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package/elf2flt: fix fatal error regression on m68k, xtensa, riscv64

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This series fixes a fatal error at link time on m68k, xtensa,
and riscv64, caused by a bad upstream elf2flt commit.

Without this patch, m68k, xtensa, and riscv64 would result in
a fatal error:
ERROR: text=0x3bab8 overlaps data=0x33f60 ?

With this patch, qemu_m68k_mcf5208_defconfig,
qemu_riscv64_nommu_virt_defconfig, and
qemu_xtensa_lx60_nommu_defconfig builds properly.

riscv64 and m68k boots to login prompt.
xtensa crashes when loading init, the same behavior as when
reverting the bad upstream elf2flt commit completely.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
This commit is contained in:
Niklas Cassel 2022-08-11 11:40:49 +02:00 committed by Thomas Petazzoni
parent 95402089c3
commit 9dd179d43f
2 changed files with 149 additions and 0 deletions
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76
package/elf2flt/0004-elf2flt-create-a-common-helper-function.patch Normal file
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@ -0,0 +1,76 @@
From 37e1e0ace8ccebf54ec2f5522bfc1f9db86946ad Mon Sep 17 00:00:00 2001
From: Niklas Cassel <niklas.cassel@wdc.com>
Date: Tue, 9 Aug 2022 12:13:50 +0200
Subject: [PATCH] elf2flt: create a common helper function
In order to make the code more maintainable,
move duplicated code to a common helper function.
No functional change intended.
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
elf2flt.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/elf2flt.c b/elf2flt.c
index 669591e..9c32f9a 100644
--- a/elf2flt.c
+++ b/elf2flt.c
@@ -337,6 +337,13 @@ compare_relocs (const void *pa, const void *pb)
}
#endif
+static bool
+ro_reloc_data_section_should_be_in_text(asection *s)
+{
+ return (s->flags & (SEC_DATA | SEC_READONLY | SEC_RELOC)) ==
+ (SEC_DATA | SEC_READONLY | SEC_RELOC);
+}
+
static uint32_t *
output_relocs (
bfd *abs_bfd,
@@ -428,8 +435,7 @@ output_relocs (
*/
if ((!pic_with_got || ALWAYS_RELOC_TEXT) &&
((a->flags & SEC_CODE) ||
- ((a->flags & (SEC_DATA | SEC_READONLY | SEC_RELOC)) ==
- (SEC_DATA | SEC_READONLY | SEC_RELOC))))
+ ro_reloc_data_section_should_be_in_text(a)))
sectionp = text + (a->vma - text_vma);
else if (a->flags & SEC_DATA)
sectionp = data + (a->vma - data_vma);
@@ -1893,8 +1899,7 @@ int main(int argc, char *argv[])
bfd_vma sec_vma;
if ((s->flags & SEC_CODE) ||
- ((s->flags & (SEC_DATA | SEC_READONLY | SEC_RELOC)) ==
- (SEC_DATA | SEC_READONLY | SEC_RELOC))) {
+ ro_reloc_data_section_should_be_in_text(s)) {
vma = &text_vma;
len = &text_len;
} else if (s->flags & SEC_DATA) {
@@ -1932,8 +1937,7 @@ int main(int argc, char *argv[])
* data sections.*/
for (s = abs_bfd->sections; s != NULL; s = s->next)
if ((s->flags & SEC_CODE) ||
- ((s->flags & (SEC_DATA | SEC_READONLY | SEC_RELOC)) ==
- (SEC_DATA | SEC_READONLY | SEC_RELOC)))
+ ro_reloc_data_section_should_be_in_text(s))
if (!bfd_get_section_contents(abs_bfd, s,
text + (s->vma - text_vma), 0,
bfd_section_size(abs_bfd, s)))
@@ -1962,8 +1966,7 @@ int main(int argc, char *argv[])
* data sections already included in the text output section.*/
for (s = abs_bfd->sections; s != NULL; s = s->next)
if ((s->flags & SEC_DATA) &&
- ((s->flags & (SEC_READONLY | SEC_RELOC)) !=
- (SEC_READONLY | SEC_RELOC)))
+ !ro_reloc_data_section_should_be_in_text(s))
if (!bfd_get_section_contents(abs_bfd, s,
data + (s->vma - data_vma), 0,
bfd_section_size(abs_bfd, s)))
--
2.37.1

73
package/elf2flt/0005-elf2flt-fix-fatal-error-regression-on-m68k-xtensa-ri.patch Normal file
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@ -0,0 +1,73 @@
From 65ac5f9e69cfb989d970da74c41e478774d29be5 Mon Sep 17 00:00:00 2001
From: Niklas Cassel <niklas.cassel@wdc.com>
Date: Tue, 9 Aug 2022 21:06:05 +0200
Subject: [PATCH] elf2flt: fix fatal error regression on m68k, xtensa,
riscv64
Commit ba379d08bb78 ("elf2flt: fix for segfault on some ARM ELFs")
changed the condition of which input sections that should be included
in the .text output section from:
((a->flags & (SEC_DATA | SEC_READONLY)) == (SEC_DATA | SEC_READONLY))
to:
((a->flags & (SEC_DATA | SEC_READONLY | SEC_RELOC)) ==
(SEC_DATA | SEC_READONLY | SEC_RELOC))
On ARM, the .eh_frame input section does not have the SEC_RELOC flag
set, so this specific change had no effect on ARM.
However, on e.g. m68k and riscv64, the .eh_frame input section does
have the SEC_RELOC flag set, which means that after commit ba379d08bb78
("elf2flt: fix for segfault on some ARM ELFs"), read-only relocation
data sections were placed in .text output section, instead of .data
output section.
This will result in a fatal error on m68k, xtensa and riscv64:
ERROR: text=0x3bab8 overlaps data=0x33f60 ?
This is because elf2flt cannot append to .text after .data has been
appended to.
Note that the binutils maintainer says that the correct thing is
to put read-only relocation data sections in .text:
https://sourceware.org/legacy-ml/binutils/2019-10/msg00132.html
So the proper fix is probably to rewrite elf2flt so that it can append
to .text after .data has been appended to (which will require elf2flt
to move/relocate everything that has already been appended to .data,
since the virtual addresses are contiguous).
However, for now, add an exception for m68k, xtensa and riscv64
(specifically for the problematic input section, .eh_frame), so that we
get the same behavior as older elf2flt releases, where we put read-only
relocation data in .data, which was working perfectly fine.
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
elf2flt.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/elf2flt.c b/elf2flt.c
index 9c32f9a..a680c89 100644
--- a/elf2flt.c
+++ b/elf2flt.c
@@ -340,8 +340,15 @@ compare_relocs (const void *pa, const void *pb)
static bool
ro_reloc_data_section_should_be_in_text(asection *s)
{
- return (s->flags & (SEC_DATA | SEC_READONLY | SEC_RELOC)) ==
- (SEC_DATA | SEC_READONLY | SEC_RELOC);
+ if ((s->flags & (SEC_DATA | SEC_READONLY | SEC_RELOC)) ==
+ (SEC_DATA | SEC_READONLY | SEC_RELOC)) {
+#if defined(TARGET_m68k) || defined(TARGET_riscv64) || defined(TARGET_xtensa)
+ if (!strcmp(".eh_frame", s->name))
+ return false;
+#endif
+ return true;
+ }
+ return false;
}
static uint32_t *
--
2.37.1