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| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2015-10-14 16:58:41 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2015-10-14 17:01:12 +0100 |
| commit | 1fae5a6800b07d0a8225664ac65a628bbe98cae7 (patch) | |
| tree | a56d1b35fec55a7326d7bee2dfea7a9fd57396b1 /sysdeps/arm | |
| parent | f45e45a3e07ccd555a3130a9413fcebe6d8f5213 (diff) | |
| download | glibc-1fae5a6800b07d0a8225664ac65a628bbe98cae7.tar.gz glibc-1fae5a6800b07d0a8225664ac65a628bbe98cae7.tar.xz glibc-1fae5a6800b07d0a8225664ac65a628bbe98cae7.zip | |
[BZ #19129][ARM] Fix _dl_tlsdesc_resolve_hold to save r0
_dl_tlsdesc_resolve_hold calls into a C function that clobbers r0, but it assumes the original argument is still in r0 after the call. This can cause crash in case of concurrent TLS access when TLSDESC is in use (-mtls-dialect=gnu2). Run into this while fixing BZ 18572. Both r0 and r1 are saved/restored so the stack remains 8 byte aligned. [BZ #19129] * sysdeps/arm/dl-tlsdesc.S (_dl_tlsdesc_resolve_hold): Save and restore r0 and r1.
Diffstat (limited to 'sysdeps/arm')
| -rw-r--r-- | sysdeps/arm/dl-tlsdesc.S | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/sysdeps/arm/dl-tlsdesc.S b/sysdeps/arm/dl-tlsdesc.S index e42ca68eda..33a269573e 100644 --- a/sysdeps/arm/dl-tlsdesc.S +++ b/sysdeps/arm/dl-tlsdesc.S @@ -196,21 +196,30 @@ _dl_tlsdesc_lazy_resolver: eabi_fnstart .align 2 _dl_tlsdesc_resolve_hold: - eabi_save ({r2,r3,ip,lr}) - push {r2, r3, ip, lr} - cfi_adjust_cfa_offset (16) - cfi_rel_offset (r2, 0) - cfi_rel_offset (r3, 4) - cfi_rel_offset (ip, 8) - cfi_rel_offset (lr, 12) + /* r0 is saved so its original value can be used after the call and + r1 is saved only to keep the stack aligned. (r0 points to the tls + descriptor, it is passed to _dl_tlsdesc_resolve_hold_fixup which + is a void function that may clobber r0, later r0 is used to load + the new resolver.) */ + eabi_save ({r0,r1,r2,r3,ip,lr}) + push {r0, r1, r2, r3, ip, lr} + cfi_adjust_cfa_offset (24) + cfi_rel_offset (r0, 0) + cfi_rel_offset (r1, 4) + cfi_rel_offset (r2, 8) + cfi_rel_offset (r3, 12) + cfi_rel_offset (ip, 16) + cfi_rel_offset (lr, 20) adr r1, _dl_tlsdesc_resolve_hold bl _dl_tlsdesc_resolve_hold_fixup - pop {r2, r3, ip, lr} - cfi_adjust_cfa_offset (-16) + pop {r0, r1, r2, r3, ip, lr} + cfi_adjust_cfa_offset (-24) cfi_restore (lr) cfi_restore (ip) cfi_restore (r3) cfi_restore (r2) + cfi_restore (r1) + cfi_restore (r0) sfi_breg r0, \ ldr r1, [\B, #4] BX (r1) |