* [Buildroot] [git commit] package/elf2flt: fix error when building gdb for target on m68k
@ 2023-02-05 14:13 Thomas Petazzoni via buildroot
2023-02-21 19:58 ` Peter Korsgaard
0 siblings, 1 reply; 2+ messages in thread
From: Thomas Petazzoni via buildroot @ 2023-02-05 14:13 UTC (permalink / raw)
To: buildroot
commit: https://git.buildroot.net/buildroot/commit/?id=f6f15e85b3ac58ba1d387ea86945d3fabf4f8990
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master
Thomas reported that m68k fails to build when enabling BR2_PACKAGE_GDB.
It fails when building gdb for the target with the following error:
elf2flt: ERROR: text=0x3c826 overlaps data=0x256e0 ?
It turns out that the gdb binary has another problematic input section
(.gcc_except_table), which causes elf2flt to try to append to the .text
output section, after it has already moved on with appending sections
to the .data output section.
elf2flt cannot append to a previous output section once it has moved on
to another output section.
Update the existing elf2flt patch to also add an exception for
.gcc_except_table.
Reported-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
---
...-fatal-error-regression-on-m68k-xtensa-ri.patch | 47 +++++++++++-----------
1 file changed, 24 insertions(+), 23 deletions(-)
diff --git a/package/elf2flt/0005-elf2flt-fix-fatal-error-regression-on-m68k-xtensa-ri.patch b/package/elf2flt/0005-elf2flt-fix-fatal-error-regression-on-m68k-xtensa-ri.patch
index 278709cb1c..616bbc891f 100644
--- a/package/elf2flt/0005-elf2flt-fix-fatal-error-regression-on-m68k-xtensa-ri.patch
+++ b/package/elf2flt/0005-elf2flt-fix-fatal-error-regression-on-m68k-xtensa-ri.patch
@@ -1,8 +1,7 @@
-From 65ac5f9e69cfb989d970da74c41e478774d29be5 Mon Sep 17 00:00:00 2001
+From a8c9f650b82109abf7aa730f298ea5182ed62613 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
+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
@@ -12,16 +11,15 @@ 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.
+On ARM, the .eh_frame input section does not have the SEC_RELOC flag set,
+so on ARM, this change caused .eh_frame to move from .text to .data.
-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.
+However, on e.g. m68k, xtensa and riscv64, the .eh_frame input section
+does have the SEC_RELOC flag set, which means that the change in
+commit ba379d08bb78 ("elf2flt: fix for segfault on some ARM ELFs")
+caused .eh_frame to move in an opposite way, i.e. from .data to .text.
-This will result in a fatal error on m68k, xtensa and riscv64:
+This resulted 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
@@ -36,21 +34,26 @@ 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.
+However, for now, add an exception for input sections which have all
+three flags SEC_DATA, SEC_READONLY, and SEC_RELOC set, and which have a
+name equal to a problematic input section (.eh_frame, .gcc_except_table).
+That way, we get the same behavior as older elf2flt releases for m68k,
+xtensa and riscv64, where we put read-only relocation data in .data,
+which was working perfectly fine.
+
+This exception will not change any behavior on ARM, as the .eh_frame
+input section does not have flag SEC_RELOC set.
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
- elf2flt.c | 11 +++++++++--
- 1 file changed, 9 insertions(+), 2 deletions(-)
+ elf2flt.c | 9 +++++++--
+ 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/elf2flt.c b/elf2flt.c
-index 9c32f9a..a680c89 100644
+index e0d7891..39d035f 100644
--- a/elf2flt.c
+++ b/elf2flt.c
-@@ -340,8 +340,15 @@ compare_relocs (const void *pa, const void *pb)
+@@ -341,8 +341,13 @@ compare_relocs (const void *pa, const void *pb)
static bool
ro_reloc_data_section_should_be_in_text(asection *s)
{
@@ -58,10 +61,8 @@ index 9c32f9a..a680c89 100644
- (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))
++ if (!strcmp(".eh_frame", s->name) || !strcmp(".gcc_except_table", s->name))
+ return false;
-+#endif
+ return true;
+ }
+ return false;
@@ -69,5 +70,5 @@ index 9c32f9a..a680c89 100644
static uint32_t *
--
-2.37.1
+2.39.0
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [Buildroot] [git commit] package/elf2flt: fix error when building gdb for target on m68k
2023-02-05 14:13 [Buildroot] [git commit] package/elf2flt: fix error when building gdb for target on m68k Thomas Petazzoni via buildroot
@ 2023-02-21 19:58 ` Peter Korsgaard
0 siblings, 0 replies; 2+ messages in thread
From: Peter Korsgaard @ 2023-02-21 19:58 UTC (permalink / raw)
To: Thomas Petazzoni via buildroot; +Cc: Thomas Petazzoni
>>>>> "Thomas" == Thomas Petazzoni via buildroot <buildroot@buildroot.org> writes:
> commit: https://git.buildroot.net/buildroot/commit/?id=f6f15e85b3ac58ba1d387ea86945d3fabf4f8990
> branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master
> Thomas reported that m68k fails to build when enabling BR2_PACKAGE_GDB.
> It fails when building gdb for the target with the following error:
> elf2flt: ERROR: text=0x3c826 overlaps data=0x256e0 ?
> It turns out that the gdb binary has another problematic input section
> (.gcc_except_table), which causes elf2flt to try to append to the .text
> output section, after it has already moved on with appending sections
> to the .data output section.
> elf2flt cannot append to a previous output section once it has moved on
> to another output section.
> Update the existing elf2flt patch to also add an exception for
> .gcc_except_table.
> Reported-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Committed to 2022.11.x and 2022.02.x, thanks.
--
Bye, Peter Korsgaard
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2023-02-05 14:13 [Buildroot] [git commit] package/elf2flt: fix error when building gdb for target on m68k Thomas Petazzoni via buildroot
2023-02-21 19:58 ` Peter Korsgaard
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