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Subject[PATCH v2 4/9] uprobes/x86: Gather "riprel" functions together
Cosmetic. Move pre_xol_rip_insn() and handle_riprel_post_xol() up to
the closely related handle_riprel_insn(). This way it is simpler to
read and understand this code, and this lessens the number of ifdef's.

While at it, update the comment in handle_riprel_post_xol() as Jim
suggested.

TODO: rename them somehow to make the naming consistent.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
---
arch/x86/kernel/uprobes.c | 118 ++++++++++++++++++++-------------------------
1 files changed, 53 insertions(+), 65 deletions(-)

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 963c121..c52c30f 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -313,6 +313,48 @@ handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn)
}
}

+/*
+ * If we're emulating a rip-relative instruction, save the contents
+ * of the scratch register and store the target address in that register.
+ */
+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) {
+ 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) {
+ autask->saved_scratch_register = regs->cx;
+ regs->cx = current->utask->vaddr;
+ regs->cx += auprobe->rip_rela_target_address;
+ }
+}
+
+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)) {
+ struct arch_uprobe_task *autask;
+
+ autask = &current->utask->autask;
+ if (auprobe->fixups & UPROBE_FIX_RIP_AX)
+ regs->ax = autask->saved_scratch_register;
+ else
+ regs->cx = autask->saved_scratch_register;
+
+ /*
+ * The original instruction includes a displacement, and so
+ * is 4 bytes longer than what we've just single-stepped.
+ * Caller may need to apply other fixups to handle stuff
+ * like "jmpq *...(%rip)" and "callq *...(%rip)".
+ */
+ if (correction)
+ *correction += 4;
+ }
+}
+
static int validate_insn_64bits(struct arch_uprobe *auprobe, struct insn *insn)
{
insn_init(insn, auprobe->insn, true);
@@ -339,9 +381,19 @@ static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm,
return validate_insn_64bits(auprobe, insn);
}
#else /* 32-bit: */
+/*
+ * No RIP-relative addressing on 32-bit
+ */
static void handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn)
{
- /* No RIP-relative addressing on 32-bit */
+}
+static void pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
+ struct arch_uprobe_task *autask)
+{
+}
+static void handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs,
+ long *correction)
+{
}

static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn)
@@ -415,34 +467,6 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
return 0;
}

-#ifdef CONFIG_X86_64
-/*
- * If we're emulating a rip-relative instruction, save the contents
- * of the scratch register and store the target address in that register.
- */
-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) {
- 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) {
- autask->saved_scratch_register = regs->cx;
- regs->cx = current->utask->vaddr;
- regs->cx += auprobe->rip_rela_target_address;
- }
-}
-#else
-static void
-pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
- struct arch_uprobe_task *autask)
-{
- /* No RIP-relative addressing on 32-bit */
-}
-#endif
-
/*
* arch_uprobe_pre_xol - prepare to execute out of line.
* @auprobe: the probepoint information.
@@ -492,42 +516,6 @@ static int adjust_ret_addr(unsigned long sp, long correction)
return 0;
}

-#ifdef CONFIG_X86_64
-static bool is_riprel_insn(struct arch_uprobe *auprobe)
-{
- return ((auprobe->fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) != 0);
-}
-
-static void
-handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction)
-{
- if (is_riprel_insn(auprobe)) {
- struct arch_uprobe_task *autask;
-
- autask = &current->utask->autask;
- if (auprobe->fixups & UPROBE_FIX_RIP_AX)
- regs->ax = autask->saved_scratch_register;
- else
- regs->cx = autask->saved_scratch_register;
-
- /*
- * The original instruction includes a displacement, and so
- * is 4 bytes longer than what we've just single-stepped.
- * Fall through to handle stuff like "jmpq *...(%rip)" and
- * "callq *...(%rip)".
- */
- if (correction)
- *correction += 4;
- }
-}
-#else
-static void
-handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction)
-{
- /* No RIP-relative addressing on 32-bit */
-}
-#endif
-
/*
* If xol insn itself traps and generates a signal(Say,
* SIGILL/SIGSEGV/etc), then detect the case where a singlestepped
--
1.5.5.1


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