ELF: Support .noinit and .persistent sections

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.

15 files changed, 145 insertions, 18 deletions

diff --git a/ld/ChangeLog b/ld/ChangeLog
index fb831d9..fbc2d8a 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -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
diff --git a/ld/emulparams/armelf.sh b/ld/emulparams/armelf.sh
index 24ca8ed..1995c44 100644
--- a/ld/emulparams/armelf.sh
+++ b/ld/emulparams/armelf.sh
@@ -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
diff --git a/ld/scripttempl/avr.sc b/ld/scripttempl/avr.sc
index b85748b..77238d6 100644
--- a/ld/scripttempl/avr.sc
+++ b/ld/scripttempl/avr.sc
@@ -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 = .) ; }
diff --git a/ld/scripttempl/elf.sc b/ld/scripttempl/elf.sc
index eb74743..d9e63e7 100644
--- a/ld/scripttempl/elf.sc
+++ b/ld/scripttempl/elf.sc
@@ -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
 
diff --git a/ld/scripttempl/elf32msp430.sc b/ld/scripttempl/elf32msp430.sc
index 4206d79..fafd775 100644
--- a/ld/scripttempl/elf32msp430.sc
+++ b/ld/scripttempl/elf32msp430.sc
@@ -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}
 
diff --git a/ld/scripttempl/elfarcv2.sc b/ld/scripttempl/elfarcv2.sc
index b6cab6c..a0c4f7e 100644
--- a/ld/scripttempl/elfarcv2.sc
+++ b/ld/scripttempl/elfarcv2.sc
@@ -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}}
diff --git a/ld/scripttempl/pru.sc b/ld/scripttempl/pru.sc
index 9ef7980..08aceaa 100644
--- a/ld/scripttempl/pru.sc
+++ b/ld/scripttempl/pru.sc
@@ -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 ; }
diff --git a/ld/testsuite/ld-elf/noinit-sections-1.d b/ld/testsuite/ld-elf/noinit-sections-1.d
new file mode 100644
index 0000000..133205c
--- /dev/null
+++ b/ld/testsuite/ld-elf/noinit-sections-1.d
@@ -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
diff --git a/ld/testsuite/ld-elf/noinit-sections-2.d b/ld/testsuite/ld-elf/noinit-sections-2.d
new file mode 100644
index 0000000..f3eb4e5
--- /dev/null
+++ b/ld/testsuite/ld-elf/noinit-sections-2.d
@@ -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
diff --git a/ld/testsuite/ld-elf/noinit-sections-2.l b/ld/testsuite/ld-elf/noinit-sections-2.l
new file mode 100644
index 0000000..0784c9e
--- /dev/null
+++ b/ld/testsuite/ld-elf/noinit-sections-2.l
@@ -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
diff --git a/ld/testsuite/ld-elf/noinit-sections.s b/ld/testsuite/ld-elf/noinit-sections.s
new file mode 100644
index 0000000..f840bb0
--- /dev/null
+++ b/ld/testsuite/ld-elf/noinit-sections.s
@@ -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
diff --git a/ld/testsuite/ld-elf/persistent-sections-1.d b/ld/testsuite/ld-elf/persistent-sections-1.d
new file mode 100644
index 0000000..5815cfa
--- /dev/null
+++ b/ld/testsuite/ld-elf/persistent-sections-1.d
@@ -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
diff --git a/ld/testsuite/ld-elf/persistent-sections-2.d b/ld/testsuite/ld-elf/persistent-sections-2.d
new file mode 100644
index 0000000..3778514
--- /dev/null
+++ b/ld/testsuite/ld-elf/persistent-sections-2.d
@@ -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
diff --git a/ld/testsuite/ld-elf/persistent-sections-2.l b/ld/testsuite/ld-elf/persistent-sections-2.l
new file mode 100644
index 0000000..a5bbe4b
--- /dev/null
+++ b/ld/testsuite/ld-elf/persistent-sections-2.l
@@ -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
diff --git a/ld/testsuite/ld-elf/persistent-sections.s b/ld/testsuite/ld-elf/persistent-sections.s
new file mode 100644
index 0000000..04f6155
--- /dev/null
+++ b/ld/testsuite/ld-elf/persistent-sections.s
@@ -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