Merge tag 'for_russell/arm-be-probes' of...

Merge tag 'for_russell/arm-be-probes' of git://git.linaro.org/people/taras.kondratiuk/linux into devel-stable

It is reworked initial Ben's series for big endian support [1].
Dropped patches that are not directly related to probes and rebased
series on top of Dave Long's ARM uprobes series. Current set of
patches is enough to have functional BE kprobes and uprobes.

One ARM kprobe test fails on Cortex-A15 boards (TC2 and Keystone2 EVM),
while it passes on Pandaboard. The issue is not related to this series
and already present since v3.13-rc7.

v1..v2: Rebased series on top of Dave Long's ARM uprobes series.
        Now this series fixes both BE kprobes and BE uprobes.

Tested on Pandaboard ES and TI Keystone2 EVM.

pull req v1: http://www.spinics.net/lists/arm-kernel/msg300227.html
[1] http://www.spinics.net/lists/arm-kernel/msg285210.html

arch/arm/kernel/kprobes-common.c

@@ -13,6 +13,7 @@
 
 #include <linux/kernel.h>
 #include <linux/kprobes.h>
+#include <asm/opcodes.h>
 
 #include "kprobes.h"
 
@@ -153,7 +154,8 @@ kprobe_decode_ldmstm(probes_opcode_t insn, struct arch_probes_insn *asi,
 
 	if (handler) {
 		/* We can emulate the instruction in (possibly) modified form */
-		asi->insn[0] = (insn & 0xfff00000) | (rn << 16) | reglist;
+		asi->insn[0] = __opcode_to_mem_arm((insn & 0xfff00000) |
+						   (rn << 16) | reglist);
 		asi->insn_handler = handler;
 		return INSN_GOOD;
 	}

arch/arm/kernel/kprobes-test.c

@@ -113,7 +113,7 @@
  *	@ start of inline data...
  *	.ascii "mov r0, r7"	@ text title for test case
  *	.byte	0
- *	.align	2
+ *	.align	2, 0
  *
  *	@ TEST_ARG_REG
  *	.byte	ARG_TYPE_REG
@@ -1333,7 +1333,8 @@ static void test_case_failed(const char *message)
 static unsigned long next_instruction(unsigned long pc)
 {
 #ifdef CONFIG_THUMB2_KERNEL
-	if ((pc & 1) && !is_wide_instruction(*(u16 *)(pc - 1)))
+	if ((pc & 1) &&
+	    !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
 		return pc + 2;
 	else
 #endif
@@ -1378,13 +1379,13 @@ static uintptr_t __used kprobes_test_case_start(const char *title, void *stack)
 
 	if (test_case_is_thumb) {
 		u16 *p = (u16 *)(test_code & ~1);
-		current_instruction = p[0];
+		current_instruction = __mem_to_opcode_thumb16(p[0]);
 		if (is_wide_instruction(current_instruction)) {
-			current_instruction <<= 16;
-			current_instruction |= p[1];
+			u16 instr2 = __mem_to_opcode_thumb16(p[1]);
+			current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
 		}
 	} else {
-		current_instruction = *(u32 *)test_code;
+		current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
 	}
 
 	if (current_title[0] == '.')

arch/arm/kernel/kprobes-test.h

@@ -115,7 +115,7 @@ struct test_arg_end {
 	/* multiple strings to be concatenated.  */		\
 	".ascii "#title"				\n\t"	\
 	".byte	0					\n\t"	\
-	".align	2					\n\t"
+	".align	2, 0					\n\t"
 
 #define	TEST_ARG_REG(reg, val)					\
 	".byte	"__stringify(ARG_TYPE_REG)"		\n\t"	\

arch/arm/kernel/kprobes-thumb.c

@@ -149,9 +149,9 @@ t32_decode_ldmstm(probes_opcode_t insn, struct arch_probes_insn *asi,
 	enum probes_insn ret = kprobe_decode_ldmstm(insn, asi, d);
 
 	/* Fixup modified instruction to have halfwords in correct order...*/
-	insn = asi->insn[0];
-	((u16 *)asi->insn)[0] = insn >> 16;
-	((u16 *)asi->insn)[1] = insn & 0xffff;
+	insn = __mem_to_opcode_arm(asi->insn[0]);
+	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(insn >> 16);
+	((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0xffff);
 
 	return ret;
 }
@@ -516,7 +516,7 @@ t16_decode_hiregs(probes_opcode_t insn, struct arch_probes_insn *asi,
 {
 	insn &= ~0x00ff;
 	insn |= 0x001; /* Set Rdn = R1 and Rm = R0 */
-	((u16 *)asi->insn)[0] = insn;
+	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(insn);
 	asi->insn_handler = t16_emulate_hiregs;
 	return INSN_GOOD;
 }
@@ -547,8 +547,10 @@ t16_decode_push(probes_opcode_t insn, struct arch_probes_insn *asi,
 	 * and call it with R9=SP and LR in the register list represented
 	 * by R8.
 	 */
-	((u16 *)asi->insn)[0] = 0xe929;		/* 1st half STMDB R9!,{} */
-	((u16 *)asi->insn)[1] = insn & 0x1ff;	/* 2nd half (register list) */
+	/* 1st half STMDB R9!,{} */
+	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(0xe929);
+	/* 2nd half (register list) */
+	((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0x1ff);
 	asi->insn_handler = t16_emulate_push;
 	return INSN_GOOD;
 }
@@ -600,8 +602,10 @@ t16_decode_pop(probes_opcode_t insn, struct arch_probes_insn *asi,
 	 * and call it with R9=SP and PC in the register list represented
 	 * by R8.
 	 */
-	((u16 *)asi->insn)[0] = 0xe8b9;		/* 1st half LDMIA R9!,{} */
-	((u16 *)asi->insn)[1] = insn & 0x1ff;	/* 2nd half (register list) */
+	/* 1st half LDMIA R9!,{} */
+	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(0xe8b9);
+	/* 2nd half (register list) */
+	((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0x1ff);
 	asi->insn_handler = insn & 0x100 ? t16_emulate_pop_pc
 					 : t16_emulate_pop_nopc;
 	return INSN_GOOD;

arch/arm/kernel/kprobes.c

@@ -26,6 +26,7 @@
 #include <linux/stop_machine.h>
 #include <linux/stringify.h>
 #include <asm/traps.h>
+#include <asm/opcodes.h>
 #include <asm/cacheflush.h>
 #include <linux/percpu.h>
 #include <linux/bug.h>
@@ -67,10 +68,10 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 #ifdef CONFIG_THUMB2_KERNEL
 	thumb = true;
 	addr &= ~1; /* Bit 0 would normally be set to indicate Thumb code */
-	insn = ((u16 *)addr)[0];
+	insn = __mem_to_opcode_thumb16(((u16 *)addr)[0]);
 	if (is_wide_instruction(insn)) {
-		insn <<= 16;
-		insn |= ((u16 *)addr)[1];
+		u16 inst2 = __mem_to_opcode_thumb16(((u16 *)addr)[1]);
+		insn = __opcode_thumb32_compose(insn, inst2);
 		decode_insn = thumb32_probes_decode_insn;
 		actions = kprobes_t32_actions;
 	} else {
@@ -81,7 +82,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	thumb = false;
 	if (addr & 0x3)
 		return -EINVAL;
-	insn = *p->addr;
+	insn = __mem_to_opcode_arm(*p->addr);
 	decode_insn = arm_probes_decode_insn;
 	actions = kprobes_arm_actions;
 #endif

arch/arm/kernel/probes.c

@@ -202,13 +202,14 @@ prepare_emulated_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
 #ifdef CONFIG_THUMB2_KERNEL
 	if (thumb) {
 		u16 *thumb_insn = (u16 *)asi->insn;
-		thumb_insn[1] = 0x4770; /* Thumb bx lr */
-		thumb_insn[2] = 0x4770; /* Thumb bx lr */
+		/* Thumb bx lr */
+		thumb_insn[1] = __opcode_to_mem_thumb16(0x4770);
+		thumb_insn[2] = __opcode_to_mem_thumb16(0x4770);
 		return insn;
 	}
-	asi->insn[1] = 0xe12fff1e; /* ARM bx lr */
+	asi->insn[1] = __opcode_to_mem_arm(0xe12fff1e); /* ARM bx lr */
 #else
-	asi->insn[1] = 0xe1a0f00e; /* mov pc, lr */
+	asi->insn[1] = __opcode_to_mem_arm(0xe1a0f00e); /* mov pc, lr */
 #endif
 	/* Make an ARM instruction unconditional */
 	if (insn < 0xe0000000)
@@ -228,12 +229,12 @@ set_emulated_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
 	if (thumb) {
 		u16 *ip = (u16 *)asi->insn;
 		if (is_wide_instruction(insn))
-			*ip++ = insn >> 16;
-		*ip++ = insn;
+			*ip++ = __opcode_to_mem_thumb16(insn >> 16);
+		*ip++ = __opcode_to_mem_thumb16(insn);
 		return;
 	}
 #endif
-	asi->insn[0] = insn;
+	asi->insn[0] = __opcode_to_mem_arm(insn);
 }
 
 /*