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Annotation of qemu/roms/openbios/arch/sparc32/context.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * context switching
                      3:  * 2003-10 by SONE Takeshi
                      4:  */
                      5: 
                      6: #include "config.h"
                      7: #include "kernel/kernel.h"
                      8: #include "context.h"
                      9: #include "libopenbios/sys_info.h"
                     10: #include "boot.h"
                     11: #include "openbios.h"
                     12: 
                     13: #define MAIN_STACK_SIZE 16384
                     14: #define IMAGE_STACK_SIZE 4096*2
                     15: 
                     16: #define debug printk
                     17: 
                     18: static void start_main(void); /* forward decl. */
                     19: void __exit_context(void); /* assembly routine */
                     20: 
                     21: /*
                     22:  * Main context structure
                     23:  * It is placed at the bottom of our stack, and loaded by assembly routine
                     24:  * to start us up.
                     25:  */
                     26: static struct context main_ctx = {
                     27:     .regs[REG_SP] = (uint32_t) &_estack - 96,
                     28:     .pc = (uint32_t) start_main,
                     29:     .npc = (uint32_t) start_main + 4,
                     30:     .return_addr = (uint32_t) __exit_context,
                     31: };
                     32: 
                     33: /* This is used by assembly routine to load/store the context which
                     34:  * it is to switch/switched.  */
                     35: struct context *__context = &main_ctx;
                     36: 
                     37: /* Stack for loaded ELF image */
                     38: static uint8_t image_stack[IMAGE_STACK_SIZE];
                     39: 
                     40: /* Pointer to startup context (physical address) */
                     41: unsigned long __boot_ctx;
                     42: 
                     43: /*
                     44:  * Main starter
                     45:  * This is the C function that runs first.
                     46:  */
                     47: static void start_main(void)
                     48: {
                     49:     /* Save startup context, so we can refer to it later.
                     50:      * We have to keep it in physical address since we will relocate. */
                     51:     __boot_ctx = virt_to_phys(__context);
                     52: 
                     53:     /* Start the real fun */
                     54:     openbios();
                     55: 
                     56:     /* Returning from here should jump to __exit_context */
                     57:     __context = boot_ctx;
                     58: }
                     59: 
                     60: /* Setup a new context using the given stack.
                     61:  */
                     62: struct context *
                     63: init_context(uint8_t *stack, uint32_t stack_size, int num_params)
                     64: {
                     65:     struct context *ctx;
                     66: 
                     67:     ctx = (struct context *)
                     68:        (stack + stack_size - (sizeof(*ctx) + num_params*sizeof(uint32_t)));
                     69:     memset(ctx, 0, sizeof(*ctx));
                     70: 
                     71:     /* Fill in reasonable default for flat memory model */
                     72:     ctx->regs[REG_SP] = virt_to_phys(SP_LOC(ctx));
                     73:     ctx->return_addr = virt_to_phys(__exit_context);
                     74: 
                     75:     return ctx;
                     76: }
                     77: 
                     78: /* Switch to another context. */
                     79: struct context *switch_to(struct context *ctx)
                     80: {
                     81:     volatile struct context *save;
                     82:     struct context *ret;
                     83: 
                     84:     debug("switching to new context:\n");
                     85:     save = __context;
                     86:     __context = ctx;
                     87:     asm __volatile__ ("\n\tcall __switch_context"
                     88:                       "\n\tnop" ::: "g1", "g2", "g3", "g4", "g5", "g6", "g7",
                     89:                       "o0", "o1", "o2", "o3", "o4", "o5", "sp", "o7",
                     90:                       "l0", "l1", "l2", "l3", "l4", "l5", "l6", "l7",
                     91:                       "i0", "i1", "i2", "i3", "i4", "i5", "i7",
                     92:                       "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", "f8", "f9",
                     93:                       "f10", "f11", "f12", "f13", "f14", "f15", "f16", "f17", "f18", "f19",
                     94:                       "f20", "f21", "f22", "f23", "f24", "f25", "f26", "f27", "f28", "f29",
                     95:                       "f30", "f31",
                     96:                       "memory");
                     97:     ret = __context;
                     98:     __context = (struct context *)save;
                     99:     return ret;
                    100: }
                    101: 
                    102: /* Start ELF Boot image */
                    103: unsigned int start_elf(unsigned long entry_point, unsigned long param)
                    104: {
                    105:     struct context *ctx;
                    106: 
                    107:     ctx = init_context(image_stack, sizeof image_stack, 1);
                    108:     ctx->pc = entry_point;
                    109:     ctx->param[0] = param;
                    110: 
                    111:     ctx = switch_to(ctx);
                    112:     return ctx->regs[REG_O0];
                    113: }

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