[v10,3/8] RISC-V: Add arch functions for non-retentive suspend entry/exit

Message ID	20220126114452.692512-4-apatel@ventanamicro.com
State	New
Headers	show Return-Path: <devicetree-owner@kernel.org> From: Anup Patel <apatel@ventanamicro.com> To: Palmer Dabbelt <palmer@dabbelt.com>, Paul Walmsley <paul.walmsley@sifive.com>, Albert Ou <aou@eecs.berkeley.edu>, Daniel Lezcano <daniel.lezcano@linaro.org>, Ulf Hansson <ulf.hansson@linaro.org>, "Rafael J . Wysocki" <rjw@rjwysocki.net>, Pavel Machek <pavel@ucw.cz>, Rob Herring <robh+dt@kernel.org> Cc: Sandeep Tripathy <milun.tripathy@gmail.com>, Atish Patra <atishp@atishpatra.org>, Alistair Francis <Alistair.Francis@wdc.com>, Liush <liush@allwinnertech.com>, Anup Patel <anup@brainfault.org>, devicetree@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvm-riscv@lists.infradead.org, Anup Patel <apatel@ventanamicro.com> Subject: [PATCH v10 3/8] RISC-V: Add arch functions for non-retentive suspend entry/exit Date: Wed, 26 Jan 2022 17:14:47 +0530 Message-Id: <20220126114452.692512-4-apatel@ventanamicro.com> In-Reply-To: <20220126114452.692512-1-apatel@ventanamicro.com> References: <20220126114452.692512-1-apatel@ventanamicro.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	RISC-V CPU Idle Support \| expand [v10,0/8] RISC-V CPU Idle Support [v10,1/8] RISC-V: Enable CPU_IDLE drivers [v10,2/8] RISC-V: Rename relocate() and make it global [v10,3/8] RISC-V: Add arch functions for non-retentive suspend entry/exit [v10,4/8] RISC-V: Add SBI HSM suspend related defines [v10,5/8] cpuidle: Factor-out power domain related code from PSCI domain driver [v10,6/8] cpuidle: Add RISC-V SBI CPU idle driver [v10,7/8] dt-bindings: Add common bindings for ARM and RISC-V idle states [v10,8/8] RISC-V: Enable RISC-V SBI CPU Idle driver for QEMU virt machine

diff --git a/arch/riscv/include/asm/asm.h b/arch/riscv/include/asm/asm.h index 618d7c5af1a2..48b4baa4d706 100644 --- a/arch/riscv/include/asm/asm.h +++ b/arch/riscv/include/asm/asm.h @@ -67,4 +67,31 @@ #error "Unexpected __SIZEOF_SHORT__" #endif +#ifdef __ASSEMBLY__ + +/* Common assembly source macros */ + +#ifdef CONFIG_XIP_KERNEL +.macro XIP_FIXUP_OFFSET reg + REG_L t0, _xip_fixup + add \reg, \reg, t0 +.endm +.macro XIP_FIXUP_FLASH_OFFSET reg + la t1, __data_loc + li t0, XIP_OFFSET_MASK + and t1, t1, t0 + li t1, XIP_OFFSET + sub t0, t0, t1 + sub \reg, \reg, t0 +.endm +_xip_fixup: .dword CONFIG_PHYS_RAM_BASE - CONFIG_XIP_PHYS_ADDR - XIP_OFFSET +#else +.macro XIP_FIXUP_OFFSET reg +.endm +.macro XIP_FIXUP_FLASH_OFFSET reg +.endm +#endif /* CONFIG_XIP_KERNEL */ + +#endif /* __ASSEMBLY__ */ + #endif /* _ASM_RISCV_ASM_H */ diff --git a/arch/riscv/include/asm/suspend.h b/arch/riscv/include/asm/suspend.h new file mode 100644 index 000000000000..8be391c2aecb --- /dev/null +++ b/arch/riscv/include/asm/suspend.h @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2021 Western Digital Corporation or its affiliates. + * Copyright (c) 2022 Ventana Micro Systems Inc. + */ + +#ifndef _ASM_RISCV_SUSPEND_H +#define _ASM_RISCV_SUSPEND_H + +#include <asm/ptrace.h> + +struct suspend_context { + /* Saved and restored by low-level functions */ + struct pt_regs regs; + /* Saved and restored by high-level functions */ + unsigned long scratch; + unsigned long tvec; + unsigned long ie; +#ifdef CONFIG_MMU + unsigned long satp; +#endif +}; + +/* Low-level CPU suspend entry function */ +int __cpu_suspend_enter(struct suspend_context *context); + +/* High-level CPU suspend which will save context and call finish() */ +int cpu_suspend(unsigned long arg, + int (*finish)(unsigned long arg, + unsigned long entry, + unsigned long context)); + +/* Low-level CPU resume entry function */ +int __cpu_resume_enter(unsigned long hartid, unsigned long context); + +#endif diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 612556faa527..13fa5733f5e7 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -48,6 +48,8 @@ obj-$(CONFIG_RISCV_BOOT_SPINWAIT) += cpu_ops_spinwait.o obj-$(CONFIG_MODULES) += module.o obj-$(CONFIG_MODULE_SECTIONS) += module-sections.o +obj-$(CONFIG_CPU_PM) += suspend_entry.o suspend.o + obj-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o obj-$(CONFIG_DYNAMIC_FTRACE) += mcount-dyn.o diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c index df0519a64eaf..df9444397908 100644 --- a/arch/riscv/kernel/asm-offsets.c +++ b/arch/riscv/kernel/asm-offsets.c @@ -13,6 +13,7 @@ #include <asm/thread_info.h> #include <asm/ptrace.h> #include <asm/cpu_ops_sbi.h> +#include <asm/suspend.h> void asm_offsets(void); @@ -113,6 +114,8 @@ void asm_offsets(void) OFFSET(PT_BADADDR, pt_regs, badaddr); OFFSET(PT_CAUSE, pt_regs, cause); + OFFSET(SUSPEND_CONTEXT_REGS, suspend_context, regs); + OFFSET(KVM_ARCH_GUEST_ZERO, kvm_vcpu_arch, guest_context.zero); OFFSET(KVM_ARCH_GUEST_RA, kvm_vcpu_arch, guest_context.ra); OFFSET(KVM_ARCH_GUEST_SP, kvm_vcpu_arch, guest_context.sp); diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 5f4c6b6c4974..893b8bb69391 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -16,27 +16,6 @@ #include <asm/image.h> #include "efi-header.S" -#ifdef CONFIG_XIP_KERNEL -.macro XIP_FIXUP_OFFSET reg - REG_L t0, _xip_fixup - add \reg, \reg, t0 -.endm -.macro XIP_FIXUP_FLASH_OFFSET reg - la t1, __data_loc - li t0, XIP_OFFSET_MASK - and t1, t1, t0 - li t1, XIP_OFFSET - sub t0, t0, t1 - sub \reg, \reg, t0 -.endm -_xip_fixup: .dword CONFIG_PHYS_RAM_BASE - CONFIG_XIP_PHYS_ADDR - XIP_OFFSET -#else -.macro XIP_FIXUP_OFFSET reg -.endm -.macro XIP_FIXUP_FLASH_OFFSET reg -.endm -#endif /* CONFIG_XIP_KERNEL */ - __HEAD ENTRY(_start) /* diff --git a/arch/riscv/kernel/suspend.c b/arch/riscv/kernel/suspend.c new file mode 100644 index 000000000000..9ba24fb8cc93 --- /dev/null +++ b/arch/riscv/kernel/suspend.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2021 Western Digital Corporation or its affiliates. + * Copyright (c) 2022 Ventana Micro Systems Inc. + */ + +#include <linux/ftrace.h> +#include <asm/csr.h> +#include <asm/suspend.h> + +static void suspend_save_csrs(struct suspend_context *context) +{ + context->scratch = csr_read(CSR_SCRATCH); + context->tvec = csr_read(CSR_TVEC); + context->ie = csr_read(CSR_IE); + + /* + * No need to save/restore IP CSR (i.e. MIP or SIP) because: + * + * 1. For no-MMU (M-mode) kernel, the bits in MIP are set by + * external devices (such as interrupt controller, timer, etc). + * 2. For MMU (S-mode) kernel, the bits in SIP are set by + * M-mode firmware and external devices (such as interrupt + * controller, etc). + */ + +#ifdef CONFIG_MMU + context->satp = csr_read(CSR_SATP); +#endif +} + +static void suspend_restore_csrs(struct suspend_context *context) +{ + csr_write(CSR_SCRATCH, context->scratch); + csr_write(CSR_TVEC, context->tvec); + csr_write(CSR_IE, context->ie); + +#ifdef CONFIG_MMU + csr_write(CSR_SATP, context->satp); +#endif +} + +int cpu_suspend(unsigned long arg, + int (*finish)(unsigned long arg, + unsigned long entry, + unsigned long context)) +{ + int rc = 0; + struct suspend_context context = { 0 }; + + /* Finisher should be non-NULL */ + if (!finish) + return -EINVAL; + + /* Save additional CSRs*/ + suspend_save_csrs(&context); + + /* + * Function graph tracer state gets incosistent when the kernel + * calls functions that never return (aka finishers) hence disable + * graph tracing during their execution. + */ + pause_graph_tracing(); + + /* Save context on stack */ + if (__cpu_suspend_enter(&context)) { + /* Call the finisher */ + rc = finish(arg, __pa_symbol(__cpu_resume_enter), + (ulong)&context); + + /* + * Should never reach here, unless the suspend finisher + * fails. Successful cpu_suspend() should return from + * __cpu_resume_entry() + */ + if (!rc) + rc = -EOPNOTSUPP; + } + + /* Enable function graph tracer */ + unpause_graph_tracing(); + + /* Restore additional CSRs */ + suspend_restore_csrs(&context); + + return rc; +} diff --git a/arch/riscv/kernel/suspend_entry.S b/arch/riscv/kernel/suspend_entry.S new file mode 100644 index 000000000000..4b07b809a2b8 --- /dev/null +++ b/arch/riscv/kernel/suspend_entry.S @@ -0,0 +1,124 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2021 Western Digital Corporation or its affiliates. + * Copyright (c) 2022 Ventana Micro Systems Inc. + */ + +#include <linux/linkage.h> +#include <asm/asm.h> +#include <asm/asm-offsets.h> +#include <asm/csr.h> + + .text + .altmacro + .option norelax + +ENTRY(__cpu_suspend_enter) + /* Save registers (except A0 and T0-T6) */ + REG_S ra, (SUSPEND_CONTEXT_REGS + PT_RA)(a0) + REG_S sp, (SUSPEND_CONTEXT_REGS + PT_SP)(a0) + REG_S gp, (SUSPEND_CONTEXT_REGS + PT_GP)(a0) + REG_S tp, (SUSPEND_CONTEXT_REGS + PT_TP)(a0) + REG_S s0, (SUSPEND_CONTEXT_REGS + PT_S0)(a0) + REG_S s1, (SUSPEND_CONTEXT_REGS + PT_S1)(a0) + REG_S a1, (SUSPEND_CONTEXT_REGS + PT_A1)(a0) + REG_S a2, (SUSPEND_CONTEXT_REGS + PT_A2)(a0) + REG_S a3, (SUSPEND_CONTEXT_REGS + PT_A3)(a0) + REG_S a4, (SUSPEND_CONTEXT_REGS + PT_A4)(a0) + REG_S a5, (SUSPEND_CONTEXT_REGS + PT_A5)(a0) + REG_S a6, (SUSPEND_CONTEXT_REGS + PT_A6)(a0) + REG_S a7, (SUSPEND_CONTEXT_REGS + PT_A7)(a0) + REG_S s2, (SUSPEND_CONTEXT_REGS + PT_S2)(a0) + REG_S s3, (SUSPEND_CONTEXT_REGS + PT_S3)(a0) + REG_S s4, (SUSPEND_CONTEXT_REGS + PT_S4)(a0) + REG_S s5, (SUSPEND_CONTEXT_REGS + PT_S5)(a0) + REG_S s6, (SUSPEND_CONTEXT_REGS + PT_S6)(a0) + REG_S s7, (SUSPEND_CONTEXT_REGS + PT_S7)(a0) + REG_S s8, (SUSPEND_CONTEXT_REGS + PT_S8)(a0) + REG_S s9, (SUSPEND_CONTEXT_REGS + PT_S9)(a0) + REG_S s10, (SUSPEND_CONTEXT_REGS + PT_S10)(a0) + REG_S s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0) + + /* Save CSRs */ + csrr t0, CSR_EPC + REG_S t0, (SUSPEND_CONTEXT_REGS + PT_EPC)(a0) + csrr t0, CSR_STATUS + REG_S t0, (SUSPEND_CONTEXT_REGS + PT_STATUS)(a0) + csrr t0, CSR_TVAL + REG_S t0, (SUSPEND_CONTEXT_REGS + PT_BADADDR)(a0) + csrr t0, CSR_CAUSE + REG_S t0, (SUSPEND_CONTEXT_REGS + PT_CAUSE)(a0) + + /* Return non-zero value */ + li a0, 1 + + /* Return to C code */ + ret +END(__cpu_suspend_enter) + +ENTRY(__cpu_resume_enter) + /* Load the global pointer */ + .option push + .option norelax + la gp, __global_pointer$ + .option pop + +#ifdef CONFIG_MMU + /* Save A0 and A1 */ + add t0, a0, zero + add t1, a1, zero + + /* Enable MMU */ + la a0, swapper_pg_dir + XIP_FIXUP_OFFSET a0 + call relocate_enable_mmu + + /* Restore A0 and A1 */ + add a0, t0, zero + add a1, t1, zero +#endif + + /* Make A0 point to suspend context */ + add a0, a1, zero + + /* Restore CSRs */ + REG_L t0, (SUSPEND_CONTEXT_REGS + PT_EPC)(a0) + csrw CSR_EPC, t0 + REG_L t0, (SUSPEND_CONTEXT_REGS + PT_STATUS)(a0) + csrw CSR_STATUS, t0 + REG_L t0, (SUSPEND_CONTEXT_REGS + PT_BADADDR)(a0) + csrw CSR_TVAL, t0 + REG_L t0, (SUSPEND_CONTEXT_REGS + PT_CAUSE)(a0) + csrw CSR_CAUSE, t0 + + /* Restore registers (except A0 and T0-T6) */ + REG_L ra, (SUSPEND_CONTEXT_REGS + PT_RA)(a0) + REG_L sp, (SUSPEND_CONTEXT_REGS + PT_SP)(a0) + REG_L gp, (SUSPEND_CONTEXT_REGS + PT_GP)(a0) + REG_L tp, (SUSPEND_CONTEXT_REGS + PT_TP)(a0) + REG_L s0, (SUSPEND_CONTEXT_REGS + PT_S0)(a0) + REG_L s1, (SUSPEND_CONTEXT_REGS + PT_S1)(a0) + REG_L a1, (SUSPEND_CONTEXT_REGS + PT_A1)(a0) + REG_L a2, (SUSPEND_CONTEXT_REGS + PT_A2)(a0) + REG_L a3, (SUSPEND_CONTEXT_REGS + PT_A3)(a0) + REG_L a4, (SUSPEND_CONTEXT_REGS + PT_A4)(a0) + REG_L a5, (SUSPEND_CONTEXT_REGS + PT_A5)(a0) + REG_L a6, (SUSPEND_CONTEXT_REGS + PT_A6)(a0) + REG_L a7, (SUSPEND_CONTEXT_REGS + PT_A7)(a0) + REG_L s2, (SUSPEND_CONTEXT_REGS + PT_S2)(a0) + REG_L s3, (SUSPEND_CONTEXT_REGS + PT_S3)(a0) + REG_L s4, (SUSPEND_CONTEXT_REGS + PT_S4)(a0) + REG_L s5, (SUSPEND_CONTEXT_REGS + PT_S5)(a0) + REG_L s6, (SUSPEND_CONTEXT_REGS + PT_S6)(a0) + REG_L s7, (SUSPEND_CONTEXT_REGS + PT_S7)(a0) + REG_L s8, (SUSPEND_CONTEXT_REGS + PT_S8)(a0) + REG_L s9, (SUSPEND_CONTEXT_REGS + PT_S9)(a0) + REG_L s10, (SUSPEND_CONTEXT_REGS + PT_S10)(a0) + REG_L s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0) + + /* Return zero value */ + add a0, zero, zero + + /* Return to C code */ + ret +END(__cpu_resume_enter)

[v10,3/8] RISC-V: Add arch functions for non-retentive suspend entry/exit

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