[XTENSA] Add kernel module support

Add kernel module support.

Signed-off-by: Chris Zankel <chris@zankel.net>

2 files changed, 227 insertions, 18 deletions

diff --git a/arch/xtensa/kernel/module.c b/arch/xtensa/kernel/module.c
index 2ea1755a085..ddf14dcf2ad 100644
--- a/arch/xtensa/kernel/module.c
+++ b/arch/xtensa/kernel/module.c
@@ -7,7 +7,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 2001 - 2005 Tensilica Inc.
+ * Copyright (C) 2001 - 2006 Tensilica Inc.
  *
  * Chris Zankel <chris@zankel.net>
  *
@@ -22,57 +22,216 @@
 #include <linux/kernel.h>
 #include <linux/cache.h>
 
-LIST_HEAD(module_buf_list);
+#undef DEBUG_RELOCATE
 
 void *module_alloc(unsigned long size)
 {
-  panic("module_alloc not implemented");
+	if (size == 0)
+		return NULL;
+	return vmalloc(size);
 }
 
 void module_free(struct module *mod, void *module_region)
 {
-  panic("module_free not implemented");
+	vfree(module_region);
+	/* FIXME: If module_region == mod->init_region, trim exception
+	   table entries. */
 }
 
 int module_frob_arch_sections(Elf32_Ehdr *hdr,
     			      Elf32_Shdr *sechdrs,
 			      char *secstrings,
-			      struct module *me)
+			      struct module *mod)
 {
-  panic("module_frob_arch_sections not implemented");
+	return 0;
+}
+
+static int
+decode_calln_opcode (unsigned char *location)
+{
+#ifdef __XTENSA_EB__
+	return (location[0] & 0xf0) == 0x50;
+#endif
+#ifdef __XTENSA_EL__
+	return (location[0] & 0xf) == 0x5;
+#endif
+}
+
+static int
+decode_l32r_opcode (unsigned char *location)
+{
+#ifdef __XTENSA_EB__
+	return (location[0] & 0xf0) == 0x10;
+#endif
+#ifdef __XTENSA_EL__
+	return (location[0] & 0xf) == 0x1;
+#endif
 }
 
 int apply_relocate(Elf32_Shdr *sechdrs,
     		   const char *strtab,
 		   unsigned int symindex,
 		   unsigned int relsec,
-		   struct module *module)
+		   struct module *mod)
 {
-  panic ("apply_relocate not implemented");
+        printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
+               mod->name);
+        return -ENOEXEC;
+
 }
 
 int apply_relocate_add(Elf32_Shdr *sechdrs,
 		       const char *strtab,
 		       unsigned int symindex,
 		       unsigned int relsec,
-		       struct module *module)
+		       struct module *mod)
 {
-  panic("apply_relocate_add not implemented");
+	unsigned int i;
+        Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
+	Elf32_Sym *sym;
+	unsigned char *location;
+	uint32_t value;
+
+#ifdef DEBUG_RELOCATE
+	printk("Applying relocate section %u to %u\n", relsec,
+	       sechdrs[relsec].sh_info);
+#endif
+	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
+		location = (char *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+			+ rela[i].r_offset;
+		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+			+ ELF32_R_SYM(rela[i].r_info);
+		value = sym->st_value + rela[i].r_addend;
+
+		switch (ELF32_R_TYPE(rela[i].r_info)) {
+		case R_XTENSA_NONE:
+		case R_XTENSA_DIFF8:
+		case R_XTENSA_DIFF16:
+		case R_XTENSA_DIFF32:
+		case R_XTENSA_ASM_EXPAND:
+			break;
+
+		case R_XTENSA_32:
+		case R_XTENSA_PLT:
+			*(uint32_t *)location += value;
+			break;
+
+		case R_XTENSA_SLOT0_OP:
+			if (decode_calln_opcode(location)) {
+				value -= ((unsigned long)location & -4) + 4;
+				if ((value & 3) != 0 ||
+				    ((value + (1 << 19)) >> 20) != 0) {
+					printk("%s: relocation out of range, "
+					       "section %d reloc %d "
+					       "sym '%s'\n",
+					       mod->name, relsec, i,
+					       strtab + sym->st_name);
+					return -ENOEXEC;
+				}
+				value = (signed int)value >> 2;
+#ifdef __XTENSA_EB__
+				location[0] = ((location[0] & ~0x3) |
+					    ((value >> 16) & 0x3));
+				location[1] = (value >> 8) & 0xff;
+				location[2] = value & 0xff;
+#endif
+#ifdef __XTENSA_EL__
+				location[0] = ((location[0] & ~0xc0) |
+					    ((value << 6) & 0xc0));
+				location[1] = (value >> 2) & 0xff;
+				location[2] = (value >> 10) & 0xff;
+#endif
+			} else if (decode_l32r_opcode(location)) {
+				value -= (((unsigned long)location + 3) & -4);
+				if ((value & 3) != 0 ||
+				    (signed int)value >> 18 != -1) {
+					printk("%s: relocation out of range, "
+					       "section %d reloc %d "
+					       "sym '%s'\n",
+					       mod->name, relsec, i,
+					       strtab + sym->st_name);
+					return -ENOEXEC;
+				}
+				value = (signed int)value >> 2;
+
+#ifdef __XTENSA_EB__
+				location[1] = (value >> 8) & 0xff;
+				location[2] = value & 0xff;
+#endif
+#ifdef __XTENSA_EL__
+				location[1] = value & 0xff;
+				location[2] = (value >> 8) & 0xff;
+#endif
+			}
+			/* FIXME: Ignore any other opcodes.  The Xtensa
+			   assembler currently assumes that the linker will
+			   always do relaxation and so all PC-relative
+			   operands need relocations.  (The assembler also
+			   writes out the tentative PC-relative values,
+			   assuming no link-time relaxation, so it is usually
+			   safe to ignore the relocations.)  If the
+			   assembler's "--no-link-relax" flag can be made to
+			   work, and if all kernel modules can be assembled
+			   with that flag, then unexpected relocations could
+			   be detected here.  */
+			break;
+
+		case R_XTENSA_SLOT1_OP:
+		case R_XTENSA_SLOT2_OP:
+		case R_XTENSA_SLOT3_OP:
+		case R_XTENSA_SLOT4_OP:
+		case R_XTENSA_SLOT5_OP:
+		case R_XTENSA_SLOT6_OP:
+		case R_XTENSA_SLOT7_OP:
+		case R_XTENSA_SLOT8_OP:
+		case R_XTENSA_SLOT9_OP:
+		case R_XTENSA_SLOT10_OP:
+		case R_XTENSA_SLOT11_OP:
+		case R_XTENSA_SLOT12_OP:
+		case R_XTENSA_SLOT13_OP:
+		case R_XTENSA_SLOT14_OP:
+			printk("%s: unexpected FLIX relocation: %u\n",
+			       mod->name,
+			       ELF32_R_TYPE(rela[i].r_info));
+			return -ENOEXEC;
+
+		case R_XTENSA_SLOT0_ALT:
+		case R_XTENSA_SLOT1_ALT:
+		case R_XTENSA_SLOT2_ALT:
+		case R_XTENSA_SLOT3_ALT:
+		case R_XTENSA_SLOT4_ALT:
+		case R_XTENSA_SLOT5_ALT:
+		case R_XTENSA_SLOT6_ALT:
+		case R_XTENSA_SLOT7_ALT:
+		case R_XTENSA_SLOT8_ALT:
+		case R_XTENSA_SLOT9_ALT:
+		case R_XTENSA_SLOT10_ALT:
+		case R_XTENSA_SLOT11_ALT:
+		case R_XTENSA_SLOT12_ALT:
+		case R_XTENSA_SLOT13_ALT:
+		case R_XTENSA_SLOT14_ALT:
+			printk("%s: unexpected ALT relocation: %u\n",
+			       mod->name,
+			       ELF32_R_TYPE(rela[i].r_info));
+			return -ENOEXEC;
+
+		default:
+			printk("%s: unexpected relocation: %u\n",
+			       mod->name,
+			       ELF32_R_TYPE(rela[i].r_info));
+			return -ENOEXEC;
+		}
+	}
+	return 0;
 }
 
 int module_finalize(const Elf_Ehdr *hdr,
     		    const Elf_Shdr *sechdrs,
-		    struct module *me)
+		    struct module *mod)
 {
-  panic ("module_finalize not implemented");
+	return 0;
 }
 
 void module_arch_cleanup(struct module *mod)
 {
-  panic("module_arch_cleanup not implemented");
-}
-
-struct bug_entry *module_find_bug(unsigned long bugaddr)
-{
-  panic("module_find_bug not implemented");
 }
diff --git a/include/asm-xtensa/elf.h b/include/asm-xtensa/elf.h
index 1569b53cec9..7083d46766a 100644
--- a/include/asm-xtensa/elf.h
+++ b/include/asm-xtensa/elf.h
@@ -20,6 +20,56 @@
 #define EM_XTENSA	94
 #define EM_XTENSA_OLD	0xABC7
 
+/* Xtensa relocations defined by the ABIs */
+
+#define R_XTENSA_NONE           0
+#define R_XTENSA_32             1
+#define R_XTENSA_RTLD           2
+#define R_XTENSA_GLOB_DAT       3
+#define R_XTENSA_JMP_SLOT       4
+#define R_XTENSA_RELATIVE       5
+#define R_XTENSA_PLT            6
+#define R_XTENSA_OP0            8
+#define R_XTENSA_OP1            9
+#define R_XTENSA_OP2            10
+#define R_XTENSA_ASM_EXPAND	11
+#define R_XTENSA_ASM_SIMPLIFY	12
+#define R_XTENSA_GNU_VTINHERIT	15
+#define R_XTENSA_GNU_VTENTRY	16
+#define R_XTENSA_DIFF8		17
+#define R_XTENSA_DIFF16		18
+#define R_XTENSA_DIFF32		19
+#define R_XTENSA_SLOT0_OP	20
+#define R_XTENSA_SLOT1_OP	21
+#define R_XTENSA_SLOT2_OP	22
+#define R_XTENSA_SLOT3_OP	23
+#define R_XTENSA_SLOT4_OP	24
+#define R_XTENSA_SLOT5_OP	25
+#define R_XTENSA_SLOT6_OP	26
+#define R_XTENSA_SLOT7_OP	27
+#define R_XTENSA_SLOT8_OP	28
+#define R_XTENSA_SLOT9_OP	29
+#define R_XTENSA_SLOT10_OP	30
+#define R_XTENSA_SLOT11_OP	31
+#define R_XTENSA_SLOT12_OP	32
+#define R_XTENSA_SLOT13_OP	33
+#define R_XTENSA_SLOT14_OP	34
+#define R_XTENSA_SLOT0_ALT	35
+#define R_XTENSA_SLOT1_ALT	36
+#define R_XTENSA_SLOT2_ALT	37
+#define R_XTENSA_SLOT3_ALT	38
+#define R_XTENSA_SLOT4_ALT	39
+#define R_XTENSA_SLOT5_ALT	40
+#define R_XTENSA_SLOT6_ALT	41
+#define R_XTENSA_SLOT7_ALT	42
+#define R_XTENSA_SLOT8_ALT	43
+#define R_XTENSA_SLOT9_ALT	44
+#define R_XTENSA_SLOT10_ALT	45
+#define R_XTENSA_SLOT11_ALT	46
+#define R_XTENSA_SLOT12_ALT	47
+#define R_XTENSA_SLOT13_ALT	48
+#define R_XTENSA_SLOT14_ALT	49
+
 /* ELF register definitions. This is needed for core dump support.  */
 
 /*