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authorOleg Nesterov <oleg@redhat.com>2014-03-31 15:16:22 +0200
committerOleg Nesterov <oleg@redhat.com>2014-04-17 21:58:16 +0200
commitddb69f276c4af8bb47ad4f24a72f72ddf58c228a (patch)
tree6d4daad064b45ec6be22199a84ffef9eccda25b5 /arch/x86/kernel/uprobes.c
parent8a6b173287bb94b3ef8360119020e856afb1c934 (diff)
uprobes/x86: Fold prepare_fixups() into arch_uprobe_analyze_insn()
No functional changes, preparation. Shift the code from prepare_fixups() to arch_uprobe_analyze_insn() with the following modifications: - Do not call insn_get_opcode() again, it was already called by validate_insn_bits(). - Move "case 0xea" up. This way "case 0xff" can fall through to default case. - change "case 0xff" to use the nested "switch (MODRM_REG)", this way the code looks a bit simpler. - Make the comments look consistent. While at it, kill the initialization of rip_rela_target_address and ->fixups, we can rely on kzalloc(). We will add the new members into arch_uprobe, it would be better to assume that everything is zero by default. TODO: cleanup/fix the mess in validate_insn_bits() paths: - validate_insn_64bits() and validate_insn_32bits() should be unified. - "ifdef" is not used consistently; if good_insns_64 depends on CONFIG_X86_64, then probably good_insns_32 should depend on CONFIG_X86_32/EMULATION - the usage of mm->context.ia32_compat looks wrong if the task is TIF_X32. 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> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Diffstat (limited to 'arch/x86/kernel/uprobes.c')
-rw-r--r--arch/x86/kernel/uprobes.c110
1 files changed, 47 insertions, 63 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 2ed845928b5f..098e56ec7954 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -53,7 +53,7 @@
#define OPCODE1(insn) ((insn)->opcode.bytes[0])
#define OPCODE2(insn) ((insn)->opcode.bytes[1])
#define OPCODE3(insn) ((insn)->opcode.bytes[2])
-#define MODRM_REG(insn) X86_MODRM_REG(insn->modrm.value)
+#define MODRM_REG(insn) X86_MODRM_REG((insn)->modrm.value)
#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
@@ -229,63 +229,6 @@ static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn)
return -ENOTSUPP;
}
-/*
- * Figure out which fixups arch_uprobe_post_xol() will need to perform, and
- * annotate arch_uprobe->fixups accordingly. To start with,
- * arch_uprobe->fixups is either zero or it reflects rip-related fixups.
- */
-static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn)
-{
- bool fix_ip = true, fix_call = false; /* defaults */
- int reg;
-
- insn_get_opcode(insn); /* should be a nop */
-
- switch (OPCODE1(insn)) {
- case 0x9d:
- /* popf */
- auprobe->fixups |= UPROBE_FIX_SETF;
- break;
- case 0xc3: /* ret/lret */
- case 0xcb:
- case 0xc2:
- case 0xca:
- /* ip is correct */
- fix_ip = false;
- break;
- case 0xe8: /* call relative - Fix return addr */
- fix_call = true;
- break;
- case 0x9a: /* call absolute - Fix return addr, not ip */
- fix_call = true;
- fix_ip = false;
- break;
- case 0xff:
- insn_get_modrm(insn);
- reg = MODRM_REG(insn);
- if (reg == 2 || reg == 3) {
- /* call or lcall, indirect */
- /* Fix return addr; ip is correct. */
- fix_call = true;
- fix_ip = false;
- } else if (reg == 4 || reg == 5) {
- /* jmp or ljmp, indirect */
- /* ip is correct. */
- fix_ip = false;
- }
- break;
- case 0xea: /* jmp absolute -- ip is correct */
- fix_ip = false;
- break;
- default:
- break;
- }
- if (fix_ip)
- auprobe->fixups |= UPROBE_FIX_IP;
- if (fix_call)
- auprobe->fixups |= UPROBE_FIX_CALL;
-}
-
#ifdef CONFIG_X86_64
/*
* If arch_uprobe->insn doesn't use rip-relative addressing, return
@@ -318,7 +261,6 @@ handle_riprel_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, struct ins
if (mm->context.ia32_compat)
return;
- auprobe->rip_rela_target_address = 0x0;
if (!insn_rip_relative(insn))
return;
@@ -421,16 +363,58 @@ static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm,
*/
int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long addr)
{
- int ret;
struct insn insn;
+ bool fix_ip = true, fix_call = false;
+ int ret;
- auprobe->fixups = 0;
ret = validate_insn_bits(auprobe, mm, &insn);
- if (ret != 0)
+ if (ret)
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.
+ */
handle_riprel_insn(auprobe, mm, &insn);
- prepare_fixups(auprobe, &insn);
+
+ switch (OPCODE1(&insn)) {
+ case 0x9d: /* popf */
+ auprobe->fixups |= UPROBE_FIX_SETF;
+ break;
+ case 0xc3: /* ret or lret -- ip is correct */
+ case 0xcb:
+ case 0xc2:
+ case 0xca:
+ fix_ip = false;
+ break;
+ case 0xe8: /* call relative - Fix return addr */
+ fix_call = true;
+ break;
+ case 0x9a: /* call absolute - Fix return addr, not ip */
+ fix_call = true;
+ fix_ip = false;
+ break;
+ case 0xea: /* jmp absolute -- ip is correct */
+ fix_ip = false;
+ break;
+ case 0xff:
+ insn_get_modrm(&insn);
+ switch (MODRM_REG(&insn)) {
+ case 2: case 3: /* call or lcall, indirect */
+ fix_call = true;
+ case 4: case 5: /* jmp or ljmp, indirect */
+ fix_ip = false;
+ }
+ break;
+ default:
+ break;
+ }
+
+ if (fix_ip)
+ auprobe->fixups |= UPROBE_FIX_IP;
+ if (fix_call)
+ auprobe->fixups |= UPROBE_FIX_CALL;
return 0;
}