uprobes/x86: Move default_xol_ops's data into arch_uprobe->def

Finally we can move arch_uprobe->fixups/rip_rela_target_address
into the new "def" struct and place this struct in the union, they
are only used by default_xol_ops paths.

The patch also renames rip_rela_target_address to riprel_target just
to make this name shorter.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>

2 files changed, 28 insertions, 27 deletions

diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
index 93bee7b93854..72caff7afbde 100644
--- a/arch/x86/include/asm/uprobes.h
+++ b/arch/x86/include/asm/uprobes.h
@@ -41,18 +41,20 @@ struct arch_uprobe {
                 u8                      ixol[MAX_UINSN_BYTES];
         };
 
-        u16                             fixups;
         const struct uprobe_xol_ops     *ops;
 
         union {
-#ifdef CONFIG_X86_64
-                unsigned long                   rip_rela_target_address;
-#endif
                 struct {
                         s32     offs;
                         u8      ilen;
                         u8      opc1;
-                }                               branch;
+                }                       branch;
+                struct {
+#ifdef CONFIG_X86_64
+                        long    riprel_target;
+#endif
+                        u16     fixups;
+                }                       def;
         };
 };
 
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index b2bca293fc57..7824ce248f8f 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -251,10 +251,9 @@ static inline bool is_64bit_mm(struct mm_struct *mm)
  * 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
- * 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.)
+ * def->fixups and def->riprel_target accordingly. (The contents of the
+ * scratch register will be saved before we single-step the modified
+ * instruction, and restored afterward).
  *
  * We do this because a rip-relative instruction can access only a
  * relatively small area (+/- 2 GB from the instruction), and the XOL
@@ -308,18 +307,18 @@ handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn)
                  * is NOT the register operand, so we use %rcx (register
                  * #1) for the scratch register.
                  */
-                auprobe->fixups = UPROBE_FIX_RIP_CX;
+                auprobe->def.fixups = UPROBE_FIX_RIP_CX;
                 /* Change modrm from 00 000 101 to 00 000 001. */
                 *cursor = 0x1;
         } else {
                 /* Use %rax (register #0) for the scratch register. */
-                auprobe->fixups = UPROBE_FIX_RIP_AX;
+                auprobe->def.fixups = UPROBE_FIX_RIP_AX;
                 /* Change modrm from 00 xxx 101 to 00 xxx 000 */
                 *cursor = (reg << 3);
         }
 
         /* Target address = address of next instruction + (signed) offset */
-        auprobe->rip_rela_target_address = (long)insn->length + insn->displacement.value;
+        auprobe->def.riprel_target = (long)insn->length + insn->displacement.value;
 
         /* Displacement field is gone; slide immediate field (if any) over. */
         if (insn->immediate.nbytes) {
@@ -336,25 +335,25 @@ static void
 pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
                                 struct arch_uprobe_task *autask)
 {
-        if (auprobe->fixups & UPROBE_FIX_RIP_AX) {
+        if (auprobe->def.fixups & UPROBE_FIX_RIP_AX) {
                 autask->saved_scratch_register = regs->ax;
                 regs->ax = current->utask->vaddr;
-                regs->ax += auprobe->rip_rela_target_address;
-        } else if (auprobe->fixups & UPROBE_FIX_RIP_CX) {
+                regs->ax += auprobe->def.riprel_target;
+        } else if (auprobe->def.fixups & UPROBE_FIX_RIP_CX) {
                 autask->saved_scratch_register = regs->cx;
                 regs->cx = current->utask->vaddr;
-                regs->cx += auprobe->rip_rela_target_address;
+                regs->cx += auprobe->def.riprel_target;
         }
 }
 
 static void
 handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction)
 {
-        if (auprobe->fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) {
+        if (auprobe->def.fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) {
                 struct arch_uprobe_task *autask;
 
                 autask = &current->utask->autask;
-                if (auprobe->fixups & UPROBE_FIX_RIP_AX)
+                if (auprobe->def.fixups & UPROBE_FIX_RIP_AX)
                         regs->ax = autask->saved_scratch_register;
                 else
                         regs->cx = autask->saved_scratch_register;
@@ -432,17 +431,17 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs
         long correction = (long)(utask->vaddr - utask->xol_vaddr);
 
         handle_riprel_post_xol(auprobe, regs, &correction);
-        if (auprobe->fixups & UPROBE_FIX_IP)
+        if (auprobe->def.fixups & UPROBE_FIX_IP)
                 regs->ip += correction;
 
-        if (auprobe->fixups & UPROBE_FIX_CALL) {
+        if (auprobe->def.fixups & UPROBE_FIX_CALL) {
                 if (adjust_ret_addr(regs->sp, correction)) {
                         regs->sp += sizeof_long();
                         return -ERESTART;
                 }
         }
         /* popf; tell the caller to not touch TF */
-        if (auprobe->fixups & UPROBE_FIX_SETF)
+        if (auprobe->def.fixups & UPROBE_FIX_SETF)
                 utask->autask.saved_tf = true;
 
         return 0;
@@ -646,13 +645,13 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
                 return ret;
 
         /*
-         * Figure out which fixups arch_uprobe_post_xol() will need to perform,
-         * and annotate arch_uprobe->fixups accordingly. To start with, ->fixups
-         * is either zero or it reflects rip-related fixups.
+         * Figure out which fixups default_post_xol_op() will need to perform,
+         * and annotate def->fixups accordingly. To start with, ->fixups is
+         * either zero or it reflects rip-related fixups.
          */
         switch (OPCODE1(&insn)) {
         case 0x9d:              /* popf */
-                auprobe->fixups |= UPROBE_FIX_SETF;
+                auprobe->def.fixups |= UPROBE_FIX_SETF;
                 break;
         case 0xc3:              /* ret or lret -- ip is correct */
         case 0xcb:
@@ -680,9 +679,9 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
         }
 
         if (fix_ip)
-                auprobe->fixups |= UPROBE_FIX_IP;
+                auprobe->def.fixups |= UPROBE_FIX_IP;
         if (fix_call)
-                auprobe->fixups |= UPROBE_FIX_CALL;
+                auprobe->def.fixups |= UPROBE_FIX_CALL;
 
         auprobe->ops = &default_xol_ops;
         return 0;