initial sparc64 version

git-svn-id: svn://coreboot.org/openbios/openbios-devel@58 f158a5a8-5612-0410-a976-696ce0be7e32

arch/sparc64/context.c

@@ -0,0 +1,109 @@
+/*
+ * context switching
+ * 2003-10 by SONE Takeshi
+ */
+
+#include "openbios/config.h"
+#include "openbios/kernel.h"
+#include "context.h"
+
+#define MAIN_STACK_SIZE 16384
+#define IMAGE_STACK_SIZE 4096
+
+#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.
+ */
+struct context main_ctx = {
+    .regs[REG_SP] = (uint64_t) &_estack - 96,
+    .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 *__context = &main_ctx;
+
+/* Stack for loaded ELF image */
+static uint8_t image_stack[IMAGE_STACK_SIZE];
+
+/* Pointer to startup context (physical address) */
+unsigned long __boot_ctx;
+
+/*
+ * Main starter
+ * This is the C function that runs first.
+ */
+static void start_main(void)
+{
+    int retval;
+    extern int openbios(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);
+
+    /* Start the real fun */
+    retval = openbios();
+
+    /* Pass return value to startup context. Bootloader may see it. */
+    //boot_ctx->eax = retval;
+
+    /* Returning from here should jump to __exit_context */
+    __context = boot_ctx;
+}
+
+/* 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;
+
+    ctx = (struct context *)
+	(stack + stack_size - (sizeof(*ctx) + num_params*sizeof(uint32_t)));
+    memset(ctx, 0, sizeof(*ctx));
+
+    /* Fill in reasonable default for flat memory model */
+    ctx->regs[REG_SP] = virt_to_phys(SP_LOC(ctx));
+    ctx->return_addr = virt_to_phys(__exit_context);
+
+    return ctx;
+}
+
+/* Switch to another context. */
+struct context *switch_to(struct context *ctx)
+{
+    struct context *save, *ret;
+
+    debug("switching to new context:\n");
+    save = __context;
+    __context = ctx;
+    //asm ("pushl %cs; call __switch_context");
+    ret = __context;
+    __context = save;
+    return ret;
+}
+
+/* Start ELF Boot image */
+uint64_t start_elf(uint64_t entry_point, uint64_t param)
+{
+    struct context *ctx;
+
+    ctx = init_context(image_stack, sizeof image_stack, 1);
+    ctx->pc = entry_point;
+    ctx->param[0] = param;
+    //ctx->eax = 0xe1fb007;
+    //ctx->ebx = param;
+
+    ctx = switch_to(ctx);
+    //return ctx->eax;
+    return 0;
+}