From: Nick Kossifidis Date: Mon, 19 Apr 2021 00:55:38 +0000 (+0300) Subject: RISC-V: Add kdump support X-Git-Tag: accepted/tizen/unified/20230118.172025~7277^2~10 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e53d28180d4d0fd12b6d2bde49cb87aa775b6ba8;p=platform%2Fkernel%2Flinux-rpi.git RISC-V: Add kdump support This patch adds support for kdump, the kernel will reserve a region for the crash kernel and jump there on panic. In order for userspace tools (kexec-tools) to prepare the crash kernel kexec image, we also need to expose some information on /proc/iomem for the memory regions used by the kernel and for the region reserved for crash kernel. Note that on userspace the device tree is used to determine the system's memory layout so the "System RAM" on /proc/iomem is ignored. I tested this on riscv64 qemu and works as expected, you may test it by triggering a crash through /proc/sysrq_trigger: echo c > /proc/sysrq_trigger Signed-off-by: Nick Kossifidis Signed-off-by: Palmer Dabbelt --- diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h index 5c725e1..f4b490c 100644 --- a/arch/riscv/include/asm/elf.h +++ b/arch/riscv/include/asm/elf.h @@ -81,4 +81,10 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp); #endif /* CONFIG_MMU */ +#define ELF_CORE_COPY_REGS(dest, regs) \ +do { \ + *(struct user_regs_struct *)&(dest) = \ + *(struct user_regs_struct *)regs; \ +} while (0); + #endif /* _ASM_RISCV_ELF_H */ diff --git a/arch/riscv/include/asm/kexec.h b/arch/riscv/include/asm/kexec.h index 86e6e49..1e95410 100644 --- a/arch/riscv/include/asm/kexec.h +++ b/arch/riscv/include/asm/kexec.h @@ -23,11 +23,16 @@ #define KEXEC_ARCH KEXEC_ARCH_RISCV +extern void riscv_crash_save_regs(struct pt_regs *newregs); + static inline void crash_setup_regs(struct pt_regs *newregs, struct pt_regs *oldregs) { - /* Dummy implementation for now */ + if (oldregs) + memcpy(newregs, oldregs, sizeof(struct pt_regs)); + else + riscv_crash_save_regs(newregs); } @@ -40,10 +45,12 @@ struct kimage_arch { const extern unsigned char riscv_kexec_relocate[]; const extern unsigned int riscv_kexec_relocate_size; -typedef void (*riscv_kexec_do_relocate)(unsigned long first_ind_entry, - unsigned long jump_addr, - unsigned long fdt_addr, - unsigned long hartid, - unsigned long va_pa_off); +typedef void (*riscv_kexec_method)(unsigned long first_ind_entry, + unsigned long jump_addr, + unsigned long fdt_addr, + unsigned long hartid, + unsigned long va_pa_off); + +extern riscv_kexec_method riscv_kexec_norelocate; #endif diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 96650aa..3ee07bf 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -58,7 +58,7 @@ obj-$(CONFIG_SMP) += cpu_ops_sbi.o endif obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o obj-$(CONFIG_KGDB) += kgdb.o -obj-$(CONFIG_KEXEC) += kexec_relocate.o machine_kexec.o +obj-$(CONFIG_KEXEC) += kexec_relocate.o crash_save_regs.o machine_kexec.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o diff --git a/arch/riscv/kernel/crash_save_regs.S b/arch/riscv/kernel/crash_save_regs.S new file mode 100644 index 0000000..7832fb7 --- /dev/null +++ b/arch/riscv/kernel/crash_save_regs.S @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020 FORTH-ICS/CARV + * Nick Kossifidis + */ + +#include /* For RISCV_* and REG_* macros */ +#include /* For CSR_* macros */ +#include /* For offsets on pt_regs */ +#include /* For SYM_* macros */ + +.section ".text" +SYM_CODE_START(riscv_crash_save_regs) + 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 */ + REG_S a0, PT_A0(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 t1, CSR_STATUS + csrr t2, CSR_EPC + csrr t3, CSR_TVAL + csrr t4, CSR_CAUSE + + REG_S t1, PT_STATUS(a0) + REG_S t2, PT_EPC(a0) + REG_S t3, PT_BADADDR(a0) + REG_S t4, PT_CAUSE(a0) + ret +SYM_CODE_END(riscv_crash_save_regs) diff --git a/arch/riscv/kernel/kexec_relocate.S b/arch/riscv/kernel/kexec_relocate.S index 84101d0..88c3bea 100644 --- a/arch/riscv/kernel/kexec_relocate.S +++ b/arch/riscv/kernel/kexec_relocate.S @@ -151,7 +151,73 @@ SYM_CODE_START(riscv_kexec_relocate) SYM_CODE_END(riscv_kexec_relocate) riscv_kexec_relocate_end: - .section ".rodata" + +/* Used for jumping to crashkernel */ +.section ".text" +SYM_CODE_START(riscv_kexec_norelocate) + /* + * s0: (const) Phys address to jump to + * s1: (const) Phys address of the FDT image + * s2: (const) The hartid of the current hart + * s3: (const) va_pa_offset, used when switching MMU off + */ + mv s0, a1 + mv s1, a2 + mv s2, a3 + mv s3, a4 + + /* Disable / cleanup interrupts */ + csrw CSR_SIE, zero + csrw CSR_SIP, zero + + /* Switch to physical addressing */ + la s4, 1f + sub s4, s4, s3 + csrw CSR_STVEC, s4 + csrw CSR_SATP, zero + +.align 2 +1: + /* Pass the arguments to the next kernel / Cleanup*/ + mv a0, s2 + mv a1, s1 + mv a2, s0 + + /* Cleanup */ + mv a3, zero + mv a4, zero + mv a5, zero + mv a6, zero + mv a7, zero + + mv s0, zero + mv s1, zero + mv s2, zero + mv s3, zero + mv s4, zero + mv s5, zero + mv s6, zero + mv s7, zero + mv s8, zero + mv s9, zero + mv s10, zero + mv s11, zero + + mv t0, zero + mv t1, zero + mv t2, zero + mv t3, zero + mv t4, zero + mv t5, zero + mv t6, zero + csrw CSR_SEPC, zero + csrw CSR_SCAUSE, zero + csrw CSR_SSCRATCH, zero + + jalr zero, a2, 0 +SYM_CODE_END(riscv_kexec_norelocate) + +.section ".rodata" SYM_DATA(riscv_kexec_relocate_size, .long riscv_kexec_relocate_end - riscv_kexec_relocate) diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c index e165c78..cc04814 100644 --- a/arch/riscv/kernel/machine_kexec.c +++ b/arch/riscv/kernel/machine_kexec.c @@ -59,11 +59,6 @@ machine_kexec_prepare(struct kimage *image) kexec_image_info(image); - if (image->type == KEXEC_TYPE_CRASH) { - pr_warn("Loading a crash kernel is unsupported for now.\n"); - return -EINVAL; - } - /* Find the Flattened Device Tree and save its physical address */ for (i = 0; i < image->nr_segments; i++) { if (image->segment[i].memsz <= sizeof(fdt)) @@ -85,17 +80,21 @@ machine_kexec_prepare(struct kimage *image) } /* Copy the assembler code for relocation to the control page */ - control_code_buffer = page_address(image->control_code_page); - control_code_buffer_sz = page_size(image->control_code_page); - if (unlikely(riscv_kexec_relocate_size > control_code_buffer_sz)) { - pr_err("Relocation code doesn't fit within a control page\n"); - return -EINVAL; - } - memcpy(control_code_buffer, riscv_kexec_relocate, - riscv_kexec_relocate_size); + if (image->type != KEXEC_TYPE_CRASH) { + control_code_buffer = page_address(image->control_code_page); + control_code_buffer_sz = page_size(image->control_code_page); - /* Mark the control page executable */ - set_memory_x((unsigned long) control_code_buffer, 1); + if (unlikely(riscv_kexec_relocate_size > control_code_buffer_sz)) { + pr_err("Relocation code doesn't fit within a control page\n"); + return -EINVAL; + } + + memcpy(control_code_buffer, riscv_kexec_relocate, + riscv_kexec_relocate_size); + + /* Mark the control page executable */ + set_memory_x((unsigned long) control_code_buffer, 1); + } return 0; } @@ -147,6 +146,9 @@ void machine_shutdown(void) void machine_crash_shutdown(struct pt_regs *regs) { + crash_save_cpu(regs, smp_processor_id()); + machine_shutdown(); + pr_info("Starting crashdump kernel...\n"); } /** @@ -169,7 +171,12 @@ machine_kexec(struct kimage *image) unsigned long this_hart_id = raw_smp_processor_id(); unsigned long fdt_addr = internal->fdt_addr; void *control_code_buffer = page_address(image->control_code_page); - riscv_kexec_do_relocate do_relocate = control_code_buffer; + riscv_kexec_method kexec_method = NULL; + + if (image->type != KEXEC_TYPE_CRASH) + kexec_method = control_code_buffer; + else + kexec_method = (riscv_kexec_method) &riscv_kexec_norelocate; pr_notice("Will call new kernel at %08lx from hart id %lx\n", jump_addr, this_hart_id); @@ -180,7 +187,7 @@ machine_kexec(struct kimage *image) /* Jump to the relocation code */ pr_notice("Bye...\n"); - do_relocate(first_ind_entry, jump_addr, fdt_addr, - this_hart_id, va_pa_offset); + kexec_method(first_ind_entry, jump_addr, fdt_addr, + this_hart_id, va_pa_offset); unreachable(); } diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 9193ba3..0aa9f83 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include @@ -160,6 +161,14 @@ static void __init init_resources(void) if (ret < 0) goto error; +#ifdef CONFIG_KEXEC_CORE + if (crashk_res.start != crashk_res.end) { + ret = add_resource(&iomem_resource, &crashk_res); + if (ret < 0) + goto error; + } +#endif + for_each_reserved_mem_region(region) { res = &mem_res[res_idx--]; @@ -252,7 +261,6 @@ void __init setup_arch(char **cmdline_p) efi_init(); setup_bootmem(); paging_init(); - init_resources(); #if IS_ENABLED(CONFIG_BUILTIN_DTB) unflatten_and_copy_device_tree(); #else @@ -263,6 +271,7 @@ void __init setup_arch(char **cmdline_p) #endif misc_mem_init(); + init_resources(); sbi_init(); if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) { diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index a2f4c148..63c94d3 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -2,6 +2,8 @@ /* * Copyright (C) 2012 Regents of the University of California * Copyright (C) 2019 Western Digital Corporation or its affiliates. + * Copyright (C) 2020 FORTH-ICS/CARV + * Nick Kossifidis */ #include @@ -14,6 +16,7 @@ #include #include #include +#include #include #include @@ -658,6 +661,71 @@ void mark_rodata_ro(void) } #endif +#ifdef CONFIG_KEXEC_CORE +/* + * reserve_crashkernel() - reserves memory for crash kernel + * + * This function reserves memory area given in "crashkernel=" kernel command + * line parameter. The memory reserved is used by dump capture kernel when + * primary kernel is crashing. + */ +static void __init reserve_crashkernel(void) +{ + unsigned long long crash_base = 0; + unsigned long long crash_size = 0; + unsigned long search_start = memblock_start_of_DRAM(); + unsigned long search_end = memblock_end_of_DRAM(); + + int ret = 0; + + ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), + &crash_size, &crash_base); + if (ret || !crash_size) + return; + + crash_size = PAGE_ALIGN(crash_size); + + if (crash_base == 0) { + /* + * Current riscv boot protocol requires 2MB alignment for + * RV64 and 4MB alignment for RV32 (hugepage size) + */ + crash_base = memblock_find_in_range(search_start, search_end, + crash_size, PMD_SIZE); + + if (crash_base == 0) { + pr_warn("crashkernel: couldn't allocate %lldKB\n", + crash_size >> 10); + return; + } + } else { + /* User specifies base address explicitly. */ + if (!memblock_is_region_memory(crash_base, crash_size)) { + pr_warn("crashkernel: requested region is not memory\n"); + return; + } + + if (memblock_is_region_reserved(crash_base, crash_size)) { + pr_warn("crashkernel: requested region is reserved\n"); + return; + } + + + if (!IS_ALIGNED(crash_base, PMD_SIZE)) { + pr_warn("crashkernel: requested region is misaligned\n"); + return; + } + } + memblock_reserve(crash_base, crash_size); + + pr_info("crashkernel: reserved 0x%016llx - 0x%016llx (%lld MB)\n", + crash_base, crash_base + crash_size, crash_size >> 20); + + crashk_res.start = crash_base; + crashk_res.end = crash_base + crash_size - 1; +} +#endif /* CONFIG_KEXEC_CORE */ + void __init paging_init(void) { setup_vm_final(); @@ -670,6 +738,9 @@ void __init misc_mem_init(void) arch_numa_init(); sparse_init(); zone_sizes_init(); +#ifdef CONFIG_KEXEC_CORE + reserve_crashkernel(); +#endif memblock_dump_all(); }