Initial import

1 files changed, 671 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
new file mode 100644
index 000000000..683845145
--- /dev/null
+++ b/arch/powerpc/kernel/module_64.c
@@ -0,0 +1,671 @@
+/*  Kernel module help for PPC64.
+    Copyright (C) 2001, 2003 Rusty Russell IBM Corporation.
+
+    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
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/elf.h>
+#include <linux/moduleloader.h>
+#include <linux/err.h>
+#include <linux/vmalloc.h>
+#include <linux/ftrace.h>
+#include <linux/bug.h>
+#include <linux/uaccess.h>
+#include <asm/module.h>
+#include <asm/firmware.h>
+#include <asm/code-patching.h>
+#include <linux/sort.h>
+#include <asm/setup.h>
+
+/* FIXME: We don't do .init separately.  To do this, we'd need to have
+   a separate r2 value in the init and core section, and stub between
+   them, too.
+
+   Using a magic allocator which places modules within 32MB solves
+   this, and makes other things simpler.  Anton?
+   --RR.  */
+
+#if defined(_CALL_ELF) && _CALL_ELF == 2
+#define R2_STACK_OFFSET 24
+
+/* An address is simply the address of the function. */
+typedef unsigned long func_desc_t;
+
+static func_desc_t func_desc(unsigned long addr)
+{
+	return addr;
+}
+static unsigned long func_addr(unsigned long addr)
+{
+	return addr;
+}
+static unsigned long stub_func_addr(func_desc_t func)
+{
+	return func;
+}
+
+/* PowerPC64 specific values for the Elf64_Sym st_other field.  */
+#define STO_PPC64_LOCAL_BIT	5
+#define STO_PPC64_LOCAL_MASK	(7 << STO_PPC64_LOCAL_BIT)
+#define PPC64_LOCAL_ENTRY_OFFSET(other)					\
+ (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2)
+
+static unsigned int local_entry_offset(const Elf64_Sym *sym)
+{
+	/* sym->st_other indicates offset to local entry point
+	 * (otherwise it will assume r12 is the address of the start
+	 * of function and try to derive r2 from it). */
+	return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);
+}
+#else
+#define R2_STACK_OFFSET 40
+
+/* An address is address of the OPD entry, which contains address of fn. */
+typedef struct ppc64_opd_entry func_desc_t;
+
+static func_desc_t func_desc(unsigned long addr)
+{
+	return *(struct ppc64_opd_entry *)addr;
+}
+static unsigned long func_addr(unsigned long addr)
+{
+	return func_desc(addr).funcaddr;
+}
+static unsigned long stub_func_addr(func_desc_t func)
+{
+	return func.funcaddr;
+}
+static unsigned int local_entry_offset(const Elf64_Sym *sym)
+{
+	return 0;
+}
+#endif
+
+/* Like PPC32, we need little trampolines to do > 24-bit jumps (into
+   the kernel itself).  But on PPC64, these need to be used for every
+   jump, actually, to reset r2 (TOC+0x8000). */
+struct ppc64_stub_entry
+{
+	/* 28 byte jump instruction sequence (7 instructions). We only
+	 * need 6 instructions on ABIv2 but we always allocate 7 so
+	 * so we don't have to modify the trampoline load instruction. */
+	u32 jump[7];
+	u32 unused;
+	/* Data for the above code */
+	func_desc_t funcdata;
+};
+
+/*
+ * PPC64 uses 24 bit jumps, but we need to jump into other modules or
+ * the kernel which may be further.  So we jump to a stub.
+ *
+ * For ELFv1 we need to use this to set up the new r2 value (aka TOC
+ * pointer).  For ELFv2 it's the callee's responsibility to set up the
+ * new r2, but for both we need to save the old r2.
+ *
+ * We could simply patch the new r2 value and function pointer into
+ * the stub, but it's significantly shorter to put these values at the
+ * end of the stub code, and patch the stub address (32-bits relative
+ * to the TOC ptr, r2) into the stub.
+ */
+
+static u32 ppc64_stub_insns[] = {
+	0x3d620000,			/* addis   r11,r2, <high> */
+	0x396b0000,			/* addi    r11,r11, <low> */
+	/* Save current r2 value in magic place on the stack. */
+	0xf8410000|R2_STACK_OFFSET,	/* std     r2,R2_STACK_OFFSET(r1) */
+	0xe98b0020,			/* ld      r12,32(r11) */
+#if !defined(_CALL_ELF) || _CALL_ELF != 2
+	/* Set up new r2 from function descriptor */
+	0xe84b0028,			/* ld      r2,40(r11) */
+#endif
+	0x7d8903a6,			/* mtctr   r12 */
+	0x4e800420			/* bctr */
+};
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+static u32 ppc64_stub_mask[] = {
+	0xffff0000,
+	0xffff0000,
+	0xffffffff,
+	0xffffffff,
+#if !defined(_CALL_ELF) || _CALL_ELF != 2
+	0xffffffff,
+#endif
+	0xffffffff,
+	0xffffffff
+};
+
+bool is_module_trampoline(u32 *p)
+{
+	unsigned int i;
+	u32 insns[ARRAY_SIZE(ppc64_stub_insns)];
+
+	BUILD_BUG_ON(sizeof(ppc64_stub_insns) != sizeof(ppc64_stub_mask));
+
+	if (probe_kernel_read(insns, p, sizeof(insns)))
+		return -EFAULT;
+
+	for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) {
+		u32 insna = insns[i];
+		u32 insnb = ppc64_stub_insns[i];
+		u32 mask = ppc64_stub_mask[i];
+
+		if ((insna & mask) != (insnb & mask))
+			return false;
+	}
+
+	return true;
+}
+
+int module_trampoline_target(struct module *mod, u32 *trampoline,
+			     unsigned long *target)
+{
+	u32 buf[2];
+	u16 upper, lower;
+	long offset;
+	void *toc_entry;
+
+	if (probe_kernel_read(buf, trampoline, sizeof(buf)))
+		return -EFAULT;
+
+	upper = buf[0] & 0xffff;
+	lower = buf[1] & 0xffff;
+
+	/* perform the addis/addi, both signed */
+	offset = ((short)upper << 16) + (short)lower;
+
+	/*
+	 * Now get the address this trampoline jumps to. This
+	 * is always 32 bytes into our trampoline stub.
+	 */
+	toc_entry = (void *)mod->arch.toc + offset + 32;
+
+	if (probe_kernel_read(target, toc_entry, sizeof(*target)))
+		return -EFAULT;
+
+	return 0;
+}
+
+#endif
+
+/* Count how many different 24-bit relocations (different symbol,
+   different addend) */
+static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num)
+{
+	unsigned int i, r_info, r_addend, _count_relocs;
+
+	/* FIXME: Only count external ones --RR */
+	_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 (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
+		    (r_info != ELF64_R_SYM(rela[i].r_info) ||
+		     r_addend != rela[i].r_addend)) {
+			_count_relocs++;
+			r_info = ELF64_R_SYM(rela[i].r_info);
+			r_addend = rela[i].r_addend;
+		}
+
+	return _count_relocs;
+}
+
+static int relacmp(const void *_x, const void *_y)
+{
+	const Elf64_Rela *x, *y;
+
+	y = (Elf64_Rela *)_x;
+	x = (Elf64_Rela *)_y;
+
+	/* Compare the entire r_info (as opposed to ELF64_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)
+{
+	uint64_t *x, *y, tmp;
+	int i;
+
+	y = (uint64_t *)_x;
+	x = (uint64_t *)_y;
+
+	for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) {
+		tmp = x[i];
+		x[i] = y[i];
+		y[i] = tmp;
+	}
+}
+
+/* Get size of potential trampolines required. */
+static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
+				    const Elf64_Shdr *sechdrs)
+{
+	/* One extra reloc so it's always 0-funcaddr terminated */
+	unsigned long relocs = 1;
+	unsigned i;
+
+	/* Every relocated section... */
+	for (i = 1; i < hdr->e_shnum; i++) {
+		if (sechdrs[i].sh_type == SHT_RELA) {
+			pr_debug("Found relocations in section %u\n", i);
+			pr_debug("Ptr: %p.  Number: %Lu\n",
+			       (void *)sechdrs[i].sh_addr,
+			       sechdrs[i].sh_size / sizeof(Elf64_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 *)sechdrs[i].sh_addr,
+			     sechdrs[i].sh_size / sizeof(Elf64_Rela),
+			     sizeof(Elf64_Rela), relacmp, relaswap);
+
+			relocs += count_relocs((void *)sechdrs[i].sh_addr,
+					       sechdrs[i].sh_size
+					       / sizeof(Elf64_Rela));
+		}
+	}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	/* make the trampoline to the ftrace_caller */
+	relocs++;
+#endif
+
+	pr_debug("Looks like a total of %lu stubs, max\n", relocs);
+	return relocs * sizeof(struct ppc64_stub_entry);
+}
+
+/* Still needed for ELFv2, for .TOC. */
+static void dedotify_versions(struct modversion_info *vers,
+			      unsigned long size)
+{
+	struct modversion_info *end;
+
+	for (end = (void *)vers + size; vers < end; vers++)
+		if (vers->name[0] == '.') {
+			memmove(vers->name, vers->name+1, strlen(vers->name));
+#ifdef ARCH_RELOCATES_KCRCTAB
+			/* The TOC symbol has no CRC computed. To avoid CRC
+			 * check failing, we must force it to the expected
+			 * value (see CRC check in module.c).
+			 */
+			if (!strcmp(vers->name, "TOC."))
+				vers->crc = -(unsigned long)reloc_start;
+#endif
+		}
+}
+
+/* Undefined symbols which refer to .funcname, hack to funcname (or .TOC.) */
+static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
+{
+	unsigned int i;
+
+	for (i = 1; i < numsyms; i++) {
+		if (syms[i].st_shndx == SHN_UNDEF) {
+			char *name = strtab + syms[i].st_name;
+			if (name[0] == '.')
+				memmove(name, name+1, strlen(name));
+		}
+	}
+}
+
+static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
+			       const char *strtab,
+			       unsigned int symindex)
+{
+	unsigned int i, numsyms;
+	Elf64_Sym *syms;
+
+	syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
+	numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
+
+	for (i = 1; i < numsyms; i++) {
+		if (syms[i].st_shndx == SHN_UNDEF
+		    && strcmp(strtab + syms[i].st_name, "TOC.") == 0)
+			return &syms[i];
+	}
+	return NULL;
+}
+
+int module_frob_arch_sections(Elf64_Ehdr *hdr,
+			      Elf64_Shdr *sechdrs,
+			      char *secstrings,
+			      struct module *me)
+{
+	unsigned int i;
+
+	/* Find .toc and .stubs sections, symtab and strtab */
+	for (i = 1; i < hdr->e_shnum; i++) {
+		char *p;
+		if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
+			me->arch.stubs_section = i;
+		else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0)
+			me->arch.toc_section = i;
+		else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
+			dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
+					  sechdrs[i].sh_size);
+
+		/* We don't handle .init for the moment: rename to _init */
+		while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init")))
+			p[0] = '_';
+
+		if (sechdrs[i].sh_type == SHT_SYMTAB)
+			dedotify((void *)hdr + sechdrs[i].sh_offset,
+				 sechdrs[i].sh_size / sizeof(Elf64_Sym),
+				 (void *)hdr
+				 + sechdrs[sechdrs[i].sh_link].sh_offset);
+	}
+
+	if (!me->arch.stubs_section) {
+		pr_err("%s: doesn't contain .stubs.\n", me->name);
+		return -ENOEXEC;
+	}
+
+	/* If we don't have a .toc, just use .stubs.  We need to set r2
+	   to some reasonable value in case the module calls out to
+	   other functions via a stub, or if a function pointer escapes
+	   the module by some means.  */
+	if (!me->arch.toc_section)
+		me->arch.toc_section = me->arch.stubs_section;
+
+	/* Override the stubs size */
+	sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
+	return 0;
+}
+
+/* r2 is the TOC pointer: it actually points 0x8000 into the TOC (this
+   gives the value maximum span in an instruction which uses a signed
+   offset) */
+static inline unsigned long my_r2(Elf64_Shdr *sechdrs, struct module *me)
+{
+	return sechdrs[me->arch.toc_section].sh_addr + 0x8000;
+}
+
+/* Both low and high 16 bits are added as SIGNED additions, so if low
+   16 bits has high bit set, high 16 bits must be adjusted.  These
+   macros do that (stolen from binutils). */
+#define PPC_LO(v) ((v) & 0xffff)
+#define PPC_HI(v) (((v) >> 16) & 0xffff)
+#define PPC_HA(v) PPC_HI ((v) + 0x8000)
+
+/* Patch stub to reference function and correct r2 value. */
+static inline int create_stub(Elf64_Shdr *sechdrs,
+			      struct ppc64_stub_entry *entry,
+			      unsigned long addr,
+			      struct module *me)
+{
+	long reladdr;
+
+	memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns));
+
+	/* Stub uses address relative to r2. */
+	reladdr = (unsigned long)entry - my_r2(sechdrs, me);
+	if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
+		pr_err("%s: Address %p of stub out of range of %p.\n",
+		       me->name, (void *)reladdr, (void *)my_r2);
+		return 0;
+	}
+	pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
+
+	entry->jump[0] |= PPC_HA(reladdr);
+	entry->jump[1] |= PPC_LO(reladdr);
+	entry->funcdata = func_desc(addr);
+	return 1;
+}
+
+/* Create stub to jump to function described in this OPD/ptr: we need the
+   stub to set up the TOC ptr (r2) for the function. */
+static unsigned long stub_for_addr(Elf64_Shdr *sechdrs,
+				   unsigned long addr,
+				   struct module *me)
+{
+	struct ppc64_stub_entry *stubs;
+	unsigned int i, num_stubs;
+
+	num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
+
+	/* Find this stub, or if that fails, the next avail. entry */
+	stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
+	for (i = 0; stub_func_addr(stubs[i].funcdata); i++) {
+		BUG_ON(i >= num_stubs);
+
+		if (stub_func_addr(stubs[i].funcdata) == func_addr(addr))
+			return (unsigned long)&stubs[i];
+	}
+
+	if (!create_stub(sechdrs, &stubs[i], addr, me))
+		return 0;
+
+	return (unsigned long)&stubs[i];
+}
+
+/* We expect a noop next: if it is, replace it with instruction to
+   restore r2. */
+static int restore_r2(u32 *instruction, struct module *me)
+{
+	if (*instruction != PPC_INST_NOP) {
+		pr_err("%s: Expect noop after relocate, got %08x\n",
+		       me->name, *instruction);
+		return 0;
+	}
+	/* ld r2,R2_STACK_OFFSET(r1) */
+	*instruction = 0xe8410000 | R2_STACK_OFFSET;
+	return 1;
+}
+
+int apply_relocate_add(Elf64_Shdr *sechdrs,
+		       const char *strtab,
+		       unsigned int symindex,
+		       unsigned int relsec,
+		       struct module *me)
+{
+	unsigned int i;
+	Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
+	Elf64_Sym *sym;
+	unsigned long *location;
+	unsigned long value;
+
+	pr_debug("Applying ADD relocate section %u to %u\n", relsec,
+	       sechdrs[relsec].sh_info);
+
+	/* First time we're called, we can fix up .TOC. */
+	if (!me->arch.toc_fixed) {
+		sym = find_dot_toc(sechdrs, strtab, symindex);
+		/* It's theoretically possible that a module doesn't want a
+		 * .TOC. so don't fail it just for that. */
+		if (sym)
+			sym->st_value = my_r2(sechdrs, me);
+		me->arch.toc_fixed = true;
+	}
+
+	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 */
+		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+			+ ELF64_R_SYM(rela[i].r_info);
+
+		pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n",
+		       location, (long)ELF64_R_TYPE(rela[i].r_info),
+		       strtab + sym->st_name, (unsigned long)sym->st_value,
+		       (long)rela[i].r_addend);
+
+		/* `Everything is relative'. */
+		value = sym->st_value + rela[i].r_addend;
+
+		switch (ELF64_R_TYPE(rela[i].r_info)) {
+		case R_PPC64_ADDR32:
+			/* Simply set it */
+			*(u32 *)location = value;
+			break;
+
+		case R_PPC64_ADDR64:
+			/* Simply set it */
+			*(unsigned long *)location = value;
+			break;
+
+		case R_PPC64_TOC:
+			*(unsigned long *)location = my_r2(sechdrs, me);
+			break;
+
+		case R_PPC64_TOC16:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			if (value + 0x8000 > 0xffff) {
+				pr_err("%s: bad TOC16 relocation (0x%lx)\n",
+				       me->name, value);
+				return -ENOEXEC;
+			}
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+
+		case R_PPC64_TOC16_LO:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+
+		case R_PPC64_TOC16_DS:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
+				pr_err("%s: bad TOC16_DS relocation (0x%lx)\n",
+				       me->name, value);
+				return -ENOEXEC;
+			}
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xfffc)
+				| (value & 0xfffc);
+			break;
+
+		case R_PPC64_TOC16_LO_DS:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			if ((value & 3) != 0) {
+				pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n",
+				       me->name, value);
+				return -ENOEXEC;
+			}
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xfffc)
+				| (value & 0xfffc);
+			break;
+
+		case R_PPC64_TOC16_HA:
+			/* Subtract TOC pointer */
+			value -= my_r2(sechdrs, me);
+			value = ((value + 0x8000) >> 16);
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+
+		case R_PPC_REL24:
+			/* FIXME: Handle weak symbols here --RR */
+			if (sym->st_shndx == SHN_UNDEF) {
+				/* External: go via stub */
+				value = stub_for_addr(sechdrs, value, me);
+				if (!value)
+					return -ENOENT;
+				if (!restore_r2((u32 *)location + 1, me))
+					return -ENOEXEC;
+			} else
+				value += local_entry_offset(sym);
+
+			/* Convert value to relative */
+			value -= (unsigned long)location;
+			if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
+				pr_err("%s: REL24 %li out of range!\n",
+				       me->name, (long int)value);
+				return -ENOEXEC;
+			}
+
+			/* Only replace bits 2 through 26 */
+			*(uint32_t *)location
+				= (*(uint32_t *)location & ~0x03fffffc)
+				| (value & 0x03fffffc);
+			break;
+
+		case R_PPC64_REL64:
+			/* 64 bits relative (used by features fixups) */
+			*location = value - (unsigned long)location;
+			break;
+
+		case R_PPC64_TOCSAVE:
+			/*
+			 * Marker reloc indicates we don't have to save r2.
+			 * That would only save us one instruction, so ignore
+			 * it.
+			 */
+			break;
+
+		case R_PPC64_REL16_HA:
+			/* Subtract location pointer */
+			value -= (unsigned long)location;
+			value = ((value + 0x8000) >> 16);
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+
+		case R_PPC64_REL16_LO:
+			/* Subtract location pointer */
+			value -= (unsigned long)location;
+			*((uint16_t *) location)
+				= (*((uint16_t *) location) & ~0xffff)
+				| (value & 0xffff);
+			break;
+
+		default:
+			pr_err("%s: Unknown ADD relocation: %lu\n",
+			       me->name,
+			       (unsigned long)ELF64_R_TYPE(rela[i].r_info));
+			return -ENOEXEC;
+		}
+	}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	me->arch.toc = my_r2(sechdrs, me);
+	me->arch.tramp = stub_for_addr(sechdrs,
+				       (unsigned long)ftrace_caller,
+				       me);
+#endif
+
+	return 0;
+}