From 12e7fbb6a84e6c90a61330d152319e870bc01c46 Mon Sep 17 00:00:00 2001 From: Conor Dooley Date: Wed, 12 Mar 2025 13:11:46 +0000 Subject: [PATCH] RISC-V: add f & d extension validation checks MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Using Clement's new validation callbacks, support checking that dependencies have been satisfied for the floating point extensions. The check for "d" might be slightly confusingly shorter than that of "f", despite "d" depending on "f". This is because the requirement that a hart supporting double precision must also support single precision, should be validated by dt-bindings etc, not the kernel but lack of support for single precision only is a limitation of the kernel. Tested-by: Clément Léger Reviewed-by: Clément Léger Signed-off-by: Conor Dooley Reviewed-by: Alexandre Ghiti Link: https://lore.kernel.org/r/20250312-reptile-platinum-62ee0f444a32@spud Signed-off-by: Alexandre Ghiti --- arch/riscv/kernel/cpufeature.c | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 654dd4cfc479a..4024da3fc1ddf 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -109,6 +109,33 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data, return 0; } +static int riscv_ext_f_validate(const struct riscv_isa_ext_data *data, + const unsigned long *isa_bitmap) +{ + if (!IS_ENABLED(CONFIG_FPU)) + return -EINVAL; + + /* + * Due to extension ordering, d is checked before f, so no deferral + * is required. + */ + if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d)) { + pr_warn_once("This kernel does not support systems with F but not D\n"); + return -EINVAL; + } + + return 0; +} + +static int riscv_ext_d_validate(const struct riscv_isa_ext_data *data, + const unsigned long *isa_bitmap) +{ + if (!IS_ENABLED(CONFIG_FPU)) + return -EINVAL; + + return 0; +} + static int riscv_ext_vector_x_validate(const struct riscv_isa_ext_data *data, const unsigned long *isa_bitmap) { @@ -371,8 +398,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = { __RISCV_ISA_EXT_DATA(i, RISCV_ISA_EXT_i), __RISCV_ISA_EXT_DATA(m, RISCV_ISA_EXT_m), __RISCV_ISA_EXT_DATA(a, RISCV_ISA_EXT_a), - __RISCV_ISA_EXT_DATA(f, RISCV_ISA_EXT_f), - __RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d), + __RISCV_ISA_EXT_DATA_VALIDATE(f, RISCV_ISA_EXT_f, riscv_ext_f_validate), + __RISCV_ISA_EXT_DATA_VALIDATE(d, RISCV_ISA_EXT_d, riscv_ext_d_validate), __RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q), __RISCV_ISA_EXT_SUPERSET(c, RISCV_ISA_EXT_c, riscv_c_exts), __RISCV_ISA_EXT_SUPERSET_VALIDATE(v, RISCV_ISA_EXT_v, riscv_v_exts, riscv_ext_vector_float_validate), -- 2.39.5