1/* 2 * Copyright 2017, Data61 3 * Commonwealth Scientific and Industrial Research Organisation (CSIRO) 4 * ABN 41 687 119 230. 5 * 6 * This software may be distributed and modified according to the terms of 7 * the BSD 2-Clause license. Note that NO WARRANTY is provided. 8 * See "LICENSE_BSD2.txt" for details. 9 * 10 * @TAG(DATA61_BSD) 11 */ 12#include <autoconf.h> 13#include <sel4utils/gen_config.h> 14#include <sel4/types.h> 15#include <sel4utils/thread.h> 16#include <sel4utils/helpers.h> 17#include <utils/zf_log.h> 18#include <utils/stack.h> 19#include <stdbool.h> 20 21int sel4utils_arch_init_context(void *entry_point, void *stack_top, seL4_UserContext *context) 22{ 23 context->esp = (seL4_Word) stack_top; 24 /* set edx to zero in case we are setting this when spawning a process as 25 * edx is the atexit parameter, which we currently do not use */ 26 context->edx = 0; 27 context->eip = (seL4_Word) entry_point; 28 29 return 0; 30} 31 32int sel4utils_arch_init_context_with_args(sel4utils_thread_entry_fn entry_point, void *arg0, void *arg1, void *arg2, 33 bool local_stack, void *stack_top, seL4_UserContext *context, 34 vka_t *vka, vspace_t *local_vspace, vspace_t *remote_vspace) 35{ 36 37 if (!IS_ALIGNED((uintptr_t)stack_top, STACK_CALL_ALIGNMENT_BITS)) { 38 ZF_LOGE("Initial stack pointer must be %d byte aligned", STACK_CALL_ALIGNMENT); 39 return -1; 40 } 41 42 /* arguments as they should appear on the stack */ 43 seL4_Word stack_args[] = {(seL4_Word) arg0, (seL4_Word) arg1, (seL4_Word) arg2}; 44 if (stack_top) { 45 /* if we were to increase the stack pointer such that after the arguments are 46 * pushed, the stack pointer would be correctly aligned, we would add this 47 * value */ 48 size_t up_padding = sizeof(stack_args) % STACK_CALL_ALIGNMENT; 49 50 /* but we can't add to the stack pointer as we might run off the end of our stack, 51 * so we'll decrease it by this value */ 52 size_t down_padding = (STACK_CALL_ALIGNMENT - up_padding) % STACK_CALL_ALIGNMENT; 53 54 stack_top = (void *)((uintptr_t) stack_top - down_padding); 55 } 56 57 if (local_stack && stack_top) { 58 seL4_Word *stack_ptr = (seL4_Word *) stack_top; 59 stack_ptr[-3] = (seL4_Word) arg0; 60 stack_ptr[-2] = (seL4_Word) arg1; 61 stack_ptr[-1] = (seL4_Word) arg2; 62 stack_top = (void *)((uintptr_t) stack_top - sizeof(stack_args)); 63 } else if (local_vspace && remote_vspace && vka) { 64 int error = sel4utils_stack_write(local_vspace, remote_vspace, vka, stack_args, sizeof(stack_args), 65 (uintptr_t *) &stack_top); 66 if (error) { 67 ZF_LOGE("Failed to copy arguments"); 68 return -1; 69 } 70 } 71 72 /* we've pushed the arguments, so at this point our stack should be aligned 73 * thanks to our padding */ 74 assert(IS_ALIGNED((uintptr_t)stack_top, STACK_CALL_ALIGNMENT_BITS)); 75 76 /* the entry point function was compiled under the assumption that it will 77 * be called, and thus expects a return address to follow the arguments */ 78 stack_top = (void *)((uintptr_t) stack_top - sizeof(uintptr_t)); 79 80 return sel4utils_arch_init_context(entry_point, stack_top, context); 81} 82