commit 494d65129e
Author: Michael Jeanson <mjeanson@efficios.com>
Date: Thu Aug 1 10:35:34 2024 -0400
nptl: Introduce <rseq-access.h> for RSEQ_* accessors
added things like
asm volatile ("movl %%fs:%P1(%q2),%0" \
: "=r" (__value) \
: "i" (offsetof (struct rseq_area, member)), \
"r" (__rseq_offset)); \
But this doesn't work for x32 when __rseq_offset is negative since the
address is computed as
FS + 32-bit to 64-bit zero extension of __rseq_offset
+ offsetof (struct rseq_area, member)
Cast __rseq_offset to long long int
"r" ((long long int) __rseq_offset)); \
to sign-extend 32-bit __rseq_offset to 64-bit. This is a no-op for x86-64
since x86-64 __rseq_offset is 64-bit. This fixes BZ #32543.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
In preparation to move the rseq area to the 'extra TLS' block, we need
accessors based on the thread pointer and the rseq offset. The ONCE
variant of the accessors ensures single-copy atomicity for loads and
stores which is required for all fields once the registration is active.
A separate header is required to allow including <atomic.h> which
results in an include loop when added to <tcb-access.h>.
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
