| /* |
| * context switching |
| * 2003-10 by SONE Takeshi |
| */ |
| |
| #include "config.h" |
| #include "kernel/kernel.h" |
| #include "context.h" |
| #include "libopenbios/bindings.h" |
| #include "libopenbios/initprogram.h" |
| #include "libopenbios/sys_info.h" |
| #include "boot.h" |
| #include "openbios.h" |
| |
| #define MAIN_STACK_SIZE 16384 |
| #define IMAGE_STACK_SIZE 4096*4 |
| |
| #define debug printk |
| |
| static void start_main(void); /* forward decl. */ |
| void __exit_context(void); /* assembly routine */ |
| |
| /* |
| * Main context structure |
| * It is placed at the bottom of our stack, and loaded by assembly routine |
| * to start us up. |
| */ |
| static struct context main_ctx = { |
| .pc = (uint64_t) start_main, |
| .npc = (uint64_t) start_main + 4, |
| .return_addr = (uint64_t) __exit_context, |
| }; |
| |
| /* This is used by assembly routine to load/store the context which |
| * it is to switch/switched. */ |
| struct context * volatile __context = &main_ctx; |
| |
| /* Client program context */ |
| static struct context *client_ctx; |
| |
| /* Stack for loaded ELF image */ |
| static uint8_t image_stack[IMAGE_STACK_SIZE]; |
| |
| /* Pointer to startup context (physical address) */ |
| unsigned long __boot_ctx; |
| |
| /* Pointer to Forth context stack */ |
| void *_fcstack_ptr = &_efcstack; |
| |
| |
| /* |
| * Main starter |
| * This is the C function that runs first. |
| */ |
| static void start_main(void) |
| { |
| /* Save startup context, so we can refer to it later. |
| * We have to keep it in physical address since we will relocate. */ |
| __boot_ctx = virt_to_phys(__context); |
| |
| /* Set up client context */ |
| client_ctx = init_context(image_stack, sizeof image_stack, 1); |
| __context = client_ctx; |
| |
| /* Start the real fun */ |
| openbios(); |
| |
| /* Returning from here should jump to __exit_context */ |
| __context = boot_ctx; |
| } |
| |
| static uint64_t ALIGN_SIZE(uint64_t x, uint64_t a) |
| { |
| return (x + a - 1) & ~(a-1); |
| } |
| |
| #define CTX_OFFSET(n) ALIGN_SIZE(sizeof(struct context) + n * sizeof(uint64_t), sizeof(uint64_t)) |
| |
| /* Setup a new context using the given stack. |
| */ |
| struct context * |
| init_context(uint8_t *stack, uint64_t stack_size, int num_params) |
| { |
| struct context *ctx; |
| uint8_t *stack_top = stack + stack_size; |
| |
| ctx = (struct context *)(stack_top - CTX_OFFSET(num_params)); |
| /* Use valid window state from startup */ |
| memcpy(ctx, &main_ctx, sizeof(struct context)); |
| |
| /* Fill in reasonable default for flat memory model */ |
| ctx->return_addr = virt_to_phys(__exit_context); |
| |
| return ctx; |
| } |
| |
| /* init-program */ |
| extern uint64_t sparc64_of_client_interface; |
| |
| int |
| arch_init_program(void) |
| { |
| volatile struct context *ctx = __context; |
| ucell entry, param; |
| |
| ctx->regs[REG_O0] = 0; |
| ctx->regs[REG_O0+4] = (uint64_t)&sparc64_of_client_interface; |
| ctx->regs[REG_SP] = (uint64_t)malloc(IMAGE_STACK_SIZE) + IMAGE_STACK_SIZE - CTX_OFFSET(0) - STACK_BIAS; |
| |
| /* Set param */ |
| feval("load-state >ls.param @"); |
| param = POP(); |
| ctx->param[0] = param; |
| |
| /* Set entry point */ |
| feval("load-state >ls.entry @"); |
| entry = POP(); |
| ctx->pc = entry; |
| ctx->npc = entry+4; |
| |
| return 0; |
| } |
| |
| /* Switch to another context. */ |
| struct context *switch_to(struct context *ctx) |
| { |
| volatile struct context *save; |
| struct context *ret; |
| |
| //debug("switching to new context: entry point %#llx stack 0x%016llx\n", ctx->pc, ctx->regs[REG_SP]); |
| save = __context; |
| __context = ctx; |
| //asm ("pushl %cs; call __switch_context"); |
| asm ("call __switch_context; nop"); |
| ret = __context; |
| __context = (struct context *)save; |
| return ret; |
| } |
| |
| /* Start ELF Boot image */ |
| unsigned int start_elf(void) |
| { |
| volatile struct context *ctx = __context; |
| |
| ctx = switch_to((struct context *)ctx); |
| |
| return 0; |
| } |