Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 asm updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Cross-arch changes to move the linker sections for NOTES and
     EXCEPTION_TABLE into the RO_DATA area, where they belong on most
     architectures. (Kees Cook)

   - Switch the x86 linker fill byte from x90 (NOP) to 0xcc (INT3), to
     trap jumps into the middle of those padding areas instead of
     sliding execution. (Kees Cook)

   - A thorough cleanup of symbol definitions within x86 assembler code.
     The rather randomly named macros got streamlined around a
     (hopefully) straightforward naming scheme:

        SYM_START(name, linkage, align...)
        SYM_END(name, sym_type)

        SYM_FUNC_START(name)
        SYM_FUNC_END(name)

        SYM_CODE_START(name)
        SYM_CODE_END(name)

        SYM_DATA_START(name)
        SYM_DATA_END(name)

     etc - with about three times of these basic primitives with some
     label, local symbol or attribute variant, expressed via postfixes.

     No change in functionality intended. (Jiri Slaby)

   - Misc other changes, cleanups and smaller fixes"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits)
  x86/entry/64: Remove pointless jump in paranoid_exit
  x86/entry/32: Remove unused resume_userspace label
  x86/build/vdso: Remove meaningless CFLAGS_REMOVE_*.o
  m68k: Convert missed RODATA to RO_DATA
  x86/vmlinux: Use INT3 instead of NOP for linker fill bytes
  x86/mm: Report actual image regions in /proc/iomem
  x86/mm: Report which part of kernel image is freed
  x86/mm: Remove redundant address-of operators on addresses
  xtensa: Move EXCEPTION_TABLE to RO_DATA segment
  powerpc: Move EXCEPTION_TABLE to RO_DATA segment
  parisc: Move EXCEPTION_TABLE to RO_DATA segment
  microblaze: Move EXCEPTION_TABLE to RO_DATA segment
  ia64: Move EXCEPTION_TABLE to RO_DATA segment
  h8300: Move EXCEPTION_TABLE to RO_DATA segment
  c6x: Move EXCEPTION_TABLE to RO_DATA segment
  arm64: Move EXCEPTION_TABLE to RO_DATA segment
  alpha: Move EXCEPTION_TABLE to RO_DATA segment
  x86/vmlinux: Move EXCEPTION_TABLE to RO_DATA segment
  x86/vmlinux: Actually use _etext for the end of the text segment
  vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
  ...

2 files changed, 280 insertions, 22 deletions

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index a9c4e4721434..63cedc3c0c77 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -23,12 +23,11 @@
  *	_etext = .;
  *
  *      _sdata = .;
- *	RO_DATA_SECTION(PAGE_SIZE)
- *	RW_DATA_SECTION(...)
+ *	RO_DATA(PAGE_SIZE)
+ *	RW_DATA(...)
  *	_edata = .;
  *
  *	EXCEPTION_TABLE(...)
- *	NOTES
  *
  *	BSS_SECTION(0, 0, 0)
  *	_end = .;
@@ -54,6 +53,33 @@
 #define LOAD_OFFSET 0
 #endif
 
+/*
+ * Only some architectures want to have the .notes segment visible in
+ * a separate PT_NOTE ELF Program Header. When this happens, it needs
+ * to be visible in both the kernel text's PT_LOAD and the PT_NOTE
+ * Program Headers. In this case, though, the PT_LOAD needs to be made
+ * the default again so that all the following sections don't also end
+ * up in the PT_NOTE Program Header.
+ */
+#ifdef EMITS_PT_NOTE
+#define NOTES_HEADERS		:text :note
+#define NOTES_HEADERS_RESTORE	__restore_ph : { *(.__restore_ph) } :text
+#else
+#define NOTES_HEADERS
+#define NOTES_HEADERS_RESTORE
+#endif
+
+/*
+ * Some architectures have non-executable read-only exception tables.
+ * They can be added to the RO_DATA segment by specifying their desired
+ * alignment.
+ */
+#ifdef RO_EXCEPTION_TABLE_ALIGN
+#define RO_EXCEPTION_TABLE	EXCEPTION_TABLE(RO_EXCEPTION_TABLE_ALIGN)
+#else
+#define RO_EXCEPTION_TABLE
+#endif
+
 /* Align . to a 8 byte boundary equals to maximum function alignment. */
 #define ALIGN_FUNCTION()  . = ALIGN(8)
 
@@ -348,7 +374,7 @@
 /*
  * Read only Data
  */
-#define RO_DATA_SECTION(align)						\
+#define RO_DATA(align)							\
 	. = ALIGN((align));						\
 	.rodata           : AT(ADDR(.rodata) - LOAD_OFFSET) {		\
 		__start_rodata = .;					\
@@ -496,15 +522,13 @@
 		__start___modver = .;					\
 		KEEP(*(__modver))					\
 		__stop___modver = .;					\
-		. = ALIGN((align));					\
-		__end_rodata = .;					\
 	}								\
-	. = ALIGN((align));
-
-/* RODATA & RO_DATA provided for backward compatibility.
- * All archs are supposed to use RO_DATA() */
-#define RODATA          RO_DATA_SECTION(4096)
-#define RO_DATA(align)  RO_DATA_SECTION(align)
+									\
+	RO_EXCEPTION_TABLE						\
+	NOTES								\
+									\
+	. = ALIGN((align));						\
+	__end_rodata = .;
 
 /*
  * .text section. Map to function alignment to avoid address changes
@@ -790,7 +814,8 @@
 		__start_notes = .;					\
 		KEEP(*(.note.*))					\
 		__stop_notes = .;					\
-	}
+	} NOTES_HEADERS							\
+	NOTES_HEADERS_RESTORE
 
 #define INIT_SETUP(initsetup_align)					\
 		. = ALIGN(initsetup_align);				\
@@ -962,7 +987,7 @@
  * matches the requirement of PAGE_ALIGNED_DATA.
  *
  * use 0 as page_align if page_aligned data is not used */
-#define RW_DATA_SECTION(cacheline, pagealigned, inittask)		\
+#define RW_DATA(cacheline, pagealigned, inittask)			\
 	. = ALIGN(PAGE_SIZE);						\
 	.data : AT(ADDR(.data) - LOAD_OFFSET) {				\
 		INIT_TASK_DATA(inittask)				\
diff --git a/include/linux/linkage.h b/include/linux/linkage.h
index 7e020782ade2..9280209d1f62 100644
--- a/include/linux/linkage.h
+++ b/include/linux/linkage.h
@@ -75,32 +75,61 @@
 
 #ifdef __ASSEMBLY__
 
+/* SYM_T_FUNC -- type used by assembler to mark functions */
+#ifndef SYM_T_FUNC
+#define SYM_T_FUNC				STT_FUNC
+#endif
+
+/* SYM_T_OBJECT -- type used by assembler to mark data */
+#ifndef SYM_T_OBJECT
+#define SYM_T_OBJECT				STT_OBJECT
+#endif
+
+/* SYM_T_NONE -- type used by assembler to mark entries of unknown type */
+#ifndef SYM_T_NONE
+#define SYM_T_NONE				STT_NOTYPE
+#endif
+
+/* SYM_A_* -- align the symbol? */
+#define SYM_A_ALIGN				ALIGN
+#define SYM_A_NONE				/* nothing */
+
+/* SYM_L_* -- linkage of symbols */
+#define SYM_L_GLOBAL(name)			.globl name
+#define SYM_L_WEAK(name)			.weak name
+#define SYM_L_LOCAL(name)			/* nothing */
+
 #ifndef LINKER_SCRIPT
 #define ALIGN __ALIGN
 #define ALIGN_STR __ALIGN_STR
 
+/* === DEPRECATED annotations === */
+
+#ifndef CONFIG_X86
 #ifndef GLOBAL
+/* deprecated, use SYM_DATA*, SYM_ENTRY, or similar */
 #define GLOBAL(name) \
 	.globl name ASM_NL \
 	name:
 #endif
 
 #ifndef ENTRY
+/* deprecated, use SYM_FUNC_START */
 #define ENTRY(name) \
-	.globl name ASM_NL \
-	ALIGN ASM_NL \
-	name:
+	SYM_FUNC_START(name)
 #endif
+#endif /* CONFIG_X86 */
 #endif /* LINKER_SCRIPT */
 
+#ifndef CONFIG_X86
 #ifndef WEAK
+/* deprecated, use SYM_FUNC_START_WEAK* */
 #define WEAK(name)	   \
-	.weak name ASM_NL   \
-	ALIGN ASM_NL \
-	name:
+	SYM_FUNC_START_WEAK(name)
 #endif
 
 #ifndef END
+/* deprecated, use SYM_FUNC_END, SYM_DATA_END, or SYM_END */
 #define END(name) \
 	.size name, .-name
 #endif
@@ -110,11 +139,215 @@
  * static analysis tools such as stack depth analyzer.
  */
 #ifndef ENDPROC
+/* deprecated, use SYM_FUNC_END */
 #define ENDPROC(name) \
-	.type name, @function ASM_NL \
-	END(name)
+	SYM_FUNC_END(name)
+#endif
+#endif /* CONFIG_X86 */
+
+/* === generic annotations === */
+
+/* SYM_ENTRY -- use only if you have to for non-paired symbols */
+#ifndef SYM_ENTRY
+#define SYM_ENTRY(name, linkage, align...)		\
+	linkage(name) ASM_NL				\
+	align ASM_NL					\
+	name:
+#endif
+
+/* SYM_START -- use only if you have to */
+#ifndef SYM_START
+#define SYM_START(name, linkage, align...)		\
+	SYM_ENTRY(name, linkage, align)
+#endif
+
+/* SYM_END -- use only if you have to */
+#ifndef SYM_END
+#define SYM_END(name, sym_type)				\
+	.type name sym_type ASM_NL			\
+	.size name, .-name
+#endif
+
+/* === code annotations === */
+
+/*
+ * FUNC -- C-like functions (proper stack frame etc.)
+ * CODE -- non-C code (e.g. irq handlers with different, special stack etc.)
+ *
+ * Objtool validates stack for FUNC, but not for CODE.
+ * Objtool generates debug info for both FUNC & CODE, but needs special
+ * annotations for each CODE's start (to describe the actual stack frame).
+ *
+ * ALIAS -- does not generate debug info -- the aliased function will
+ */
+
+/* SYM_INNER_LABEL_ALIGN -- only for labels in the middle of code */
+#ifndef SYM_INNER_LABEL_ALIGN
+#define SYM_INNER_LABEL_ALIGN(name, linkage)	\
+	.type name SYM_T_NONE ASM_NL			\
+	SYM_ENTRY(name, linkage, SYM_A_ALIGN)
+#endif
+
+/* SYM_INNER_LABEL -- only for labels in the middle of code */
+#ifndef SYM_INNER_LABEL
+#define SYM_INNER_LABEL(name, linkage)		\
+	.type name SYM_T_NONE ASM_NL			\
+	SYM_ENTRY(name, linkage, SYM_A_NONE)
+#endif
+
+/*
+ * SYM_FUNC_START_LOCAL_ALIAS -- use where there are two local names for one
+ * function
+ */
+#ifndef SYM_FUNC_START_LOCAL_ALIAS
+#define SYM_FUNC_START_LOCAL_ALIAS(name)		\
+	SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)
+#endif
+
+/*
+ * SYM_FUNC_START_ALIAS -- use where there are two global names for one
+ * function
+ */
+#ifndef SYM_FUNC_START_ALIAS
+#define SYM_FUNC_START_ALIAS(name)			\
+	SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
+#endif
+
+/* SYM_FUNC_START -- use for global functions */
+#ifndef SYM_FUNC_START
+/*
+ * The same as SYM_FUNC_START_ALIAS, but we will need to distinguish these two
+ * later.
+ */
+#define SYM_FUNC_START(name)				\
+	SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
+#endif
+
+/* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */
+#ifndef SYM_FUNC_START_NOALIGN
+#define SYM_FUNC_START_NOALIGN(name)			\
+	SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
+#endif
+
+/* SYM_FUNC_START_LOCAL -- use for local functions */
+#ifndef SYM_FUNC_START_LOCAL
+/* the same as SYM_FUNC_START_LOCAL_ALIAS, see comment near SYM_FUNC_START */
+#define SYM_FUNC_START_LOCAL(name)			\
+	SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)
 #endif
 
+/* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */
+#ifndef SYM_FUNC_START_LOCAL_NOALIGN
+#define SYM_FUNC_START_LOCAL_NOALIGN(name)		\
+	SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
 #endif
 
+/* SYM_FUNC_START_WEAK -- use for weak functions */
+#ifndef SYM_FUNC_START_WEAK
+#define SYM_FUNC_START_WEAK(name)			\
+	SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN)
 #endif
+
+/* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */
+#ifndef SYM_FUNC_START_WEAK_NOALIGN
+#define SYM_FUNC_START_WEAK_NOALIGN(name)		\
+	SYM_START(name, SYM_L_WEAK, SYM_A_NONE)
+#endif
+
+/* SYM_FUNC_END_ALIAS -- the end of LOCAL_ALIASed or ALIASed function */
+#ifndef SYM_FUNC_END_ALIAS
+#define SYM_FUNC_END_ALIAS(name)			\
+	SYM_END(name, SYM_T_FUNC)
+#endif
+
+/*
+ * SYM_FUNC_END -- the end of SYM_FUNC_START_LOCAL, SYM_FUNC_START,
+ * SYM_FUNC_START_WEAK, ...
+ */
+#ifndef SYM_FUNC_END
+/* the same as SYM_FUNC_END_ALIAS, see comment near SYM_FUNC_START */
+#define SYM_FUNC_END(name)				\
+	SYM_END(name, SYM_T_FUNC)
+#endif
+
+/* SYM_CODE_START -- use for non-C (special) functions */
+#ifndef SYM_CODE_START
+#define SYM_CODE_START(name)				\
+	SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
+#endif
+
+/* SYM_CODE_START_NOALIGN -- use for non-C (special) functions, w/o alignment */
+#ifndef SYM_CODE_START_NOALIGN
+#define SYM_CODE_START_NOALIGN(name)			\
+	SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
+#endif
+
+/* SYM_CODE_START_LOCAL -- use for local non-C (special) functions */
+#ifndef SYM_CODE_START_LOCAL
+#define SYM_CODE_START_LOCAL(name)			\
+	SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)
+#endif
+
+/*
+ * SYM_CODE_START_LOCAL_NOALIGN -- use for local non-C (special) functions,
+ * w/o alignment
+ */
+#ifndef SYM_CODE_START_LOCAL_NOALIGN
+#define SYM_CODE_START_LOCAL_NOALIGN(name)		\
+	SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
+#endif
+
+/* SYM_CODE_END -- the end of SYM_CODE_START_LOCAL, SYM_CODE_START, ... */
+#ifndef SYM_CODE_END
+#define SYM_CODE_END(name)				\
+	SYM_END(name, SYM_T_NONE)
+#endif
+
+/* === data annotations === */
+
+/* SYM_DATA_START -- global data symbol */
+#ifndef SYM_DATA_START
+#define SYM_DATA_START(name)				\
+	SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
+#endif
+
+/* SYM_DATA_START -- local data symbol */
+#ifndef SYM_DATA_START_LOCAL
+#define SYM_DATA_START_LOCAL(name)			\
+	SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
+#endif
+
+/* SYM_DATA_END -- the end of SYM_DATA_START symbol */
+#ifndef SYM_DATA_END
+#define SYM_DATA_END(name)				\
+	SYM_END(name, SYM_T_OBJECT)
+#endif
+
+/* SYM_DATA_END_LABEL -- the labeled end of SYM_DATA_START symbol */
+#ifndef SYM_DATA_END_LABEL
+#define SYM_DATA_END_LABEL(name, linkage, label)	\
+	linkage(label) ASM_NL				\
+	.type label SYM_T_OBJECT ASM_NL			\
+	label:						\
+	SYM_END(name, SYM_T_OBJECT)
+#endif
+
+/* SYM_DATA -- start+end wrapper around simple global data */
+#ifndef SYM_DATA
+#define SYM_DATA(name, data...)				\
+	SYM_DATA_START(name) ASM_NL				\
+	data ASM_NL						\
+	SYM_DATA_END(name)
+#endif
+
+/* SYM_DATA_LOCAL -- start+end wrapper around simple local data */
+#ifndef SYM_DATA_LOCAL
+#define SYM_DATA_LOCAL(name, data...)			\
+	SYM_DATA_START_LOCAL(name) ASM_NL			\
+	data ASM_NL						\
+	SYM_DATA_END(name)
+#endif
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _LINUX_LINKAGE_H */