Szabolcs Nagy <szabolcs.n...@arm.com> writes:
> The call ABI for SME (Scalable Matrix Extension) requires a number of
> helper routines which are added to libgcc so they are tied to the
> compiler version instead of the libc version. See
> https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#sme-support-routines
>
> The routines are in shared libgcc and static libgcc eh, even though
> they are not related to exception handling.  This is to avoid linking
> a copy of the routines into dynamic linked binaries, because TPIDR2_EL0
> block can be extended in the future which is better to handle in a
> single place per process.
>
> The support routines have to decide if SME is accessible or not. Linux
> tells userspace if SME is accessible via AT_HWCAP2, otherwise a new
> __aarch64_sme_accessible symbol was introduced that a libc can define.
> Due to libgcc and libc build order, the symbol availability cannot be
> checked so for __aarch64_sme_accessible an unistd.h feature test macro
> is used while such detection mechanism is not available for __getauxval
> so we rely on configure checks based on the target triplet.
>
> Asm helper code is added to make writing the routines easier.
>
> libgcc/ChangeLog:
>
>       * config/aarch64/t-aarch64: Add sources to the build.
>       * config/aarch64/__aarch64_have_sme.c: New file.
>       * config/aarch64/__arm_sme_state.S: New file.
>       * config/aarch64/__arm_tpidr2_restore.S: New file.
>       * config/aarch64/__arm_tpidr2_save.S: New file.
>       * config/aarch64/__arm_za_disable.S: New file.
>       * config/aarch64/aarch64-asm.h: New file.
>       * config/aarch64/libgcc-sme.ver: New file.
> ---
> v2:
> - do not include unistd.h when inhibit_libc is set.
> - use msr tpidr2_el0,xzr in __arm_za_disable.

LGTM, thanks.

>  libgcc/config/aarch64/__aarch64_have_sme.c   |  75 ++++++++++++++
>  libgcc/config/aarch64/__arm_sme_state.S      |  55 ++++++++++
>  libgcc/config/aarch64/__arm_tpidr2_restore.S |  89 ++++++++++++++++
>  libgcc/config/aarch64/__arm_tpidr2_save.S    | 101 +++++++++++++++++++
>  libgcc/config/aarch64/__arm_za_disable.S     |  65 ++++++++++++
>  libgcc/config/aarch64/aarch64-asm.h          |  98 ++++++++++++++++++
>  libgcc/config/aarch64/libgcc-sme.ver         |  24 +++++
>  libgcc/config/aarch64/t-aarch64              |  10 ++
>  8 files changed, 517 insertions(+)
>  create mode 100644 libgcc/config/aarch64/__aarch64_have_sme.c
>  create mode 100644 libgcc/config/aarch64/__arm_sme_state.S
>  create mode 100644 libgcc/config/aarch64/__arm_tpidr2_restore.S
>  create mode 100644 libgcc/config/aarch64/__arm_tpidr2_save.S
>  create mode 100644 libgcc/config/aarch64/__arm_za_disable.S
>  create mode 100644 libgcc/config/aarch64/aarch64-asm.h
>  create mode 100644 libgcc/config/aarch64/libgcc-sme.ver
>
> diff --git a/libgcc/config/aarch64/__aarch64_have_sme.c 
> b/libgcc/config/aarch64/__aarch64_have_sme.c
> new file mode 100644
> index 00000000000..5e649246270
> --- /dev/null
> +++ b/libgcc/config/aarch64/__aarch64_have_sme.c
> @@ -0,0 +1,75 @@
> +/* Initializer for SME support.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +   This file is part of GCC.
> +
> +   GCC is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published
> +   by the Free Software Foundation; either version 3, or (at your
> +   option) any later version.
> +
> +   GCC 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 General Public
> +   License for more details.
> +
> +   Under Section 7 of GPL version 3, you are granted additional
> +   permissions described in the GCC Runtime Library Exception, version
> +   3.1, as published by the Free Software Foundation.
> +
> +   You should have received a copy of the GNU General Public License and
> +   a copy of the GCC Runtime Library Exception along with this program;
> +   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include "auto-target.h"
> +
> +#ifndef inhibit_libc
> +/* For libc feature test macros.  */
> +# include <unistd.h>
> +#endif
> +
> +#if __ARM_FEATURE_SME
> +/* Avoid runtime SME detection if libgcc is built with SME.  */
> +# define HAVE_SME_CONST const
> +# define HAVE_SME_VALUE 1
> +#elif HAVE___GETAUXVAL
> +/* SME access detection on Linux.  */
> +# define HAVE_SME_CONST
> +# define HAVE_SME_VALUE 0
> +# define HAVE_SME_CTOR sme_accessible ()
> +
> +# define AT_HWCAP2   26
> +# define HWCAP2_SME  (1 << 23)
> +unsigned long int __getauxval (unsigned long int);
> +
> +static _Bool
> +sme_accessible (void)
> +{
> +  unsigned long hwcap2 = __getauxval (AT_HWCAP2);
> +  return (hwcap2 & HWCAP2_SME) != 0;
> +}
> +#elif __LIBC___AARCH64_SME_ACCESSIBLE
> +/* Alternative SME access detection.  */
> +# define HAVE_SME_CONST
> +# define HAVE_SME_VALUE 0
> +# define HAVE_SME_CTOR __aarch64_sme_accessible ()
> +_Bool __aarch64_sme_accessible (void);
> +#else
> +# define HAVE_SME_CONST const
> +# define HAVE_SME_VALUE 0
> +#endif
> +
> +/* Define the symbol gating SME support in libgcc.  */
> +HAVE_SME_CONST _Bool __aarch64_have_sme
> +  __attribute__((visibility("hidden"), nocommon)) = HAVE_SME_VALUE;
> +
> +#ifdef HAVE_SME_CTOR
> +/* Use a higher priority to ensure it runs before user constructors
> +   with priority 100. */
> +static void __attribute__((constructor (90)))
> +init_have_sme (void)
> +{
> +  __aarch64_have_sme = HAVE_SME_CTOR;
> +}
> +#endif
> diff --git a/libgcc/config/aarch64/__arm_sme_state.S 
> b/libgcc/config/aarch64/__arm_sme_state.S
> new file mode 100644
> index 00000000000..c4e16cac00d
> --- /dev/null
> +++ b/libgcc/config/aarch64/__arm_sme_state.S
> @@ -0,0 +1,55 @@
> +/* Support routine for SME.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +   This file is part of GCC.
> +
> +   GCC is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published
> +   by the Free Software Foundation; either version 3, or (at your
> +   option) any later version.
> +
> +   GCC 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 General Public
> +   License for more details.
> +
> +   Under Section 7 of GPL version 3, you are granted additional
> +   permissions described in the GCC Runtime Library Exception, version
> +   3.1, as published by the Free Software Foundation.
> +
> +   You should have received a copy of the GNU General Public License and
> +   a copy of the GCC Runtime Library Exception along with this program;
> +   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include "aarch64-asm.h"
> +
> +/* Query SME state.  Call ABI:
> +   - Private ZA, streaming-compatible.
> +   - x2-x15, x19-x29, sp and fp regs are call preserved.
> +   - Takes no argument.
> +   - Returns SME state in x0 and TPIDR2_EL0 in x1.  */
> +
> +.hidden __aarch64_have_sme
> +
> +variant_pcs (__arm_sme_state)
> +
> +ENTRY (__arm_sme_state)
> +     /* Check if SME is available.  */
> +     adrp    x1, __aarch64_have_sme
> +     ldrb    w1, [x1, :lo12:__aarch64_have_sme]
> +     cbz     w1, L(nosme)
> +
> +     /* Expose the bottom 2 bits of svcr (SM, ZA) in x0 and set the
> +        top 2 bits indicating that SME and TPIDR2_EL0 are available.  */
> +     .inst   0xd53b4240  /* mrs      x0, svcr  */
> +     .inst   0xd53bd0a1  /* mrs      x1, tpidr2_el0  */
> +     and     x0, x0, 3
> +     orr     x0, x0, 0xc000000000000000
> +     ret
> +
> +L(nosme):
> +     mov     x0, 0
> +     mov     x1, 0
> +     ret
> +END (__arm_sme_state)
> diff --git a/libgcc/config/aarch64/__arm_tpidr2_restore.S 
> b/libgcc/config/aarch64/__arm_tpidr2_restore.S
> new file mode 100644
> index 00000000000..4569d04a2d0
> --- /dev/null
> +++ b/libgcc/config/aarch64/__arm_tpidr2_restore.S
> @@ -0,0 +1,89 @@
> +/* Support routine for SME.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +   This file is part of GCC.
> +
> +   GCC is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published
> +   by the Free Software Foundation; either version 3, or (at your
> +   option) any later version.
> +
> +   GCC 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 General Public
> +   License for more details.
> +
> +   Under Section 7 of GPL version 3, you are granted additional
> +   permissions described in the GCC Runtime Library Exception, version
> +   3.1, as published by the Free Software Foundation.
> +
> +   You should have received a copy of the GNU General Public License and
> +   a copy of the GCC Runtime Library Exception along with this program;
> +   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include "aarch64-asm.h"
> +
> +/* Used for lazy ZA restore.  Call ABI:
> +   - Shared ZA, streaming-compatible.
> +   - x0 is a pointer to a TPIDR2 block.
> +   - x0-x13, x19-x29, sp and fp regs are call preserved.
> +   - Does not return a value.
> +   - Can abort on failure (then registers are not preserved).  */
> +
> +variant_pcs (__arm_tpidr2_restore)
> +
> +ENTRY (__arm_tpidr2_restore)
> +     .inst   0xd53bd0ae  /* mrs      x14, tpidr2_el0  */
> +     cbnz    x14, L(fail)
> +
> +     /* check reserved bytes.  */
> +     ldrh    w15, [x0, 10]
> +     ldr     w16, [x0, 12]
> +     orr     w15, w15, w16
> +     cbnz    w15, L(fail)
> +
> +     ldr     x16, [x0]
> +     cbz     x16, L(end)
> +     ldrh    w17, [x0, 8]
> +     cbz     w17, L(end)
> +
> +     /* x0: blk, x14: 0, x15: 0,
> +        x16: za_save_buffer, x17: num_za_save_slices.  */
> +
> +L(restore_loop):
> +     .inst   0xe1006200  /* ldr      za[w15, 0], [x16]  */
> +     .inst   0xe1006201  /* ldr      za[w15, 1], [x16, 1, mul vl]  */
> +     .inst   0xe1006202  /* ldr      za[w15, 2], [x16, 2, mul vl]  */
> +     .inst   0xe1006203  /* ldr      za[w15, 3], [x16, 3, mul vl]  */
> +     .inst   0xe1006204  /* ldr      za[w15, 4], [x16, 4, mul vl]  */
> +     .inst   0xe1006205  /* ldr      za[w15, 5], [x16, 5, mul vl]  */
> +     .inst   0xe1006206  /* ldr      za[w15, 6], [x16, 6, mul vl]  */
> +     .inst   0xe1006207  /* ldr      za[w15, 7], [x16, 7, mul vl]  */
> +     .inst   0xe1006208  /* ldr      za[w15, 8], [x16, 8, mul vl]  */
> +     .inst   0xe1006209  /* ldr      za[w15, 9], [x16, 9, mul vl]  */
> +     .inst   0xe100620a  /* ldr      za[w15, 10], [x16, 10, mul vl]  */
> +     .inst   0xe100620b  /* ldr      za[w15, 11], [x16, 11, mul vl]  */
> +     .inst   0xe100620c  /* ldr      za[w15, 12], [x16, 12, mul vl]  */
> +     .inst   0xe100620d  /* ldr      za[w15, 13], [x16, 13, mul vl]  */
> +     .inst   0xe100620e  /* ldr      za[w15, 14], [x16, 14, mul vl]  */
> +     .inst   0xe100620f  /* ldr      za[w15, 15], [x16, 15, mul vl]  */
> +     add     w15, w15, 16
> +     .inst   0x04305a10  /* addsvl   x16, x16, 16  */
> +     cmp     w17, w15
> +     bhi     L(restore_loop)
> +L(end):
> +     ret
> +L(fail):
> +     PACIASP
> +     stp     x29, x30, [sp, -32]!
> +     .cfi_adjust_cfa_offset 32
> +     .cfi_rel_offset x29, 0
> +     .cfi_rel_offset x30, 8
> +     mov     x29, sp
> +     .inst   0x04e0e3f0  /* cntd     x16  */
> +     str     x16, [sp, 16]
> +     .cfi_rel_offset 46, 16
> +     .inst   0xd503467f  /* smstop  */
> +     bl      abort
> +END (__arm_tpidr2_restore)
> diff --git a/libgcc/config/aarch64/__arm_tpidr2_save.S 
> b/libgcc/config/aarch64/__arm_tpidr2_save.S
> new file mode 100644
> index 00000000000..879cf798079
> --- /dev/null
> +++ b/libgcc/config/aarch64/__arm_tpidr2_save.S
> @@ -0,0 +1,101 @@
> +/* Support routine for SME.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +   This file is part of GCC.
> +
> +   GCC is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published
> +   by the Free Software Foundation; either version 3, or (at your
> +   option) any later version.
> +
> +   GCC 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 General Public
> +   License for more details.
> +
> +   Under Section 7 of GPL version 3, you are granted additional
> +   permissions described in the GCC Runtime Library Exception, version
> +   3.1, as published by the Free Software Foundation.
> +
> +   You should have received a copy of the GNU General Public License and
> +   a copy of the GCC Runtime Library Exception along with this program;
> +   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include "aarch64-asm.h"
> +
> +/* Used for lazy ZA save.  Call ABI:
> +   - Private ZA, streaming-compatible.
> +   - x0-x13, x19-x29, sp and fp regs are call preserved.
> +   - Takes no argument.
> +   - Does not return a value.
> +   - Can abort on failure (then registers are not preserved).  */
> +
> +.hidden __aarch64_have_sme
> +
> +variant_pcs (__arm_tpidr2_save)
> +
> +ENTRY (__arm_tpidr2_save)
> +     /* Check if SME is available.  */
> +     adrp    x14, __aarch64_have_sme
> +     ldrb    w14, [x14, :lo12:__aarch64_have_sme]
> +     cbz     w14, L(end)
> +
> +     .inst   0xd53bd0ae  /* mrs      x14, tpidr2_el0  */
> +     cbz     x14, L(end)
> +
> +     /* check reserved bytes.  */
> +     ldrh    w15, [x14, 10]
> +     ldr     w16, [x14, 12]
> +     orr     w15, w15, w16
> +     cbnz    w15, L(fail)
> +
> +     ldr     x16, [x14]
> +     cbz     x16, L(end)
> +     ldrh    w17, [x14, 8]
> +     cbz     w17, L(end)
> +
> +     /* x14: tpidr2, x15: 0,
> +        x16: za_save_buffer, x17: num_za_save_slices.  */
> +
> +L(save_loop):
> +     .inst   0xe1206200  /* str      za[w15, 0], [x16]  */
> +     .inst   0xe1206201  /* str      za[w15, 1], [x16, 1, mul vl] */
> +     .inst   0xe1206202  /* str      za[w15, 2], [x16, 2, mul vl] */
> +     .inst   0xe1206203  /* str      za[w15, 3], [x16, 3, mul vl] */
> +     .inst   0xe1206204  /* str      za[w15, 4], [x16, 4, mul vl] */
> +     .inst   0xe1206205  /* str      za[w15, 5], [x16, 5, mul vl] */
> +     .inst   0xe1206206  /* str      za[w15, 6], [x16, 6, mul vl] */
> +     .inst   0xe1206207  /* str      za[w15, 7], [x16, 7, mul vl] */
> +     .inst   0xe1206208  /* str      za[w15, 8], [x16, 8, mul vl] */
> +     .inst   0xe1206209  /* str      za[w15, 9], [x16, 9, mul vl] */
> +     .inst   0xe120620a  /* str      za[w15, 10], [x16, 10, mul vl] */
> +     .inst   0xe120620b  /* str      za[w15, 11], [x16, 11, mul vl] */
> +     .inst   0xe120620c  /* str      za[w15, 12], [x16, 12, mul vl] */
> +     .inst   0xe120620d  /* str      za[w15, 13], [x16, 13, mul vl] */
> +     .inst   0xe120620e  /* str      za[w15, 14], [x16, 14, mul vl] */
> +     .inst   0xe120620f  /* str      za[w15, 15], [x16, 15, mul vl] */
> +     add     w15, w15, 16
> +     .inst   0x04305a10  /* addsvl   x16, x16, 16  */
> +     cmp     w17, w15
> +     bhi     L(save_loop)
> +L(end):
> +     ret
> +L(fail):
> +     PACIASP
> +     stp     x29, x30, [sp, -32]!
> +     .cfi_adjust_cfa_offset 32
> +     .cfi_rel_offset x29, 0
> +     .cfi_rel_offset x30, 8
> +     mov     x29, sp
> +     .inst   0x04e0e3f0  /* cntd     x16  */
> +     str     x16, [sp, 16]
> +     .cfi_rel_offset 46, 16
> +     .inst   0xd503467f  /* smstop  */
> +     bl      abort
> +END (__arm_tpidr2_save)
> +
> +/* Hidden alias used by __arm_za_disable.  */
> +.global __libgcc_arm_tpidr2_save
> +.hidden __libgcc_arm_tpidr2_save
> +.set __libgcc_arm_tpidr2_save, __arm_tpidr2_save
> diff --git a/libgcc/config/aarch64/__arm_za_disable.S 
> b/libgcc/config/aarch64/__arm_za_disable.S
> new file mode 100644
> index 00000000000..cff5b9cec47
> --- /dev/null
> +++ b/libgcc/config/aarch64/__arm_za_disable.S
> @@ -0,0 +1,65 @@
> +/* Support routine for SME.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +   This file is part of GCC.
> +
> +   GCC is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published
> +   by the Free Software Foundation; either version 3, or (at your
> +   option) any later version.
> +
> +   GCC 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 General Public
> +   License for more details.
> +
> +   Under Section 7 of GPL version 3, you are granted additional
> +   permissions described in the GCC Runtime Library Exception, version
> +   3.1, as published by the Free Software Foundation.
> +
> +   You should have received a copy of the GNU General Public License and
> +   a copy of the GCC Runtime Library Exception along with this program;
> +   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include "aarch64-asm.h"
> +
> +/* Disable ZA.  Call ABI:
> +   - Private ZA, streaming-compatible.
> +   - x0-x13, x19-x29, sp and fp regs are call preserved.
> +   - Takes no argument.
> +   - Does not return a value.
> +   - Can abort on failure (then registers are not preserved).  */
> +
> +.hidden __aarch64_have_sme
> +
> +.hidden __libgcc_arm_tpidr2_save
> +
> +variant_pcs (__arm_za_disable)
> +
> +ENTRY (__arm_za_disable)
> +     /* Check if SME is available.  */
> +     adrp    x14, __aarch64_have_sme
> +     ldrb    w14, [x14, :lo12:__aarch64_have_sme]
> +     cbz     w14, L(end)
> +
> +     .inst   0xd53bd0ae  /* mrs      x14, tpidr2_el0  */
> +     cbz     x14, L(end)
> +
> +     PACIASP
> +     stp     x29, x30, [sp, -16]!
> +     .cfi_adjust_cfa_offset 16
> +     .cfi_rel_offset x29, 0
> +     .cfi_rel_offset x30, 8
> +     mov     x29, sp
> +     bl      __libgcc_arm_tpidr2_save
> +     .inst   0xd51bd0bf  /* msr      tpidr2_el0, xzr  */
> +     .inst   0xd503447f  /* smstop   za  */
> +     ldp     x29, x30, [sp], 16
> +     .cfi_adjust_cfa_offset -16
> +     .cfi_restore x29
> +     .cfi_restore x30
> +     AUTIASP
> +L(end):
> +     ret
> +END (__arm_za_disable)
> diff --git a/libgcc/config/aarch64/aarch64-asm.h 
> b/libgcc/config/aarch64/aarch64-asm.h
> new file mode 100644
> index 00000000000..8969b06b09c
> --- /dev/null
> +++ b/libgcc/config/aarch64/aarch64-asm.h
> @@ -0,0 +1,98 @@
> +/* AArch64 asm definitions.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +   This file is part of GCC.
> +
> +   GCC is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published
> +   by the Free Software Foundation; either version 3, or (at your
> +   option) any later version.
> +
> +   GCC 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 General Public
> +   License for more details.
> +
> +   Under Section 7 of GPL version 3, you are granted additional
> +   permissions described in the GCC Runtime Library Exception, version
> +   3.1, as published by the Free Software Foundation.
> +
> +   You should have received a copy of the GNU General Public License and
> +   a copy of the GCC Runtime Library Exception along with this program;
> +   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include "auto-target.h"
> +
> +#define L(label) .L ## label
> +
> +/* Marking variant PCS symbol references is important for PLT calls
> +   otherwise it is for documenting the PCS in the symbol table.  */
> +#ifdef HAVE_AS_VARIANT_PCS
> +# define variant_pcs(name) .variant_pcs name
> +#else
> +# define variant_pcs(name)
> +#endif
> +
> +/* GNU_PROPERTY_AARCH64_* macros from elf.h for use in asm code.  */
> +#define FEATURE_1_AND 0xc0000000
> +#define FEATURE_1_BTI 1
> +#define FEATURE_1_PAC 2
> +
> +/* Supported features based on the code generation options.  */
> +#if defined(__ARM_FEATURE_BTI_DEFAULT)
> +# define BTI_FLAG FEATURE_1_BTI
> +# define BTI_C hint  34
> +#else
> +# define BTI_FLAG 0
> +# define BTI_C
> +#endif
> +
> +#if __ARM_FEATURE_PAC_DEFAULT & 3
> +# define PAC_FLAG FEATURE_1_PAC
> +# define PACIASP hint        25; .cfi_window_save
> +# define AUTIASP hint        29; .cfi_window_save
> +#else
> +# define PAC_FLAG 0
> +# define PACIASP
> +# define AUTIASP
> +#endif
> +
> +/* Add a NT_GNU_PROPERTY_TYPE_0 note.  */
> +#define GNU_PROPERTY(type, value)    \
> +  .section .note.gnu.property, "a";  \
> +  .p2align 3;                                \
> +  .word 4;                           \
> +  .word 16;                          \
> +  .word 5;                           \
> +  .asciz "GNU";                              \
> +  .word type;                                \
> +  .word 4;                           \
> +  .word value;                               \
> +  .word 0;                           \
> +  .previous
> +
> +#if defined(__linux__) || defined(__FreeBSD__)
> +/* Do not require executable stack.  */
> +.section .note.GNU-stack, "", %progbits
> +.previous
> +
> +/* Add GNU property note if built with branch protection.  */
> +# if (BTI_FLAG|PAC_FLAG) != 0
> +GNU_PROPERTY (FEATURE_1_AND, BTI_FLAG|PAC_FLAG)
> +# endif
> +#endif
> +
> +#define ENTRY_ALIGN(name, align) \
> +  .global name;              \
> +  .type name,%function;      \
> +  .balign align;     \
> +  name:                      \
> +  .cfi_startproc;    \
> +  BTI_C
> +
> +#define ENTRY(name) ENTRY_ALIGN(name, 16)
> +
> +#define END(name) \
> +  .cfi_endproc;              \
> +  .size name, .-name
> diff --git a/libgcc/config/aarch64/libgcc-sme.ver 
> b/libgcc/config/aarch64/libgcc-sme.ver
> new file mode 100644
> index 00000000000..da889c6c09e
> --- /dev/null
> +++ b/libgcc/config/aarch64/libgcc-sme.ver
> @@ -0,0 +1,24 @@
> +# Copyright (C) 2023 Free Software Foundation, Inc.
> +#
> +# This file is part of GCC.
> +#
> +# GCC is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3, or (at your option)
> +# any later version.
> +#
> +# GCC 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 General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with GCC; see the file COPYING3.  If not see
> +# <http://www.gnu.org/licenses/>.
> +
> +GCC_14.0 {
> +  __arm_sme_state
> +  __arm_tpidr2_restore
> +  __arm_tpidr2_save
> +  __arm_za_disable
> +}
> diff --git a/libgcc/config/aarch64/t-aarch64 b/libgcc/config/aarch64/t-aarch64
> index a40b6241c86..7b852022a4d 100644
> --- a/libgcc/config/aarch64/t-aarch64
> +++ b/libgcc/config/aarch64/t-aarch64
> @@ -19,3 +19,13 @@
>  # <http://www.gnu.org/licenses/>.
>  
>  LIB2ADD += $(srcdir)/config/aarch64/sync-cache.c
> +
> +# Add sme runtime to shared libgcc
> +LIB2ADDEH += \
> +     $(srcdir)/config/aarch64/__aarch64_have_sme.c \
> +     $(srcdir)/config/aarch64/__arm_sme_state.S \
> +     $(srcdir)/config/aarch64/__arm_tpidr2_restore.S \
> +     $(srcdir)/config/aarch64/__arm_tpidr2_save.S \
> +     $(srcdir)/config/aarch64/__arm_za_disable.S
> +
> +SHLIB_MAPFILES += $(srcdir)/config/aarch64/libgcc-sme.ver

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