kprobes/x86: Cleanup save/restore registers

Introduce SAVE/RESOTRE_REGS_STRING for cleanup
kretprobe-trampoline asm code. These macros will be used for
emulating interruption.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133430.6725.83342.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index c69bb65006f3daaef11e83c1f5f7d3eafb6b79f0..4ae95befd0eb584cbbe2408fd2e4f83f35e2826d 100644 (file)
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -554,6 +554,69 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
        return 0;
 }
 
+#ifdef CONFIG_X86_64
+#define SAVE_REGS_STRING               \
+       /* Skip cs, ip, orig_ax. */     \
+       "       subq $24, %rsp\n"       \
+       "       pushq %rdi\n"           \
+       "       pushq %rsi\n"           \
+       "       pushq %rdx\n"           \
+       "       pushq %rcx\n"           \
+       "       pushq %rax\n"           \
+       "       pushq %r8\n"            \
+       "       pushq %r9\n"            \
+       "       pushq %r10\n"           \
+       "       pushq %r11\n"           \
+       "       pushq %rbx\n"           \
+       "       pushq %rbp\n"           \
+       "       pushq %r12\n"           \
+       "       pushq %r13\n"           \
+       "       pushq %r14\n"           \
+       "       pushq %r15\n"
+#define RESTORE_REGS_STRING            \
+       "       popq %r15\n"            \
+       "       popq %r14\n"            \
+       "       popq %r13\n"            \
+       "       popq %r12\n"            \
+       "       popq %rbp\n"            \
+       "       popq %rbx\n"            \
+       "       popq %r11\n"            \
+       "       popq %r10\n"            \
+       "       popq %r9\n"             \
+       "       popq %r8\n"             \
+       "       popq %rax\n"            \
+       "       popq %rcx\n"            \
+       "       popq %rdx\n"            \
+       "       popq %rsi\n"            \
+       "       popq %rdi\n"            \
+       /* Skip orig_ax, ip, cs */      \
+       "       addq $24, %rsp\n"
+#else
+#define SAVE_REGS_STRING               \
+       /* Skip cs, ip, orig_ax and gs. */      \
+       "       subl $16, %esp\n"       \
+       "       pushl %fs\n"            \
+       "       pushl %ds\n"            \
+       "       pushl %es\n"            \
+       "       pushl %eax\n"           \
+       "       pushl %ebp\n"           \
+       "       pushl %edi\n"           \
+       "       pushl %esi\n"           \
+       "       pushl %edx\n"           \
+       "       pushl %ecx\n"           \
+       "       pushl %ebx\n"
+#define RESTORE_REGS_STRING            \
+       "       popl %ebx\n"            \
+       "       popl %ecx\n"            \
+       "       popl %edx\n"            \
+       "       popl %esi\n"            \
+       "       popl %edi\n"            \
+       "       popl %ebp\n"            \
+       "       popl %eax\n"            \
+       /* Skip ds, es, fs, gs, orig_ax, and ip. Note: don't pop cs here*/\
+       "       addl $24, %esp\n"
+#endif
+
 /*
  * When a retprobed function returns, this code saves registers and
  * calls trampoline_handler() runs, which calls the kretprobe's handler.
@@ -567,65 +630,16 @@ static void __used __kprobes kretprobe_trampoline_holder(void)
                        /* We don't bother saving the ss register */
                        "       pushq %rsp\n"
                        "       pushfq\n"
-                       /*
-                        * Skip cs, ip, orig_ax.
-                        * trampoline_handler() will plug in these values
-                        */
-                       "       subq $24, %rsp\n"
-                       "       pushq %rdi\n"
-                       "       pushq %rsi\n"
-                       "       pushq %rdx\n"
-                       "       pushq %rcx\n"
-                       "       pushq %rax\n"
-                       "       pushq %r8\n"
-                       "       pushq %r9\n"
-                       "       pushq %r10\n"
-                       "       pushq %r11\n"
-                       "       pushq %rbx\n"
-                       "       pushq %rbp\n"
-                       "       pushq %r12\n"
-                       "       pushq %r13\n"
-                       "       pushq %r14\n"
-                       "       pushq %r15\n"
+                       SAVE_REGS_STRING
                        "       movq %rsp, %rdi\n"
                        "       call trampoline_handler\n"
                        /* Replace saved sp with true return address. */
                        "       movq %rax, 152(%rsp)\n"
-                       "       popq %r15\n"
-                       "       popq %r14\n"
-                       "       popq %r13\n"
-                       "       popq %r12\n"
-                       "       popq %rbp\n"
-                       "       popq %rbx\n"
-                       "       popq %r11\n"
-                       "       popq %r10\n"
-                       "       popq %r9\n"
-                       "       popq %r8\n"
-                       "       popq %rax\n"
-                       "       popq %rcx\n"
-                       "       popq %rdx\n"
-                       "       popq %rsi\n"
-                       "       popq %rdi\n"
-                       /* Skip orig_ax, ip, cs */
-                       "       addq $24, %rsp\n"
+                       RESTORE_REGS_STRING
                        "       popfq\n"
 #else
                        "       pushf\n"
-                       /*
-                        * Skip cs, ip, orig_ax and gs.
-                        * trampoline_handler() will plug in these values
-                        */
-                       "       subl $16, %esp\n"
-                       "       pushl %fs\n"
-                       "       pushl %es\n"
-                       "       pushl %ds\n"
-                       "       pushl %eax\n"
-                       "       pushl %ebp\n"
-                       "       pushl %edi\n"
-                       "       pushl %esi\n"
-                       "       pushl %edx\n"
-                       "       pushl %ecx\n"
-                       "       pushl %ebx\n"
+                       SAVE_REGS_STRING
                        "       movl %esp, %eax\n"
                        "       call trampoline_handler\n"
                        /* Move flags to cs */
@@ -633,15 +647,7 @@ static void __used __kprobes kretprobe_trampoline_holder(void)
                        "       movl %edx, 52(%esp)\n"
                        /* Replace saved flags with true return address. */
                        "       movl %eax, 56(%esp)\n"
-                       "       popl %ebx\n"
-                       "       popl %ecx\n"
-                       "       popl %edx\n"
-                       "       popl %esi\n"
-                       "       popl %edi\n"
-                       "       popl %ebp\n"
-                       "       popl %eax\n"
-                       /* Skip ds, es, fs, gs, orig_ax and ip */
-                       "       addl $24, %esp\n"
+                       RESTORE_REGS_STRING
                        "       popf\n"
 #endif
                        "       ret\n");