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>

4 files changed, 61 insertions, 66 deletions

diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
index 072df3902636..f7ce310a429d 100644
--- a/arch/x86/include/asm/uprobes.h
+++ b/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 */
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 13d616d6519b..04dfcef2d028 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/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;
 }
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index fd45b70750d4..9c6be62787ed 100644
--- a/include/linux/uprobes.h
+++ b/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);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index ee496ad95db3..13f1b5909af4 100644
--- a/kernel/events/uprobes.c
+++ b/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)