Messages in this thread Patch in this message | | | Date | Tue, 29 Jan 2019 11:57:39 -0500 (EST) | From | Mathieu Desnoyers <> | Subject | Re: [RFC PATCH glibc 1/4] glibc: Perform rseq(2) registration at C startup and thread creation (v6) |
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----- On Jan 21, 2019, at 4:35 PM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote: [...]
> diff --git a/sysdeps/unix/sysv/linux/sys/rseq.h > b/sysdeps/unix/sysv/linux/sys/rseq.h > new file mode 100644 > index 0000000000..61937fb193 > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/sys/rseq.h > @@ -0,0 +1,64 @@ [...] > + > +#ifndef _SYS_RSEQ_H > +#define _SYS_RSEQ_H 1 > + > +/* We use the structures declarations from the kernel headers. */ > +#include <linux/rseq.h> > +#include <stdint.h> > + > +/* Signature required before each abort handler code. */ > +#define RSEQ_SIG 0x53053053
I recalled that aarch64 defines RSEQ_SIG to a different value which maps to a valid trap instruction. So I plan to move the RSEQ_SIG define to per-arch headers like this:
sysdeps/unix/sysv/linux/aarch64/bits/rseq.h | 24 ++ sysdeps/unix/sysv/linux/arm/bits/rseq.h | 24 ++ sysdeps/unix/sysv/linux/bits/rseq.h | 23 ++ sysdeps/unix/sysv/linux/mips/bits/rseq.h | 24 ++ sysdeps/unix/sysv/linux/powerpc/bits/rseq.h | 24 ++ sysdeps/unix/sysv/linux/s390/bits/rseq.h | 24 ++ sysdeps/unix/sysv/linux/x86/bits/rseq.h | 24 ++ where "bits/rseq.h" contains a #error:
# error "Architecture does not define RSEQ_SIG.
sys/rseq.h will now include <bits/rseq.h>.
> + > +enum rseq_register_state > +{ > + /* Value RSEQ_REGISTER_ALLOWED means it is allowed to update > + the refcount field and to register/unregister rseq. */ > + RSEQ_REGISTER_ALLOWED = 0, > + /* Value RSEQ_REGISTER_NESTED means it is temporarily forbidden > + to update the refcount field or to register/unregister rseq. */ > + RSEQ_REGISTER_NESTED = 1,
I plan to rename "RSEQ_REGISTER_NESTED" to "RSEQ_REGISTER_ONGOING" which seems to better represent the current registration state.
Please let me know if anything is wrong with those changes.
Thanks,
Mathieu
> + /* Value RSEQ_REGISTER_EXITING means it is forbidden to update the > + refcount field or to register/unregister rseq for the rest of the > + thread's lifetime. */ > + RSEQ_REGISTER_EXITING = 2, > +}; -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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