Hi Andreas,
On 3/24/22 07:05, Andreas K. Hüttel wrote:
With the command line flag -mplt and a recent toolchain, ELF binaries
generated by gcc can obtain EI_ABIVERSION=1, see below, which makes, e.g.,
gcc three-stage bootstrap in a mips-unknown-linux-gnu qemu-user chroot
fail since the binfmt-misc magic does not match anymore.
qemu executes these binaries just fine, so relax the mask slightly.
CHOST=mips-unknown-linux-gnu (and also mipsel-unknown-linux-gnu)
CFLAGS="-O2 -march=mips32 -mabi=32 -mplt -pipe"
gcc-11.2, binutils-2.37, glibc-2.34
| /*
| - * ELF dump of './prev-gcc/build/gengenrtl'
| - * 29608 (0x73A8) bytes
| + * ELF dump of './gcc/build/gengenrtl'
| + * 54532 (0xD504) bytes
| */
|
| Elf32_Dyn dumpedelf_dyn_0[];
| struct {
| Elf32_Ehdr ehdr;
| Elf32_Phdr phdrs[12];
| - Elf32_Shdr shdrs[33];
| + Elf32_Shdr shdrs[44];
| Elf32_Dyn *dyns;
| } dumpedelf_0 = {
|
| .ehdr = {
| .e_ident = { /* (EI_NIDENT bytes) */
| /* [0] EI_MAG:*/ 0x7F,'E','L','F',
| /* [4] EI_CLASS: */ 1 , /* (ELFCLASS32) */
| /* [5] EI_DATA: */ 2 , /* (ELFDATA2MSB) */
| /* [6] EI_VERSION:*/ 1 , /* (EV_CURRENT) */
| /* [7] EI_OSABI: */ 0 , /* (ELFOSABI_NONE) */
| - /* [8] EI_ABIVERSION: */ 0 ,
| + /* [8] EI_ABIVERSION: */ 1 ,
It seems we could have more values than 0 or 1 here, according to
binutils sources [1], so we might as well relax the mask for this byte...
| /* [9-15] EI_PAD: */ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
| },
| .e_type = 2 , /* (ET_EXEC) */
| .e_machine = 8 , /* (EM_MIPS) */
| .e_version = 1 , /* (EV_CURRENT) */
| (...)
Signed-off-by: Andreas K. Hüttel
---
scripts/qemu-binfmt-conf.sh | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
index e9bfeb94d3..fc2f856800 100755
--- a/scripts/qemu-binfmt-conf.sh
+++ b/scripts/qemu-binfmt-conf.sh
@@ -61,11 +61,11 @@ m68k_family=m68k
# FIXME: We could use the other endianness on a MIPS host.
mips_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'
-mips_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+mips_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
... to just \x00, to allow any future MIPS libc ABI bumps. Libc ABI
should not interfere with instruction semantics and emulation, so we're
safe.
mips_family=mips
mipsel_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'
-mipsel_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+mipsel_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xfe\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
mipsel_family=mips
mipsn32_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'
[1]:
https://github.com/bminor/binutils-gdb/blob/binutils-2_38/bfd/elfxx-mips.c#L16691-L16739
--
WANG Xuerui
xe...@gentoo.org
Gentoo Linux developer
PGP: 7C52 19E3 26A0 7311 3EA3 8806 C01F 7214 BC93 1414
