blob: 41fcf00e49dfc7ca9549ce5e4dd26f360ee81353 [file] [log] [blame]
Linus Torvaldsbafaecd2010-01-12 18:16:42 -08001/*
2 * x86-64 rwsem wrappers
3 *
4 * This interfaces the inline asm code to the slow-path
5 * C routines. We need to save the call-clobbered regs
6 * that the asm does not mark as clobbered, and move the
7 * argument from %rax to %rdi.
8 *
9 * NOTE! We don't need to save %rax, because the functions
10 * will always return the semaphore pointer in %rax (which
11 * is also the input argument to these helpers)
12 *
13 * The following can clobber %rdx because the asm clobbers it:
14 * call_rwsem_down_write_failed
15 * call_rwsem_wake
16 * but %rdi, %rsi, %rcx, %r8-r11 always need saving.
17 */
18
19#include <linux/linkage.h>
20#include <asm/rwlock.h>
21#include <asm/alternative-asm.h>
22#include <asm/frame.h>
23#include <asm/dwarf2.h>
24
25#define save_common_regs \
26 pushq %rdi; \
27 pushq %rsi; \
28 pushq %rcx; \
29 pushq %r8; \
30 pushq %r9; \
31 pushq %r10; \
32 pushq %r11
33
34#define restore_common_regs \
35 popq %r11; \
36 popq %r10; \
37 popq %r9; \
38 popq %r8; \
39 popq %rcx; \
40 popq %rsi; \
41 popq %rdi
42
43/* Fix up special calling conventions */
44ENTRY(call_rwsem_down_read_failed)
45 save_common_regs
46 pushq %rdx
47 movq %rax,%rdi
48 call rwsem_down_read_failed
49 popq %rdx
50 restore_common_regs
51 ret
52 ENDPROC(call_rwsem_down_read_failed)
53
54ENTRY(call_rwsem_down_write_failed)
55 save_common_regs
56 movq %rax,%rdi
57 call rwsem_down_write_failed
58 restore_common_regs
59 ret
60 ENDPROC(call_rwsem_down_write_failed)
61
62ENTRY(call_rwsem_wake)
David Howellsa66f6372010-05-04 13:42:53 +010063 decl %edx /* do nothing if still outstanding active readers */
Linus Torvaldsbafaecd2010-01-12 18:16:42 -080064 jnz 1f
65 save_common_regs
66 movq %rax,%rdi
67 call rwsem_wake
68 restore_common_regs
691: ret
70 ENDPROC(call_rwsem_wake)
71
72/* Fix up special calling conventions */
73ENTRY(call_rwsem_downgrade_wake)
74 save_common_regs
75 pushq %rdx
76 movq %rax,%rdi
77 call rwsem_downgrade_wake
78 popq %rdx
79 restore_common_regs
80 ret
81 ENDPROC(call_rwsem_downgrade_wake)