1 files changed, 138 insertions, 0 deletions
diff --git a/roms/openbios/arch/sparc32/context.c b/roms/openbios/arch/sparc32/context.c
new file mode 100644
index 000000000..b4b0ae3a3
--- /dev/null
+++ b/roms/openbios/arch/sparc32/context.c
@@ -0,0 +1,138 @@
+/*
+ * 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*2
+
+#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 = (uint32_t) start_main,
+    .npc = (uint32_t) start_main + 4,
+    .return_addr = (uint32_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;
+
+/*
+ * 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;
+}
+
+#define CTX_OFFSET(n) (sizeof(struct context) + n * sizeof(uint32_t))
+
+/* Setup a new context using the given stack.
+ */
+struct context *
+init_context(uint8_t *stack, uint32_t stack_size, int num_params)
+{
+    struct context *ctx;
+
+    ctx = (struct context *)
+	(stack + stack_size - 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->regs[REG_SP] = virt_to_phys(SP_LOC(ctx));
+    ctx->return_addr = virt_to_phys(__exit_context);
+
+    return ctx;
+}
+
+/* init-program */
+int
+arch_init_program(void)
+{
+    volatile struct context *ctx = __context;
+    ucell entry;
+
+    ctx->regs[REG_O0] = (unsigned long)romvec;
+    ctx->regs[REG_SP] = (unsigned long)malloc(IMAGE_STACK_SIZE) + IMAGE_STACK_SIZE - CTX_OFFSET(1);
+
+    /* Set entry point */
+    feval("load-state >ls.entry @");
+    entry = POP();
+    ctx->pc = entry;
+
+    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:\n");
+    save = __context;
+    __context = ctx;
+    asm __volatile__ ("\n\tcall __switch_context"
+                      "\n\tnop" ::: "g1", "g2", "g3", "g4", "g5", "g6", "g7",
+                      "o0", "o1", "o2", "o3", "o4", "o5", "o7",
+                      "l0", "l1", "l2", "l3", "l4", "l5", "l6", "l7",
+                      "i0", "i1", "i2", "i3", "i4", "i5", "i7",
+                      "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", "f8", "f9",
+                      "f10", "f11", "f12", "f13", "f14", "f15", "f16", "f17", "f18", "f19",
+                      "f20", "f21", "f22", "f23", "f24", "f25", "f26", "f27", "f28", "f29",
+                      "f30", "f31",
+                      "memory");
+    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 ctx->regs[REG_O0];
+}