https://gcc.gnu.org/g:41b4a73f370116af73b24cf7d74099790c2f3223
commit r16-7637-g41b4a73f370116af73b24cf7d74099790c2f3223 Author: Alice Carlotti <[email protected]> Date: Tue Dec 30 08:52:24 2025 +0000 libgcc: aarch64: Add __arm_get_current_vg AAPCS64* specifies several runtime support routines that must be supported by any platform that supports SME. Add __arm_get_current_vg to libgcc to help meet this requirement. This will be used to enable support for SME without (non-streaming) SVE. *https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst libgcc/ChangeLog: * config/aarch64/libgcc-sme.ver: Add __arm_get_current_vg. * config/aarch64/t-aarch64: Add new source file. * config/aarch64/__arm_get_current_vg.S: New file. Diff: --- libgcc/config/aarch64/__arm_get_current_vg.S | 56 ++++++++++++++++++++++++++++ libgcc/config/aarch64/libgcc-sme.ver | 4 ++ libgcc/config/aarch64/t-aarch64 | 1 + 3 files changed, 61 insertions(+) diff --git a/libgcc/config/aarch64/__arm_get_current_vg.S b/libgcc/config/aarch64/__arm_get_current_vg.S new file mode 100644 index 000000000000..edce8340efa3 --- /dev/null +++ b/libgcc/config/aarch64/__arm_get_current_vg.S @@ -0,0 +1,56 @@ +/* Support routine for SME. + Copyright (C) 2025 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. + - x1-x15, x19-x29, sp and fp regs are call preserved. + - Takes no argument. + - Returns the value of the current VG in x0 if this value exists, and + returns zero otherwise. */ + +HIDDEN (__aarch64_cpu_features) + +variant_pcs (__arm_get_current_vg) + +ENTRY (__arm_get_current_vg) + /* Check if SVE is available. */ + adrp x16, __aarch64_cpu_features + ldr x16, [x16, :lo12:__aarch64_cpu_features] + tbnz x16, #30, L(end_cntd) + + /* Check if SME is available. */ + tbz x16, #42, L(end_zero) + + /* Check if we're in streaming mode */ + .inst 0xd53b4250 /* mrs x16, svcr */ + tbz x16, #0, L(end_zero) +L(end_cntd): + .inst 0x04e0e3e0 /* cntd x0 */ + ret +L(end_zero): + mov x0, 0 + ret +END (__arm_get_current_vg) diff --git a/libgcc/config/aarch64/libgcc-sme.ver b/libgcc/config/aarch64/libgcc-sme.ver index 3bfed444102c..f8c67905ba71 100644 --- a/libgcc/config/aarch64/libgcc-sme.ver +++ b/libgcc/config/aarch64/libgcc-sme.ver @@ -22,3 +22,7 @@ GCC_14.0 { __arm_tpidr2_save __arm_za_disable } + +GCC_16.0 { + __arm_get_current_vg +} diff --git a/libgcc/config/aarch64/t-aarch64 b/libgcc/config/aarch64/t-aarch64 index b67ece153d01..7bc51ad65248 100644 --- a/libgcc/config/aarch64/t-aarch64 +++ b/libgcc/config/aarch64/t-aarch64 @@ -24,6 +24,7 @@ LIB2ADD += $(srcdir)/config/aarch64/cpuinfo.c # Add sme runtime to shared libgcc LIB2ADDEH += \ $(srcdir)/config/aarch64/__aarch64_have_sme.c \ + $(srcdir)/config/aarch64/__arm_get_current_vg.S \ $(srcdir)/config/aarch64/__arm_sme_state.S \ $(srcdir)/config/aarch64/__arm_tpidr2_restore.S \ $(srcdir)/config/aarch64/__arm_tpidr2_save.S \
