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new 9da9d3ea8c binfmt/elf_loadfile: Set sh_addr even if SHF_ALLOC == 0
9da9d3ea8c is described below
commit 9da9d3ea8c8ccac0b2b3f44f18e48239c7c9c482
Author: Ville Juven <[email protected]>
AuthorDate: Tue Aug 6 12:28:08 2024 +0300
binfmt/elf_loadfile: Set sh_addr even if SHF_ALLOC == 0
Set sh_addr for regions that are not allocated. Some relocations might
depend on this.
The fault in my case occurs when setting CONFIG_HAVE_CXX=y. In this case,
the .ctor and .dtor sections do not get allocated, but the crt code
depends on linker defined symbols _sctors/_ectors etc. These generate PC
relative relocations and thus, the .ctor and .dtor output sections need
an output VMA even though nothing is there. Otherwise the relocations will
point to god knows where (in my case to address 0).
The problem results in full system crash later:
elf_symvalue: Other: 00000000+00000001=00000001
up_relocateadd: PCREL_HI20 at c00002dc [00000417] to sym=0x80409e80
st_value=1
_calc_imm: offset=-3221226203: hi=-786432 lo=-731
up_relocateadd: ERROR: PCREL_HI20 at c00002dc bad:ffffffff40000000
elf_relocateadd: ERROR: Section 2 reloc 52: Relocation failed: -22
The RISC-V elf64 linker does not like the uninitialized PC relative
relocation entries, as the relocation offset cannot be reached with
with the RV64 instruction set.
More about this issue can be found here:
https://github.com/apache/nuttx/pull/11322
---
binfmt/libelf/libelf_load.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/binfmt/libelf/libelf_load.c b/binfmt/libelf/libelf_load.c
index 44986b8f5e..c066ac8d87 100644
--- a/binfmt/libelf/libelf_load.c
+++ b/binfmt/libelf/libelf_load.c
@@ -191,15 +191,6 @@ static inline int elf_loadfile(FAR struct elf_loadinfo_s
*loadinfo)
{
FAR Elf_Shdr *shdr = &loadinfo->shdr[i];
- /* SHF_ALLOC indicates that the section requires memory during
- * execution.
- */
-
- if ((shdr->sh_flags & SHF_ALLOC) == 0)
- {
- continue;
- }
-
/* SHF_WRITE indicates that the section address space is write-
* able
*/
@@ -217,6 +208,18 @@ static inline int elf_loadfile(FAR struct elf_loadinfo_s
*loadinfo)
pptr = &text;
}
+ /* SHF_ALLOC indicates that the section requires memory during
+ * execution.
+ */
+
+ if ((shdr->sh_flags & SHF_ALLOC) == 0)
+ {
+ /* Set the VMA regardless, some relocations might depend on this */
+
+ shdr->sh_addr = (uintptr_t)*pptr;
+ continue;
+ }
+
if (*pptr == NULL)
{
if (shdr->sh_type != SHT_NOBITS)
