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
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
/*
* x86-64 rwsem wrappers
*
* This interfaces the inline asm code to the slow-path
* C routines. We need to save the call-clobbered regs
* that the asm does not mark as clobbered, and move the
* argument from %rax to %rdi.
*
* NOTE! We don't need to save %rax, because the functions
* will always return the semaphore pointer in %rax (which
* is also the input argument to these helpers)
*
* The following can clobber %rdx because the asm clobbers it:
* call_rwsem_down_write_failed
* call_rwsem_wake
* but %rdi, %rsi, %rcx, %r8-r11 always need saving.
*/
#include <linux/linkage.h>
#include <asm/rwlock.h>
#include <asm/alternative-asm.h>
#include <asm/frame.h>
#include <asm/dwarf2.h>
#define save_common_regs \
pushq_cfi %rdi; CFI_REL_OFFSET rdi, 0; \
pushq_cfi %rsi; CFI_REL_OFFSET rsi, 0; \
pushq_cfi %rcx; CFI_REL_OFFSET rcx, 0; \
pushq_cfi %r8; CFI_REL_OFFSET r8, 0; \
pushq_cfi %r9; CFI_REL_OFFSET r9, 0; \
pushq_cfi %r10; CFI_REL_OFFSET r10, 0; \
pushq_cfi %r11; CFI_REL_OFFSET r11, 0
#define restore_common_regs \
popq_cfi %r11; CFI_RESTORE r11; \
popq_cfi %r10; CFI_RESTORE r10; \
popq_cfi %r9; CFI_RESTORE r9; \
popq_cfi %r8; CFI_RESTORE r8; \
popq_cfi %rcx; CFI_RESTORE rcx; \
popq_cfi %rsi; CFI_RESTORE rsi; \
popq_cfi %rdi; CFI_RESTORE rdi
/* Fix up special calling conventions */
ENTRY(call_rwsem_down_read_failed)
CFI_STARTPROC
save_common_regs
pushq_cfi %rdx
CFI_REL_OFFSET rdx, 0
movq %rax,%rdi
call rwsem_down_read_failed
popq_cfi %rdx
CFI_RESTORE rdx
restore_common_regs
ret
CFI_ENDPROC
ENDPROC(call_rwsem_down_read_failed)
ENTRY(call_rwsem_down_write_failed)
CFI_STARTPROC
save_common_regs
movq %rax,%rdi
call rwsem_down_write_failed
restore_common_regs
ret
CFI_ENDPROC
ENDPROC(call_rwsem_down_write_failed)
ENTRY(call_rwsem_wake)
CFI_STARTPROC
decl %edx /* do nothing if still outstanding active readers */
jnz 1f
save_common_regs
movq %rax,%rdi
call rwsem_wake
restore_common_regs
1: ret
CFI_ENDPROC
ENDPROC(call_rwsem_wake)
/* Fix up special calling conventions */
ENTRY(call_rwsem_downgrade_wake)
CFI_STARTPROC
save_common_regs
pushq_cfi %rdx
CFI_REL_OFFSET rdx, 0
movq %rax,%rdi
call rwsem_downgrade_wake
popq_cfi %rdx
CFI_RESTORE rdx
restore_common_regs
ret
CFI_ENDPROC
ENDPROC(call_rwsem_downgrade_wake)
|
