Unverified Commit 5a83e731 authored by Charlie Jenkins's avatar Charlie Jenkins Committed by Palmer Dabbelt
Browse files

riscv: lib: Introduce has_fast_unaligned_access() 



Create has_fast_unaligned_access to avoid needing to explicitly check
the fast_misaligned_access_speed_key static key.

Signed-off-by: default avatarCharlie Jenkins <charlie@rivosinc.com>
Reviewed-by: default avatarEvan Green <evan@rivosinc.com>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Tested-by: default avatarSamuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240308-disable_misaligned_probe_config-v9-1-a388770ba0ce@rivosinc.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 6613476e

arch/riscv/include/asm/cpufeature.h

+8 −3
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Copyright 2022-2023 Rivos, Inc

 * Copyright 2022-2024 Rivos, Inc

 */



#ifndef _ASM_CPUFEATURE_H
@@ -53,6 +53,13 @@ static inline bool check_unaligned_access_emulated(int cpu) 
static inline void unaligned_emulation_finish(void) {}

#endif



DECLARE_STATIC_KEY_FALSE(fast_unaligned_access_speed_key);



static __always_inline bool has_fast_unaligned_accesses(void)

{

	return static_branch_likely(&fast_unaligned_access_speed_key);

}



unsigned long riscv_get_elf_hwcap(void);



struct riscv_isa_ext_data {
@@ -135,6 +142,4 @@ static __always_inline bool riscv_cpu_has_extension_unlikely(int cpu, const unsi 
	return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);

}



DECLARE_STATIC_KEY_FALSE(fast_misaligned_access_speed_key);



#endif

arch/riscv/kernel/cpufeature.c

+3 −3
Original line number Diff line number Diff line
@@ -810,14 +810,14 @@ static void check_unaligned_access_nonboot_cpu(void *param) 
		check_unaligned_access(pages[cpu]);

}



DEFINE_STATIC_KEY_FALSE(fast_misaligned_access_speed_key);

DEFINE_STATIC_KEY_FALSE(fast_unaligned_access_speed_key);



static void modify_unaligned_access_branches(cpumask_t *mask, int weight)

{

	if (cpumask_weight(mask) == weight)

		static_branch_enable_cpuslocked(&fast_misaligned_access_speed_key);

		static_branch_enable_cpuslocked(&fast_unaligned_access_speed_key);

	else

		static_branch_disable_cpuslocked(&fast_misaligned_access_speed_key);

		static_branch_disable_cpuslocked(&fast_unaligned_access_speed_key);

}



static void set_unaligned_access_static_branches_except_cpu(int cpu)

arch/riscv/lib/csum.c

+2 −5
Original line number Diff line number Diff line
@@ -3,7 +3,7 @@ 
 * Checksum library

 *

 * Influenced by arch/arm64/lib/csum.c

 * Copyright (C) 2023 Rivos Inc.

 * Copyright (C) 2023-2024 Rivos Inc.

 */

#include <linux/bitops.h>

#include <linux/compiler.h>
@@ -318,10 +318,7 @@ unsigned int do_csum(const unsigned char *buff, int len) 
	 * branches. The largest chunk of overlap was delegated into the

	 * do_csum_common function.

	 */

	if (static_branch_likely(&fast_misaligned_access_speed_key))

		return do_csum_no_alignment(buff, len);



	if (((unsigned long)buff & OFFSET_MASK) == 0)

	if (has_fast_unaligned_accesses() || (((unsigned long)buff & OFFSET_MASK) == 0))

		return do_csum_no_alignment(buff, len);



	return do_csum_with_alignment(buff, len);