diff options
Diffstat (limited to 'bsps/riscv/riscv/start/start.S')
| -rw-r--r-- | bsps/riscv/riscv/start/start.S | 75 |
1 files changed, 57 insertions, 18 deletions
diff --git a/bsps/riscv/riscv/start/start.S b/bsps/riscv/riscv/start/start.S index 83926a9272..290c95a166 100644 --- a/bsps/riscv/riscv/start/start.S +++ b/bsps/riscv/riscv/start/start.S @@ -48,26 +48,34 @@ SYM(_start): LADDR gp, __global_pointer$ .option pop + /* Init FPU unit if it's there */ + li t0, MSTATUS_FS + csrs mstatus, t0 + + /* Set exception handler */ + LADDR t0, _RISCV_Exception_handler + csrw mtvec, t0 + + /* Load stack pointer and branch to secondary processor start if necessary */ #ifdef RTEMS_SMP + LADDR sp, _Configuration_Interrupt_stack_area_begin + LADDR t2, _Configuration_Interrupt_stack_size csrr s0, mhartid LADDR t0, _Per_CPU_Information slli t1, s0, PER_CPU_CONTROL_SIZE_LOG2 - add t0, t0, t1 - csrw mscratch, t0 - bnez s0, .Lwait_for_go -#endif - - /* load stack and frame pointers */ + add s1, t0, t1 + csrw mscratch, s1 + bnez s0, .Lstart_on_secondary_processor + add sp, sp, t2 +#else LADDR sp, _Configuration_Interrupt_stack_area_end +#endif #ifdef BSP_START_COPY_FDT_FROM_U_BOOT mv a0, a1 call bsp_fdt_copy #endif - LADDR t0, _RISCV_Exception_handler - csrw mtvec, t0 - /* Clear .bss */ LADDR a0, bsp_section_bss_begin li a1, 0 @@ -81,24 +89,55 @@ SYM(_start): amoswap.w zero, zero, 0(t0) #endif - /* Init FPU unit if it's there */ - li t0, MSTATUS_FS - csrs mstatus, t0 - j boot_card #ifdef RTEMS_SMP + +.Lstart_on_secondary_processor: + + /* Adjust stack pointer */ +#ifdef __riscv_mul + addi t0, s0, 1 + mul t2, t2, t0 +#else + mv t0, s0 + mv t3, t2 + +.Ladd_more: + + add t2, t2, t3 + addi t0, t0, -1 + bnez t0, .Ladd_more +#endif + add sp, sp, t2 + /* Wait for go issued by the boot processor (mhartid == 0) */ -.Lwait_for_go: LADDR t0, .Lsecondary_processor_go + .Lwait_for_go_again: + lw t1, 0(t0) fence iorw, iorw - sext.w t1, t1 bnez t1, .Lwait_for_go_again -.Lloop_forever: - j .Lloop_forever + + mv a0, s1 + call bsp_start_on_secondary_processor + +#if __riscv_xlen == 32 + .align 2 +#elif __riscv_xlen == 64 + .align 3 +#endif .Lsecondary_processor_go: - .word 0xdeadbeef + + /* + * These are ebreak instructions, just in case we end up here executing + * code. + */ + .word 0x00100073 +#if __riscv_xlen == 64 + .word 0x00100073 #endif + +#endif /* RTEMS_SMP */ |