Use __seg_gs named address space qualifiers in PTR_MANGLE() and
PTR_DEMANGLE() macros to access the pointer_guard field in the TCB.
This change allows the compiler to eliminate redundant reads of
the variable, reducing the number of reads from 105 to 94 and
decreasing the text size of the library by 280 bytes.
While at it, fix a few trivial whitespace issues as well
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
This allows us to define a generic no-op version of PTR_MANGLE and
PTR_DEMANGLE. In the future, we can use PTR_MANGLE and PTR_DEMANGLE
unconditionally in C sources, avoiding an unintended loss of hardening
due to missing include files or unlucky header inclusion ordering.
In i386 and x86_64, we can avoid a <tls.h> dependency in the C
code by using the computed constant from <tcb-offsets.h>. <sysdep.h>
no longer includes these definitions, so there is no cyclic dependency
anymore when computing the <tcb-offsets.h> constants.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
