diff options
Diffstat (limited to 'arch/riscv/kernel/head.S')
| -rw-r--r-- | arch/riscv/kernel/head.S | 180 |
1 files changed, 109 insertions, 71 deletions
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 85f2073e7fe4..98a406474e7d 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -14,7 +14,7 @@ #include <asm/hwcap.h> #include <asm/image.h> -__INIT +__HEAD ENTRY(_start) /* * Image header expected by Linux boot-loaders. The image header data @@ -45,8 +45,111 @@ ENTRY(_start) .ascii RISCV_IMAGE_MAGIC2 .word 0 -.global _start_kernel -_start_kernel: +.align 2 +#ifdef CONFIG_MMU +relocate: + /* Relocate return address */ + li a1, PAGE_OFFSET + 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 + li a1, SATP_MODE + 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 + 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 guarnteed 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 to detect illegal usage of + * floating point in kernel space + */ + li t0, SR_FS + csrc CSR_STATUS, t0 + + /* Set trap vector to spin forever to help debug */ + la a3, .Lsecondary_park + csrw CSR_TVEC, a3 + + slli a3, a0, LGREG + la a4, __cpu_up_stack_pointer + la a5, __cpu_up_task_pointer + add a4, a3, a4 + add a5, a3, a5 + REG_L sp, (a4) + REG_L tp, (a5) + + .global secondary_start_common +secondary_start_common: + +#ifdef CONFIG_MMU + /* Enable virtual memory and relocate to virtual address */ + la a0, swapper_pg_dir + call relocate +#endif + tail smp_callin +#endif /* CONFIG_SMP */ + +.Lsecondary_park: + /* We lack SMP support or have too many harts, so park this hart */ + wfi + j .Lsecondary_park + +END(_start) + + __INIT +ENTRY(_start_kernel) /* Mask all interrupts */ csrw CSR_IE, zero csrw CSR_IP, zero @@ -131,62 +234,10 @@ clear_bss_done: call kasan_early_init #endif /* Start the kernel */ + call soc_early_init call parse_dtb tail start_kernel -#ifdef CONFIG_MMU -relocate: - /* Relocate return address */ - li a1, PAGE_OFFSET - 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 - li a1, SATP_MODE - 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 - 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 guarnteed to work - * because that first superpage is translated the same way. - */ - csrw CSR_SATP, a2 - sfence.vma - - ret -#endif /* CONFIG_MMU */ - .Lsecondary_start: #ifdef CONFIG_SMP /* Set trap vector to spin forever to help debug */ @@ -211,16 +262,10 @@ 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 + tail secondary_start_common #endif - tail smp_callin -#endif - -END(_start) +END(_start_kernel) #ifdef CONFIG_RISCV_M_MODE ENTRY(reset_regs) @@ -301,13 +346,6 @@ ENTRY(reset_regs) END(reset_regs) #endif /* CONFIG_RISCV_M_MODE */ -.section ".text", "ax",@progbits -.align 2 -.Lsecondary_park: - /* We lack SMP support or have too many harts, so park this hart */ - wfi - j .Lsecondary_park - __PAGE_ALIGNED_BSS /* Empty zero page */ .balign PAGE_SIZE |