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| author | Jiong Wang <jiong.wang@arm.com> | 2017-07-13 15:48:41 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2017-07-13 15:48:41 +0100 |
| commit | 5ba6405338c280a3d84dcab1a11dcd1df9b5bee8 (patch) | |
| tree | 91058ccecdbeea948e8d2763924bd0f9c355274c | |
| parent | 1dd577fd3382868d03ff4756dd5f7d3b8099b76a (diff) | |
| download | glibc-5ba6405338c280a3d84dcab1a11dcd1df9b5bee8.tar.gz | |
[ARM] Fix ld.so crash when built using Binutils 2.29
There is bug report that ld.so in GLIBC 2.24 built by Binutils 2.29 will crash
on arm-linux-gnueabihf. This is confirmed, and the details is at:
https://sourceware.org/bugzilla/show_bug.cgi?id=21725.
As analyzed in the PR, the old code was with the assumption that assembler
won't set bit0 of thumb function address if it comes from PC-relative
instructions and the calculation can be finished during assembling. This
assumption however does not hold after PR gas/21458.
* sysdeps/arm/dl-machine.h (elf_machine_load_address): Also strip bit 0
of pcrel_address under Thumb mode.
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | sysdeps/arm/dl-machine.h | 12 |
2 files changed, 15 insertions, 2 deletions
@@ -1,3 +1,8 @@ +2017-07-12 Jiong Wang <jiong.wang@arm.com> + + * sysdeps/arm/dl-machine.h (elf_machine_load_address): Also strip bit 0 + of pcrel_address under Thumb mode. + 2017-07-12 Akhilesh Kumar <akhilesh.k@samsung.com> [BZ #21207] diff --git a/sysdeps/arm/dl-machine.h b/sysdeps/arm/dl-machine.h index 7053ead16e..0a126ce117 100644 --- a/sysdeps/arm/dl-machine.h +++ b/sysdeps/arm/dl-machine.h @@ -56,11 +56,19 @@ elf_machine_load_address (void) extern Elf32_Addr internal_function __dl_start (void *) asm ("_dl_start"); Elf32_Addr got_addr = (Elf32_Addr) &__dl_start; Elf32_Addr pcrel_addr; + asm ("adr %0, _dl_start" : "=r" (pcrel_addr)); #ifdef __thumb__ - /* Clear the low bit of the funciton address. */ + /* Clear the low bit of the function address. + + NOTE: got_addr is from GOT table whose lsb is always set by linker if it's + Thumb function address. PCREL_ADDR comes from PC-relative calculation + which will finish during assembling. GAS assembler before the fix for + PR gas/21458 was not setting the lsb but does after that. Always do the + strip for both, so the code works with various combinations of glibc and + Binutils. */ got_addr &= ~(Elf32_Addr) 1; + pcrel_addr &= ~(Elf32_Addr) 1; #endif - asm ("adr %0, _dl_start" : "=r" (pcrel_addr)); return pcrel_addr - got_addr; } |