINIT,PERSISTENT}=yes.
* scripttempl/avr.sc (.noinit): Add .noinit.* and .gnu.linkonce.n.*
input section wildcard patterns.
* scripttempl/elf.sc: Define .noinit and .persistent sections when
HAVE_NOINIT or HAVE_PERSISTENT are defined to "yes".
* scripttempl/elf32msp430.sc (.noinit): Add .noinit.* and
.gnu.linkonce.n.*. input section wildcard patterns.
(.persistent): Add .persistent.* and
.gnu.linkonce.p.*. input section wildcard patterns.
* scripttempl/elfarcv2.sc (.noinit): Add .noinit.* and
.gnu.linkonce.n.*. input section wildcard patterns.
* scripttempl/pru.sc: Likewise.
* testsuite/ld-elf/noinit-sections-1.d: New test.
* testsuite/ld-elf/noinit-sections-2.d: New test.
* testsuite/ld-elf/noinit-sections-2.l: New test.
* testsuite/ld-elf/noinit-sections.s: New test.
* testsuite/ld-elf/persistent-sections-1.d: New test.
* testsuite/ld-elf/persistent-sections-2.d: New test.
* testsuite/ld-elf/persistent-sections-2.l: New test.
* testsuite/ld-elf/persistent-sections.s: New test.
2020-11-26 Alan Modra <amodra@gmail.com>
PR 26936

18
ld/emulparams/armelf.sh
View File

@ -10,19 +10,7 @@ OTHER_TEXT_SECTIONS='*(.glue_7t) *(.glue_7) *(.vfp11_veneer) *(.v4_bx)'
OTHER_BSS_SYMBOLS="${CREATE_SHLIB+PROVIDE (}__bss_start__ = .${CREATE_SHLIB+)};"
OTHER_BSS_END_SYMBOLS="${CREATE_SHLIB+PROVIDE (}_bss_end__ = .${CREATE_SHLIB+)}; ${CREATE_SHLIB+PROVIDE (}__bss_end__ = .${CREATE_SHLIB+)};"
OTHER_END_SYMBOLS="${CREATE_SHLIB+PROVIDE (}__end__ = .${CREATE_SHLIB+)};"
OTHER_SECTIONS='
.note.gnu.arm.ident 0 : { KEEP (*(.note.gnu.arm.ident)) }
/* This section contains data that is not initialised during load
*or* application reset. */
.noinit (NOLOAD) :
{
. = ALIGN(2);
PROVIDE (__noinit_start = .);
*(.noinit)
. = ALIGN(2);
PROVIDE (__noinit_end = .);
}
'
OTHER_SECTIONS='.note.gnu.arm.ident 0 : { KEEP (*(.note.gnu.arm.ident)) }'
ATTRS_SECTIONS='.ARM.attributes 0 : { KEEP (*(.ARM.attributes)) KEEP (*(.gnu.attributes)) }'
OTHER_READONLY_SECTIONS="
.ARM.extab ${RELOCATING-0} : { *(.ARM.extab${RELOCATING+* .gnu.linkonce.armextab.*}) }
@ -49,3 +37,7 @@ STACK_ADDR=0x80000
# ARM does not support .s* sections.
NO_SMALL_DATA=yes
# ARM supports the .noinit and .persistent sections.
HAVE_NOINIT=yes
HAVE_PERSISTENT=yes

2
ld/scripttempl/avr.sc
View File

@ -271,7 +271,7 @@ cat <<EOF
.noinit ${RELOCATING+ ADDR(.bss) + SIZEOF (.bss)} ${RELOCATING-0}: ${RELOCATING+ AT (ADDR (.noinit))}
{
${RELOCATING+ PROVIDE (__noinit_start = .) ; }
*(.noinit*)
*(.noinit${RELOCATING+ .noinit.* .gnu.linkonce.n.*})
${RELOCATING+ PROVIDE (__noinit_end = .) ; }
${RELOCATING+ _end = . ; }
${RELOCATING+ PROVIDE (__heap_start = .) ; }

28
ld/scripttempl/elf.sc
View File

@ -8,6 +8,8 @@
# NOP - four byte opcode for no-op (defaults to none)
# NO_SMALL_DATA - no .sbss/.sbss2/.sdata/.sdata2 sections if not
# empty.
# HAVE_NOINIT - Include a .noinit output section in the script.
# HAVE_PERSISTENT - Include a .persistent output section in the script.
# SMALL_DATA_CTOR - .ctors contains small data.
# SMALL_DATA_DTOR - .dtors contains small data.
# DATA_ADDR - if end-of-text-plus-one-page isn't right for data start
@ -103,6 +105,8 @@
# .lrodata .gnu.linkonce.lr.foo
# .ldata .gnu.linkonce.l.foo
# .lbss .gnu.linkonce.lb.foo
# .noinit .gnu.linkonce.n.foo
# .persistent .gnu.linkonce.p.foo
#
# Each of these can also have corresponding .rel.* and .rela.* sections.
@ -322,6 +326,28 @@ STACK=".stack ${RELOCATING-0}${RELOCATING+${STACK_ADDR}} :
*(.stack)
${RELOCATING+${STACK_SENTINEL}}
}"
test "${HAVE_NOINIT}" = "yes" && NOINIT="
/* This section contains data that is not initialized during load,
or during the application's initialization sequence. */
.noinit (NOLOAD) :
{
${RELOCATING+. = ALIGN(${ALIGNMENT});}
${RELOCATING+PROVIDE (__noinit_start = .);}
*(.noinit${RELOCATING+ .noinit.* .gnu.linkonce.n.*})
${RELOCATING+. = ALIGN(${ALIGNMENT});}
${RELOCATING+PROVIDE (__noinit_end = .);}
}"
test "${HAVE_PERSISTENT}" = "yes" && PERSISTENT="
/* This section contains data that is initialized during load,
but not during the application's initialization sequence. */
.persistent :
{
${RELOCATING+. = ALIGN(${ALIGNMENT});}
${RELOCATING+PROVIDE (__persistent_start = .);}
*(.persistent${RELOCATING+ .persistent.* .gnu.linkonce.p.*})
${RELOCATING+. = ALIGN(${ALIGNMENT});}
${RELOCATING+PROVIDE (__persistent_end = .);}
}"
TEXT_START_ADDR="SEGMENT_START(\"text-segment\", ${TEXT_START_ADDR})"
SHLIB_TEXT_START_ADDR="SEGMENT_START(\"text-segment\", ${SHLIB_TEXT_START_ADDR:-0})"
@ -645,6 +671,7 @@ cat <<EOF
${DATA_SDATA-${SDATA}}
${DATA_SDATA-${OTHER_SDATA_SECTIONS}}
${RELOCATING+${DATA_END_SYMBOLS-${CREATE_SHLIB+PROVIDE (}${USER_LABEL_PREFIX}_edata = .${CREATE_SHLIB+)}; PROVIDE (${USER_LABEL_PREFIX}edata = .);}}
${PERSISTENT}
${RELOCATING+. = .;}
${RELOCATING+${CREATE_SHLIB+PROVIDE (}${USER_LABEL_PREFIX}__bss_start = .${CREATE_SHLIB+)};}
${RELOCATING+${OTHER_BSS_SYMBOLS}}
@ -665,6 +692,7 @@ cat <<EOF
${OTHER_BSS_SECTIONS}
${LARGE_BSS_AFTER_BSS+${LARGE_BSS}}
${RELOCATING+${OTHER_BSS_END_SYMBOLS}}
${NOINIT}
${RELOCATING+. = ALIGN(${ALIGNMENT});}
EOF

12
ld/scripttempl/elf32msp430.sc
View File

@ -302,17 +302,25 @@ SECTIONS
} ${RELOCATING+ > data}
${RELOCATING+ PROVIDE (__bsssize = SIZEOF(.bss)); }
/* This section contains data that is not initialized during load,
or during the application's initialization sequence. */
.noinit ${RELOCATING-0}${RELOCATING+SIZEOF(.bss) + ADDR(.bss)} :
{
${RELOCATING+. = ALIGN(2);}
${RELOCATING+ PROVIDE (__noinit_start = .) ; }
*(.noinit)
*(.noinit${RELOCATING+ .noinit.* .gnu.linkonce.n.*})
${RELOCATING+. = ALIGN(2);}
${RELOCATING+ PROVIDE (__noinit_end = .) ; }
} ${RELOCATING+ > data}
/* This section contains data that is initialized during load,
but not during the application's initialization sequence. */
.persistent ${RELOCATING-0}${RELOCATING+SIZEOF(.noinit) + ADDR(.noinit)} :
{
${RELOCATING+. = ALIGN(2);}
${RELOCATING+ PROVIDE (__persistent_start = .) ; }
*(.persistent)
*(.persistent${RELOCATING+ .persistent.* .gnu.linkonce.p.*})
${RELOCATING+. = ALIGN(2);}
${RELOCATING+ PROVIDE (__persistent_end = .) ; }
} ${RELOCATING+ > data}

2
ld/scripttempl/elfarcv2.sc
View File

@ -283,7 +283,7 @@ SECTIONS
/* Global data not cleared after reset. */
.noinit ${RELOCATING-0}:
{
*(.noinit*)
*(.noinit${RELOCATING+ .noinit.* .gnu.linkonce.n.*})
${RELOCATING+. = ALIGN(${ALIGNMENT});}
${RELOCATING+ PROVIDE (__start_heap = .) ; }
} ${RELOCATING+ > ${DATA_MEMORY}}

2
ld/scripttempl/pru.sc
View File

@ -167,7 +167,7 @@ SECTIONS
.noinit ${RELOCATING-0} :
{
${RELOCATING+ PROVIDE (_noinit_start = .) ; }
*(.noinit)
*(.noinit${RELOCATING+ .noinit.* .gnu.linkonce.n.*})
${RELOCATING+ PROVIDE (_noinit_end = .) ; }
${RELOCATING+ PROVIDE (_heap_start = .) ; }
${RELOCATING+ . += __HEAP_SIZE ; }

9
ld/testsuite/ld-elf/noinit-sections-1.d Normal file
View File

@ -0,0 +1,9 @@
#name: .noinit sections
#ld: --orphan-handling=warn -e _start
#source: noinit-sections.s
#target: [supports_noinit_section]
#readelf: -SW
#...
+\[ *[0-9]+\] \.noinit +NOBITS +[0-9a-f]+ +[0-9a-f]+ [0-9a-f]+ +00 +WA .*
#pass

10
ld/testsuite/ld-elf/noinit-sections-2.d Normal file
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@ -0,0 +1,10 @@
#name: .noinit sections (ld -r)
#ld: --orphan-handling=warn -e _start -r
#source: noinit-sections.s
#target: [supports_noinit_section]
#readelf: -SW
#warning_output: noinit-sections-2.l
#...
+\[ *[0-9]+\] \.noinit +NOBITS +[0-9a-f]+ +[0-9a-f]+ [0-9a-f]+ +00 +WA .*
#pass

5
ld/testsuite/ld-elf/noinit-sections-2.l Normal file
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@ -0,0 +1,5 @@
#...
[^:]*: warning: orphan section `.noinit.var_noinit' from \S+ being placed in section `.noinit.var_noinit'
#...
[^:]*: warning: orphan section `.gnu.linkonce.n.var_noinit2' from \S+ being placed in section `.gnu.linkonce.n.var_noinit2'
#pass

13
ld/testsuite/ld-elf/noinit-sections.s Normal file
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@ -0,0 +1,13 @@
.section .noinit,"aw",%nobits
.word 0
.section .noinit.var_noinit,"aw",%nobits
.word 0
.section .gnu.linkonce.n.var_noinit2,"aw",%nobits
.word 0
.text
.global _start
_start:
.word 0

9
ld/testsuite/ld-elf/persistent-sections-1.d Normal file
View File

@ -0,0 +1,9 @@
#name: .persistent sections
#ld: --orphan-handling=warn -e _start
#source: persistent-sections.s
#target: [supports_persistent_section]
#readelf: -SW
#...
+\[ *[0-9]+\] \.persistent +PROGBITS +[0-9a-f]+ +[0-9a-f]+ [0-9a-f]+ +00 +WA .*
#pass

10
ld/testsuite/ld-elf/persistent-sections-2.d Normal file
View File

@ -0,0 +1,10 @@
#name: .persistent sections (ld -r)
#ld: --orphan-handling=warn -e _start -r
#source: persistent-sections.s
#target: [supports_persistent_section]
#readelf: -SW
#warning_output: persistent-sections-2.l
#...
+\[ *[0-9]+\] \.persistent +PROGBITS +[0-9a-f]+ +[0-9a-f]+ [0-9a-f]+ +00 +WA .*
#pass

5
ld/testsuite/ld-elf/persistent-sections-2.l Normal file
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@ -0,0 +1,5 @@
#...
[^:]*: warning: orphan section `.persistent.var_persistent' from \S+ being placed in section `.persistent.var_persistent'
#...
[^:]*: warning: orphan section `.gnu.linkonce.p.var_persistent2' from \S+ being placed in section `.gnu.linkonce.p.var_persistent2'
#pass

13
ld/testsuite/ld-elf/persistent-sections.s Normal file
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@ -0,0 +1,13 @@
.section .persistent,"aw"
.word 1
.section .persistent.var_persistent,"aw"
.word 2
.section .gnu.linkonce.p.var_persistent2,"aw"
.word 3
.text
.global _start
_start:
.word 0