1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
From 2a53b2da8c31676ddf53564ac95a01fcb78f2d20 Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Tue, 5 May 2015 20:34:50 +0200
Subject: [PATCH gnumach 08/10] document, check for sysenter at the right
location
---
i386/i386/locore.S | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/i386/i386/locore.S b/i386/i386/locore.S
index 4c2a253..8b4d766 100644
--- a/i386/i386/locore.S
+++ b/i386/i386/locore.S
@@ -521,6 +521,9 @@ _return_to_user:
*/
_return_from_kernel:
+ cmpl $0x7fffffff, R_TRAPNO(%esp) /* YYY */
+ je return_from_sysenter
+
_kret_popl_gs:
popl %gs /* restore segment registers */
_kret_popl_fs:
@@ -592,8 +595,6 @@ ENTRY(thread_syscall_return)
or $(KERNEL_STACK_SIZE-1),%ecx
movl -3-IKS_SIZE(%ecx),%esp /* switch back to PCB stack */
movl %eax,R_EAX(%esp) /* save return value */
- cmpl $0x7fffffff, R_TRAPNO(%esp) /* YYY */
- je return_from_sysenter
jmp _return_from_trap
ENTRY(call_continuation)
@@ -1231,6 +1232,7 @@ user_sysenter_stub_end:
* Control enters at `sysenter_entry' with %esp pointing to the
* per-cpu sysenter stack. We store all arguments here. We keep %ebp
* pointing to the top of this structure to copy the arguments.
+
*
* sysenter stack layout:
*
@@ -1291,11 +1293,10 @@ ENTRY(sysenter_entry)
/* Populate trap save area. */
pushl $0x7fffffff /* trap number */
- pushl $0x12345678 /* unused */
- pushl SE_STACK_POINTER(%ebp) /* ecx */
- pushl SE_RETURN_ADDRESS(%ebp) /* edx */
- subl $(5 * 4), %esp /* Unused. We save the
- arguments in userspace. */
+ pushl %eax /* %eax: unused */
+ pushl SE_STACK_POINTER(%ebp) /* %ecx: for sysexit */
+ pushl SE_RETURN_ADDRESS(%ebp) /* %edx: for sysexit */
+ subl $(5 * 4), %esp /* unused */
pushl SE_DS(%ebp) /* copy the segment registers */
pushl SE_ES(%ebp)
pushl SE_FS(%ebp)
@@ -1363,8 +1364,8 @@ se_args_0:
movl %ebx, %esp /* clean parameters from stack */
popl %esp /* switch to pcb stack */
movl %eax, R_EAX(%esp) /* save return value */
-return_from_sysenter:
- /* xxx: process ast */
+ jmp _return_from_trap /* check for AST, then... */
+return_from_sysenter: /* return here */
popl %gs /* restore segment registers */
popl %fs
popl %es
--
2.1.4
|
