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package/elf2flt: update RISC-V 64-bits support
Remove the old elf2flt 0002-elf2flt-add-riscv-64-bits-support.patch
patch file for riscv64 architecture and replace it with 3 patches:
(1) The first patch fixes the data section alignment
(2) The second patch fixes a bug with the handling of the eh_frame
section causing text and data section overlap problems.
(3) The third patch adds a simpler riscv64 flat bin relocation support.
These 3 patches are submitted to the upstream elf2flt project as pull
request #22:
uclinux-dev/elf2flt#22
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>- Loading branch information
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package/elf2flt/0002-elf2flt.ld-reinstate-32-byte-alignment-for-.data-sec.patch
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,81 @@ | ||
| From 85ba5664eb368eb1cbd2c30b7cd574acd75edd4c Mon Sep 17 00:00:00 2001 | ||
| From: Niklas Cassel <niklas.cassel@wdc.com> | ||
| Date: Mon, 4 Apr 2022 15:30:24 +0200 | ||
| Subject: [PATCH] elf2flt.ld: reinstate 32 byte alignment for .data section | ||
|
|
||
| Commit 8a3e74446fe7 ("allow to build arm flat binaries") moved the | ||
| following commands: | ||
| . = ALIGN(0x20) ; | ||
| @SYMBOL_PREFIX@_etext = . ; | ||
| from the .text section to the top level in the SECTIONS node. | ||
|
|
||
| The .text output section is being directed to a memory region using the | ||
| "> flatmem :text" output section attribute. Commands in the top level in | ||
| the SECTIONS node are not. | ||
|
|
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| This means that the ALIGN() command is no longer being appended to the | ||
| flatmem memory region, it will simply update the Location Counter. | ||
|
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| The heuristic for placing an output section is described here: | ||
| https://sourceware.org/binutils/docs-2.38/ld.html#Output-Section-Address | ||
|
|
||
| "If an output memory region is set for the section then it is added to this | ||
| region and its address will be the next free address in that region." | ||
|
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||
| Since the .data section is being directed to the same memory region as the | ||
| .text section, this means that the Location Counter is not used when | ||
| assigning an address to the .data output section, it will simply use the | ||
| next free address. | ||
|
|
||
| No longer directing these commands to the flatmem memory region means that | ||
| the .data output section is no longer aligned to a 32 byte boundary. | ||
|
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||
| Before commit 8a3e74446fe7 ("allow to build arm flat binaries"): | ||
| $ readelf -S busybox_unstripped.gdb | grep data | ||
| [ 3] .data PROGBITS 0000000000035ac0 00036ac0 | ||
| $ readelf -s busybox_unstripped.gdb | grep _etext | ||
| 19286: 0000000000035ac0 0 NOTYPE GLOBAL DEFAULT 1 _etext | ||
|
|
||
| After commit 8a3e74446fe7 ("allow to build arm flat binaries"): | ||
| $ readelf -S busybox_unstripped.gdb | grep data | ||
| [ 3] .data PROGBITS 0000000000035ab0 00036ab0 | ||
| $ readelf -s busybox_unstripped.gdb | grep _etext | ||
| 19287: 0000000000035ac0 0 NOTYPE GLOBAL DEFAULT 3 _etext | ||
|
|
||
| The .data output section has to be aligned to a 32 byte boundary, see the | ||
| FLAT_DATA_ALIGN 0x20 macro and its usage in fs/binfmt_flat.c: | ||
| https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/binfmt_flat.c?h=v5.17#n59 | ||
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|
||
| Readd an explicit ALIGN attribute on the .data section itself, since the | ||
| linker will obey this attribute regardless if being directed to a memory | ||
| region or not. Also remove the ALIGN() command before the .data section, | ||
| since this misleads the reader to think that the Location Counter is used | ||
| when assigning an address to the .data section, when it actually is not. | ||
|
|
||
| Fixes: 8a3e74446fe7 ("allow to build arm flat binaries") | ||
| Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com> | ||
| --- | ||
| elf2flt.ld.in | 5 +---- | ||
| 1 file changed, 1 insertion(+), 4 deletions(-) | ||
|
|
||
| diff --git a/elf2flt.ld.in b/elf2flt.ld.in | ||
| index 0df999d..e5aea14 100644 | ||
| --- a/elf2flt.ld.in | ||
| +++ b/elf2flt.ld.in | ||
| @@ -94,12 +94,9 @@ W_RODAT: *(.gnu.linkonce.r*) | ||
| *(.ARM.exidx* .gnu.linkonce.armexidx.*) | ||
| } > flatmem | ||
| @SYMBOL_PREFIX@__exidx_end = .; | ||
| - | ||
| - . = ALIGN(0x20) ; | ||
| @SYMBOL_PREFIX@_etext = . ; | ||
|
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||
| - .data : { | ||
| - . = ALIGN(0x4) ; | ||
| + .data ALIGN(0x20): { | ||
| @SYMBOL_PREFIX@_sdata = . ; | ||
| @SYMBOL_PREFIX@__data_start = . ; | ||
| @SYMBOL_PREFIX@data_start = . ; | ||
| -- | ||
| 2.35.1 | ||
|
|
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package/elf2flt/0003-elf2flt-fix-.eh_frame-section-handling.patch
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,73 @@ | ||
| From 8b7fdb1dedfb8a6e858b46e5af33029fe0462ab8 Mon Sep 17 00:00:00 2001 | ||
| From: Damien Le Moal <damien.lemoal@opensource.wdc.com> | ||
| Date: Tue, 10 May 2022 23:14:36 +0900 | ||
| Subject: [PATCH] elf2flt: fix .eh_frame section handling | ||
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||
| elf2flt.ld linker script positions the .eh_frame section in an output | ||
| section after the .text and .data output sections. | ||
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||
| However, when elf2flt.c is supplied the ELF linked using the elf2flt.ld | ||
| linker script, it only looks at the flags for each input section, and | ||
| then puts it in either a bFLT text, data or bss output section. | ||
|
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||
| Commit ba379d08bb7 ("elf2flt: fix for segfault on some ARM ELFs") | ||
| modified the section scanning loop of elf2flt main() function to put | ||
| read-only relocation data sections in the bFLT text output section so | ||
| that the .ARM.exidx section is placed in the .text flat output section. | ||
| Previously a read-only relocation data section would be put in the data | ||
| output section. | ||
|
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||
| On ARM, the .eh_frame section does not have the SEC_RELOC flag set, so | ||
| it will still end up in the data output section. However, on | ||
| architectures that generates the .eh_frame section with the SEC_RELOC | ||
| flag set, this section will now be placed in the text output section. | ||
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||
| The logic in elf2flt will handle all sections in order, and since the | ||
| input order is .text, .data, and .eh_frame, putting .eh_frame in text | ||
| output section does not work, since elf2flt.c has already put the .data | ||
| input section in the bFLT data output section. This leads to the | ||
| following print (example for riscv64 architecture): | ||
|
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||
| buildroot/output/host/riscv64-buildroot-linux-uclibc/bin/elf2flt: | ||
| ERROR: text=0x3bab8 overlaps data=0x33f60 ? | ||
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| The way that elf2flt is written, we cannot append to the text output | ||
| section after an input section has been added to the data output | ||
| section. It might be possible to change this, but that would require | ||
| moving all the code the was already placed in the data output section. | ||
|
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| Instead, let's allow putting a read-only relocation data section in the | ||
| text output section (so that .ARM.exidx will still be placed correctly), | ||
| but only if there has not yet been anything placed in the data output | ||
| section. | ||
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| That way .ARM.exidx will still be placed correctly, and .eh_frame will | ||
| be placed correctly in the .data output section, regardless if it has | ||
| flag SEC_RELOC set or not. | ||
|
|
||
| Fixes: ba379d08bb7 ("elf2flt: fix for segfault on some ARM ELFs") | ||
| Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> | ||
| Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com> | ||
| --- | ||
| elf2flt.c | 5 +++-- | ||
| 1 file changed, 3 insertions(+), 2 deletions(-) | ||
|
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||
| diff --git a/elf2flt.c b/elf2flt.c | ||
| index 7ac0617..da25e93 100644 | ||
| --- a/elf2flt.c | ||
| +++ b/elf2flt.c | ||
| @@ -1877,8 +1877,9 @@ int main(int argc, char *argv[]) | ||
| bfd_vma sec_vma; | ||
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||
| if ((s->flags & SEC_CODE) || | ||
| - ((s->flags & (SEC_DATA | SEC_READONLY | SEC_RELOC)) == | ||
| - (SEC_DATA | SEC_READONLY | SEC_RELOC))) { | ||
| + (((s->flags & (SEC_DATA | SEC_READONLY | SEC_RELOC)) == | ||
| + (SEC_DATA | SEC_READONLY | SEC_RELOC)) && | ||
| + !data_len)) { | ||
| vma = &text_vma; | ||
| len = &text_len; | ||
| } else if (s->flags & SEC_DATA) { | ||
| -- | ||
| 2.35.1 | ||
|
|
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