From 43cbf049f5b017316f6fb1ea5f95784194323a51 Mon Sep 17 00:00:00 2001 From: Alice Carlotti Date: Tue, 15 Apr 2025 17:36:25 +0100 Subject: [PATCH] aarch64: Disable sysreg feature gating This applies to the sysreg read/write intrinsics __arm_[wr]sr*. It does not depend on changes to Binutils, because GCC converts recognised sysreg names to an encoding based form, which is already ungated in Binutils. We have, however, agreed to make an equivalent change in Binutils (which would then disable feature gating for sysreg accesses in inline assembly), but this has not yet been posted upstream. In the future we may introduce a new flag to renable some checking, but these checks could not be comprehensive because many system registers depend on architecture features that don't have corresponding GCC/GAS --march options. This would also depend on addressing numerous inconsistencies in the existing list of sysreg feature dependencies. gcc/ChangeLog: * config/aarch64/aarch64.cc (aarch64_valid_sysreg_name_p): Remove feature check. (aarch64_retrieve_sysreg): Ditto. gcc/testsuite/ChangeLog: * gcc.target/aarch64/acle/rwsr-ungated.c: New test. --- gcc/config/aarch64/aarch64.cc | 4 ---- .../gcc.target/aarch64/acle/rwsr-ungated.c | 13 +++++++++++++ 2 files changed, 13 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.target/aarch64/acle/rwsr-ungated.c diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc index 4e801146c60..433ec975d7e 100644 --- a/gcc/config/aarch64/aarch64.cc +++ b/gcc/config/aarch64/aarch64.cc @@ -31073,8 +31073,6 @@ aarch64_valid_sysreg_name_p (const char *regname) const sysreg_t *sysreg = aarch64_lookup_sysreg_map (regname); if (sysreg == NULL) return aarch64_is_implem_def_reg (regname); - if (sysreg->arch_reqs) - return bool (aarch64_isa_flags & sysreg->arch_reqs); return true; } @@ -31098,8 +31096,6 @@ aarch64_retrieve_sysreg (const char *regname, bool write_p, bool is128op) if ((write_p && (sysreg->properties & F_REG_READ)) || (!write_p && (sysreg->properties & F_REG_WRITE))) return NULL; - if ((~aarch64_isa_flags & sysreg->arch_reqs) != 0) - return NULL; return sysreg->encoding; } diff --git a/gcc/testsuite/gcc.target/aarch64/acle/rwsr-ungated.c b/gcc/testsuite/gcc.target/aarch64/acle/rwsr-ungated.c new file mode 100644 index 00000000000..d67a4267373 --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/acle/rwsr-ungated.c @@ -0,0 +1,13 @@ +/* Test that __arm_[r,w]sr intrinsics aren't gated (by default). */ + +/* { dg-do compile } */ +/* { dg-options "-march=armv8-a" } */ + +#include + +uint64_t +foo (uint64_t a) +{ + __arm_wsr64 ("zcr_el1", a); + return __arm_rsr64 ("smcr_el1"); +}