1 files changed, 455 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
new file mode 100644
index 000000000000..928b8581fcb0
--- /dev/null
+++ b/arch/powerpc/kernel/module_64.c
@@ -0,0 +1,455 @@
+/*  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
+*/
+#include <linux/module.h>
+#include <linux/elf.h>
+#include <linux/moduleloader.h>
+#include <linux/err.h>
+#include <linux/vmalloc.h>
+#include <asm/module.h>
+#include <asm/uaccess.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 0
+#define DEBUGP printk
+#else
+#define DEBUGP(fmt , ...)
+#endif
+
+/* There's actually a third entry here, but it's unused */
+struct ppc64_opd_entry
+{
+        unsigned long funcaddr;
+        unsigned long r2;
+};
+
+/* 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) */
+        unsigned char jump[28];
+        unsigned char unused[4];
+        /* Data for the above code */
+        struct ppc64_opd_entry opd;
+};
+
+/* We use a stub to fix up r2 (TOC ptr) and to jump to the (external)
+   function which may be more than 24-bits away.  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 struct ppc64_stub_entry ppc64_stub =
+{ .jump = {
+        0x3d, 0x82, 0x00, 0x00, /* addis   r12,r2, <high> */
+        0x39, 0x8c, 0x00, 0x00, /* addi    r12,r12, <low> */
+        /* Save current r2 value in magic place on the stack. */
+        0xf8, 0x41, 0x00, 0x28, /* std     r2,40(r1) */
+        0xe9, 0x6c, 0x00, 0x20, /* ld      r11,32(r12) */
+        0xe8, 0x4c, 0x00, 0x28, /* ld      r2,40(r12) */
+        0x7d, 0x69, 0x03, 0xa6, /* mtctr   r11 */
+        0x4e, 0x80, 0x04, 0x20  /* bctr */
+} };
+
+/* 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, j, ret = 0;
+
+        /* FIXME: Only count external ones --RR */
+        /* Sure, this is order(n^2), but it's usually short, and not
+           time critical */
+        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)
+                        continue;
+                for (j = 0; j < i; j++) {
+                        /* If this addend appeared before, it's
+                           already been counted */
+                        if (rela[i].r_info == rela[j].r_info
+                            && rela[i].r_addend == rela[j].r_addend)
+                                break;
+                }
+                if (j == i) ret++;
+        }
+        return ret;
+}
+
+void *module_alloc(unsigned long size)
+{
+        if (size == 0)
+                return NULL;
+
+        return vmalloc_exec(size);
+}
+
+/* Free memory returned from module_alloc */
+void module_free(struct module *mod, void *module_region)
+{
+        vfree(module_region);
+        /* FIXME: If module_region == mod->init_region, trim exception
+           table entries. */
+}
+
+/* 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) {
+                        DEBUGP("Found relocations in section %u\n", i);
+                        DEBUGP("Ptr: %p.  Number: %lu\n",
+                               (void *)sechdrs[i].sh_addr,
+                               sechdrs[i].sh_size / sizeof(Elf64_Rela));
+                        relocs += count_relocs((void *)sechdrs[i].sh_addr,
+                                               sechdrs[i].sh_size
+                                               / sizeof(Elf64_Rela));
+                }
+        }
+
+        DEBUGP("Looks like a total of %lu stubs, max\n", relocs);
+        return relocs * sizeof(struct ppc64_stub_entry);
+}
+
+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));
+}
+
+/* Undefined symbols which refer to .funcname, hack to funcname */
+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));
+                }
+        }
+}
+
+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 || !me->arch.toc_section) {
+                printk("%s: doesn't contain .toc or .stubs.\n", me->name);
+                return -ENOEXEC;
+        }
+
+        /* Override the stubs size */
+        sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
+        return 0;
+}
+
+int apply_relocate(Elf64_Shdr *sechdrs,
+                   const char *strtab,
+                   unsigned int symindex,
+                   unsigned int relsec,
+                   struct module *me)
+{
+        printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n", me->name);
+        return -ENOEXEC;
+}
+
+/* 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,
+                              struct ppc64_opd_entry *opd,
+                              struct module *me)
+{
+        Elf64_Half *loc1, *loc2;
+        long reladdr;
+
+        *entry = ppc64_stub;
+
+        loc1 = (Elf64_Half *)&entry->jump[2];
+        loc2 = (Elf64_Half *)&entry->jump[6];
+
+        /* Stub uses address relative to r2. */
+        reladdr = (unsigned long)entry - my_r2(sechdrs, me);
+        if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
+                printk("%s: Address %p of stub out of range of %p.\n",
+                       me->name, (void *)reladdr, (void *)my_r2);
+                return 0;
+        }
+        DEBUGP("Stub %p get data from reladdr %li\n", entry, reladdr);
+
+        *loc1 = PPC_HA(reladdr);
+        *loc2 = PPC_LO(reladdr);
+        entry->opd.funcaddr = opd->funcaddr;
+        entry->opd.r2 = opd->r2;
+        return 1;
+}
+
+/* Create stub to jump to function described in this OPD: 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 opdaddr,
+                                   struct module *me)
+{
+        struct ppc64_stub_entry *stubs;
+        struct ppc64_opd_entry *opd = (void *)opdaddr;
+        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; stubs[i].opd.funcaddr; i++) {
+                BUG_ON(i >= num_stubs);
+
+                if (stubs[i].opd.funcaddr == opd->funcaddr)
+                        return (unsigned long)&stubs[i];
+        }
+
+        if (!create_stub(sechdrs, &stubs[i], opd, 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 != 0x60000000) {
+                printk("%s: Expect noop after relocate, got %08x\n",
+                       me->name, *instruction);
+                return 0;
+        }
+        *instruction = 0xe8410028;      /* ld r2,40(r1) */
+        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;
+
+        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 */
+                sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+                        + ELF64_R_SYM(rela[i].r_info);
+
+                DEBUGP("RELOC at %p: %li-type as %s (%lu) + %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:
+                        /* Subtact TOC pointer */
+                        value -= my_r2(sechdrs, me);
+                        if (value + 0x8000 > 0xffff) {
+                                printk("%s: bad TOC16 relocation (%lu)\n",
+                                       me->name, value);
+                                return -ENOEXEC;
+                        }
+                        *((uint16_t *) location)
+                                = (*((uint16_t *) location) & ~0xffff)
+                                | (value & 0xffff);
+                        break;
+
+                case R_PPC64_TOC16_DS:
+                        /* Subtact TOC pointer */
+                        value -= my_r2(sechdrs, me);
+                        if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
+                                printk("%s: bad TOC16_DS relocation (%lu)\n",
+                                       me->name, value);
+                                return -ENOEXEC;
+                        }
+                        *((uint16_t *) location)
+                                = (*((uint16_t *) location) & ~0xfffc)
+                                | (value & 0xfffc);
+                        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;
+                        }
+
+                        /* Convert value to relative */
+                        value -= (unsigned long)location;
+                        if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
+                                printk("%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;
+
+                default:
+                        printk("%s: Unknown ADD relocation: %lu\n",
+                               me->name,
+                               (unsigned long)ELF64_R_TYPE(rela[i].r_info));
+                        return -ENOEXEC;
+                }
+        }
+
+        return 0;
+}
+
+LIST_HEAD(module_bug_list);
+
+int module_finalize(const Elf_Ehdr *hdr,
+                const Elf_Shdr *sechdrs, struct module *me)
+{
+        char *secstrings;
+        unsigned int i;
+
+        me->arch.bug_table = NULL;
+        me->arch.num_bugs = 0;
+
+        /* Find the __bug_table section, if present */
+        secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+        for (i = 1; i < hdr->e_shnum; i++) {
+                if (strcmp(secstrings+sechdrs[i].sh_name, "__bug_table"))
+                        continue;
+                me->arch.bug_table = (void *) sechdrs[i].sh_addr;
+                me->arch.num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry);
+                break;
+        }
+
+        /*
+         * Strictly speaking this should have a spinlock to protect against
+         * traversals, but since we only traverse on BUG()s, a spinlock
+         * could potentially lead to deadlock and thus be counter-productive.
+         */
+        list_add(&me->arch.bug_list, &module_bug_list);
+
+        return 0;
+}
+
+void module_arch_cleanup(struct module *mod)
+{
+        list_del(&mod->arch.bug_list);
+}
+
+struct bug_entry *module_find_bug(unsigned long bugaddr)
+{
+        struct mod_arch_specific *mod;
+        unsigned int i;
+        struct bug_entry *bug;
+
+        list_for_each_entry(mod, &module_bug_list, bug_list) {
+                bug = mod->bug_table;
+                for (i = 0; i < mod->num_bugs; ++i, ++bug)
+                        if (bugaddr == bug->bug_addr)
+                                return bug;
+        }
+        return NULL;
+}