initial_commit

1 files changed, 319 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
new file mode 100644
index 00000000..449a7e05
--- /dev/null
+++ b/arch/powerpc/kernel/module_32.c
@@ -0,0 +1,319 @@
+/*  Kernel module help for PPC.
+    Copyright (C) 2001 Rusty Russell.
+
+    This program 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 2 of the License, or
+    (at your option) any later version.
+
+    This program 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 this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+#include <linux/module.h>
+#include <linux/moduleloader.h>
+#include <linux/elf.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/ftrace.h>
+#include <linux/cache.h>
+#include <linux/bug.h>
+#include <linux/sort.h>
+
+#include "setup.h"
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(fmt , ...)
+#endif
+
+/* Count how many different relocations (different symbol, different
+   addend) */
+static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
+{
+	unsigned int i, r_info, r_addend, _count_relocs;
+
+	_count_relocs = 0;
+	r_info = 0;
+	r_addend = 0;
+	for (i = 0; i < num; i++)
+		/* Only count 24-bit relocs, others don't need stubs */
+		if (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
+		    (r_info != ELF32_R_SYM(rela[i].r_info) ||
+		     r_addend != rela[i].r_addend)) {
+			_count_relocs++;
+			r_info = ELF32_R_SYM(rela[i].r_info);
+			r_addend = rela[i].r_addend;
+		}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	_count_relocs++;	/* add one for ftrace_caller */
+#endif
+	return _count_relocs;
+}
+
+static int relacmp(const void *_x, const void *_y)
+{
+	const Elf32_Rela *x, *y;
+
+	y = (Elf32_Rela *)_x;
+	x = (Elf32_Rela *)_y;
+
+	/* Compare the entire r_info (as opposed to ELF32_R_SYM(r_info) only) to
+	 * make the comparison cheaper/faster. It won't affect the sorting or
+	 * the counting algorithms' performance
+	 */
+	if (x->r_info < y->r_info)
+		return -1;
+	else if (x->r_info > y->r_info)
+		return 1;
+	else if (x->r_addend < y->r_addend)
+		return -1;
+	else if (x->r_addend > y->r_addend)
+		return 1;
+	else
+		return 0;
+}
+
+static void relaswap(void *_x, void *_y, int size)
+{
+	uint32_t *x, *y, tmp;
+	int i;
+
+	y = (uint32_t *)_x;
+	x = (uint32_t *)_y;
+
+	for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
+		tmp = x[i];
+		x[i] = y[i];
+		y[i] = tmp;
+	}
+}
+
+/* Get the potential trampolines size required of the init and
+   non-init sections */
+static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
+				  const Elf32_Shdr *sechdrs,
+				  const char *secstrings,
+				  int is_init)
+{
+	unsigned long ret = 0;
+	unsigned i;
+
+	/* Everything marked ALLOC (this includes the exported
+           symbols) */
+	for (i = 1; i < hdr->e_shnum; i++) {
+		/* If it's called *.init*, and we're not init, we're
+                   not interested */
+		if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
+		    != is_init)
+			continue;
+
+		/* We don't want to look at debug sections. */
+		if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0)
+			continue;
+
+		if (sechdrs[i].sh_type == SHT_RELA) {
+			DEBUGP("Found relocations in section %u\n", i);
+			DEBUGP("Ptr: %p.  Number: %u\n",
+			       (void *)hdr + sechdrs[i].sh_offset,
+			       sechdrs[i].sh_size / sizeof(Elf32_Rela));
+
+			/* Sort the relocation information based on a symbol and
+			 * addend key. This is a stable O(n*log n) complexity
+			 * alogrithm but it will reduce the complexity of
+			 * count_relocs() to linear complexity O(n)
+			 */
+			sort((void *)hdr + sechdrs[i].sh_offset,
+			     sechdrs[i].sh_size / sizeof(Elf32_Rela),
+			     sizeof(Elf32_Rela), relacmp, relaswap);
+
+			ret += count_relocs((void *)hdr
+					     + sechdrs[i].sh_offset,
+					     sechdrs[i].sh_size
+					     / sizeof(Elf32_Rela))
+				* sizeof(struct ppc_plt_entry);
+		}
+	}
+
+	return ret;
+}
+
+int module_frob_arch_sections(Elf32_Ehdr *hdr,
+			      Elf32_Shdr *sechdrs,
+			      char *secstrings,
+			      struct module *me)
+{
+	unsigned int i;
+
+	/* Find .plt and .init.plt sections */
+	for (i = 0; i < hdr->e_shnum; i++) {
+		if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
+			me->arch.init_plt_section = i;
+		else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
+			me->arch.core_plt_section = i;
+	}
+	if (!me->arch.core_plt_section || !me->arch.init_plt_section) {
+		printk("Module doesn't contain .plt or .init.plt sections.\n");
+		return -ENOEXEC;
+	}
+
+	/* Override their sizes */
+	sechdrs[me->arch.core_plt_section].sh_size
+		= get_plt_size(hdr, sechdrs, secstrings, 0);
+	sechdrs[me->arch.init_plt_section].sh_size
+		= get_plt_size(hdr, sechdrs, secstrings, 1);
+	return 0;
+}
+
+int apply_relocate(Elf32_Shdr *sechdrs,
+		   const char *strtab,
+		   unsigned int symindex,
+		   unsigned int relsec,
+		   struct module *module)
+{
+	printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n",
+	       module->name);
+	return -ENOEXEC;
+}
+
+static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
+{
+	if (entry->jump[0] == 0x3d800000 + ((val + 0x8000) >> 16)
+	    && entry->jump[1] == 0x398c0000 + (val & 0xffff))
+		return 1;
+	return 0;
+}
+
+/* Set up a trampoline in the PLT to bounce us to the distant function */
+static uint32_t do_plt_call(void *location,
+			    Elf32_Addr val,
+			    Elf32_Shdr *sechdrs,
+			    struct module *mod)
+{
+	struct ppc_plt_entry *entry;
+
+	DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
+	/* Init, or core PLT? */
+	if (location >= mod->module_core
+	    && location < mod->module_core + mod->core_size)
+		entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
+	else
+		entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;
+
+	/* Find this entry, or if that fails, the next avail. entry */
+	while (entry->jump[0]) {
+		if (entry_matches(entry, val)) return (uint32_t)entry;
+		entry++;
+	}
+
+	entry->jump[0] = 0x3d800000+((val+0x8000)>>16); /* lis r12,sym@ha */
+	entry->jump[1] = 0x398c0000 + (val&0xffff);     /* addi r12,r12,sym@l*/
+	entry->jump[2] = 0x7d8903a6;                    /* mtctr r12 */
+	entry->jump[3] = 0x4e800420;			/* bctr */
+
+	DEBUGP("Initialized plt for 0x%x at %p\n", val, entry);
+	return (uint32_t)entry;
+}
+
+int apply_relocate_add(Elf32_Shdr *sechdrs,
+		       const char *strtab,
+		       unsigned int symindex,
+		       unsigned int relsec,
+		       struct module *module)
+{
+	unsigned int i;
+	Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
+	Elf32_Sym *sym;
+	uint32_t *location;
+	uint32_t value;
+
+	DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
+	       sechdrs[relsec].sh_info);
+	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
+		/* This is where to make the change */
+		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+			+ rela[i].r_offset;
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
+		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+			+ ELF32_R_SYM(rela[i].r_info);
+		/* `Everything is relative'. */
+		value = sym->st_value + rela[i].r_addend;
+
+		switch (ELF32_R_TYPE(rela[i].r_info)) {
+		case R_PPC_ADDR32:
+			/* Simply set it */
+			*(uint32_t *)location = value;
+			break;
+
+		case R_PPC_ADDR16_LO:
+			/* Low half of the symbol */
+			*(uint16_t *)location = value;
+			break;
+
+		case R_PPC_ADDR16_HI:
+			/* Higher half of the symbol */
+			*(uint16_t *)location = (value >> 16);
+			break;
+
+		case R_PPC_ADDR16_HA:
+			/* Sign-adjusted lower 16 bits: PPC ELF ABI says:
+			   (((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
+			   This is the same, only sane.
+			 */
+			*(uint16_t *)location = (value + 0x8000) >> 16;
+			break;
+
+		case R_PPC_REL24:
+			if ((int)(value - (uint32_t)location) < -0x02000000
+			    || (int)(value - (uint32_t)location) >= 0x02000000)
+				value = do_plt_call(location, value,
+						    sechdrs, module);
+
+			/* Only replace bits 2 through 26 */
+			DEBUGP("REL24 value = %08X. location = %08X\n",
+			       value, (uint32_t)location);
+			DEBUGP("Location before: %08X.\n",
+			       *(uint32_t *)location);
+			*(uint32_t *)location
+				= (*(uint32_t *)location & ~0x03fffffc)
+				| ((value - (uint32_t)location)
+				   & 0x03fffffc);
+			DEBUGP("Location after: %08X.\n",
+			       *(uint32_t *)location);
+			DEBUGP("ie. jump to %08X+%08X = %08X\n",
+			       *(uint32_t *)location & 0x03fffffc,
+			       (uint32_t)location,
+			       (*(uint32_t *)location & 0x03fffffc)
+			       + (uint32_t)location);
+			break;
+
+		case R_PPC_REL32:
+			/* 32-bit relative jump. */
+			*(uint32_t *)location = value - (uint32_t)location;
+			break;
+
+		default:
+			printk("%s: unknown ADD relocation: %u\n",
+			       module->name,
+			       ELF32_R_TYPE(rela[i].r_info));
+			return -ENOEXEC;
+		}
+	}
+#ifdef CONFIG_DYNAMIC_FTRACE
+	module->arch.tramp =
+		do_plt_call(module->module_core,
+			    (unsigned long)ftrace_caller,
+			    sechdrs, module);
+#endif
+	return 0;
+}