From bc38f61313d316d74c16ce7287d6dba2f42502c9 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Cl=C3=A9ment=20L=C3=A9ger?= Date: Wed, 4 Oct 2023 17:14:02 +0200 Subject: [PATCH] riscv: add support for sysctl unaligned_enabled control MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This sysctl tuning option allows the user to disable misaligned access handling globally on the system. This will also be used by misaligned detection code to temporarily disable misaligned access handling. Signed-off-by: Clément Léger Reviewed-by: Björn Töpel Link: https://lore.kernel.org/r/20231004151405.521596-6-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt --- arch/riscv/Kconfig | 1 + arch/riscv/kernel/traps_misaligned.c | 9 +++++++++ 2 files changed, 10 insertions(+) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 6e167358a8975..1313f83bb0cba 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -638,6 +638,7 @@ config THREAD_SIZE_ORDER config RISCV_MISALIGNED bool "Support misaligned load/store traps for kernel and userspace" + select SYSCTL_ARCH_UNALIGN_ALLOW default y help Say Y here if you want the kernel to embed support for misaligned diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c index 041fd2dbd955a..b5fb1ff078e32 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -396,6 +396,9 @@ union reg_data { u64 data_u64; }; +/* sysctl hooks */ +int unaligned_enabled __read_mostly = 1; /* Enabled by default */ + int handle_misaligned_load(struct pt_regs *regs) { union reg_data val; @@ -406,6 +409,9 @@ int handle_misaligned_load(struct pt_regs *regs) perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr); + if (!unaligned_enabled) + return -1; + if (get_insn(regs, epc, &insn)) return -1; @@ -502,6 +508,9 @@ int handle_misaligned_store(struct pt_regs *regs) perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr); + if (!unaligned_enabled) + return -1; + if (get_insn(regs, epc, &insn)) return -1; -- 2.30.2