diff options
Diffstat (limited to 'arch/riscv/kernel/head.S')
| -rw-r--r-- | arch/riscv/kernel/head.S | 112 |
1 files changed, 106 insertions, 6 deletions
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 72f89b7590dd..84a6f0a4b120 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -11,6 +11,7 @@ #include <asm/thread_info.h> #include <asm/page.h> #include <asm/csr.h> +#include <asm/hwcap.h> #include <asm/image.h> __INIT @@ -47,8 +48,22 @@ ENTRY(_start) .global _start_kernel _start_kernel: /* Mask all interrupts */ - csrw CSR_SIE, zero - csrw CSR_SIP, zero + 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 + + /* + * 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 @@ -61,7 +76,7 @@ _start_kernel: * floating point in kernel space */ li t0, SR_FS - csrc CSR_SSTATUS, t0 + csrc CSR_STATUS, t0 #ifdef CONFIG_SMP li t0, CONFIG_NR_CPUS @@ -94,8 +109,10 @@ clear_bss_done: la sp, init_thread_union + THREAD_SIZE mv a0, s1 call setup_vm +#ifdef CONFIG_MMU la a0, early_pg_dir call relocate +#endif /* CONFIG_MMU */ /* Restore C environment */ la tp, init_task @@ -106,6 +123,7 @@ clear_bss_done: call parse_dtb tail start_kernel +#ifdef CONFIG_MMU relocate: /* Relocate return address */ li a1, PAGE_OFFSET @@ -116,7 +134,7 @@ relocate: /* Point stvec to virtual address of intruction after satp write */ la a2, 1f add a2, a2, a1 - csrw CSR_STVEC, a2 + csrw CSR_TVEC, a2 /* Compute satp for kernel page tables, but don't load it yet */ srl a2, a0, PAGE_SHIFT @@ -138,7 +156,7 @@ relocate: 1: /* Set trap vector to spin forever to help debug */ la a0, .Lsecondary_park - csrw CSR_STVEC, a0 + csrw CSR_TVEC, a0 /* Reload the global pointer */ .option push @@ -156,12 +174,13 @@ relocate: sfence.vma ret +#endif /* CONFIG_MMU */ .Lsecondary_start: #ifdef CONFIG_SMP /* Set trap vector to spin forever to help debug */ la a3, .Lsecondary_park - csrw CSR_STVEC, a3 + csrw CSR_TVEC, a3 slli a3, a0, LGREG la a1, __cpu_up_stack_pointer @@ -181,9 +200,11 @@ relocate: beqz tp, .Lwait_for_cpu_up fence +#ifdef CONFIG_MMU /* Enable virtual memory and relocate to virtual address */ la a0, swapper_pg_dir call relocate +#endif tail smp_callin #endif @@ -195,6 +216,85 @@ relocate: j .Lsecondary_park END(_start) +#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 sscratch, 0 + +#ifdef CONFIG_FPU + csrr t0, CSR_MISA + andi t0, t0, (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D) + bnez t0, .Lreset_regs_done + + 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 */ +#endif /* CONFIG_FPU */ +.Lreset_regs_done: + ret +END(reset_regs) +#endif /* CONFIG_RISCV_M_MODE */ + __PAGE_ALIGNED_BSS /* Empty zero page */ .balign PAGE_SIZE |