[kvm-unit-tests,09/24] riscv: Add exception handling

Message ID	20240124071815.6898-35-andrew.jones@linux.dev (mailing list archive)
State	New, archived
Headers	show Received: from out-186.mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 16F5717586 for <kvm@vger.kernel.org>; Wed, 24 Jan 2024 07:18:43 +0000 (UTC) From: Andrew Jones <andrew.jones@linux.dev> To: kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, kvmarm@lists.linux.dev Cc: ajones@ventanamicro.com, anup@brainfault.org, atishp@atishpatra.org, pbonzini@redhat.com, thuth@redhat.com, alexandru.elisei@arm.com, eric.auger@redhat.com Subject: [kvm-unit-tests PATCH 09/24] riscv: Add exception handling Date: Wed, 24 Jan 2024 08:18:25 +0100 Message-ID: <20240124071815.6898-35-andrew.jones@linux.dev> In-Reply-To: <20240124071815.6898-26-andrew.jones@linux.dev> References: <20240124071815.6898-26-andrew.jones@linux.dev> Precedence: bulk MIME-Version: 1.0 Content-type: text/plain Content-Transfer-Encoding: 8bit
Series	Introduce RISC-V \| expand [kvm-unit-tests,00/24] Introduce RISC-V [kvm-unit-tests,01/24] configure: Add ARCH_LIBDIR [kvm-unit-tests,02/24] riscv: Initial port, hello world [kvm-unit-tests,03/24] arm/arm64: Move cpumask.h to common lib [kvm-unit-tests,04/24] arm/arm64: Share cpu online, present and idle masks [kvm-unit-tests,05/24] riscv: Add DT parsing [kvm-unit-tests,06/24] riscv: Add initial SBI support [kvm-unit-tests,07/24] riscv: Add run script and unittests.cfg [kvm-unit-tests,08/24] riscv: Add riscv32 support [kvm-unit-tests,09/24] riscv: Add exception handling [kvm-unit-tests,10/24] riscv: Add backtrace support [kvm-unit-tests,11/24] arm/arm64: Generalize wfe/sev names in smp.c [kvm-unit-tests,12/24] arm/arm64: Remove spinlocks from on_cpu_async [kvm-unit-tests,13/24] arm/arm64: Share on_cpus [kvm-unit-tests,14/24] riscv: Compile with march [kvm-unit-tests,15/24] riscv: Add SMP support [kvm-unit-tests,16/24] arm/arm64: Share memregions [kvm-unit-tests,17/24] riscv: Populate memregions and switch to page allocator [kvm-unit-tests,18/24] riscv: Add MMU support [kvm-unit-tests,19/24] riscv: Enable the MMU in secondaries [kvm-unit-tests,20/24] riscv: Enable vmalloc [kvm-unit-tests,21/24] lib: Add strcasecmp and strncasecmp [kvm-unit-tests,22/24] riscv: Add isa string parsing [kvm-unit-tests,23/24] gitlab-ci: Add riscv64 tests [kvm-unit-tests,24/24] MAINTAINERS: Add riscv

diff --git a/lib/riscv/asm-offsets.c b/lib/riscv/asm-offsets.c index eb337b7547b8..7b88d16fd0e4 100644 --- a/lib/riscv/asm-offsets.c +++ b/lib/riscv/asm-offsets.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0-only #include <kbuild.h> #include <elf.h> +#include <asm/ptrace.h> int main(void) { @@ -13,5 +14,42 @@ int main(void) OFFSET(ELF_RELA_ADDEND, elf64_rela, r_addend); DEFINE(ELF_RELA_SIZE, sizeof(struct elf64_rela)); #endif + OFFSET(PT_EPC, pt_regs, epc); + OFFSET(PT_RA, pt_regs, ra); + OFFSET(PT_SP, pt_regs, sp); + OFFSET(PT_GP, pt_regs, gp); + OFFSET(PT_TP, pt_regs, tp); + OFFSET(PT_T0, pt_regs, t0); + OFFSET(PT_T1, pt_regs, t1); + OFFSET(PT_T2, pt_regs, t2); + OFFSET(PT_S0, pt_regs, s0); + OFFSET(PT_S1, pt_regs, s1); + OFFSET(PT_A0, pt_regs, a0); + OFFSET(PT_A1, pt_regs, a1); + OFFSET(PT_A2, pt_regs, a2); + OFFSET(PT_A3, pt_regs, a3); + OFFSET(PT_A4, pt_regs, a4); + OFFSET(PT_A5, pt_regs, a5); + OFFSET(PT_A6, pt_regs, a6); + OFFSET(PT_A7, pt_regs, a7); + OFFSET(PT_S2, pt_regs, s2); + OFFSET(PT_S3, pt_regs, s3); + OFFSET(PT_S4, pt_regs, s4); + OFFSET(PT_S5, pt_regs, s5); + OFFSET(PT_S6, pt_regs, s6); + OFFSET(PT_S7, pt_regs, s7); + OFFSET(PT_S8, pt_regs, s8); + OFFSET(PT_S9, pt_regs, s9); + OFFSET(PT_S10, pt_regs, s10); + OFFSET(PT_S11, pt_regs, s11); + OFFSET(PT_T3, pt_regs, t3); + OFFSET(PT_T4, pt_regs, t4); + OFFSET(PT_T5, pt_regs, t5); + OFFSET(PT_T6, pt_regs, t6); + OFFSET(PT_STATUS, pt_regs, status); + OFFSET(PT_BADADDR, pt_regs, badaddr); + OFFSET(PT_CAUSE, pt_regs, cause); + OFFSET(PT_ORIG_A0, pt_regs, orig_a0); + DEFINE(PT_SIZE, sizeof(struct pt_regs)); return 0; } diff --git a/lib/riscv/asm/bug.h b/lib/riscv/asm/bug.h new file mode 100644 index 000000000000..a6f4136ba1b6 --- /dev/null +++ b/lib/riscv/asm/bug.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _ASMRISCV_BUG_H_ +#define _ASMRISCV_BUG_H_ + +#ifndef __ASSEMBLY__ + +static inline void bug(void) +{ + asm volatile("ebreak"); +} + +#else + +.macro bug + ebreak +.endm + +#endif + +#endif /* _ASMRISCV_BUG_H_ */ diff --git a/lib/riscv/asm/csr.h b/lib/riscv/asm/csr.h index 356ae054bfff..eeddd1fb448a 100644 --- a/lib/riscv/asm/csr.h +++ b/lib/riscv/asm/csr.h @@ -3,7 +3,19 @@ #define _ASMRISCV_CSR_H_ #include <linux/const.h> +#define CSR_SSTATUS 0x100 +#define CSR_STVEC 0x105 #define CSR_SSCRATCH 0x140 +#define CSR_SEPC 0x141 +#define CSR_SCAUSE 0x142 +#define CSR_STVAL 0x143 + +/* Exception cause high bit - is an interrupt if set */ +#define CAUSE_IRQ_FLAG (_AC(1, UL) << (__riscv_xlen - 1)) + +/* Exception causes */ +#define EXC_INST_ILLEGAL 2 +#define EXC_BREAKPOINT 3 #ifndef __ASSEMBLY__ diff --git a/lib/riscv/asm/processor.h b/lib/riscv/asm/processor.h new file mode 100644 index 000000000000..d8b7018c9102 --- /dev/null +++ b/lib/riscv/asm/processor.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _ASMRISCV_PROCESSOR_H_ +#define _ASMRISCV_PROCESSOR_H_ +#include <asm/csr.h> +#include <asm/ptrace.h> + +#define EXCEPTION_CAUSE_MAX 16 + +typedef void (*exception_fn)(struct pt_regs *); + +struct thread_info { + int cpu; + unsigned long hartid; + exception_fn exception_handlers[EXCEPTION_CAUSE_MAX]; +}; + +static inline struct thread_info *current_thread_info(void) +{ + return (struct thread_info *)csr_read(CSR_SSCRATCH); +} + +void install_exception_handler(unsigned long cause, void (*handler)(struct pt_regs *)); +void do_handle_exception(struct pt_regs *regs); +void thread_info_init(void); + +#endif /* _ASMRISCV_PROCESSOR_H_ */ diff --git a/lib/riscv/asm/ptrace.h b/lib/riscv/asm/ptrace.h new file mode 100644 index 000000000000..0873a8ae749f --- /dev/null +++ b/lib/riscv/asm/ptrace.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _ASMRISCV_PTRACE_H_ +#define _ASMRISCV_PTRACE_H_ + +struct pt_regs { + unsigned long epc; + unsigned long ra; + unsigned long sp; + unsigned long gp; + unsigned long tp; + unsigned long t0; + unsigned long t1; + unsigned long t2; + unsigned long s0; + unsigned long s1; + unsigned long a0; + unsigned long a1; + unsigned long a2; + unsigned long a3; + unsigned long a4; + unsigned long a5; + unsigned long a6; + unsigned long a7; + unsigned long s2; + unsigned long s3; + unsigned long s4; + unsigned long s5; + unsigned long s6; + unsigned long s7; + unsigned long s8; + unsigned long s9; + unsigned long s10; + unsigned long s11; + unsigned long t3; + unsigned long t4; + unsigned long t5; + unsigned long t6; + /* Supervisor/Machine CSRs */ + unsigned long status; + unsigned long badaddr; + unsigned long cause; + /* a0 value before the syscall */ + unsigned long orig_a0; +}; + +#endif /* _ASMRISCV_PTRACE_H_ */ diff --git a/lib/riscv/asm/setup.h b/lib/riscv/asm/setup.h index c8cfebb4f2c1..e58dd53071ae 100644 --- a/lib/riscv/asm/setup.h +++ b/lib/riscv/asm/setup.h @@ -2,9 +2,10 @@ #ifndef _ASMRISCV_SETUP_H_ #define _ASMRISCV_SETUP_H_ #include <libcflat.h> +#include <asm/processor.h> #define NR_CPUS 16 -extern unsigned long cpus[NR_CPUS]; /* per-cpu IDs (hartids) */ +extern struct thread_info cpus[NR_CPUS]; extern int nr_cpus; int hartid_to_cpu(unsigned long hartid); diff --git a/lib/riscv/processor.c b/lib/riscv/processor.c new file mode 100644 index 000000000000..3790349aadd1 --- /dev/null +++ b/lib/riscv/processor.c @@ -0,0 +1,60 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2023, Ventana Micro Systems Inc., Andrew Jones <ajones@ventanamicro.com> + */ +#include <libcflat.h> +#include <asm/csr.h> +#include <asm/processor.h> +#include <asm/setup.h> + +extern unsigned long _text; + +static void show_regs(struct pt_regs *regs) +{ + uintptr_t text = (uintptr_t)&_text; + unsigned int w = __riscv_xlen / 4; + + printf("Load address: %" PRIxPTR "\n", text); + printf("status : %.*lx\n", w, regs->status); + printf("cause : %.*lx\n", w, regs->cause); + printf("badaddr: %.*lx\n", w, regs->badaddr); + printf("pc: %.*lx ra: %.*lx\n", w, regs->epc, w, regs->ra); + printf("sp: %.*lx gp: %.*lx tp : %.*lx\n", w, regs->sp, w, regs->gp, w, regs->tp); + printf("a0: %.*lx a1: %.*lx a2 : %.*lx a3 : %.*lx\n", w, regs->a0, w, regs->a1, w, regs->a2, w, regs->a3); + printf("a4: %.*lx a5: %.*lx a6 : %.*lx a7 : %.*lx\n", w, regs->a4, w, regs->a5, w, regs->a6, w, regs->a7); + printf("t0: %.*lx t1: %.*lx t2 : %.*lx t3 : %.*lx\n", w, regs->t0, w, regs->t1, w, regs->t2, w, regs->t3); + printf("t4: %.*lx t5: %.*lx t6 : %.*lx\n", w, regs->t4, w, regs->t5, w, regs->t6); + printf("s0: %.*lx s1: %.*lx s2 : %.*lx s3 : %.*lx\n", w, regs->s0, w, regs->s1, w, regs->s2, w, regs->s3); + printf("s4: %.*lx s5: %.*lx s6 : %.*lx s7 : %.*lx\n", w, regs->s4, w, regs->s5, w, regs->s6, w, regs->s7); + printf("s8: %.*lx s9: %.*lx s10: %.*lx s11: %.*lx\n", w, regs->s8, w, regs->s9, w, regs->s10, w, regs->s11); +} + +void do_handle_exception(struct pt_regs *regs) +{ + struct thread_info *info = current_thread_info(); + + assert(regs->cause < EXCEPTION_CAUSE_MAX); + if (info->exception_handlers[regs->cause]) { + info->exception_handlers[regs->cause](regs); + return; + } + + show_regs(regs); + assert(0); +} + +void install_exception_handler(unsigned long cause, void (*handler)(struct pt_regs *)) +{ + struct thread_info *info = current_thread_info(); + + assert(cause < EXCEPTION_CAUSE_MAX); + info->exception_handlers[cause] = handler; +} + +void thread_info_init(void) +{ + unsigned long hartid = csr_read(CSR_SSCRATCH); + int cpu = hartid_to_cpu(hartid); + + csr_write(CSR_SSCRATCH, &cpus[cpu]); +} diff --git a/lib/riscv/setup.c b/lib/riscv/setup.c index 44c26b125a27..57eb4797f798 100644 --- a/lib/riscv/setup.c +++ b/lib/riscv/setup.c @@ -12,12 +12,13 @@ #include <devicetree.h> #include <asm/csr.h> #include <asm/page.h> +#include <asm/processor.h> #include <asm/setup.h> char *initrd; u32 initrd_size; -unsigned long cpus[NR_CPUS] = { [0 ... NR_CPUS - 1] = ~0UL }; +struct thread_info cpus[NR_CPUS]; int nr_cpus; int hartid_to_cpu(unsigned long hartid) @@ -25,7 +26,7 @@ int hartid_to_cpu(unsigned long hartid) int cpu; for_each_present_cpu(cpu) - if (cpus[cpu] == hartid) + if (cpus[cpu].hartid == hartid) return cpu; return -1; } @@ -36,7 +37,8 @@ static void cpu_set_fdt(int fdtnode __unused, u64 regval, void *info __unused) assert_msg(cpu < NR_CPUS, "Number cpus exceeds maximum supported (%d).", NR_CPUS); - cpus[cpu] = regval; + cpus[cpu].cpu = cpu; + cpus[cpu].hartid = regval; set_cpu_present(cpu, true); } @@ -104,6 +106,7 @@ void setup(const void *fdt, phys_addr_t freemem_start) mem_init(PAGE_ALIGN((unsigned long)freemem)); cpu_init(); + thread_info_init(); io_init(); ret = dt_get_bootargs(&bootargs); diff --git a/riscv/Makefile b/riscv/Makefile index fb97e678a456..1243be125c00 100644 --- a/riscv/Makefile +++ b/riscv/Makefile @@ -26,6 +26,7 @@ cflatobjs += lib/alloc_phys.o cflatobjs += lib/devicetree.o cflatobjs += lib/riscv/bitops.o cflatobjs += lib/riscv/io.o +cflatobjs += lib/riscv/processor.o cflatobjs += lib/riscv/sbi.o cflatobjs += lib/riscv/setup.o cflatobjs += lib/riscv/smp.o diff --git a/riscv/cstart.S b/riscv/cstart.S index 6ec2231e5812..ac7858ef398f 100644 --- a/riscv/cstart.S +++ b/riscv/cstart.S @@ -37,8 +37,9 @@ .global start start: /* - * Stash the hartid in scratch and shift the dtb - * address into a0 + * Stash the hartid in scratch and shift the dtb address into a0. + * thread_info_init() will later promote scratch to point at thread + * local storage. */ csrw CSR_SSCRATCH, a0 mv a0, a1 @@ -74,7 +75,8 @@ start: zero_range a1, sp /* set up exception handling */ - //TODO + la a1, exception_vectors + csrw CSR_STVEC, a1 /* complete setup */ la a1, stacktop // a1 is the base of free memory @@ -97,3 +99,111 @@ start: halt: 1: wfi j 1b + +/* + * Save context to address in a0. + * For a0, sets PT_A0(a0) to the contents of PT_ORIG_A0(a0). + * Clobbers a1. + */ +.macro save_context + REG_S ra, PT_RA(a0) // x1 + REG_S sp, PT_SP(a0) // x2 + REG_S gp, PT_GP(a0) // x3 + REG_S tp, PT_TP(a0) // x4 + REG_S t0, PT_T0(a0) // x5 + REG_S t1, PT_T1(a0) // x6 + REG_S t2, PT_T2(a0) // x7 + REG_S s0, PT_S0(a0) // x8 / fp + REG_S s1, PT_S1(a0) // x9 + /* a0 */ // x10 + REG_S a1, PT_A1(a0) // x11 + REG_S a2, PT_A2(a0) // x12 + REG_S a3, PT_A3(a0) // x13 + REG_S a4, PT_A4(a0) // x14 + REG_S a5, PT_A5(a0) // x15 + REG_S a6, PT_A6(a0) // x16 + REG_S a7, PT_A7(a0) // x17 + REG_S s2, PT_S2(a0) // x18 + REG_S s3, PT_S3(a0) // x19 + REG_S s4, PT_S4(a0) // x20 + REG_S s5, PT_S5(a0) // x21 + REG_S s6, PT_S6(a0) // x22 + REG_S s7, PT_S7(a0) // x23 + REG_S s8, PT_S8(a0) // x24 + REG_S s9, PT_S9(a0) // x25 + REG_S s10, PT_S10(a0) // x26 + REG_S s11, PT_S11(a0) // x27 + REG_S t3, PT_T3(a0) // x28 + REG_S t4, PT_T4(a0) // x29 + REG_S t5, PT_T5(a0) // x30 + REG_S t6, PT_T6(a0) // x31 + csrr a1, CSR_SEPC + REG_S a1, PT_EPC(a0) + csrr a1, CSR_SSTATUS + REG_S a1, PT_STATUS(a0) + csrr a1, CSR_STVAL + REG_S a1, PT_BADADDR(a0) + csrr a1, CSR_SCAUSE + REG_S a1, PT_CAUSE(a0) + REG_L a1, PT_ORIG_A0(a0) + REG_S a1, PT_A0(a0) +.endm + +/* + * Restore context from address in a0. + * Also restores a0. + */ +.macro restore_context + REG_L ra, PT_RA(a0) // x1 + REG_L sp, PT_SP(a0) // x2 + REG_L gp, PT_GP(a0) // x3 + REG_L tp, PT_TP(a0) // x4 + REG_L t0, PT_T0(a0) // x5 + REG_L t1, PT_T1(a0) // x6 + REG_L t2, PT_T2(a0) // x7 + REG_L s0, PT_S0(a0) // x8 / fp + REG_L s1, PT_S1(a0) // x9 + /* a0 */ // x10 + /* a1 */ // x11 + REG_L a2, PT_A2(a0) // x12 + REG_L a3, PT_A3(a0) // x13 + REG_L a4, PT_A4(a0) // x14 + REG_L a5, PT_A5(a0) // x15 + REG_L a6, PT_A6(a0) // x16 + REG_L a7, PT_A7(a0) // x17 + REG_L s2, PT_S2(a0) // x18 + REG_L s3, PT_S3(a0) // x19 + REG_L s4, PT_S4(a0) // x20 + REG_L s5, PT_S5(a0) // x21 + REG_L s6, PT_S6(a0) // x22 + REG_L s7, PT_S7(a0) // x23 + REG_L s8, PT_S8(a0) // x24 + REG_L s9, PT_S9(a0) // x25 + REG_L s10, PT_S10(a0) // x26 + REG_L s11, PT_S11(a0) // x27 + REG_L t3, PT_T3(a0) // x28 + REG_L t4, PT_T4(a0) // x29 + REG_L t5, PT_T5(a0) // x30 + REG_L t6, PT_T6(a0) // x31 + REG_L a1, PT_EPC(a0) + csrw CSR_SEPC, a1 + REG_L a1, PT_STATUS(a0) + csrw CSR_SSTATUS, a1 + REG_L a1, PT_BADADDR(a0) + csrw CSR_STVAL, a1 + REG_L a1, PT_CAUSE(a0) + csrw CSR_SCAUSE, a1 + REG_L a1, PT_A1(a0) + REG_L a0, PT_A0(a0) +.endm + +.balign 4 +.global exception_vectors +exception_vectors: + REG_S a0, (-PT_SIZE + PT_ORIG_A0)(sp) + addi a0, sp, -PT_SIZE + save_context + mv sp, a0 + call do_handle_exception + restore_context + sret diff --git a/riscv/selftest.c b/riscv/selftest.c index d3b269cf6255..219093489b62 100644 --- a/riscv/selftest.c +++ b/riscv/selftest.c @@ -6,6 +6,7 @@ */ #include <libcflat.h> #include <cpumask.h> +#include <asm/processor.h> #include <asm/setup.h> static void check_cpus(void) @@ -13,7 +14,23 @@ static void check_cpus(void) int cpu; for_each_present_cpu(cpu) - report_info("CPU%3d: hartid=%08lx", cpu, cpus[cpu]); + report_info("CPU%3d: hartid=%08lx", cpu, cpus[cpu].hartid); +} + +static bool exceptions_work; + +static void handler(struct pt_regs *regs) +{ + exceptions_work = true; + regs->epc += 2; +} + +static void check_exceptions(void) +{ + install_exception_handler(EXC_INST_ILLEGAL, handler); + asm volatile(".4byte 0"); + install_exception_handler(EXC_INST_ILLEGAL, NULL); + report(exceptions_work, "exceptions"); } int main(int argc, char **argv) @@ -45,6 +62,7 @@ int main(int argc, char **argv) report_skip("environ parsing"); } + check_exceptions(); check_cpus(); return report_summary();

[kvm-unit-tests,09/24] riscv: Add exception handling

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