/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2012 Regents of the University of California */ #include #include #include #include #include #include #include #include #include #include #include #include #include "efi-header.S" __HEAD ENTRY(_start) /* * Image header expected by Linux boot-loaders. The image header data * structure is described in asm/image.h. * Do not modify it without modifying the structure and all bootloaders * that expects this header format!! */ #ifdef CONFIG_EFI /* * This instruction decodes to "MZ" ASCII required by UEFI. */ c.li s4,-13 j _start_kernel #else /* jump to start kernel */ j _start_kernel /* reserved */ .word 0 #endif .balign 8 #ifdef CONFIG_RISCV_M_MODE /* Image load offset (0MB) from start of RAM for M-mode */ .dword 0 #else #if __riscv_xlen == 64 /* Image load offset(2MB) from start of RAM */ .dword 0x200000 #else /* Image load offset(4MB) from start of RAM */ .dword 0x400000 #endif #endif /* Effective size of kernel image */ .dword _end - _start .dword __HEAD_FLAGS .word RISCV_HEADER_VERSION .word 0 .dword 0 .ascii RISCV_IMAGE_MAGIC .balign 4 .ascii RISCV_IMAGE_MAGIC2 #ifdef CONFIG_EFI .word pe_head_start - _start pe_head_start: __EFI_PE_HEADER #else .word 0 #endif .align 2 #ifdef CONFIG_MMU .global relocate_enable_mmu relocate_enable_mmu: /* Relocate return address */ la a1, kernel_map XIP_FIXUP_OFFSET a1 REG_L a1, KERNEL_MAP_VIRT_ADDR(a1) la a2, _start sub a1, a1, a2 add ra, ra, a1 /* Point stvec to virtual address of intruction after satp write */ la a2, 1f add a2, a2, a1 csrw CSR_TVEC, a2 /* Compute satp for kernel page tables, but don't load it yet */ srl a2, a0, PAGE_SHIFT la a1, satp_mode XIP_FIXUP_OFFSET a1 REG_L a1, 0(a1) or a2, a2, a1 /* * Load trampoline page directory, which will cause us to trap to * stvec if VA != PA, or simply fall through if VA == PA. We need a * full fence here because setup_vm() just wrote these PTEs and we need * to ensure the new translations are in use. */ la a0, trampoline_pg_dir XIP_FIXUP_OFFSET a0 srl a0, a0, PAGE_SHIFT or a0, a0, a1 sfence.vma csrw CSR_SATP, a0 .align 2 1: /* Set trap vector to spin forever to help debug */ la a0, .Lsecondary_park csrw CSR_TVEC, a0 /* Reload the global pointer */ .option push .option norelax la gp, __global_pointer$ .option pop /* * Switch to kernel page tables. A full fence is necessary in order to * avoid using the trampoline translations, which are only correct for * the first superpage. Fetching the fence is guaranteed to work * because that first superpage is translated the same way. */ csrw CSR_SATP, a2 sfence.vma ret #endif /* CONFIG_MMU */ #ifdef CONFIG_SMP .global secondary_start_sbi secondary_start_sbi: /* Mask all interrupts */ csrw CSR_IE, zero csrw CSR_IP, zero /* Load the global pointer */ .option push .option norelax la gp, __global_pointer$ .option pop /* * Disable FPU & VECTOR to detect illegal usage of * floating point or vector in kernel space */ li t0, SR_FS_VS csrc CSR_STATUS, t0 /* Set trap vector to spin forever to help debug */ la a3, .Lsecondary_park csrw CSR_TVEC, a3 /* a0 contains the hartid & a1 contains boot data */ li a2, SBI_HART_BOOT_TASK_PTR_OFFSET XIP_FIXUP_OFFSET a2 add a2, a2, a1 REG_L tp, (a2) li a3, SBI_HART_BOOT_STACK_PTR_OFFSET XIP_FIXUP_OFFSET a3 add a3, a3, a1 REG_L sp, (a3) .Lsecondary_start_common: #ifdef CONFIG_MMU /* Enable virtual memory and relocate to virtual address */ la a0, swapper_pg_dir XIP_FIXUP_OFFSET a0 call relocate_enable_mmu #endif call setup_trap_vector tail smp_callin #endif /* CONFIG_SMP */ .align 2 setup_trap_vector: /* Set trap vector to exception handler */ la a0, handle_exception csrw CSR_TVEC, a0 /* * Set sup0 scratch register to 0, indicating to exception vector that * we are presently executing in kernel. */ csrw CSR_SCRATCH, zero ret .align 2 .Lsecondary_park: /* We lack SMP support or have too many harts, so park this hart */ wfi j .Lsecondary_park END(_start) ENTRY(_start_kernel) /* Mask all interrupts */ csrw CSR_IE, zero csrw CSR_IP, zero #ifdef CONFIG_RISCV_M_MODE /* flush the instruction cache */ fence.i /* Reset all registers except ra, a0, a1 */ call reset_regs /* * Setup a PMP to permit access to all of memory. Some machines may * not implement PMPs, so we set up a quick trap handler to just skip * touching the PMPs on any trap. */ la a0, pmp_done csrw CSR_TVEC, a0 li a0, -1 csrw CSR_PMPADDR0, a0 li a0, (PMP_A_NAPOT | PMP_R | PMP_W | PMP_X) csrw CSR_PMPCFG0, a0 .align 2 pmp_done: /* * The hartid in a0 is expected later on, and we have no firmware * to hand it to us. */ csrr a0, CSR_MHARTID #endif /* CONFIG_RISCV_M_MODE */ /* Load the global pointer */ .option push .option norelax la gp, __global_pointer$ .option pop /* * Disable FPU & VECTOR to detect illegal usage of * floating point or vector in kernel space */ li t0, SR_FS_VS csrc CSR_STATUS, t0 #ifdef CONFIG_RISCV_BOOT_SPINWAIT li t0, CONFIG_NR_CPUS blt a0, t0, .Lgood_cores tail .Lsecondary_park .Lgood_cores: /* The lottery system is only required for spinwait booting method */ #ifndef CONFIG_XIP_KERNEL /* Pick one hart to run the main boot sequence */ la a3, hart_lottery li a2, 1 amoadd.w a3, a2, (a3) bnez a3, .Lsecondary_start #else /* hart_lottery in flash contains a magic number */ la a3, hart_lottery mv a2, a3 XIP_FIXUP_OFFSET a2 XIP_FIXUP_FLASH_OFFSET a3 lw t1, (a3) amoswap.w t0, t1, (a2) /* first time here if hart_lottery in RAM is not set */ beq t0, t1, .Lsecondary_start #endif /* CONFIG_XIP */ #endif /* CONFIG_RISCV_BOOT_SPINWAIT */ #ifdef CONFIG_XIP_KERNEL la sp, _end + THREAD_SIZE XIP_FIXUP_OFFSET sp mv s0, a0 call __copy_data /* Restore a0 copy */ mv a0, s0 #endif #ifndef CONFIG_XIP_KERNEL /* Clear BSS for flat non-ELF images */ la a3, __bss_start la a4, __bss_stop ble a4, a3, clear_bss_done clear_bss: REG_S zero, (a3) add a3, a3, RISCV_SZPTR blt a3, a4, clear_bss clear_bss_done: #endif la a2, boot_cpu_hartid XIP_FIXUP_OFFSET a2 REG_S a0, (a2) /* Initialize page tables and relocate to virtual addresses */ la tp, init_task la sp, init_thread_union + THREAD_SIZE XIP_FIXUP_OFFSET sp addi sp, sp, -PT_SIZE_ON_STACK #ifdef CONFIG_BUILTIN_DTB la a0, __dtb_start XIP_FIXUP_OFFSET a0 #else mv a0, a1 #endif /* CONFIG_BUILTIN_DTB */ call setup_vm #ifdef CONFIG_MMU la a0, early_pg_dir XIP_FIXUP_OFFSET a0 call relocate_enable_mmu #endif /* CONFIG_MMU */ call setup_trap_vector /* Restore C environment */ la tp, init_task la sp, init_thread_union + THREAD_SIZE addi sp, sp, -PT_SIZE_ON_STACK #ifdef CONFIG_KASAN call kasan_early_init #endif /* Start the kernel */ call soc_early_init tail start_kernel #ifdef CONFIG_RISCV_BOOT_SPINWAIT .Lsecondary_start: /* Set trap vector to spin forever to help debug */ la a3, .Lsecondary_park csrw CSR_TVEC, a3 slli a3, a0, LGREG la a1, __cpu_spinwait_stack_pointer XIP_FIXUP_OFFSET a1 la a2, __cpu_spinwait_task_pointer XIP_FIXUP_OFFSET a2 add a1, a3, a1 add a2, a3, a2 /* * This hart didn't win the lottery, so we wait for the winning hart to * get far enough along the boot process that it should continue. */ .Lwait_for_cpu_up: /* FIXME: We should WFI to save some energy here. */ REG_L sp, (a1) REG_L tp, (a2) beqz sp, .Lwait_for_cpu_up beqz tp, .Lwait_for_cpu_up fence tail .Lsecondary_start_common #endif /* CONFIG_RISCV_BOOT_SPINWAIT */ END(_start_kernel) #ifdef CONFIG_RISCV_M_MODE ENTRY(reset_regs) li sp, 0 li gp, 0 li tp, 0 li t0, 0 li t1, 0 li t2, 0 li s0, 0 li s1, 0 li a2, 0 li a3, 0 li a4, 0 li a5, 0 li a6, 0 li a7, 0 li s2, 0 li s3, 0 li s4, 0 li s5, 0 li s6, 0 li s7, 0 li s8, 0 li s9, 0 li s10, 0 li s11, 0 li t3, 0 li t4, 0 li t5, 0 li t6, 0 csrw CSR_SCRATCH, 0 #ifdef CONFIG_FPU csrr t0, CSR_MISA andi t0, t0, (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D) beqz t0, .Lreset_regs_done_fpu li t1, SR_FS csrs CSR_STATUS, t1 fmv.s.x f0, zero fmv.s.x f1, zero fmv.s.x f2, zero fmv.s.x f3, zero fmv.s.x f4, zero fmv.s.x f5, zero fmv.s.x f6, zero fmv.s.x f7, zero fmv.s.x f8, zero fmv.s.x f9, zero fmv.s.x f10, zero fmv.s.x f11, zero fmv.s.x f12, zero fmv.s.x f13, zero fmv.s.x f14, zero fmv.s.x f15, zero fmv.s.x f16, zero fmv.s.x f17, zero fmv.s.x f18, zero fmv.s.x f19, zero fmv.s.x f20, zero fmv.s.x f21, zero fmv.s.x f22, zero fmv.s.x f23, zero fmv.s.x f24, zero fmv.s.x f25, zero fmv.s.x f26, zero fmv.s.x f27, zero fmv.s.x f28, zero fmv.s.x f29, zero fmv.s.x f30, zero fmv.s.x f31, zero csrw fcsr, 0 /* note that the caller must clear SR_FS */ .Lreset_regs_done_fpu: #endif /* CONFIG_FPU */ #ifdef CONFIG_RISCV_ISA_V csrr t0, CSR_MISA li t1, COMPAT_HWCAP_ISA_V and t0, t0, t1 beqz t0, .Lreset_regs_done_vector /* * Clear vector registers and reset vcsr * VLMAX has a defined value, VLEN is a constant, * and this form of vsetvli is defined to set vl to VLMAX. */ li t1, SR_VS csrs CSR_STATUS, t1 csrs CSR_VCSR, x0 vsetvli t1, x0, e8, m8, ta, ma vmv.v.i v0, 0 vmv.v.i v8, 0 vmv.v.i v16, 0 vmv.v.i v24, 0 /* note that the caller must clear SR_VS */ .Lreset_regs_done_vector: #endif /* CONFIG_RISCV_ISA_V */ ret END(reset_regs) #endif /* CONFIG_RISCV_M_MODE */