1 files changed, 104 insertions, 118 deletions

diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index de317c158f38..f4c2fa190192 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -334,6 +334,92 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr,
 	return 0;
 }
 
+#ifdef CONFIG_MPROFILE_KERNEL
+
+#define PACATOC offsetof(struct paca_struct, kernel_toc)
+
+/*
+ * ld      r12,PACATOC(r13)
+ * addis   r12,r12,<high>
+ * addi    r12,r12,<low>
+ * mtctr   r12
+ * bctr
+ */
+static u32 stub_insns[] = {
+	PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R13) | PACATOC,
+	PPC_INST_ADDIS | __PPC_RT(R12) | __PPC_RA(R12),
+	PPC_INST_ADDI | __PPC_RT(R12) | __PPC_RA(R12),
+	PPC_INST_MTCTR | __PPC_RS(R12),
+	PPC_INST_BCTR,
+};
+
+/*
+ * 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 inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
+					unsigned long addr,
+					struct module *me)
+{
+	long reladdr;
+
+	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 1;
+}
+
+static bool is_mprofile_ftrace_call(const char *name)
+{
+	if (!strcmp("_mcount", name))
+		return true;
+#ifdef CONFIG_DYNAMIC_FTRACE
+	if (!strcmp("ftrace_caller", name))
+		return true;
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+	if (!strcmp("ftrace_regs_caller", name))
+		return true;
+#endif
+#endif
+
+	return false;
+}
+#else
+static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
+					unsigned long addr,
+					struct module *me)
+{
+	return 0;
+}
+
+static bool is_mprofile_ftrace_call(const char *name)
+{
+	return false;
+}
+#endif
+
 /*
  * 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
@@ -349,10 +435,14 @@ static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
 static inline int create_stub(const Elf64_Shdr *sechdrs,
 			      struct ppc64_stub_entry *entry,
 			      unsigned long addr,
-			      struct module *me)
+			      struct module *me,
+			      const char *name)
 {
 	long reladdr;
 
+	if (is_mprofile_ftrace_call(name))
+		return create_ftrace_stub(entry, addr, me);
+
 	memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns));
 
 	/* Stub uses address relative to r2. */
@@ -376,7 +466,8 @@ static inline int create_stub(const Elf64_Shdr *sechdrs,
    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 module *me,
+				   const char *name)
 {
 	struct ppc64_stub_entry *stubs;
 	unsigned int i, num_stubs;
@@ -393,45 +484,12 @@ static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
 			return (unsigned long)&stubs[i];
 	}
 
-	if (!create_stub(sechdrs, &stubs[i], addr, me))
+	if (!create_stub(sechdrs, &stubs[i], addr, me, name))
 		return 0;
 
 	return (unsigned long)&stubs[i];
 }
 
-#ifdef CONFIG_MPROFILE_KERNEL
-static bool is_mprofile_ftrace_call(const char *name)
-{
-	if (!strcmp("_mcount", name))
-		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_ftrace_call(const char *name)
-{
-	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)
@@ -576,14 +634,13 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
 			if (sym->st_shndx == SHN_UNDEF ||
 			    sym->st_shndx == SHN_LIVEPATCH) {
 				/* External: go via stub */
-				value = stub_for_addr(sechdrs, value, me);
+				value = stub_for_addr(sechdrs, value, me,
+						strtab + sym->st_name);
 				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);
 
@@ -719,88 +776,17 @@ int module_trampoline_target(struct module *mod, unsigned long addr,
 	return 0;
 }
 
-#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;
-	/*
-	 * ld      r12,PACATOC(r13)
-	 * addis   r12,r12,<high>
-	 * addi    r12,r12,<low>
-	 * mtctr   r12
-	 * bctr
-	 */
-	static u32 stub_insns[] = {
-		PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R13) | PACATOC,
-		PPC_INST_ADDIS | __PPC_RT(R12) | __PPC_RA(R12),
-		PPC_INST_ADDI | __PPC_RT(R12) | __PPC_RA(R12),
-		PPC_INST_MTCTR | __PPC_RS(R12),
-		PPC_INST_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);
+	mod->arch.tramp = stub_for_addr(sechdrs,
+					(unsigned long)ftrace_caller,
+					mod,
+					"ftrace_caller");
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
-	mod->arch.tramp_regs = create_ftrace_stub(sechdrs, mod,
-					(unsigned long)ftrace_regs_caller);
+	mod->arch.tramp_regs = stub_for_addr(sechdrs,
+					(unsigned long)ftrace_regs_caller,
+					mod,
+					"ftrace_regs_caller");
 	if (!mod->arch.tramp_regs)
 		return -ENOENT;
 #endif