3 * 2003-10 by SONE Takeshi
7 #include "kernel/kernel.h"
9 #include "libopenbios/sys_info.h"
13 #define MAIN_STACK_SIZE 16384
14 #define IMAGE_STACK_SIZE 4096*4
18 static void start_main(void); /* forward decl. */
19 void __exit_context(void); /* assembly routine */
22 * Main context structure
23 * It is placed at the bottom of our stack, and loaded by assembly routine
26 static struct context main_ctx = {
27 .regs[REG_SP] = (uint64_t) &_estack - STACK_BIAS - 96,
28 .pc = (uint64_t) start_main,
29 .npc = (uint64_t) start_main + 4,
30 .return_addr = (uint64_t) __exit_context,
33 /* This is used by assembly routine to load/store the context which
34 * it is to switch/switched. */
35 struct context * volatile __context = &main_ctx;
37 /* Stack for loaded ELF image */
38 static uint8_t image_stack[IMAGE_STACK_SIZE];
40 /* Pointer to startup context (physical address) */
41 unsigned long __boot_ctx;
43 /* Pointer to Forth context stack */
44 void *_fcstack_ptr = &_efcstack;
49 * This is the C function that runs first.
51 static void start_main(void)
53 /* Save startup context, so we can refer to it later.
54 * We have to keep it in physical address since we will relocate. */
55 __boot_ctx = virt_to_phys(__context);
57 /* Start the real fun */
60 /* Returning from here should jump to __exit_context */
64 static uint64_t ALIGN_SIZE(uint64_t x, uint64_t a)
66 return (x + a - 1) & ~(a-1);
69 /* Setup a new context using the given stack.
72 init_context(uint8_t *stack, uint64_t stack_size, int num_params)
75 uint8_t *stack_top = stack + stack_size;
77 ctx = (struct context *)
78 (stack_top - ALIGN_SIZE(sizeof(*ctx) + num_params*sizeof(uint64_t), sizeof(uint64_t)));
79 memset(ctx, 0, sizeof(*ctx));
81 /* Fill in reasonable default for flat memory model */
82 ctx->regs[REG_SP] = virt_to_phys(stack_top - STACK_BIAS - 192);
83 ctx->return_addr = virt_to_phys(__exit_context);
88 /* Switch to another context. */
89 struct context *switch_to(struct context *ctx)
91 struct context *save, *ret;
93 debug("switching to new context: entry point %#llx stack 0x%016llx\n", ctx->pc, ctx->regs[REG_SP]);
96 //asm ("pushl %cs; call __switch_context");
97 asm ("call __switch_context_nosave; nop");
103 /* Start ELF Boot image */
104 uint64_t start_elf(uint64_t entry_point, uint64_t param)
108 ctx = init_context(image_stack, sizeof image_stack, 1);
109 ctx->pc = entry_point;
110 ctx->param[0] = param;
111 //ctx->eax = 0xe1fb007;
114 ctx = switch_to(ctx);
119 /* Start client image */
120 uint64_t start_client_image(uint64_t entry_point, uint64_t cif_handler)
124 ctx = init_context(image_stack, sizeof image_stack, 0);
125 ctx->pc = entry_point;
126 ctx->npc = entry_point+4;
127 ctx->regs[REG_O0] = 0;
128 ctx->regs[REG_O0+4] = cif_handler;
130 ctx = switch_to(ctx);