Commit-ID: 78d9af4cd375880a574327210eb9dab572618364
Gitweb: http://git.kernel.org/tip/78d9af4cd375880a574327210eb9dab572618364
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Thu, 24 Apr 2014 18:52:37 +0200
Committer: Oleg Nesterov <oleg@xxxxxxxxxx>
CommitDate: Wed, 30 Apr 2014 19:10:38 +0200
uprobes/x86: Cleanup the usage of arch_uprobe->def.fixups, make it u8
handle_riprel_insn() assumes that nobody else could modify ->fixups
before. This is correct but fragile, change it to use "|=".
Also make ->fixups u8, we are going to add the new members into the
union. It is not clear why UPROBE_FIX_RIP_.X lived in the upper byte,
redefine them so that they can fit into u8.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
arch/x86/include/asm/uprobes.h | 2 +-
arch/x86/kernel/uprobes.c | 14 +++++++-------
2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
index 72caff7..9ce25ce 100644
--- a/arch/x86/include/asm/uprobes.h
+++ b/arch/x86/include/asm/uprobes.h
@@ -53,7 +53,7 @@ struct arch_uprobe {
#ifdef CONFIG_X86_64
long riprel_target;
#endif
- u16 fixups;
+ u8 fixups;
} def;
};
};
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 7824ce2..a8e1d7e 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -33,16 +33,16 @@
/* Post-execution fixups. */
/* Adjust IP back to vicinity of actual insn */
-#define UPROBE_FIX_IP 0x1
+#define UPROBE_FIX_IP 0x01
/* Adjust the return address of a call insn */
-#define UPROBE_FIX_CALL 0x2
+#define UPROBE_FIX_CALL 0x02
/* Instruction will modify TF, don't change it */
-#define UPROBE_FIX_SETF 0x4
+#define UPROBE_FIX_SETF 0x04
-#define UPROBE_FIX_RIP_AX 0x8000
-#define UPROBE_FIX_RIP_CX 0x4000
+#define UPROBE_FIX_RIP_AX 0x08
+#define UPROBE_FIX_RIP_CX 0x10
#define UPROBE_TRAP_NR UINT_MAX
@@ -307,12 +307,12 @@ 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->def.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->def.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);
}
--
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