[OpenRISC] [PATCH v3 09/13] or1k: Linux ABI

Adhemerval Zanella
2021-12-21T13:41:17Z

Some comments below.

On 10/12/2021 20:34, Stafford Horne via Libc-alpha wrote:
> ---
> sysdeps/or1k/nptl/bits/pthreadtypes-arch.h | 48 ++++++++
> sysdeps/or1k/nptl/pthreaddef.h | 36 ++++++
> sysdeps/unix/sysv/linux/or1k/bits/procfs.h | 38 ++++++
> sysdeps/unix/sysv/linux/or1k/getcontext.S | 72 +++++++++++
> sysdeps/unix/sysv/linux/or1k/makecontext.c | 77 ++++++++++++
> sysdeps/unix/sysv/linux/or1k/setcontext.S | 108 ++++++++++++++++
> sysdeps/unix/sysv/linux/or1k/sigcontextinfo.h | 28 +++++
> sysdeps/unix/sysv/linux/or1k/swapcontext.S | 116 ++++++++++++++++++
> sysdeps/unix/sysv/linux/or1k/sys/ucontext.h | 53 ++++++++
> sysdeps/unix/sysv/linux/or1k/sys/user.h | 1 +
> sysdeps/unix/sysv/linux/or1k/ucontext_i.sym | 26 ++++
> 11 files changed, 603 insertions(+)
> create mode 100644 sysdeps/or1k/nptl/bits/pthreadtypes-arch.h
> create mode 100644 sysdeps/or1k/nptl/pthreaddef.h
> create mode 100644 sysdeps/unix/sysv/linux/or1k/bits/procfs.h
> create mode 100644 sysdeps/unix/sysv/linux/or1k/getcontext.S
> create mode 100644 sysdeps/unix/sysv/linux/or1k/makecontext.c
> create mode 100644 sysdeps/unix/sysv/linux/or1k/setcontext.S
> create mode 100644 sysdeps/unix/sysv/linux/or1k/sigcontextinfo.h
> create mode 100644 sysdeps/unix/sysv/linux/or1k/swapcontext.S
> create mode 100644 sysdeps/unix/sysv/linux/or1k/sys/ucontext.h
> create mode 100644 sysdeps/unix/sysv/linux/or1k/sys/user.h
> create mode 100644 sysdeps/unix/sysv/linux/or1k/ucontext_i.sym
>
> diff --git a/sysdeps/or1k/nptl/bits/pthreadtypes-arch.h b/sysdeps/or1k/nptl/bits/pthreadtypes-arch.h
> new file mode 100644
> index 0000000000..56a62a7161
> --- /dev/null
> +++ b/sysdeps/or1k/nptl/bits/pthreadtypes-arch.h
> @@ -0,0 +1,48 @@
> +/* Machine-specific pthread type layouts. OpenRISC version.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#ifndef _BITS_PTHREADTYPES_H
> +#define _BITS_PTHREADTYPES_H 1
> +
> +#include <bits/wordsize.h>
> +
> +/* Opaque union sizes for:
> + pthread_attr_t - internally pthread_attr
> + pthread_mutex_t - internally __pthread_mutex_s
> + pthread_mutexattr_t - internally pthread_mutexattr
> + pthread_cond_t - internally __pthread_cond_s
> + pthread_condattr_t - internally pthread_condattr
> + pthread_rwlock_t - internally __pthread_rwlock_arch_t
> + pthread_rwlockattr_t - internally pthread_rwlockattr
> + pthread_barrier_t - internally pthread_barrier
> + pthread_barrierattr_t - internally pthread_barrierattr */
> +
> +#define __SIZEOF_PTHREAD_ATTR_T 32
> +#define __SIZEOF_PTHREAD_MUTEX_T 32
> +#define __SIZEOF_PTHREAD_MUTEXATTR_T 4
> +#define __SIZEOF_PTHREAD_COND_T 48
> +#define __SIZEOF_PTHREAD_CONDATTR_T 4
> +#define __SIZEOF_PTHREAD_RWLOCK_T 44
> +#define __SIZEOF_PTHREAD_RWLOCKATTR_T 8
> +#define __SIZEOF_PTHREAD_BARRIER_T 20
> +#define __SIZEOF_PTHREAD_BARRIERATTR_T 4
> +
> +#define __LOCK_ALIGNMENT
> +#define __ONCE_ALIGNMENT
> +
> +#endif /* bits/pthreadtypes.h */

Why can't use the default values on sysdeps/nptl/bits/pthreadtypes-arch.h ?

> diff --git a/sysdeps/or1k/nptl/pthreaddef.h b/sysdeps/or1k/nptl/pthreaddef.h
> new file mode 100644
> index 0000000000..d17918ea11
> --- /dev/null
> +++ b/sysdeps/or1k/nptl/pthreaddef.h
> @@ -0,0 +1,36 @@
> +/* pthread machine parameter definitions. OpenRISC version.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> +
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public License as
> + published by the Free Software Foundation; either version 2.1 of the
> + License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +/* Default stack size. */
> +#define ARCH_STACK_DEFAULT_SIZE (2 * 1024 * 1024)
> +
> +/* Minimum guard size. */
> +#define ARCH_MIN_GUARD_SIZE 0
> +
> +/* Required stack pointer alignment at beginning. */
> +#define STACK_ALIGN 16
> +
> +/* Minimal stack size after allocating thread descriptor and guard size. */
> +#define MINIMAL_REST_STACK 2048
> +
> +/* Alignment requirement for TCB. Needs to be >= to STACK_ALIGN. */
> +#define TCB_ALIGNMENT 32
> +
> +/* Location of current stack frame. */
> +#define CURRENT_STACK_FRAME __builtin_frame_address (0)

Ok. As a side note, maybe we could provide a default header with this exact
definitions.

> diff --git a/sysdeps/unix/sysv/linux/or1k/bits/procfs.h b/sysdeps/unix/sysv/linux/or1k/bits/procfs.h
> new file mode 100644
> index 0000000000..b50c92efb1
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/or1k/bits/procfs.h
> @@ -0,0 +1,38 @@
> +/* Types for registers for sys/procfs.h. OpenRISC version.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#ifndef _SYS_PROCFS_H
> +# error "Never include <bits/procfs.h> directly; use <sys/procfs.h> instead."
> +#endif
> +
> +#include <sys/ucontext.h>
> +
> +#define ELF_NGREG __NGREG
> +
> +/* Type for a general-purpose register. */
> +typedef unsigned long int elf_greg_t;
> +
> +/* And the array of general-purpose registers. We could have used `struct
> + user_regs' directly, but tradition says that the register set is an array,
> + which does have some peculiar semantics, so leave it that way.
> + GDB uses this for prtrace GETREGSET, on OpenRISC the regset contains 32
> + gprs the PC and the SR, 34 longs. */
> +typedef elf_greg_t elf_gregset_t[34];
> +
> +/* Register set for the floating-point registers. */
> +typedef elf_greg_t elf_fpregset_t[32];

It indicates that that or1k would only support float32, is that correct?

> diff --git a/sysdeps/unix/sysv/linux/or1k/getcontext.S b/sysdeps/unix/sysv/linux/or1k/getcontext.S
> new file mode 100644
> index 0000000000..4c2e64db7a
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/or1k/getcontext.S
> @@ -0,0 +1,72 @@
> +/* Save current context. OpenRISC version.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <sysdep.h>
> +#include "ucontext_i.h"
> +
> +/* int getcontext (ucontext_t *ucp)
> +
> + Returns 0 on success -1 and errno on failure.
> + */
> + .text
> +ENTRY(__getcontext)
> + /* Store r1, the stack pointer. */
> + l.sw (UCONTEXT_MCONTEXT + 1*4)(r3), r1
> + /* Store r2, the frame pointer. */
> + l.sw (UCONTEXT_MCONTEXT + 2*4)(r3), r2
> + /* Store r9, the link register. */
> + l.sw (UCONTEXT_MCONTEXT + 9*4)(r3), r9
> + /* Store r9 to reg[11] too, as we need two links for makecontext. */
> + l.sw (UCONTEXT_MCONTEXT + 11*4)(r3), r9
> + /* Store r10, the TLS register. */
> + l.sw (UCONTEXT_MCONTEXT + 10*4)(r3), r10
> + /* Store r14-r30 even, callee saved registers. */
> + l.sw (UCONTEXT_MCONTEXT + 14*4)(r3), r14
> + l.sw (UCONTEXT_MCONTEXT + 16*4)(r3), r16
> + l.sw (UCONTEXT_MCONTEXT + 18*4)(r3), r18
> + l.sw (UCONTEXT_MCONTEXT + 20*4)(r3), r20
> + l.sw (UCONTEXT_MCONTEXT + 22*4)(r3), r22
> + l.sw (UCONTEXT_MCONTEXT + 24*4)(r3), r24
> + l.sw (UCONTEXT_MCONTEXT + 26*4)(r3), r26
> + l.sw (UCONTEXT_MCONTEXT + 28*4)(r3), r28
> + l.sw (UCONTEXT_MCONTEXT + 30*4)(r3), r30
> +
> + /* Get signal mask. */
> + /* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */
> + l.ori r6, r0, _NSIG8
> + l.addi r5, r3, UCONTEXT_SIGMASK
> + l.ori r4, r0, 0
> + l.ori r3, r0, SIG_BLOCK
> + l.ori r11, r0, SYS_ify (rt_sigprocmask)
> + /* Do the syscall. */
> + l.sys 1
> + l.nop
> +
> + /* if -4096 < ret < 0 holds, it's an error */
> + l.sfgeui r11, 0xf001
> + l.bf 1f
> + l.nop
> +
> + l.jr r9
> + l.ori r11, r0, 0
> +
> +1: l.j __syscall_error
> + l.ori r3, r11, 0
> +
> +END(__getcontext)
> +weak_alias(__getcontext, getcontext)
> diff --git a/sysdeps/unix/sysv/linux/or1k/makecontext.c b/sysdeps/unix/sysv/linux/or1k/makecontext.c
> new file mode 100644
> index 0000000000..3dd4134a6b
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/or1k/makecontext.c
> @@ -0,0 +1,77 @@
> +/* Create new context. OpenRISC version.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <sysdep.h>
> +#include <stdarg.h>
> +#include <stdint.h>
> +#include <ucontext.h>
> +
> +/* makecontext sets up a stack and the registers for the
> + user context. The stack looks like this:
> +
> + +-----------------------+
> + | padding as required |
> + +-----------------------+
> + sp -> | parameters 7 to n |
> + +-----------------------+
> +
> + The registers are set up like this:
> + r3-r8 : parameters 1 to 6
> + r14 : uc_link
> + r1 : stack pointer
> + r2 : frame pointer, set to NULL
> +*/
> +void
> +__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
> +{
> + extern void __startcontext (void);
> + unsigned long int *sp;
> + va_list ap;
> + int i;
> +
> + sp = (unsigned long int *)
> + ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
> +
> + /* Allocate stack arguments. */
> + sp -= argc < 6 ? 0 : argc - 6;
> +
> + /* Keep the stack aligned. */
> + sp = (unsigned long int *) (((uintptr_t) sp) & -4L);

Is stack required to be 4 or 16 (STACK_ALIGN from pthreaddef.h)?

> +
> + /* Keep uc_link in r14. */
> + ucp->uc_mcontext.__gprs[14] = (uintptr_t) ucp->uc_link;
> + /* Return address points to function __startcontext. */
> + ucp->uc_mcontext.__gprs[9] = (uintptr_t) &__startcontext;
> + /* Frame pointer is null. */
> + ucp->uc_mcontext.__gprs[2] = (uintptr_t) 0;
> + /* Restart in user-space starting at 'func'. */
> + ucp->uc_mcontext.__gprs[11] = (uintptr_t) func;
> + /* Set stack pointer. */
> + ucp->uc_mcontext.__gprs[1] = (uintptr_t) sp;
> +
> + va_start (ap, argc);
> + for (i = 0; i < argc; ++i)
> + if (i < 6)
> + ucp->uc_mcontext.__gprs[i + 3] = va_arg (ap, unsigned long int);
> + else
> + sp[i - 6] = va_arg (ap, unsigned long int);
> +
> + va_end (ap);
> +}
> +
> +weak_alias (__makecontext, makecontext)
> diff --git a/sysdeps/unix/sysv/linux/or1k/setcontext.S b/sysdeps/unix/sysv/linux/or1k/setcontext.S
> new file mode 100644
> index 0000000000..b4808d5422
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/or1k/setcontext.S
> @@ -0,0 +1,108 @@
> +/* Set current context. OpenRISC version.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <sysdep.h>
> +#include "ucontext_i.h"
> +
> +/* int setcontext (const ucontext_t *ucp) */
> + .text
> +ENTRY(__setcontext)
> + l.ori r30, r3, 0
> +
> + /* Restore signal mask. */
> + /* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, NULL, _NSIG8) */
> + l.ori r6, r0, _NSIG8
> + l.ori r5, r0, 0
> + l.addi r4, r3, UCONTEXT_SIGMASK
> + l.ori r3, r0, SIG_SETMASK
> + l.ori r11, r0, SYS_ify (rt_sigprocmask)
> + /* Do the syscall. */
> + l.sys 1
> + l.nop
> +
> + /* if -4096 < ret < 0 holds, it's an error */
> + l.sfgeui r11, 0xf001
> + l.bf 1f
> + l.nop
> +
> + /* Restore argument registers, for the makecontext case. */
> + l.lwz r3, (UCONTEXT_MCONTEXT + 3*4)(r30)
> + l.lwz r4, (UCONTEXT_MCONTEXT + 4*4)(r30)
> + l.lwz r5, (UCONTEXT_MCONTEXT + 5*4)(r30)
> + l.lwz r6, (UCONTEXT_MCONTEXT + 6*4)(r30)
> + l.lwz r7, (UCONTEXT_MCONTEXT + 7*4)(r30)
> + l.lwz r8, (UCONTEXT_MCONTEXT + 8*4)(r30)
> +
> + /* Restore registers stored in getcontext. */
> + l.lwz r1, (UCONTEXT_MCONTEXT + 1*4)(r30)
> + l.lwz r2, (UCONTEXT_MCONTEXT + 2*4)(r30)
> + l.lwz r9, (UCONTEXT_MCONTEXT + 9*4)(r30)
> + l.lwz r10, (UCONTEXT_MCONTEXT + 10*4)(r30)
> + l.lwz r11, (UCONTEXT_MCONTEXT + 11*4)(r30)
> + /* Restore r14-r30 even, callee saved registers. */
> + l.lwz r14, (UCONTEXT_MCONTEXT + 14*4)(r30)
> + l.lwz r16, (UCONTEXT_MCONTEXT + 16*4)(r30)
> + l.lwz r18, (UCONTEXT_MCONTEXT + 18*4)(r30)
> + l.lwz r20, (UCONTEXT_MCONTEXT + 20*4)(r30)
> + l.lwz r22, (UCONTEXT_MCONTEXT + 22*4)(r30)
> + l.lwz r24, (UCONTEXT_MCONTEXT + 24*4)(r30)
> + l.lwz r26, (UCONTEXT_MCONTEXT + 26*4)(r30)
> + l.lwz r28, (UCONTEXT_MCONTEXT + 28*4)(r30)
> + l.lwz r30, (UCONTEXT_MCONTEXT + 30*4)(r30)
> +
> + l.jr r11
> + l.ori r11, r0, 0
> +
> +1: l.j __syscall_error
> + l.ori r3, r11, 0
> +
> +END (__setcontext)
> +weak_alias (__setcontext, setcontext)
> +
> + /* We add a NOP here because when the unwinder is looking for the
> + enclosing function of the link register (r9) address FDE lookup will
> + use '$r9 - 1' finding setcontext which is wrong. This is because in
> + makecontext we have set r9 to the start of &__startcontext.
> +
> + If this NOP did not exist the unwinder would repeatedly find
> + __setcontext's FDE in an infinite loop. Modifiying/deleting the below
> + __startcontext's FDE has no help on this. */
> + l.nop
> +
> +ENTRY(__startcontext)
> +
> + l.ori r3, r14, 0
> + l.sfeq r3, r0
> + /* If uc_link is not 0 resume there, otherwise exit. */
> + l.bnf __setcontext
> + l.nop
> +
> +#ifdef SHARED
> + /* Obtain a pointer to .got in r16 */
> + l.jal 0x8
> + l.movhi r16, gotpchi(_GLOBAL_OFFSET_TABLE_-4)
> + l.ori r16, r16, gotpclo(_GLOBAL_OFFSET_TABLE_+0)
> + l.add r16, r16, r9
> + l.lwz r16, got(exit)(r16)
> + l.jr r16
> +#else
> + l.j exit
> +#endif
> + l.nop
> +
> +END(__startcontext)
> diff --git a/sysdeps/unix/sysv/linux/or1k/sigcontextinfo.h b/sysdeps/unix/sysv/linux/or1k/sigcontextinfo.h
> new file mode 100644
> index 0000000000..de94b59578
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/or1k/sigcontextinfo.h
> @@ -0,0 +1,28 @@
> +/* Profile counter helper to get PC from sigcontext. OpenRISC version.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#ifndef _SIGCONTEXTINFO_H
> +#define _SIGCONTEXTINFO_H
> +
> +static inline uintptr_t
> +sigcontext_get_pc (const ucontext_t *ctx)
> +{
> + return ctx->uc_mcontext.__pc;
> +}
> +
> +#endif /* _SIGCONTEXTINFO_H */
> diff --git a/sysdeps/unix/sysv/linux/or1k/swapcontext.S b/sysdeps/unix/sysv/linux/or1k/swapcontext.S
> new file mode 100644
> index 0000000000..2acdc6d9bd
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/or1k/swapcontext.S
> @@ -0,0 +1,116 @@
> +/* Swap two contexts. OpenRISC version.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <sysdep.h>
> +#include "ucontext_i.h"
> +
> +/* int swapcontext (ucontext_t *oucp, const ucontext_t *ucp) */
> + .text
> +ENTRY(__swapcontext)
> +
> + /* Same as getcontext. */
> + /* Store r1, the stack pointer. */
> + l.sw (UCONTEXT_MCONTEXT + 1*4)(r3), r1
> + /* Store r2, the frame pointer. */
> + l.sw (UCONTEXT_MCONTEXT + 2*4)(r3), r2
> + /* Store r9, the link register. */
> + l.sw (UCONTEXT_MCONTEXT + 9*4)(r3), r9
> + /* Store r9 to reg[11] too, as we need two links for makecontext. */
> + l.sw (UCONTEXT_MCONTEXT + 11*4)(r3), r9
> + /* Store r10, the TLS register. */
> + l.sw (UCONTEXT_MCONTEXT + 10*4)(r3), r10
> + /* Store r14-r30 even, callee saved registers. */
> + l.sw (UCONTEXT_MCONTEXT + 14*4)(r3), r14
> + l.sw (UCONTEXT_MCONTEXT + 16*4)(r3), r16
> + l.sw (UCONTEXT_MCONTEXT + 18*4)(r3), r18
> + l.sw (UCONTEXT_MCONTEXT + 20*4)(r3), r20
> + l.sw (UCONTEXT_MCONTEXT + 22*4)(r3), r22
> + l.sw (UCONTEXT_MCONTEXT + 24*4)(r3), r24
> + l.sw (UCONTEXT_MCONTEXT + 26*4)(r3), r26
> + l.sw (UCONTEXT_MCONTEXT + 28*4)(r3), r28
> + l.sw (UCONTEXT_MCONTEXT + 30*4)(r3), r30
> +
> + /* Store ucp to non-argument syscall preserved register. */
> + l.ori r30, r4, 0
> +
> + /* Get signal mask. */
> + /* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */
> + l.ori r6, r0, _NSIG8
> + l.addi r5, r3, UCONTEXT_SIGMASK
> + l.ori r4, r0, 0
> + l.ori r3, r0, SIG_BLOCK
> + l.ori r11, r0, SYS_ify (rt_sigprocmask)
> + /* Do the syscall. */
> + l.sys 1
> + l.nop
> +
> + /* if -4096 < ret < 0 holds, it's an error */
> + l.sfgeui r11, 0xf001
> + l.bf 1f
> + l.nop
> +
> + /* Same as setcontext. */
> +
> + /* Restore signal mask. */
> + /* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, NULL, _NSIG8) */
> + l.ori r6, r0, _NSIG8
> + l.ori r5, r0, 0
> + l.addi r4, r30, UCONTEXT_SIGMASK
> + l.ori r3, r0, SIG_SETMASK
> + l.ori r11, r0, SYS_ify (rt_sigprocmask)
> + /* Do the syscall. */
> + l.sys 1
> + l.nop
> +
> + /* if -4096 < ret < 0 holds, it's an error */
> + l.sfgeui r11, 0xf001
> + l.bf 1f
> + l.nop
> +
> + /* Restore argument registers, for the makecontext case. */
> + l.lwz r3, (UCONTEXT_MCONTEXT + 3*4)(r30)
> + l.lwz r4, (UCONTEXT_MCONTEXT + 4*4)(r30)
> + l.lwz r5, (UCONTEXT_MCONTEXT + 5*4)(r30)
> + l.lwz r6, (UCONTEXT_MCONTEXT + 6*4)(r30)
> + l.lwz r7, (UCONTEXT_MCONTEXT + 7*4)(r30)
> + l.lwz r8, (UCONTEXT_MCONTEXT + 8*4)(r30)
> +
> + /* Restore registers stored in getcontext. */
> + l.lwz r1, (UCONTEXT_MCONTEXT + 1*4)(r30)
> + l.lwz r2, (UCONTEXT_MCONTEXT + 2*4)(r30)
> + l.lwz r9, (UCONTEXT_MCONTEXT + 9*4)(r30)
> + l.lwz r10, (UCONTEXT_MCONTEXT + 10*4)(r30)
> + l.lwz r11, (UCONTEXT_MCONTEXT + 11*4)(r30)
> + l.lwz r14, (UCONTEXT_MCONTEXT + 14*4)(r30)
> + l.lwz r16, (UCONTEXT_MCONTEXT + 16*4)(r30)
> + l.lwz r18, (UCONTEXT_MCONTEXT + 18*4)(r30)
> + l.lwz r20, (UCONTEXT_MCONTEXT + 20*4)(r30)
> + l.lwz r22, (UCONTEXT_MCONTEXT + 22*4)(r30)
> + l.lwz r24, (UCONTEXT_MCONTEXT + 24*4)(r30)
> + l.lwz r26, (UCONTEXT_MCONTEXT + 26*4)(r30)
> + l.lwz r28, (UCONTEXT_MCONTEXT + 28*4)(r30)
> + l.lwz r30, (UCONTEXT_MCONTEXT + 30*4)(r30)
> +
> + l.jr r11
> + l.ori r11, r0, 0
> +
> +1: l.j __syscall_error
> + l.ori r3, r11, 0
> +
> +END (__swapcontext)
> +weak_alias (__swapcontext, swapcontext)
> diff --git a/sysdeps/unix/sysv/linux/or1k/sys/ucontext.h b/sysdeps/unix/sysv/linux/or1k/sys/ucontext.h
> new file mode 100644
> index 0000000000..c4aead8f93
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/or1k/sys/ucontext.h
> @@ -0,0 +1,53 @@
> +/* ucontext_t definition, OpenRISC version.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +/* System V/OpenRISC compliant context switching support. */
> +
> +#ifndef _SYS_UCONTEXT_H
> +#define _SYS_UCONTEXT_H 1
> +
> +#include <features.h>
> +
> +#include <bits/types/sigset_t.h>
> +#include <bits/types/stack_t.h>
> +
> +/* Number of general registers. */
> +#define __NGREG 32
> +#ifdef __USE_MISC
> +# define NGREG __NGREG
> +#endif
> +
> +/* Context to describe whole processor state. */
> +typedef struct
> + {
> + unsigned long int __gprs[__NGREG];
> + unsigned long int __pc;
> + unsigned long int __sr;
> + } mcontext_t;
> +
> +/* Userlevel context. */
> +typedef struct ucontext_t
> + {
> + unsigned long int __uc_flags;
> + struct ucontext_t *uc_link;
> + stack_t uc_stack;
> + mcontext_t uc_mcontext;
> + sigset_t uc_sigmask;
> + } ucontext_t;
> +
> +#endif /* sys/ucontext.h */
> diff --git a/sysdeps/unix/sysv/linux/or1k/sys/user.h b/sysdeps/unix/sysv/linux/or1k/sys/user.h
> new file mode 100644
> index 0000000000..c871f1a03d
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/or1k/sys/user.h
> @@ -0,0 +1 @@
> +/* This file is not needed, but in practice gdb might try to include it. */
> diff --git a/sysdeps/unix/sysv/linux/or1k/ucontext_i.sym b/sysdeps/unix/sysv/linux/or1k/ucontext_i.sym
> new file mode 100644
> index 0000000000..a8d4db080f
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/or1k/ucontext_i.sym
> @@ -0,0 +1,26 @@
> +#include <inttypes.h>
> +#include <signal.h>
> +#include <stddef.h>
> +#include <sys/ucontext.h>
> +
> +-- Constants used by the rt_sigprocmask call.
> +
> +SIG_BLOCK
> +SIG_SETMASK
> +
> +_NSIG8 (_NSIG / 8)
> +
> +-- Offsets of the fields in the ucontext_t structure.
> +#define ucontext(member) offsetof (ucontext_t, member)
> +#define stack(member) ucontext (uc_stack.member)
> +
> +UCONTEXT_LINK ucontext (uc_link)
> +UCONTEXT_STACK ucontext (uc_stack)
> +UCONTEXT_MCONTEXT ucontext (uc_mcontext)
> +UCONTEXT_SIGMASK ucontext (uc_sigmask)
> +
> +STACK_SP stack (ss_sp)
> +STACK_SIZE stack (ss_size)
> +STACK_FLAGS stack (ss_flags)
> +
> +UCONTEXT_SIZE sizeof (ucontext_t)