On Jul 27, 2016, at 11:08 AM, Sebastian Lackner sebastian@fds-team.de wrote:
On 27.07.2016 17:42, Ken Thomases wrote:
64-bit Windows apps have hard-coded accesses to %gs:0x30 baked into them. They need to find the TEB self pointer there.
Technically, the gsbase register and the memory it points to belong to the pthread implementation on macOS. It's used for the pthread TLS implementation. However, study of the sources and experimentation reveal that TLS slot 6 (offset 0x30) is not currently used. Furthermore, Apple has promised to not use that slot in the future. So, we hijack it for our purposes.
This removes the implementation of NtCurrentTeb() based on pthread_key_create() and pthread_set/getspecific().
Signed-off-by: Ken Thomases ken@codeweavers.com
dlls/ntdll/ntdll.spec | 2 +- dlls/ntdll/signal_x86_64.c | 34 +++------------------------------- include/winnt.h | 2 +- 3 files changed, 5 insertions(+), 33 deletions(-)
Nice to hear that Apple agreed to keep that slot reserved. Would it make sense to keep the NtCurrentTeb export neverthless, for compatibility with libraries compiled against old Wine?
Hmm. I don't know. I hadn't considered it. What sorts of libraries? Did you have some use case in mind? I guess I'd be surprised if there were such libraries around.
-Ken