Add support for pointer encryption in glibc internal structures in C
and assembler code. Pointer encryption is a glibc security feature
described here:
https://sourceware.org/glibc/wiki/PointerEncryption
The ARM implementation uses global variables instead of thread pointer
relative accesses to get the value of the pointer encryption guard
because accessing the thread pointer can be very expensive on older
ARM cores.
ports/ChangeLog.arm:
2013-10-03 Will Newton <will.newton@linaro.org>
* sysdeps/arm/__longjmp.S (__longjmp): Demangle fp, sp
and lr when restoring register values.
* sysdeps/arm/include/bits/setjmp.h (JMP_BUF_REGLIST): Remove
sp and lr from list and replace fp with a4.
* sysdeps/arm/jmpbuf-unwind.h (_jmpbuf_sp): New function.
(_JMPBUF_UNWINDS_ADJ): Call _jmpbuf_sp.
* sysdeps/arm/setjmp.S (__sigsetjmp): Mangle fp, sp and lr
before storing register values.
* sysdeps/arm/sysdep.h (LDST_GLOBAL): New macro.
* sysdeps/unix/sysv/linux/arm/sysdep.h (PTR_MANGLE): New macro.
(PTR_DEMANGLE): Likewise. (PTR_MANGLE2): Likewise.
(PTR_DEMANGLE2): Likewise.
For arm this makes no difference--the result is bit-for-bit identical;
for thumb this results in smaller encodings. Perhaps it ought not and
this is in fact an assembler bug, but I also think it's clearer.
Factor out the sequence needed to call kuser_get_tls, as we can't
play subtract into pc games in thumb mode. Prepare for hard-tp,
pulling the save of LR into the macro.
Allan McRae
Will Newton
Richard Henderson
Joseph Myers