From e64f737ad70fee4a3c57d147fc511e5d5014b5dd Mon Sep 17 00:00:00 2001 From: Heiko Stuebner Date: Wed, 11 May 2022 21:29:10 +0200 Subject: [PATCH] riscv: integrate alternatives better into the main architecture Right now the alternatives need to be explicitly enabled and erratas are limited to SiFive ones. We want to use alternatives not only for patching soc erratas, but in the future also for handling different behaviour depending on the existence of future extensions. So move the core alternatives over to the kernel subdirectory and move the CONFIG_RISCV_ALTERNATIVE to be a hidden symbol which we expect relevant erratas and extensions to just select if needed. Signed-off-by: Heiko Stuebner Reviewed-by: Philipp Tomsich Link: https://lore.kernel.org/r/20220511192921.2223629-2-heiko@sntech.de Signed-off-by: Palmer Dabbelt --- arch/riscv/Kconfig | 9 +++++++++ arch/riscv/Kconfig.erratas | 13 ++----------- arch/riscv/Kconfig.socs | 1 - arch/riscv/Makefile | 2 +- arch/riscv/errata/Makefile | 1 - arch/riscv/include/asm/alternative-macros.h | 7 ++++--- arch/riscv/include/asm/alternative.h | 8 ++++++++ arch/riscv/kernel/Makefile | 1 + arch/riscv/{errata => kernel}/alternative.c | 0 arch/riscv/kernel/smpboot.c | 2 -- arch/riscv/kernel/traps.c | 2 +- 11 files changed, 26 insertions(+), 20 deletions(-) rename arch/riscv/{errata => kernel}/alternative.c (100%) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 00fd9c548f26..26464dae8ab7 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -324,6 +324,15 @@ config NODES_SHIFT Specify the maximum number of NUMA Nodes available on the target system. Increases memory reserved to accommodate various tables. +config RISCV_ALTERNATIVE + bool + depends on !XIP_KERNEL + help + This Kconfig allows the kernel to automatically patch the + errata required by the execution platform at run time. The + code patching is performed once in the boot stages. It means + that the overhead from this mechanism is just taken once. + config RISCV_ISA_C bool "Emit compressed instructions when building Linux" default y diff --git a/arch/riscv/Kconfig.erratas b/arch/riscv/Kconfig.erratas index 0aacd7052585..c521c2ae2de2 100644 --- a/arch/riscv/Kconfig.erratas +++ b/arch/riscv/Kconfig.erratas @@ -1,18 +1,9 @@ menu "CPU errata selection" -config RISCV_ERRATA_ALTERNATIVE - bool "RISC-V alternative scheme" - depends on !XIP_KERNEL - default y - help - This Kconfig allows the kernel to automatically patch the - errata required by the execution platform at run time. The - code patching is performed once in the boot stages. It means - that the overhead from this mechanism is just taken once. - config ERRATA_SIFIVE bool "SiFive errata" - depends on RISCV_ERRATA_ALTERNATIVE + depends on !XIP_KERNEL + select RISCV_ALTERNATIVE help All SiFive errata Kconfig depend on this Kconfig. Disabling this Kconfig will disable all SiFive errata. Please say "Y" diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs index 34592d00dde8..41c0a6e9b0bf 100644 --- a/arch/riscv/Kconfig.socs +++ b/arch/riscv/Kconfig.socs @@ -14,7 +14,6 @@ config SOC_SIFIVE select CLK_SIFIVE select CLK_SIFIVE_PRCI select SIFIVE_PLIC - select RISCV_ERRATA_ALTERNATIVE if !XIP_KERNEL select ERRATA_SIFIVE if !XIP_KERNEL help This enables support for SiFive SoC platform hardware. diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 7d81102cffd4..a7ed47ce9311 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -103,7 +103,7 @@ endif head-y := arch/riscv/kernel/head.o -core-$(CONFIG_RISCV_ERRATA_ALTERNATIVE) += arch/riscv/errata/ +core-y += arch/riscv/errata/ core-$(CONFIG_KVM) += arch/riscv/kvm/ libs-y += arch/riscv/lib/ diff --git a/arch/riscv/errata/Makefile b/arch/riscv/errata/Makefile index b8f8740a3e44..0ca1c5281a2d 100644 --- a/arch/riscv/errata/Makefile +++ b/arch/riscv/errata/Makefile @@ -1,2 +1 @@ -obj-y += alternative.o obj-$(CONFIG_ERRATA_SIFIVE) += sifive/ diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h index 67406c376389..5dd8d03a13da 100644 --- a/arch/riscv/include/asm/alternative-macros.h +++ b/arch/riscv/include/asm/alternative-macros.h @@ -2,7 +2,7 @@ #ifndef __ASM_ALTERNATIVE_MACROS_H #define __ASM_ALTERNATIVE_MACROS_H -#ifdef CONFIG_RISCV_ERRATA_ALTERNATIVE +#ifdef CONFIG_RISCV_ALTERNATIVE #ifdef __ASSEMBLY__ @@ -76,7 +76,7 @@ #endif /* __ASSEMBLY__ */ -#else /* !CONFIG_RISCV_ERRATA_ALTERNATIVE*/ +#else /* CONFIG_RISCV_ALTERNATIVE */ #ifdef __ASSEMBLY__ .macro __ALTERNATIVE_CFG old_c @@ -95,7 +95,8 @@ __ALTERNATIVE_CFG(old_c) #endif /* __ASSEMBLY__ */ -#endif /* CONFIG_RISCV_ERRATA_ALTERNATIVE */ +#endif /* CONFIG_RISCV_ALTERNATIVE */ + /* * Usage: * ALTERNATIVE(old_content, new_content, vendor_id, errata_id, CONFIG_k) diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h index e625d3cafbed..7b42bcef0ecf 100644 --- a/arch/riscv/include/asm/alternative.h +++ b/arch/riscv/include/asm/alternative.h @@ -12,6 +12,8 @@ #ifndef __ASSEMBLY__ +#ifdef CONFIG_RISCV_ALTERNATIVE + #include #include #include @@ -35,5 +37,11 @@ struct errata_checkfunc_id { void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end, unsigned long archid, unsigned long impid); +#else /* CONFIG_RISCV_ALTERNATIVE */ + +static inline void apply_boot_alternatives(void) { } + +#endif /* CONFIG_RISCV_ALTERNATIVE */ + #endif #endif diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 87adbe47bc15..0f8348ac30f1 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -18,6 +18,7 @@ extra-y += head.o extra-y += vmlinux.lds obj-y += soc.o +obj-$(CONFIG_RISCV_ALTERNATIVE) += alternative.o obj-y += cpu.o obj-y += cpufeature.o obj-y += entry.o diff --git a/arch/riscv/errata/alternative.c b/arch/riscv/kernel/alternative.c similarity index 100% rename from arch/riscv/errata/alternative.c rename to arch/riscv/kernel/alternative.c diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c index 622f226454d5..a6d13dca1403 100644 --- a/arch/riscv/kernel/smpboot.c +++ b/arch/riscv/kernel/smpboot.c @@ -41,9 +41,7 @@ static DECLARE_COMPLETION(cpu_running); void __init smp_prepare_boot_cpu(void) { init_cpu_topology(); -#ifdef CONFIG_RISCV_ERRATA_ALTERNATIVE apply_boot_alternatives(); -#endif } void __init smp_prepare_cpus(unsigned int max_cpus) diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index fe92e119e6a3..b40426509244 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -86,7 +86,7 @@ static void do_trap_error(struct pt_regs *regs, int signo, int code, } } -#if defined (CONFIG_XIP_KERNEL) && defined (CONFIG_RISCV_ERRATA_ALTERNATIVE) +#if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_RISCV_ALTERNATIVE) #define __trap_section __section(".xip.traps") #else #define __trap_section