Unverified Commit 12e7fbb6 authored by Conor Dooley's avatar Conor Dooley Committed by Alexandre Ghiti
Browse files

RISC-V: add f & d extension validation checks 



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: default avatarClément Léger <cleger@rivosinc.com>
Reviewed-by: default avatarClément Léger <cleger@rivosinc.com>
Signed-off-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250312-reptile-platinum-62ee0f444a32@spud


Signed-off-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
parent 38077ec8

arch/riscv/kernel/cpufeature.c

+29 −2
Original line number Diff line number Diff line
@@ -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),