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-rw-r--r--arch/powerpc/kernel/module_64.c842
1 files changed, 842 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..4bf81a111
--- /dev/null
+++ b/arch/powerpc/kernel/module_64.c
@@ -0,0 +1,842 @@
+/* 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>
+#include <asm/sections.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. */
+
+#ifdef PPC64_ELF_ABI_v2
+
+/* 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
+
+/* 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;
+}
+
+void *dereference_module_function_descriptor(struct module *mod, void *ptr)
+{
+ if (ptr < (void *)mod->arch.start_opd ||
+ ptr >= (void *)mod->arch.end_opd)
+ return ptr;
+
+ return dereference_function_descriptor(ptr);
+}
+#endif
+
+#define STUB_MAGIC 0x73747562 /* stub */
+
+/* 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];
+ /* Used by ftrace to identify stubs */
+ u32 magic;
+ /* 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) */
+#ifdef PPC64_ELF_ABI_v1
+ /* Set up new r2 from function descriptor */
+ 0xe84b0028, /* ld r2,40(r11) */
+#endif
+ 0x7d8903a6, /* mtctr r12 */
+ 0x4e800420 /* bctr */
+};
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+int module_trampoline_target(struct module *mod, unsigned long addr,
+ unsigned long *target)
+{
+ struct ppc64_stub_entry *stub;
+ func_desc_t funcdata;
+ u32 magic;
+
+ if (!within_module_core(addr, mod)) {
+ pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name);
+ return -EFAULT;
+ }
+
+ stub = (struct ppc64_stub_entry *)addr;
+
+ if (probe_kernel_read(&magic, &stub->magic, sizeof(magic))) {
+ pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name);
+ return -EFAULT;
+ }
+
+ if (magic != STUB_MAGIC) {
+ pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name);
+ return -EFAULT;
+ }
+
+ if (probe_kernel_read(&funcdata, &stub->funcdata, sizeof(funcdata))) {
+ pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name);
+ return -EFAULT;
+ }
+
+ *target = stub_func_addr(funcdata);
+
+ 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++;
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+ /* an additional one for ftrace_regs_caller */
+ relocs++;
+#endif
+#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));
+ }
+}
+
+/*
+ * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC.
+ * seem to be defined (value set later).
+ */
+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] == '.') {
+ if (strcmp(name+1, "TOC.") == 0)
+ syms[i].st_shndx = SHN_ABS;
+ syms[i].st_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_ABS
+ && 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;
+ if (sechdrs[i].sh_addralign < 8)
+ sechdrs[i].sh_addralign = 8;
+ }
+ 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). Round down
+ * to a 256 byte boundary for the odd case where we are setting up r2 without a
+ * .toc section.
+ */
+static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
+{
+ return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 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(const 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);
+ entry->magic = STUB_MAGIC;
+
+ 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(const 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++) {
+ if (WARN_ON(i >= num_stubs))
+ return 0;
+
+ 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];
+}
+
+#ifdef CONFIG_MPROFILE_KERNEL
+static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction)
+{
+ if (strcmp("_mcount", name))
+ return false;
+
+ /*
+ * Check if this is one of the -mprofile-kernel sequences.
+ */
+ if (instruction[-1] == PPC_INST_STD_LR &&
+ instruction[-2] == PPC_INST_MFLR)
+ return true;
+
+ if (instruction[-1] == PPC_INST_MFLR)
+ return true;
+
+ return false;
+}
+
+/*
+ * In case of _mcount calls, do not save the current callee's TOC (in r2) into
+ * the original caller's stack frame. If we did we would clobber the saved TOC
+ * value of the original caller.
+ */
+static void squash_toc_save_inst(const char *name, unsigned long addr)
+{
+ struct ppc64_stub_entry *stub = (struct ppc64_stub_entry *)addr;
+
+ /* Only for calls to _mcount */
+ if (strcmp("_mcount", name) != 0)
+ return;
+
+ stub->jump[2] = PPC_INST_NOP;
+}
+#else
+static void squash_toc_save_inst(const char *name, unsigned long addr) { }
+
+static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction)
+{
+ return false;
+}
+#endif
+
+/* We expect a noop next: if it is, replace it with instruction to
+ restore r2. */
+static int restore_r2(const char *name, u32 *instruction, struct module *me)
+{
+ u32 *prev_insn = instruction - 1;
+
+ if (is_mprofile_mcount_callsite(name, prev_insn))
+ return 1;
+
+ /*
+ * Make sure the branch isn't a sibling call. Sibling calls aren't
+ * "link" branches and they don't return, so they don't need the r2
+ * restore afterwards.
+ */
+ if (!instr_is_relative_link_branch(*prev_insn))
+ return 1;
+
+ if (*instruction != PPC_INST_NOP) {
+ pr_err("%s: Expected nop after call, got %08x at %pS\n",
+ me->name, *instruction, instruction);
+ return 0;
+ }
+ /* ld r2,R2_STACK_OFFSET(r1) */
+ *instruction = PPC_INST_LD_TOC;
+ 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 ||
+ sym->st_shndx == SHN_LIVEPATCH) {
+ /* External: go via stub */
+ value = stub_for_addr(sechdrs, value, me);
+ if (!value)
+ return -ENOENT;
+ if (!restore_r2(strtab + sym->st_name,
+ (u32 *)location + 1, me))
+ return -ENOEXEC;
+
+ squash_toc_save_inst(strtab + sym->st_name, value);
+ } 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_REL32:
+ /* 32 bits relative (used by relative exception tables) */
+ /* Convert value to relative */
+ value -= (unsigned long)location;
+ if (value + 0x80000000 > 0xffffffff) {
+ pr_err("%s: REL32 %li out of range!\n",
+ me->name, (long int)value);
+ return -ENOEXEC;
+ }
+ *(u32 *)location = value;
+ 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_ENTRY:
+ /*
+ * Optimize ELFv2 large code model entry point if
+ * the TOC is within 2GB range of current location.
+ */
+ value = my_r2(sechdrs, me) - (unsigned long)location;
+ if (value + 0x80008000 > 0xffffffff)
+ break;
+ /*
+ * Check for the large code model prolog sequence:
+ * ld r2, ...(r12)
+ * add r2, r2, r12
+ */
+ if ((((uint32_t *)location)[0] & ~0xfffc)
+ != 0xe84c0000)
+ break;
+ if (((uint32_t *)location)[1] != 0x7c426214)
+ break;
+ /*
+ * If found, replace it with:
+ * addis r2, r12, (.TOC.-func)@ha
+ * addi r2, r2, (.TOC.-func)@l
+ */
+ ((uint32_t *)location)[0] = 0x3c4c0000 + PPC_HA(value);
+ ((uint32_t *)location)[1] = 0x38420000 + PPC_LO(value);
+ 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;
+ }
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+#ifdef CONFIG_MPROFILE_KERNEL
+
+#define PACATOC offsetof(struct paca_struct, kernel_toc)
+
+/*
+ * For mprofile-kernel we use a special stub for ftrace_caller() because we
+ * can't rely on r2 containing this module's TOC when we enter the stub.
+ *
+ * That can happen if the function calling us didn't need to use the toc. In
+ * that case it won't have setup r2, and the r2 value will be either the
+ * kernel's toc, or possibly another modules toc.
+ *
+ * To deal with that this stub uses the kernel toc, which is always accessible
+ * via the paca (in r13). The target (ftrace_caller()) is responsible for
+ * saving and restoring the toc before returning.
+ */
+static unsigned long create_ftrace_stub(const Elf64_Shdr *sechdrs,
+ struct module *me, unsigned long addr)
+{
+ struct ppc64_stub_entry *entry;
+ unsigned int i, num_stubs;
+ static u32 stub_insns[] = {
+ 0xe98d0000 | PACATOC, /* ld r12,PACATOC(r13) */
+ 0x3d8c0000, /* addis r12,r12,<high> */
+ 0x398c0000, /* addi r12,r12,<low> */
+ 0x7d8903a6, /* mtctr r12 */
+ 0x4e800420, /* bctr */
+ };
+ long reladdr;
+
+ num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*entry);
+
+ /* Find the next available stub entry */
+ entry = (void *)sechdrs[me->arch.stubs_section].sh_addr;
+ for (i = 0; i < num_stubs && stub_func_addr(entry->funcdata); i++, entry++);
+
+ if (i >= num_stubs) {
+ pr_err("%s: Unable to find a free slot for ftrace stub.\n", me->name);
+ return 0;
+ }
+
+ memcpy(entry->jump, stub_insns, sizeof(stub_insns));
+
+ /* Stub uses address relative to kernel toc (from the paca) */
+ reladdr = addr - kernel_toc_addr();
+ if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
+ pr_err("%s: Address of %ps out of range of kernel_toc.\n",
+ me->name, (void *)addr);
+ return 0;
+ }
+
+ entry->jump[1] |= PPC_HA(reladdr);
+ entry->jump[2] |= PPC_LO(reladdr);
+
+ /* Eventhough we don't use funcdata in the stub, it's needed elsewhere. */
+ entry->funcdata = func_desc(addr);
+ entry->magic = STUB_MAGIC;
+
+ return (unsigned long)entry;
+}
+#else
+static unsigned long create_ftrace_stub(const Elf64_Shdr *sechdrs,
+ struct module *me, unsigned long addr)
+{
+ return stub_for_addr(sechdrs, addr, me);
+}
+#endif
+
+int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
+{
+ mod->arch.tramp = create_ftrace_stub(sechdrs, mod,
+ (unsigned long)ftrace_caller);
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+ mod->arch.tramp_regs = create_ftrace_stub(sechdrs, mod,
+ (unsigned long)ftrace_regs_caller);
+ if (!mod->arch.tramp_regs)
+ return -ENOENT;
+#endif
+
+ if (!mod->arch.tramp)
+ return -ENOENT;
+
+ return 0;
+}
+#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 17:21:59 +0000