GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/bootloader/u-boot-2020.01/arch/arc/lib/relocate.c

@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
+ */
+
+#include <common.h>
+#include <elf.h>
+#include <asm-generic/sections.h>
+
+extern ulong __image_copy_start;
+extern ulong __ivt_start;
+extern ulong __ivt_end;
+extern ulong __text_end;
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int copy_uboot_to_ram(void)
+{
+	size_t len = (size_t)&__image_copy_end - (size_t)&__image_copy_start;
+
+	if (gd->flags & GD_FLG_SKIP_RELOC)
+		return 0;
+
+	memcpy((void *)gd->relocaddr, (void *)&__image_copy_start, len);
+
+	return 0;
+}
+
+int clear_bss(void)
+{
+	ulong dst_addr = (ulong)&__bss_start + gd->reloc_off;
+	size_t len = (size_t)&__bss_end - (size_t)&__bss_start;
+
+	memset((void *)dst_addr, 0x00, len);
+
+	return 0;
+}
+
+/*
+ * Base functionality is taken from x86 version with added ARC-specifics
+ */
+int do_elf_reloc_fixups(void)
+{
+	Elf32_Rela *re_src = (Elf32_Rela *)(&__rel_dyn_start);
+	Elf32_Rela *re_end = (Elf32_Rela *)(&__rel_dyn_end);
+
+	if (gd->flags & GD_FLG_SKIP_RELOC)
+		return 0;
+
+	debug("Section .rela.dyn is located at %08x-%08x\n",
+	      (unsigned int)re_src, (unsigned int)re_end);
+
+	Elf32_Addr *offset_ptr_rom;
+	Elf32_Addr *offset_ptr_ram;
+
+	do {
+		/* Get the location from the relocation entry */
+		offset_ptr_rom = (Elf32_Addr *)re_src->r_offset;
+
+		/* Check that the location of the relocation is in .text */
+		if (offset_ptr_rom >= (Elf32_Addr *)&__image_copy_start &&
+		    offset_ptr_rom < (Elf32_Addr *)&__image_copy_end) {
+			unsigned int val, do_swap = 0;
+			/* Switch to the in-RAM version */
+			offset_ptr_ram = (Elf32_Addr *)((ulong)offset_ptr_rom +
+							gd->reloc_off);
+
+#ifdef __LITTLE_ENDIAN__
+			/* If location in ".text" section swap value */
+			if (((u32)offset_ptr_rom >= (u32)&__text_start &&
+			     (u32)offset_ptr_rom <= (u32)&__text_end)
+#if defined(__ARC700__) || defined(__ARC600__)
+			    || ((u32)offset_ptr_rom >= (u32)&__ivt_start &&
+				(u32)offset_ptr_rom <= (u32)&__ivt_end)
+#endif
+			   )
+				do_swap = 1;
+#endif
+
+			debug("Patching value @ %08x (relocated to %08x)%s\n",
+			      (unsigned int)offset_ptr_rom,
+			      (unsigned int)offset_ptr_ram,
+			      do_swap ? ", middle-endian encoded" : "");
+
+			/*
+			 * Use "memcpy" because target location might be
+			 * 16-bit aligned on ARC so we may need to read
+			 * byte-by-byte. On attempt to read entire word by
+			 * CPU throws an exception
+			 */
+			memcpy(&val, offset_ptr_ram, sizeof(int));
+
+			if (do_swap)
+				val = (val << 16) | (val >> 16);
+
+			/* Check that the target points into executable */
+			if (val < (unsigned int)&__image_copy_start ||
+			    val > (unsigned int)&__image_copy_end) {
+				/* TODO: Use panic() instead of debug()
+				 *
+				 * For some reason GCC might generate
+				 * fake relocation even for LD/SC of constant
+				 * inderectly. See an example below:
+				 * ----------------------->8--------------------
+				 * static int setup_mon_len(void)
+				 * {
+				 *         gd->mon_len = (ulong)&__bss_end - CONFIG_SYS_MONITOR_BASE;
+				 *         return 0;
+				 * }
+				 * ----------------------->8--------------------
+				 *
+				 * And that's what we get in the binary:
+				 * ----------------------->8--------------------
+				 * 10005cb4 <setup_mon_len>:
+				 * 10005cb4:       193c 3f80 0003 2f80     st      0x32f80,[r25,60]
+				 *                         10005cb8: R_ARC_RELATIVE        *ABS*-0x10000000
+				 * 10005cbc:       7fe0                    j_s.d   [blink]
+				 * 10005cbe:       700c                    mov_s   r0,0
+				 * ----------------------->8--------------------
+				 */
+				debug("Relocation target %08x points outside of image\n",
+				      val);
+			}
+
+			val += gd->reloc_off;
+
+			if (do_swap)
+				val = (val << 16) | (val >> 16);
+
+			memcpy(offset_ptr_ram, &val, sizeof(int));
+		}
+	} while (++re_src < re_end);
+
+	return 0;
+}