[PATCH]IA64 trap code 16 bytes atomic copy on montecito, take 2

["bibo,mao" <bibo.mao@xxxxxxxxx>]

hi,
On IA64 kprobe can not insert trap code on slot 1 because
opcode of slot 1 crosses over two consecutive 8-bytes. On
montecito machine 16 bytes atomic operation is avaiable.
This patch adds ia64_ld16/ia64_st16 instrins in gcc header
file, implements atomic instr bundle updating by cpu feature.

Signed-off-by: bibo, mao <bibo.mao@xxxxxxxxx>

thanks
bibo,mao 


diff -Nrup -X 2.6.19-rc2.org/Documentation/dontdiff 2.6.19-rc2.org/arch/ia64/kernel/kprobes.c 2.6.19-rc2/arch/ia64/kernel/kprobes.c
--- 2.6.19-rc2.org/arch/ia64/kernel/kprobes.c	2006-10-27 16:39:29.000000000 +0800
+++ 2.6.19-rc2/arch/ia64/kernel/kprobes.c	2006-11-01 19:05:18.000000000 +0800
@@ -296,7 +296,7 @@ static int __kprobes valid_kprobe_addr(i
		return -EINVAL;
	}

-	if (slot == 1 && bundle_encoding[template][1] != L) {
+	if (slot == 1 && bundle_encoding[template][1] != L && !ATOMIC_UPDATE) {
		printk(KERN_WARNING "Inserting kprobes on slot #1 "
		       "is not supported\n");
		return -EINVAL;
@@ -448,6 +448,12 @@ int __kprobes arch_prepare_kprobe(struct
	p->ainsn.insn = get_insn_slot();
	if (!p->ainsn.insn)
		return -ENOMEM;
+	if (unlikely(((unsigned long)&p->opcode & 0xF)
+				|| ((unsigned long)p->ainsn.insn & 0xF))) {
+		printk(KERN_WARNING "Kprobes opcode 16-bytes unalignment\n ");
+		return -EINVAL;
+	}
+
	memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
	memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));

@@ -463,7 +469,10 @@ void __kprobes arch_arm_kprobe(struct kp

	flush_icache_range((unsigned long)p->ainsn.insn,
			(unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
-	memcpy((char *)arm_addr, &p->opcode, sizeof(kprobe_opcode_t));
+	if (ATOMIC_UPDATE)
+		kprobe_update_bundle((void *)arm_addr, (void *)&p->opcode);
+	else
+		memcpy((char *)arm_addr, &p->opcode, sizeof(kprobe_opcode_t));
	flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
}

@@ -473,8 +482,11 @@ void __kprobes arch_disarm_kprobe(struct
	unsigned long arm_addr = addr & ~0xFULL;

	/* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
-	memcpy((char *) arm_addr, (char *) p->ainsn.insn,
-					 sizeof(kprobe_opcode_t));
+	if (ATOMIC_UPDATE)
+		kprobe_update_bundle((void *)arm_addr, (void *) p->ainsn.insn);
+	else
+		memcpy((char *) arm_addr, (char *) p->ainsn.insn,
+					sizeof(kprobe_opcode_t));
	flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
}

diff -Nrup -X 2.6.19-rc2.org/Documentation/dontdiff 2.6.19-rc2.org/include/asm-ia64/gcc_intrin.h 2.6.19-rc2/include/asm-ia64/gcc_intrin.h
--- 2.6.19-rc2.org/include/asm-ia64/gcc_intrin.h	2005-08-29 07:41:01.000000000 +0800
+++ 2.6.19-rc2/include/asm-ia64/gcc_intrin.h	2006-11-01 18:31:36.000000000 +0800
@@ -598,4 +598,8 @@ do {								\
		      :: "r"((x)) : "p6", "p7", "memory");	\
} while (0)

+#define ia64_ld16(low, addr)						\
+	asm volatile(";;ld16 %0=[%1];;":"=r"(low):"r"(addr):"memory")
+#define ia64_st16(low, addr)						\
+	asm volatile(";;st16 [%1]=%0;;"::"r"(low),"r"(addr):"memory")
#endif /* _ASM_IA64_GCC_INTRIN_H */
diff -Nrup -X 2.6.19-rc2.org/Documentation/dontdiff 2.6.19-rc2.org/include/asm-ia64/intel_intrin.h 2.6.19-rc2/include/asm-ia64/intel_intrin.h
--- 2.6.19-rc2.org/include/asm-ia64/intel_intrin.h	2006-07-24 10:47:13.000000000 +0800
+++ 2.6.19-rc2/include/asm-ia64/intel_intrin.h	2006-11-01 18:38:13.000000000 +0800
@@ -152,6 +152,10 @@ do {							\
	}						\
} while (0)

+#define ia64_st16(low, addr)    __st16(__sttype_none, __sthint_none, addr, low)
+#define ia64_ld16(low, addr)					\
+  	low =  __ld16(__ldtype_none, __ldtype_none, addr)
+
#define __builtin_trap()	__break(0);

#endif /* _ASM_IA64_INTEL_INTRIN_H */
diff -Nrup -X 2.6.19-rc2.org/Documentation/dontdiff 2.6.19-rc2.org/include/asm-ia64/kprobes.h 2.6.19-rc2/include/asm-ia64/kprobes.h
--- 2.6.19-rc2.org/include/asm-ia64/kprobes.h	2006-10-27 16:39:34.000000000 +0800
+++ 2.6.19-rc2/include/asm-ia64/kprobes.h	2006-11-01 19:08:04.000000000 +0800
@@ -88,6 +88,7 @@ struct kprobe_ctlblk {
#define SLOT0_OPCODE_SHIFT	(37)
#define SLOT1_p1_OPCODE_SHIFT	(37 - (64-46))
#define SLOT2_OPCODE_SHIFT 	(37)
+#define ATOMIC_UPDATE		(local_cpu_data->features & ITANIUM_CPUID4_AO)

#define INDIRECT_CALL_OPCODE		(1)
#define IP_RELATIVE_CALL_OPCODE		(5)
@@ -96,6 +97,12 @@ struct kprobe_ctlblk {
#define LONG_BRANCH_OPCODE		(0xC)
#define LONG_CALL_OPCODE		(0xD)
#define flush_insn_slot(p)		do { } while (0)
+#define kprobe_update_bundle(dest, src)		\
+do {						\
+	unsigned long low;			\
+	ia64_ld16(low, src);			\
+	ia64_st16(low, dest);			\
+} while (0)

typedef struct kprobe_opcode {
	bundle_t bundle;
diff -Nrup -X 2.6.19-rc2.org/Documentation/dontdiff 2.6.19-rc2.org/include/asm-ia64/kregs.h 2.6.19-rc2/include/asm-ia64/kregs.h
--- 2.6.19-rc2.org/include/asm-ia64/kregs.h	2005-08-29 07:41:01.000000000 +0800
+++ 2.6.19-rc2/include/asm-ia64/kregs.h	2006-11-01 18:54:37.000000000 +0800
@@ -160,4 +160,7 @@
#define IA64_ISR_CODE_LFETCH	4
#define IA64_ISR_CODE_PROBEF	5

+/* CPUID 4 Register */
+#define ITANIUM_CPUID4_AO_BIT	2
+#define ITANIUM_CPUID4_AO	(__IA64_UL(1) << ITANIUM_CPUID4_AO_BIT)
#endif /* _ASM_IA64_kREGS_H */
-
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