uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates

Purely cosmetic, no changes in .o,

1. As Jim pointed out arch_uprobe->def looks ambiguous, rename it to
   ->defparam.

2. Add the comment into default_post_xol_op() to explain "regs->sp +=".

3. Remove the stale part of the comment in arch_uprobe_analyze_insn().

Suggested-by: Jim Keniston <jkenisto@us.ibm.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
index 7be3c07..74f4c2f 100644 (file)
--- a/arch/x86/include/asm/uprobes.h
+++ b/arch/x86/include/asm/uprobes.h
@@ -52,7 +52,7 @@ struct arch_uprobe {
                struct {
                        u8      fixups;
                        u8      ilen;
-               }                       def;
+               }                       defparam;
        };
 };
 

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 159ca52..5d1cbfe 100644 (file)
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -254,7 +254,7 @@ 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
- * def->fixups accordingly. (The contents of the scratch register
+ * defparam->fixups accordingly. (The contents of the scratch register
  * will be saved before we single-step the modified instruction,
  * and restored afterward).
  *
@@ -372,14 +372,14 @@ static void riprel_analyze(struct arch_uprobe *auprobe, struct insn *insn)
         */
        if (reg != 6 && reg2 != 6) {
                reg2 = 6;
-               auprobe->def.fixups |= UPROBE_FIX_RIP_SI;
+               auprobe->defparam.fixups |= UPROBE_FIX_RIP_SI;
        } else if (reg != 7 && reg2 != 7) {
                reg2 = 7;
-               auprobe->def.fixups |= UPROBE_FIX_RIP_DI;
+               auprobe->defparam.fixups |= UPROBE_FIX_RIP_DI;
                /* TODO (paranoia): force maskmovq to not use di */
        } else {
                reg2 = 3;
-               auprobe->def.fixups |= UPROBE_FIX_RIP_BX;
+               auprobe->defparam.fixups |= UPROBE_FIX_RIP_BX;
        }
        /*
         * Point cursor at the modrm byte.  The next 4 bytes are the
@@ -398,9 +398,9 @@ static void riprel_analyze(struct arch_uprobe *auprobe, struct insn *insn)
 static inline unsigned long *
 scratch_reg(struct arch_uprobe *auprobe, struct pt_regs *regs)
 {
-       if (auprobe->def.fixups & UPROBE_FIX_RIP_SI)
+       if (auprobe->defparam.fixups & UPROBE_FIX_RIP_SI)
                return &regs->si;
-       if (auprobe->def.fixups & UPROBE_FIX_RIP_DI)
+       if (auprobe->defparam.fixups & UPROBE_FIX_RIP_DI)
                return &regs->di;
        return &regs->bx;
 }
@@ -411,18 +411,18 @@ scratch_reg(struct arch_uprobe *auprobe, struct pt_regs *regs)
  */
 static void riprel_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 {
-       if (auprobe->def.fixups & UPROBE_FIX_RIP_MASK) {
+       if (auprobe->defparam.fixups & UPROBE_FIX_RIP_MASK) {
                struct uprobe_task *utask = current->utask;
                unsigned long *sr = scratch_reg(auprobe, regs);
 
                utask->autask.saved_scratch_register = *sr;
-               *sr = utask->vaddr + auprobe->def.ilen;
+               *sr = utask->vaddr + auprobe->defparam.ilen;
        }
 }
 
 static void riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 {
-       if (auprobe->def.fixups & UPROBE_FIX_RIP_MASK) {
+       if (auprobe->defparam.fixups & UPROBE_FIX_RIP_MASK) {
                struct uprobe_task *utask = current->utask;
                unsigned long *sr = scratch_reg(auprobe, regs);
 
@@ -499,16 +499,16 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs
        struct uprobe_task *utask = current->utask;
 
        riprel_post_xol(auprobe, regs);
-       if (auprobe->def.fixups & UPROBE_FIX_IP) {
+       if (auprobe->defparam.fixups & UPROBE_FIX_IP) {
                long correction = utask->vaddr - utask->xol_vaddr;
                regs->ip += correction;
-       } else if (auprobe->def.fixups & UPROBE_FIX_CALL) {
-               regs->sp += sizeof_long();
-               if (push_ret_address(regs, utask->vaddr + auprobe->def.ilen))
+       } else if (auprobe->defparam.fixups & UPROBE_FIX_CALL) {
+               regs->sp += sizeof_long(); /* Pop incorrect return address */
+               if (push_ret_address(regs, utask->vaddr + auprobe->defparam.ilen))
                        return -ERESTART;
        }
        /* popf; tell the caller to not touch TF */
-       if (auprobe->def.fixups & UPROBE_FIX_SETF)
+       if (auprobe->defparam.fixups & UPROBE_FIX_SETF)
                utask->autask.saved_tf = true;
 
        return 0;
@@ -711,12 +711,11 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
 
        /*
         * 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.
+        * and annotate defparam->fixups accordingly.
         */
        switch (OPCODE1(&insn)) {
        case 0x9d:              /* popf */
-               auprobe->def.fixups |= UPROBE_FIX_SETF;
+               auprobe->defparam.fixups |= UPROBE_FIX_SETF;
                break;
        case 0xc3:              /* ret or lret -- ip is correct */
        case 0xcb:
@@ -742,8 +741,8 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
                riprel_analyze(auprobe, &insn);
        }
 
-       auprobe->def.ilen = insn.length;
-       auprobe->def.fixups |= fix_ip_or_call;
+       auprobe->defparam.ilen = insn.length;
+       auprobe->defparam.fixups |= fix_ip_or_call;
 
        auprobe->ops = &default_xol_ops;
        return 0;