decouple

grub-core/kern/arm/uboot/init.c

@@ -0,0 +1,70 @@
+/* init.c - generic U-Boot initialization and finalization */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2016  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/uboot/uboot.h>
+#include <grub/arm/startup.h>
+#include <grub/uboot/api_public.h>
+
+extern int (*grub_uboot_syscall_ptr) (int, int *, ...);
+
+grub_uint32_t
+grub_uboot_get_machine_type (void)
+{
+  return grub_arm_saved_registers.r[1];
+}
+
+grub_addr_t
+grub_uboot_get_boot_data (void)
+{
+  return grub_arm_saved_registers.r[2];
+}
+
+int
+grub_uboot_api_init (void)
+{
+  struct api_signature *start, *end;
+  struct api_signature *p;
+  grub_addr_t grub_uboot_search_hint = grub_arm_saved_registers.sp;
+  if (grub_uboot_search_hint)
+    {
+      /* Extended search range to work around Trim Slice U-Boot issue */
+      start = (struct api_signature *) ((grub_uboot_search_hint & ~0x000fffff)
+					- 0x00500000);
+      end =
+	(struct api_signature *) ((grub_addr_t) start + UBOOT_API_SEARCH_LEN -
+				  API_SIG_MAGLEN + 0x00500000);
+    }
+  else
+    {
+      start = 0;
+      end = (struct api_signature *) (256 * 1024 * 1024);
+    }
+
+  /* Structure alignment is (at least) 8 bytes */
+  for (p = start; p < end; p = (void *) ((grub_addr_t) p + 8))
+    {
+      if (grub_memcmp (&(p->magic), API_SIG_MAGIC, API_SIG_MAGLEN) == 0)
+	{
+	  grub_uboot_syscall_ptr = p->syscall;
+	  return p->version;
+	}
+    }
+
+  return 0;
+}

grub-core/kern/arm/uboot/uboot.S

@@ -0,0 +1,73 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2013  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/offsets.h>
+#include <grub/symbol.h>
+#include <grub/machine/kernel.h>
+
+	/*
+	 * uboot_syscall():
+	 *   This function is effectively a veneer, so it cannot
+	 *   modify the stack or corrupt any registers other than
+	 *   r12 (ip). Furthermore it needs to restore r8 for
+	 *   U-Boot (Global Data Pointer) and preserve it for Grub.
+	 */
+FUNCTION(grub_uboot_syscall)
+	str     r8, transition_space
+	str     lr, transition_space + 4
+	str     r9, transition_space + 8
+
+	ldr	ip, saved_registers_ptr
+	ldr	r8, [ip, #4 * 8]
+	ldr	r9, [ip, #4 * 9]
+
+	bl	do_syscall
+
+	ldr     r8, transition_space
+	ldr     lr, transition_space + 4
+	ldr     r9, transition_space + 8
+
+	bx	lr
+do_syscall:
+
+	ldr	ip, grub_uboot_syscall_ptr
+	bx	ip
+	
+FUNCTION(grub_uboot_return)
+	ldr	ip, saved_registers_ptr
+	ldr	sp, [ip, #4 * 4]
+	pop	{r4-r12, lr}
+	mov	sp, r12
+	bx	lr
+
+	
+	.align	3
+
+@ GRUB context stack space
+transition_space:	
+	.long	0	@ r8
+	.long	0	@ lr
+	.long	0	@ r9
+
+saved_registers_ptr:
+	.long EXT_C(grub_arm_saved_registers)
+
+VARIABLE(grub_uboot_syscall_ptr)
+	.long	0	@
+
+	END