commit c901c3e764d7c7079f006b4e21e877d5036eb4f5

Author: Florian Weimer <fweimer@redhat.com>

Date:   Thu Dec 9 09:49:32 2021 +0100

    nptl: Add public rseq symbols and <sys/rseq.h>

    The relationship between the thread pointer and the rseq area

    is made explicit.  The constant offset can be used by JIT compilers

    to optimize rseq access (e.g., for really fast sched_getcpu).

    Extensibility is provided through __rseq_size and __rseq_flags.

    (In the future, the kernel could request a different rseq size

    via the auxiliary vector.)

    Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

    Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>

diff --git a/manual/threads.texi b/manual/threads.texi

index 06b6b277a1228af1..ab44a92ca0f5a6a5 100644

--- a/manual/threads.texi

+++ b/manual/threads.texi

@@ -629,6 +629,8 @@ the standard.

 * Waiting with Explicit Clocks::          Functions for waiting with an

                                           explicit clock specification.

 * Single-Threaded::                       Detecting single-threaded execution.

+* Restartable Sequences::                 Linux-specific restartable sequences

+                                          integration.

 @end menu

 @node Default Thread Attributes

@@ -958,6 +960,85 @@ application-created thread because future versions of @theglibc{} may

 create background threads after the first thread has been created, and

 the application has no way of knowning that these threads are present.

+@node Restartable Sequences

+@subsubsection Restartable Sequences

+

+This section describes restartable sequences integration for

+@theglibc{}.  This functionality is only available on Linux.

+

+@deftp {Data Type} {struct rseq}

+@standards{Linux, sys/rseq.h}

+The type of the restartable sequences area.  Future versions

+of Linux may add additional fields to the end of this structure.

+

+

+Users need to obtain the address of the restartable sequences area using

+the thread pointer and the @code{__rseq_offset} variable, described

+below.

+

+One use of the restartable sequences area is to read the current CPU

+number from its @code{cpu_id} field, as an inline version of

+@code{sched_getcpu}.  @Theglibc{} sets the @code{cpu_id} field to

+@code{RSEQ_CPU_ID_REGISTRATION_FAILED} if registration failed or was

+explicitly disabled.

+

+Furthermore, users can store the address of a @code{struct rseq_cs}

+object into the @code{rseq_cs} field of @code{struct rseq}, thus

+informing the kernel that the thread enters a restartable sequence

+critical section.  This pointer and the code areas it itself points to

+must not be left pointing to memory areas which are freed or re-used.

+Several approaches can guarantee this.  If the application or library

+can guarantee that the memory used to hold the @code{struct rseq_cs} and

+the code areas it refers to are never freed or re-used, no special

+action must be taken.  Else, before that memory is re-used of freed, the

+application is responsible for setting the @code{rseq_cs} field to

+@code{NULL} in each thread's restartable sequence area to guarantee that

+it does not leak dangling references.  Because the application does not

+typically have knowledge of libraries' use of restartable sequences, it

+is recommended that libraries using restartable sequences which may end

+up freeing or re-using their memory set the @code{rseq_cs} field to

+@code{NULL} before returning from library functions which use

+restartable sequences.

+

+The manual for the @code{rseq} system call can be found

+at @uref{https://git.kernel.org/pub/scm/libs/librseq/librseq.git/tree/doc/man/rseq.2}.

+@end deftp

+

+@deftypevar {int} __rseq_offset

+@standards{Linux, sys/rseq.h}

+This variable contains the offset between the thread pointer (as defined

+by @code{__builtin_thread_pointer} or the thread pointer register for

+the architecture) and the restartable sequences area.  This value is the

+same for all threads in the process.  If the restartable sequences area

+is located at a lower address than the location to which the thread

+pointer points, the value is negative.

+@end deftypevar

+

+@deftypevar {unsigned int} __rseq_size

+@standards{Linux, sys/rseq.h}

+This variable is either zero (if restartable sequence registration

+failed or has been disabled) or the size of the restartable sequence

+registration.  This can be different from the size of @code{struct rseq}

+if the kernel has extended the size of the registration.  If

+registration is successful, @code{__rseq_size} is at least 32 (the

+initial size of @code{struct rseq}).

+@end deftypevar

+

+@deftypevar {unsigned int} __rseq_flags

+@standards{Linux, sys/rseq.h}

+The flags used during restartable sequence registration with the kernel.

+Currently zero.

+@end deftypevar

+

+@deftypevr Macro int RSEQ_SIG

+@standards{Linux, sys/rseq.h}

+Each supported architecture provides a @code{RSEQ_SIG} macro in

+@file{sys/rseq.h} which contains a signature.  That signature is

+expected to be present in the code before each restartable sequences

+abort handler.  Failure to provide the expected signature may terminate

+the process with a segmentation fault.

+@end deftypevr

+

 @c FIXME these are undocumented:

 @c pthread_atfork

 @c pthread_attr_destroy

diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c

index b39dfbff2c6678d5..4a73927f805abf94 100644

--- a/sysdeps/nptl/dl-tls_init_tp.c

+++ b/sysdeps/nptl/dl-tls_init_tp.c

@@ -22,6 +22,7 @@

 #include <pthreadP.h>

 #include <tls.h>

 #include <rseq-internal.h>

+#include <thread_pointer.h>

 #define TUNABLE_NAMESPACE pthread

 #include <dl-tunables.h>

@@ -43,6 +44,10 @@ rtld_mutex_dummy (pthread_mutex_t *lock)

 }

 #endif

+const unsigned int __rseq_flags;

+const unsigned int __rseq_size attribute_relro;

+const int __rseq_offset attribute_relro;

+

 void

 __tls_pre_init_tp (void)

 {

@@ -100,7 +105,23 @@ __tls_init_tp (void)

 #if HAVE_TUNABLES

     do_rseq = TUNABLE_GET (rseq, int, NULL);

 #endif

-    rseq_register_current_thread (pd, do_rseq);

+    if (rseq_register_current_thread (pd, do_rseq))

+      {

+        /* We need a writable view of the variables.  They are in

+           .data.relro and are not yet write-protected.  */

+        extern unsigned int size __asm__ ("__rseq_size");

+        size = sizeof (pd->rseq_area);

+      }

+

+#ifdef RSEQ_SIG

+    /* This should be a compile-time constant, but the current

+       infrastructure makes it difficult to determine its value.  Not

+       all targets support __thread_pointer, so set __rseq_offset only

+       if thre rseq registration may have happened because RSEQ_SIG is

+       defined.  */

+    extern int offset __asm__ ("__rseq_offset");

+    offset = (char *) &pd->rseq_area - (char *) __thread_pointer ();

+#endif

   }

   /* Set initial thread's stack block from 0 up to __libc_stack_end.

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile

index 0657f4003e7116c6..856a9d58cef6a879 100644

--- a/sysdeps/unix/sysv/linux/Makefile

+++ b/sysdeps/unix/sysv/linux/Makefile

@@ -110,7 +110,8 @@ sysdep_headers += sys/mount.h sys/acct.h \

 		  bits/types/struct_semid64_ds_helper.h \

 		  bits/types/struct_shmid64_ds.h \

 		  bits/types/struct_shmid64_ds_helper.h \

-		  bits/pthread_stack_min.h bits/pthread_stack_min-dynamic.h

+		  bits/pthread_stack_min.h bits/pthread_stack_min-dynamic.h \

+		  sys/rseq.h bits/rseq.h

 tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \

 	 tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \

diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions

index 26452f3f17b5421d..3f8809a1581f27d0 100644

--- a/sysdeps/unix/sysv/linux/Versions

+++ b/sysdeps/unix/sysv/linux/Versions

@@ -316,6 +316,11 @@ librt {

 }

 ld {

+  GLIBC_2.35 {

+    __rseq_flags;

+    __rseq_offset;

+    __rseq_size;

+  }

   GLIBC_PRIVATE {

     __nptl_change_stack_perm;

   }

diff --git a/sysdeps/unix/sysv/linux/aarch64/ld.abilist b/sysdeps/unix/sysv/linux/aarch64/ld.abilist

index b7196a80e2df8efc..bf4d4f9b6f2ddf97 100644

--- a/sysdeps/unix/sysv/linux/aarch64/ld.abilist

+++ b/sysdeps/unix/sysv/linux/aarch64/ld.abilist

@@ -4,3 +4,6 @@ GLIBC_2.17 __tls_get_addr F

 GLIBC_2.17 _dl_mcount F

 GLIBC_2.17 _r_debug D 0x28

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/alpha/ld.abilist b/sysdeps/unix/sysv/linux/alpha/ld.abilist

index 13f7fc74af62941d..a23325a566419b41 100644

--- a/sysdeps/unix/sysv/linux/alpha/ld.abilist

+++ b/sysdeps/unix/sysv/linux/alpha/ld.abilist

@@ -3,4 +3,7 @@ GLIBC_2.1 __libc_stack_end D 0x8

 GLIBC_2.1 _dl_mcount F

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x8

diff --git a/sysdeps/unix/sysv/linux/arc/ld.abilist b/sysdeps/unix/sysv/linux/arc/ld.abilist

index 7284383a6bea8e64..55f0c2ab9c6f7d91 100644

--- a/sysdeps/unix/sysv/linux/arc/ld.abilist

+++ b/sysdeps/unix/sysv/linux/arc/ld.abilist

@@ -4,3 +4,6 @@ GLIBC_2.32 __tls_get_addr F

 GLIBC_2.32 _dl_mcount F

 GLIBC_2.32 _r_debug D 0x14

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/arm/be/ld.abilist b/sysdeps/unix/sysv/linux/arm/be/ld.abilist

index 7987bbae1112aa3d..f1da2c636ddb359d 100644

--- a/sysdeps/unix/sysv/linux/arm/be/ld.abilist

+++ b/sysdeps/unix/sysv/linux/arm/be/ld.abilist

@@ -1,4 +1,7 @@

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __libc_stack_end D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x4

 GLIBC_2.4 __tls_get_addr F

diff --git a/sysdeps/unix/sysv/linux/arm/le/ld.abilist b/sysdeps/unix/sysv/linux/arm/le/ld.abilist

index 7987bbae1112aa3d..f1da2c636ddb359d 100644

--- a/sysdeps/unix/sysv/linux/arm/le/ld.abilist

+++ b/sysdeps/unix/sysv/linux/arm/le/ld.abilist

@@ -1,4 +1,7 @@

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __libc_stack_end D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x4

 GLIBC_2.4 __tls_get_addr F

diff --git a/sysdeps/unix/sysv/linux/csky/ld.abilist b/sysdeps/unix/sysv/linux/csky/ld.abilist

index 4939b20631dc6c54..7f482276ed8df1d5 100644

--- a/sysdeps/unix/sysv/linux/csky/ld.abilist

+++ b/sysdeps/unix/sysv/linux/csky/ld.abilist

@@ -4,3 +4,6 @@ GLIBC_2.29 __tls_get_addr F

 GLIBC_2.29 _dl_mcount F

 GLIBC_2.29 _r_debug D 0x14

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/hppa/ld.abilist b/sysdeps/unix/sysv/linux/hppa/ld.abilist

index 7cc9ebd792c2aadc..7f5527fb301b913c 100644

--- a/sysdeps/unix/sysv/linux/hppa/ld.abilist

+++ b/sysdeps/unix/sysv/linux/hppa/ld.abilist

@@ -3,4 +3,7 @@ GLIBC_2.2 _dl_mcount F

 GLIBC_2.2 _r_debug D 0x14

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x4

diff --git a/sysdeps/unix/sysv/linux/i386/ld.abilist b/sysdeps/unix/sysv/linux/i386/ld.abilist

index e8d187b14d722a64..9c4a45d8dc525e52 100644

--- a/sysdeps/unix/sysv/linux/i386/ld.abilist

+++ b/sysdeps/unix/sysv/linux/i386/ld.abilist

@@ -4,3 +4,6 @@ GLIBC_2.1 _dl_mcount F

 GLIBC_2.3 ___tls_get_addr F

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/ia64/ld.abilist b/sysdeps/unix/sysv/linux/ia64/ld.abilist

index be5122650ae2b327..8ccb5be911e0e9a2 100644

--- a/sysdeps/unix/sysv/linux/ia64/ld.abilist

+++ b/sysdeps/unix/sysv/linux/ia64/ld.abilist

@@ -3,3 +3,6 @@ GLIBC_2.2 _dl_mcount F

 GLIBC_2.2 _r_debug D 0x28

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/ld.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/ld.abilist

index 7987bbae1112aa3d..f1da2c636ddb359d 100644

--- a/sysdeps/unix/sysv/linux/m68k/coldfire/ld.abilist

+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/ld.abilist

@@ -1,4 +1,7 @@

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __libc_stack_end D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x4

 GLIBC_2.4 __tls_get_addr F

diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/ld.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/ld.abilist

index 4f2854edf7746958..dadbf852d0522e77 100644

--- a/sysdeps/unix/sysv/linux/m68k/m680x0/ld.abilist

+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/ld.abilist

@@ -3,4 +3,7 @@ GLIBC_2.1 __libc_stack_end D 0x4

 GLIBC_2.1 _dl_mcount F

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x4

diff --git a/sysdeps/unix/sysv/linux/microblaze/ld.abilist b/sysdeps/unix/sysv/linux/microblaze/ld.abilist

index 9f0fdeca38890a34..89a0b7e4fd5a95fa 100644

--- a/sysdeps/unix/sysv/linux/microblaze/ld.abilist

+++ b/sysdeps/unix/sysv/linux/microblaze/ld.abilist

@@ -4,3 +4,6 @@ GLIBC_2.18 __tls_get_addr F

 GLIBC_2.18 _dl_mcount F

 GLIBC_2.18 _r_debug D 0x14

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/mips/mips32/ld.abilist b/sysdeps/unix/sysv/linux/mips/mips32/ld.abilist

index f750067d5c34bf42..e304d1bb464b28f4 100644

--- a/sysdeps/unix/sysv/linux/mips/mips32/ld.abilist

+++ b/sysdeps/unix/sysv/linux/mips/mips32/ld.abilist

@@ -3,4 +3,7 @@ GLIBC_2.2 __libc_stack_end D 0x4

 GLIBC_2.2 _dl_mcount F

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x4

diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/ld.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/ld.abilist

index f750067d5c34bf42..e304d1bb464b28f4 100644

--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/ld.abilist

+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/ld.abilist

@@ -3,4 +3,7 @@ GLIBC_2.2 __libc_stack_end D 0x4

 GLIBC_2.2 _dl_mcount F

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x4

diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/ld.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/ld.abilist

index 2fba6a9b6ec92e47..37a47ebc0a0d16c8 100644

--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/ld.abilist

+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/ld.abilist

@@ -3,4 +3,7 @@ GLIBC_2.2 __libc_stack_end D 0x8

 GLIBC_2.2 _dl_mcount F

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x8

diff --git a/sysdeps/unix/sysv/linux/nios2/ld.abilist b/sysdeps/unix/sysv/linux/nios2/ld.abilist

index 57dfad5a53b739e8..811ae9da2fa85399 100644

--- a/sysdeps/unix/sysv/linux/nios2/ld.abilist

+++ b/sysdeps/unix/sysv/linux/nios2/ld.abilist

@@ -4,3 +4,6 @@ GLIBC_2.21 __tls_get_addr F

 GLIBC_2.21 _dl_mcount F

 GLIBC_2.21 _r_debug D 0x14

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist

index e89660739262c6ab..5a68aeb9eed33844 100644

--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist

+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist

@@ -5,3 +5,6 @@ GLIBC_2.22 __tls_get_addr_opt F

 GLIBC_2.23 __parse_hwcap_and_convert_at_platform F

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/ld.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/ld.abilist

index ce0bc639597c4bd9..da24dc7fb52ad2d4 100644

--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/ld.abilist

+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/ld.abilist

@@ -5,3 +5,6 @@ GLIBC_2.3 __tls_get_addr F

 GLIBC_2.3 _dl_mcount F

 GLIBC_2.3 _r_debug D 0x28

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/ld.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/ld.abilist

index 65b22674d2462e96..b9ae89ae8d90ed9e 100644

--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/ld.abilist

+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/ld.abilist

@@ -5,3 +5,6 @@ GLIBC_2.17 _r_debug D 0x28

 GLIBC_2.22 __tls_get_addr_opt F

 GLIBC_2.23 __parse_hwcap_and_convert_at_platform F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/riscv/rv32/ld.abilist b/sysdeps/unix/sysv/linux/riscv/rv32/ld.abilist

index 5ad4c81d12d7a612..068368878eb2406e 100644

--- a/sysdeps/unix/sysv/linux/riscv/rv32/ld.abilist

+++ b/sysdeps/unix/sysv/linux/riscv/rv32/ld.abilist

@@ -4,3 +4,6 @@ GLIBC_2.33 __tls_get_addr F

 GLIBC_2.33 _dl_mcount F

 GLIBC_2.33 _r_debug D 0x14

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/ld.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/ld.abilist

index 479efdea9bb654bb..48431c91a9fd16b0 100644

--- a/sysdeps/unix/sysv/linux/riscv/rv64/ld.abilist

+++ b/sysdeps/unix/sysv/linux/riscv/rv64/ld.abilist

@@ -4,3 +4,6 @@ GLIBC_2.27 __tls_get_addr F

 GLIBC_2.27 _dl_mcount F

 GLIBC_2.27 _r_debug D 0x28

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/rseq-internal.h b/sysdeps/unix/sysv/linux/rseq-internal.h

index 6a3441f2cc49e7c4..9e8f99fd51a063b1 100644

--- a/sysdeps/unix/sysv/linux/rseq-internal.h

+++ b/sysdeps/unix/sysv/linux/rseq-internal.h

@@ -41,7 +41,7 @@ rseq_register_current_thread (struct pthread *self, bool do_rseq)

   return false;

 }

 #else /* RSEQ_SIG */

-static inline void

+static inline bool

 rseq_register_current_thread (struct pthread *self, bool do_rseq)

 {

   THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED);

diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/ld.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/ld.abilist

index d5ecb636bb792bdf..c15288394a232a8c 100644

--- a/sysdeps/unix/sysv/linux/s390/s390-32/ld.abilist

+++ b/sysdeps/unix/sysv/linux/s390/s390-32/ld.abilist

@@ -3,3 +3,6 @@ GLIBC_2.1 __libc_stack_end D 0x4

 GLIBC_2.1 _dl_mcount F

 GLIBC_2.3 __tls_get_offset F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/ld.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/ld.abilist

index 62a5e1d99a2e6f42..117d1430a4c6272e 100644

--- a/sysdeps/unix/sysv/linux/s390/s390-64/ld.abilist

+++ b/sysdeps/unix/sysv/linux/s390/s390-64/ld.abilist

@@ -3,3 +3,6 @@ GLIBC_2.2 _dl_mcount F

 GLIBC_2.2 _r_debug D 0x28

 GLIBC_2.3 __tls_get_offset F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/sh/be/ld.abilist b/sysdeps/unix/sysv/linux/sh/be/ld.abilist

index 7cc9ebd792c2aadc..7f5527fb301b913c 100644

--- a/sysdeps/unix/sysv/linux/sh/be/ld.abilist

+++ b/sysdeps/unix/sysv/linux/sh/be/ld.abilist

@@ -3,4 +3,7 @@ GLIBC_2.2 _dl_mcount F

 GLIBC_2.2 _r_debug D 0x14

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x4

diff --git a/sysdeps/unix/sysv/linux/sh/le/ld.abilist b/sysdeps/unix/sysv/linux/sh/le/ld.abilist

index 7cc9ebd792c2aadc..7f5527fb301b913c 100644

--- a/sysdeps/unix/sysv/linux/sh/le/ld.abilist

+++ b/sysdeps/unix/sysv/linux/sh/le/ld.abilist

@@ -3,4 +3,7 @@ GLIBC_2.2 _dl_mcount F

 GLIBC_2.2 _r_debug D 0x14

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

 GLIBC_2.4 __stack_chk_guard D 0x4

diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/ld.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/ld.abilist

index 2e6054349871e7d5..3aac73f3df646cb6 100644

--- a/sysdeps/unix/sysv/linux/sparc/sparc32/ld.abilist

+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/ld.abilist

@@ -3,3 +3,6 @@ GLIBC_2.1 __libc_stack_end D 0x4

 GLIBC_2.1 _dl_mcount F

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/ld.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/ld.abilist

index be5122650ae2b327..8ccb5be911e0e9a2 100644

--- a/sysdeps/unix/sysv/linux/sparc/sparc64/ld.abilist

+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/ld.abilist

@@ -3,3 +3,6 @@ GLIBC_2.2 _dl_mcount F

 GLIBC_2.2 _r_debug D 0x28

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/sys/rseq.h b/sysdeps/unix/sysv/linux/sys/rseq.h

index c8edff50d40e29b6..1215b5d086b8852b 100644

--- a/sysdeps/unix/sysv/linux/sys/rseq.h

+++ b/sysdeps/unix/sysv/linux/sys/rseq.h

@@ -171,4 +171,14 @@ struct rseq

 #endif /* __GLIBC_HAVE_KERNEL_RSEQ */

+/* Offset from the thread pointer to the rseq area.  */

+extern const int __rseq_offset;

+

+/* Size of the registered rseq area.  0 if the registration was

+   unsuccessful.  */

+extern const unsigned int __rseq_size;

+

+/* Flags used during rseq registration.  */

+extern const unsigned int __rseq_flags;

+

 #endif /* sys/rseq.h */

diff --git a/sysdeps/unix/sysv/linux/tst-rseq-disable.c b/sysdeps/unix/sysv/linux/tst-rseq-disable.c

index 000e351872fc2f76..6d73f77e9621da42 100644

--- a/sysdeps/unix/sysv/linux/tst-rseq-disable.c

+++ b/sysdeps/unix/sysv/linux/tst-rseq-disable.c

@@ -21,6 +21,7 @@

 #include <support/namespace.h>

 #include <support/xthread.h>

 #include <sysdep.h>

+#include <thread_pointer.h>

 #include <unistd.h>

 #ifdef RSEQ_SIG

@@ -30,6 +31,11 @@ static void

 check_rseq_disabled (void)

 {

   struct pthread *pd = THREAD_SELF;

+

+  TEST_COMPARE (__rseq_flags, 0);

+  TEST_VERIFY ((char *) __thread_pointer () + __rseq_offset

+               == (char *) &pd->rseq_area);

+  TEST_COMPARE (__rseq_size, 0);

   TEST_COMPARE ((int) pd->rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED);

   int ret = syscall (__NR_rseq, &pd->rseq_area, sizeof (pd->rseq_area),

diff --git a/sysdeps/unix/sysv/linux/tst-rseq.c b/sysdeps/unix/sysv/linux/tst-rseq.c

index 926376b6a5446ece..572c11166f8b6533 100644

--- a/sysdeps/unix/sysv/linux/tst-rseq.c

+++ b/sysdeps/unix/sysv/linux/tst-rseq.c

@@ -29,12 +29,20 @@

 # include <stdlib.h>

 # include <string.h>

 # include <syscall.h>

+# include <thread_pointer.h>

+# include <tls.h>

 # include "tst-rseq.h"

 static void

 do_rseq_main_test (void)

 {

+  struct pthread *pd = THREAD_SELF;

+

   TEST_VERIFY_EXIT (rseq_thread_registered ());

+  TEST_COMPARE (__rseq_flags, 0);

+  TEST_VERIFY ((char *) __thread_pointer () + __rseq_offset

+               == (char *) &pd->rseq_area);

+  TEST_COMPARE (__rseq_size, sizeof (pd->rseq_area));

 }

 static void

diff --git a/sysdeps/unix/sysv/linux/x86_64/64/ld.abilist b/sysdeps/unix/sysv/linux/x86_64/64/ld.abilist

index afddaec57c11f837..ae622bdf9710bdbd 100644

--- a/sysdeps/unix/sysv/linux/x86_64/64/ld.abilist

+++ b/sysdeps/unix/sysv/linux/x86_64/64/ld.abilist

@@ -3,3 +3,6 @@ GLIBC_2.2.5 _dl_mcount F

 GLIBC_2.2.5 _r_debug D 0x28

 GLIBC_2.3 __tls_get_addr F

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4

diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/ld.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/ld.abilist

index defc488d137c61c3..e17496d124b0c7b7 100644

--- a/sysdeps/unix/sysv/linux/x86_64/x32/ld.abilist

+++ b/sysdeps/unix/sysv/linux/x86_64/x32/ld.abilist

@@ -3,3 +3,6 @@ GLIBC_2.16 __tls_get_addr F

 GLIBC_2.16 _dl_mcount F

 GLIBC_2.16 _r_debug D 0x14

 GLIBC_2.34 __rtld_version_placeholder F

+GLIBC_2.35 __rseq_flags D 0x4

+GLIBC_2.35 __rseq_offset D 0x4

+GLIBC_2.35 __rseq_size D 0x4