uprobes/core: Move insn to arch specific structure

Few cleanups suggested by Ingo Molnar.

- Rename struct uprobe_arch_info to struct arch_uprobe.
- Move insn from struct uprobe to struct arch_uprobe.
- Make arch specific uprobe functions to accept struct arch_uprobe
  instead of  struct uprobe.
- Move struct uprobe to kernel/uprobes.c from include/linux/uprobes.h

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Stone <jistone@redhat.com>
Link: http://lkml.kernel.org/r/20120222091602.15880.40249.sendpatchset@srdronam.in.ibm.com
[ Made various small improvements ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/uprobes.h

@@ -31,13 +31,13 @@ typedef u8 uprobe_opcode_t;
 #define UPROBES_BKPT_INSN		0xcc
 #define UPROBES_BKPT_INSN_SIZE		   1
 
-struct uprobe_arch_info {
+struct arch_uprobe {
 	u16				fixups;
+	u8				insn[MAX_UINSN_BYTES];
 #ifdef CONFIG_X86_64
 	unsigned long			rip_rela_target_address;
 #endif
 };
 
-struct uprobe;
-extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe);
+extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct arch_uprobe *arch_uprobe);
 #endif	/* _ASM_UPROBES_H */

arch/x86/kernel/uprobes.c

@@ -200,9 +200,9 @@ static bool is_prefix_bad(struct insn *insn)
 	return false;
 }
 
-static int validate_insn_32bits(struct uprobe *uprobe, struct insn *insn)
+static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn)
 {
-	insn_init(insn, uprobe->insn, false);
+	insn_init(insn, auprobe->insn, false);
 
 	/* Skip good instruction prefixes; reject "bad" ones. */
 	insn_get_opcode(insn);
@@ -222,11 +222,11 @@ static int validate_insn_32bits(struct uprobe *uprobe, struct insn *insn)
 
 /*
  * Figure out which fixups post_xol() will need to perform, and annotate
- * uprobe->arch_info.fixups accordingly.  To start with,
- * uprobe->arch_info.fixups is either zero or it reflects rip-related
+ * arch_uprobe->fixups accordingly.  To start with,
+ * arch_uprobe->fixups is either zero or it reflects rip-related
  * fixups.
  */
-static void prepare_fixups(struct uprobe *uprobe, struct insn *insn)
+static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn)
 {
 	bool fix_ip = true, fix_call = false;	/* defaults */
 	int reg;
@@ -269,17 +269,17 @@ static void prepare_fixups(struct uprobe *uprobe, struct insn *insn)
 		break;
 	}
 	if (fix_ip)
-		uprobe->arch_info.fixups |= UPROBES_FIX_IP;
+		auprobe->fixups |= UPROBES_FIX_IP;
 	if (fix_call)
-		uprobe->arch_info.fixups |= UPROBES_FIX_CALL;
+		auprobe->fixups |= UPROBES_FIX_CALL;
 }
 
 #ifdef CONFIG_X86_64
 /*
- * If uprobe->insn doesn't use rip-relative addressing, return
+ * If arch_uprobe->insn doesn't use rip-relative addressing, return
  * immediately.  Otherwise, rewrite the instruction so that it accesses
  * its memory operand indirectly through a scratch register.  Set
- * uprobe->arch_info.fixups and uprobe->arch_info.rip_rela_target_address
+ * arch_uprobe->fixups and arch_uprobe->rip_rela_target_address
  * accordingly.  (The contents of the scratch register will be saved
  * before we single-step the modified instruction, and restored
  * afterward.)
@@ -297,7 +297,7 @@ static void prepare_fixups(struct uprobe *uprobe, struct insn *insn)
  *  - There's never a SIB byte.
  *  - The displacement is always 4 bytes.
  */
-static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
+static void handle_riprel_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn)
 {
 	u8 *cursor;
 	u8 reg;
@@ -305,7 +305,7 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
 	if (mm->context.ia32_compat)
 		return;
 
-	uprobe->arch_info.rip_rela_target_address = 0x0;
+	auprobe->rip_rela_target_address = 0x0;
 	if (!insn_rip_relative(insn))
 		return;
 
@@ -315,7 +315,7 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
 	 * we want to encode rax/rcx, not r8/r9.
 	 */
 	if (insn->rex_prefix.nbytes) {
-		cursor = uprobe->insn + insn_offset_rex_prefix(insn);
+		cursor = auprobe->insn + insn_offset_rex_prefix(insn);
 		*cursor &= 0xfe;	/* Clearing REX.B bit */
 	}
 
@@ -324,7 +324,7 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
 	 * displacement.  Beyond the displacement, for some instructions,
 	 * is the immediate operand.
 	 */
-	cursor = uprobe->insn + insn_offset_modrm(insn);
+	cursor = auprobe->insn + insn_offset_modrm(insn);
 	insn_get_length(insn);
 
 	/*
@@ -341,18 +341,18 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
 		 * is NOT the register operand, so we use %rcx (register
 		 * #1) for the scratch register.
 		 */
-		uprobe->arch_info.fixups = UPROBES_FIX_RIP_CX;
+		auprobe->fixups = UPROBES_FIX_RIP_CX;
 		/* Change modrm from 00 000 101 to 00 000 001. */
 		*cursor = 0x1;
 	} else {
 		/* Use %rax (register #0) for the scratch register. */
-		uprobe->arch_info.fixups = UPROBES_FIX_RIP_AX;
+		auprobe->fixups = UPROBES_FIX_RIP_AX;
 		/* Change modrm from 00 xxx 101 to 00 xxx 000 */
 		*cursor = (reg << 3);
 	}
 
 	/* Target address = address of next instruction + (signed) offset */
-	uprobe->arch_info.rip_rela_target_address = (long)insn->length + insn->displacement.value;
+	auprobe->rip_rela_target_address = (long)insn->length + insn->displacement.value;
 
 	/* Displacement field is gone; slide immediate field (if any) over. */
 	if (insn->immediate.nbytes) {
@@ -362,9 +362,9 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
 	return;
 }
 
-static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn)
+static int validate_insn_64bits(struct arch_uprobe *auprobe, struct insn *insn)
 {
-	insn_init(insn, uprobe->insn, true);
+	insn_init(insn, auprobe->insn, true);
 
 	/* Skip good instruction prefixes; reject "bad" ones. */
 	insn_get_opcode(insn);
@@ -381,42 +381,42 @@ static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn)
 	return -ENOTSUPP;
 }
 
-static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
+static int validate_insn_bits(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn)
 {
 	if (mm->context.ia32_compat)
-		return validate_insn_32bits(uprobe, insn);
-	return validate_insn_64bits(uprobe, insn);
+		return validate_insn_32bits(auprobe, insn);
+	return validate_insn_64bits(auprobe, insn);
 }
 #else /* 32-bit: */
-static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
+static void handle_riprel_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn)
 {
 	/* No RIP-relative addressing on 32-bit */
 }
 
-static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
+static int validate_insn_bits(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn)
 {
-	return validate_insn_32bits(uprobe, insn);
+	return validate_insn_32bits(auprobe, insn);
 }
 #endif /* CONFIG_X86_64 */
 
 /**
  * arch_uprobes_analyze_insn - instruction analysis including validity and fixups.
  * @mm: the probed address space.
- * @uprobe: the probepoint information.
+ * @arch_uprobe: the probepoint information.
  * Return 0 on success or a -ve number on error.
  */
-int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe)
+int arch_uprobes_analyze_insn(struct mm_struct *mm, struct arch_uprobe *auprobe)
 {
 	int ret;
 	struct insn insn;
 
-	uprobe->arch_info.fixups = 0;
-	ret = validate_insn_bits(mm, uprobe, &insn);
+	auprobe->fixups = 0;
+	ret = validate_insn_bits(mm, auprobe, &insn);
 	if (ret != 0)
 		return ret;
 
-	handle_riprel_insn(mm, uprobe, &insn);
-	prepare_fixups(uprobe, &insn);
+	handle_riprel_insn(mm, auprobe, &insn);
+	prepare_fixups(auprobe, &insn);
 
 	return 0;
 }

include/linux/uprobes.h

@@ -29,12 +29,6 @@
 struct vm_area_struct;
 #ifdef CONFIG_ARCH_SUPPORTS_UPROBES
 #include <asm/uprobes.h>
-#else
-
-typedef u8 uprobe_opcode_t;
-struct uprobe_arch_info {};
-
-#define MAX_UINSN_BYTES 4
 #endif
 
 /* flags that denote/change uprobes behaviour */
@@ -56,22 +50,9 @@ struct uprobe_consumer {
 	struct uprobe_consumer *next;
 };
 
-struct uprobe {
-	struct rb_node		rb_node;	/* node in the rb tree */
-	atomic_t		ref;
-	struct rw_semaphore	consumer_rwsem;
-	struct list_head	pending_list;
-	struct uprobe_arch_info arch_info;
-	struct uprobe_consumer	*consumers;
-	struct inode		*inode;		/* Also hold a ref to inode */
-	loff_t			offset;
-	int			flags;
-	u8			insn[MAX_UINSN_BYTES];
-};
-
 #ifdef CONFIG_UPROBES
-extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr);
-extern int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify);
+extern int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr);
+extern int __weak set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify);
 extern bool __weak is_bkpt_insn(uprobe_opcode_t *insn);
 extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer);
 extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer);

kernel/events/uprobes.c

@@ -65,6 +65,18 @@ struct vma_info {
 	loff_t			vaddr;
 };
 
+struct uprobe {
+	struct rb_node		rb_node;	/* node in the rb tree */
+	atomic_t		ref;
+	struct rw_semaphore	consumer_rwsem;
+	struct list_head	pending_list;
+	struct uprobe_consumer	*consumers;
+	struct inode		*inode;		/* Also hold a ref to inode */
+	loff_t			offset;
+	int			flags;
+	struct arch_uprobe	arch;
+};
+
 /*
  * valid_vma: Verify if the specified vma is an executable vma
  * Relax restrictions while unregistering: vm_flags might have
@@ -180,7 +192,7 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn)
 /*
  * write_opcode - write the opcode at a given virtual address.
  * @mm: the probed process address space.
- * @uprobe: the breakpointing information.
+ * @arch_uprobe: the breakpointing information.
  * @vaddr: the virtual address to store the opcode.
  * @opcode: opcode to be written at @vaddr.
  *
@@ -190,13 +202,14 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn)
  * For mm @mm, write the opcode at @vaddr.
  * Return 0 (success) or a negative errno.
  */
-static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe,
+static int write_opcode(struct mm_struct *mm, struct arch_uprobe *auprobe,
 			unsigned long vaddr, uprobe_opcode_t opcode)
 {
 	struct page *old_page, *new_page;
 	struct address_space *mapping;
 	void *vaddr_old, *vaddr_new;
 	struct vm_area_struct *vma;
+	struct uprobe *uprobe;
 	loff_t addr;
 	int ret;
 
@@ -216,6 +229,7 @@ static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe,
 	if (!valid_vma(vma, is_bkpt_insn(&opcode)))
 		goto put_out;
 
+	uprobe = container_of(auprobe, struct uprobe, arch);
 	mapping = uprobe->inode->i_mapping;
 	if (mapping != vma->vm_file->f_mapping)
 		goto put_out;
@@ -326,7 +340,7 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr)
  * For mm @mm, store the breakpoint instruction at @vaddr.
  * Return 0 (success) or a negative errno.
  */
-int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr)
+int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr)
 {
 	int result;
 
@@ -337,7 +351,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long v
 	if (result)
 		return result;
 
-	return write_opcode(mm, uprobe, vaddr, UPROBES_BKPT_INSN);
+	return write_opcode(mm, auprobe, vaddr, UPROBES_BKPT_INSN);
 }
 
 /**
@@ -351,7 +365,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long v
  * Return 0 (success) or a negative errno.
  */
 int __weak
-set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify)
+set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify)
 {
 	if (verify) {
 		int result;
@@ -363,7 +377,7 @@ set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr,
 		if (result != 1)
 			return result;
 	}
-	return write_opcode(mm, uprobe, vaddr, *(uprobe_opcode_t *)uprobe->insn);
+	return write_opcode(mm, auprobe, vaddr, *(uprobe_opcode_t *)auprobe->insn);
 }
 
 static int match_uprobe(struct uprobe *l, struct uprobe *r)
@@ -593,13 +607,13 @@ static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned
 
 	/* Instruction at the page-boundary; copy bytes in second page */
 	if (nbytes < bytes) {
-		if (__copy_insn(mapping, vma, uprobe->insn + nbytes,
+		if (__copy_insn(mapping, vma, uprobe->arch.insn + nbytes,
 				bytes - nbytes, uprobe->offset + nbytes))
 			return -ENOMEM;
 
 		bytes = nbytes;
 	}
-	return __copy_insn(mapping, vma, uprobe->insn, bytes, uprobe->offset);
+	return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset);
 }
 
 static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
@@ -625,23 +639,23 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
 		if (ret)
 			return ret;
 
-		if (is_bkpt_insn((uprobe_opcode_t *)uprobe->insn))
+		if (is_bkpt_insn((uprobe_opcode_t *)uprobe->arch.insn))
 			return -EEXIST;
 
-		ret = arch_uprobes_analyze_insn(mm, uprobe);
+		ret = arch_uprobes_analyze_insn(mm, &uprobe->arch);
 		if (ret)
 			return ret;
 
 		uprobe->flags |= UPROBES_COPY_INSN;
 	}
-	ret = set_bkpt(mm, uprobe, addr);
+	ret = set_bkpt(mm, &uprobe->arch, addr);
 
 	return ret;
 }
 
 static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, loff_t vaddr)
 {
-	set_orig_insn(mm, uprobe, (unsigned long)vaddr, true);
+	set_orig_insn(mm, &uprobe->arch, (unsigned long)vaddr, true);
 }
 
 static void delete_uprobe(struct uprobe *uprobe)