x86/asm: Stop depending on ptrace.h in alternative.h

alternative.h pulls in ptrace.h, which means that alternatives can't
be used in anything referenced from ptrace.h, which is a mess.

Break the dependency by pulling text patching helpers into their own
header.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/99b93b13f2c9eb671f5c98bba4c2cbdc061293a2.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/alternative.h

@@ -5,7 +5,6 @@
 #include <linux/stddef.h>
 #include <linux/stringify.h>
 #include <asm/asm.h>
-#include <asm/ptrace.h>
 
 /*
  * Alternative inline assembly for SMP.
@@ -233,36 +232,4 @@ static inline int alternatives_text_reserved(void *start, void *end)
  */
 #define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr
 
-struct paravirt_patch_site;
-#ifdef CONFIG_PARAVIRT
-void apply_paravirt(struct paravirt_patch_site *start,
-		    struct paravirt_patch_site *end);
-#else
-static inline void apply_paravirt(struct paravirt_patch_site *start,
-				  struct paravirt_patch_site *end)
-{}
-#define __parainstructions	NULL
-#define __parainstructions_end	NULL
-#endif
-
-extern void *text_poke_early(void *addr, const void *opcode, size_t len);
-
-/*
- * Clear and restore the kernel write-protection flag on the local CPU.
- * Allows the kernel to edit read-only pages.
- * Side-effect: any interrupt handler running between save and restore will have
- * the ability to write to read-only pages.
- *
- * Warning:
- * Code patching in the UP case is safe if NMIs and MCE handlers are stopped and
- * no thread can be preempted in the instructions being modified (no iret to an
- * invalid instruction possible) or if the instructions are changed from a
- * consistent state to another consistent state atomically.
- * On the local CPU you need to be protected again NMI or MCE handlers seeing an
- * inconsistent instruction while you patch.
- */
-extern void *text_poke(void *addr, const void *opcode, size_t len);
-extern int poke_int3_handler(struct pt_regs *regs);
-extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
-
 #endif /* _ASM_X86_ALTERNATIVE_H */

arch/x86/include/asm/kgdb.h

@@ -6,6 +6,8 @@
  * Copyright (C) 2008 Wind River Systems, Inc.
  */
 
+#include <asm/ptrace.h>
+
 /*
  * BUFMAX defines the maximum number of characters in inbound/outbound
  * buffers at least NUMREGBYTES*2 are needed for register packets

arch/x86/include/asm/setup.h

@@ -6,6 +6,7 @@
 #define COMMAND_LINE_SIZE 2048
 
 #include <linux/linkage.h>
+#include <asm/page_types.h>
 
 #ifdef __i386__
 

arch/x86/include/asm/text-patching.h

@@ -0,0 +1,40 @@
+#ifndef _ASM_X86_TEXT_PATCHING_H
+#define _ASM_X86_TEXT_PATCHING_H
+
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <asm/ptrace.h>
+
+struct paravirt_patch_site;
+#ifdef CONFIG_PARAVIRT
+void apply_paravirt(struct paravirt_patch_site *start,
+		    struct paravirt_patch_site *end);
+#else
+static inline void apply_paravirt(struct paravirt_patch_site *start,
+				  struct paravirt_patch_site *end)
+{}
+#define __parainstructions	NULL
+#define __parainstructions_end	NULL
+#endif
+
+extern void *text_poke_early(void *addr, const void *opcode, size_t len);
+
+/*
+ * Clear and restore the kernel write-protection flag on the local CPU.
+ * Allows the kernel to edit read-only pages.
+ * Side-effect: any interrupt handler running between save and restore will have
+ * the ability to write to read-only pages.
+ *
+ * Warning:
+ * Code patching in the UP case is safe if NMIs and MCE handlers are stopped and
+ * no thread can be preempted in the instructions being modified (no iret to an
+ * invalid instruction possible) or if the instructions are changed from a
+ * consistent state to another consistent state atomically.
+ * On the local CPU you need to be protected again NMI or MCE handlers seeing an
+ * inconsistent instruction while you patch.
+ */
+extern void *text_poke(void *addr, const void *opcode, size_t len);
+extern int poke_int3_handler(struct pt_regs *regs);
+extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
+
+#endif /* _ASM_X86_TEXT_PATCHING_H */

arch/x86/kernel/alternative.c

@@ -11,6 +11,7 @@
 #include <linux/stop_machine.h>
 #include <linux/slab.h>
 #include <linux/kdebug.h>
+#include <asm/text-patching.h>
 #include <asm/alternative.h>
 #include <asm/sections.h>
 #include <asm/pgtable.h>

arch/x86/kernel/jump_label.c

@@ -13,6 +13,7 @@
 #include <linux/cpu.h>
 #include <asm/kprobes.h>
 #include <asm/alternative.h>
+#include <asm/text-patching.h>
 
 #ifdef HAVE_JUMP_LABEL
 

arch/x86/kernel/kgdb.c

@@ -45,6 +45,7 @@
 #include <linux/uaccess.h>
 #include <linux/memory.h>
 
+#include <asm/text-patching.h>
 #include <asm/debugreg.h>
 #include <asm/apicdef.h>
 #include <asm/apic.h>

arch/x86/kernel/kprobes/core.c

@@ -51,6 +51,7 @@
 #include <linux/ftrace.h>
 #include <linux/frame.h>
 
+#include <asm/text-patching.h>
 #include <asm/cacheflush.h>
 #include <asm/desc.h>
 #include <asm/pgtable.h>

arch/x86/kernel/kprobes/opt.c

@@ -29,6 +29,7 @@
 #include <linux/kallsyms.h>
 #include <linux/ftrace.h>
 
+#include <asm/text-patching.h>
 #include <asm/cacheflush.h>
 #include <asm/desc.h>
 #include <asm/pgtable.h>

arch/x86/kernel/module.c

@@ -31,6 +31,7 @@
 #include <linux/jump_label.h>
 #include <linux/random.h>
 
+#include <asm/text-patching.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/setup.h>

arch/x86/kernel/traps.c

@@ -51,6 +51,7 @@
 #include <asm/processor.h>
 #include <asm/debugreg.h>
 #include <linux/atomic.h>
+#include <asm/text-patching.h>
 #include <asm/ftrace.h>
 #include <asm/traps.h>
 #include <asm/desc.h>