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[/] [c0or1k/] [trunk/] [conts/] [libl4/] [src/] [arch/] [arm/] [v6/] [mutex.c] - Blame information for rev 2

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/*
 * Copyright (C) 2010 B Labs Ltd.
 * Author: Prem Mallappa <prem.mallappa@b-labs.co.uk>
 */
 
#include <l4lib/mutex.h>
#include <l4lib/types.h>
#include L4LIB_INC_ARCH(syslib.h)       /* for BUG/BUG_ON,  */
#include L4LIB_INC_ARCH(asm.h)
#include INC_SUBARCH(mmu_ops.h)
 
int __l4_mutex_lock(void *m, l4id_t tid)
{
        int tmp, ret;
 loop:
        __asm__ __volatile__(
                             "ldrex %0, [%1]\n"
                             : "=&r"(tmp)
                             : "r"(m)
                             : "memory"
        );
 
        if(tmp != L4_MUTEX_UNLOCKED)
                ret = L4_MUTEX_CONTENDED;
        else
                ret = L4_MUTEX_SUCCESS;
 
        /* Store our 'tid' */
        __asm__ __volatile__(
                             "strex     %0, %1, [%2]\n"
                             :"=&r"(tmp)
                             :"r"(tid), "r"(m)
                             );
        if (tmp != 0) {
                /* We couldn't succeed the store, we retry */
#ifdef CONFIG_SMP
                  /* don't hog the CPU, sleep till an event */
                __asm__ __volatile__("wfe\n");
#endif
                goto loop;
        }
 
        dsb();
 
        return ret;
}
 
int __l4_mutex_unlock(void *m, l4id_t tid)
{
        int tmp, ret;
 loop:
        /* Load and see if the lock had our tid */
        __asm__ __volatile__(
                             "ldrex %0, [%1]\n"
                             : "=r"(tmp)
                             : "r"(m)
                             );
 
        if(tmp != tid)
                ret = L4_MUTEX_CONTENDED;
        else
                ret = L4_MUTEX_SUCCESS;
 
        /* We store unlock value '0' */
        __asm__ __volatile__(
                             "strex     %0, %1, [%2]\n"
                             :"=&r"(tmp)
                             :"rI"(L4_MUTEX_UNLOCKED), "r"(m)
                             );
        if(tmp != 0) {
                /* The store wasn't successfull, retry */
                goto loop;
        }
 
        dsb();
 
#ifdef CONFIG_SMP
        __asm__ __volatile__("sev\n");
#endif
        return ret;
}
 
u8 l4_atomic_dest_readb(unsigned long *location)
{
        unsigned int tmp, res;
        __asm__ __volatile__ (
                "1:                             \n"
                "       ldrex %0, [%2]          \n"
                "       strex %1, %3, [%2]      \n"
                "       teq %1, #0              \n"
                "       bne 1b                  \n"
                : "=&r"(tmp), "=&r"(res)
                : "r"(location), "r"(0)
                : "cc", "memory"
        );
 
        return (u8)tmp;
}

Line No.	Rev	Author	Line
1	2	drasko	`/*`
2			`* Copyright (C) 2010 B Labs Ltd.`
3			`* Author: Prem Mallappa <prem.mallappa@b-labs.co.uk>`
4			`*/`
5
6			`#include <l4lib/mutex.h>`
7			`#include <l4lib/types.h>`
8			`#include L4LIB_INC_ARCH(syslib.h) /* for BUG/BUG_ON, */`
9			`#include L4LIB_INC_ARCH(asm.h)`
10			`#include INC_SUBARCH(mmu_ops.h)`
11
12			`int __l4_mutex_lock(void *m, l4id_t tid)`
13			`{`
14			`int tmp, ret;`
15			`loop:`
16			`__asm__ __volatile__(`
17			`"ldrex %0, [%1]\n"`
18			`: "=&r"(tmp)`
19			`: "r"(m)`
20			`: "memory"`
21			`);`
22
23			`if(tmp != L4_MUTEX_UNLOCKED)`
24			`ret = L4_MUTEX_CONTENDED;`
25			`else`
26			`ret = L4_MUTEX_SUCCESS;`
27
28			`/* Store our 'tid' */`
29			`__asm__ __volatile__(`
30			`"strex %0, %1, [%2]\n"`
31			`:"=&r"(tmp)`
32			`:"r"(tid), "r"(m)`
33			`);`
34			`if (tmp != 0) {`
35			`/* We couldn't succeed the store, we retry */`
36			`#ifdef CONFIG_SMP`
37			`/* don't hog the CPU, sleep till an event */`
38			`__asm__ __volatile__("wfe\n");`
39			`#endif`
40			`goto loop;`
41			`}`
42
43			`dsb();`
44
45			`return ret;`
46			`}`
47
48			`int __l4_mutex_unlock(void *m, l4id_t tid)`
49			`{`
50			`int tmp, ret;`
51			`loop:`
52			`/* Load and see if the lock had our tid */`
53			`__asm__ __volatile__(`
54			`"ldrex %0, [%1]\n"`
55			`: "=r"(tmp)`
56			`: "r"(m)`
57			`);`
58
59			`if(tmp != tid)`
60			`ret = L4_MUTEX_CONTENDED;`
61			`else`
62			`ret = L4_MUTEX_SUCCESS;`
63
64			`/* We store unlock value '0' */`
65			`__asm__ __volatile__(`
66			`"strex %0, %1, [%2]\n"`
67			`:"=&r"(tmp)`
68			`:"rI"(L4_MUTEX_UNLOCKED), "r"(m)`
69			`);`
70			`if(tmp != 0) {`
71			`/* The store wasn't successfull, retry */`
72			`goto loop;`
73			`}`
74
75			`dsb();`
76
77			`#ifdef CONFIG_SMP`
78			`__asm__ __volatile__("sev\n");`
79			`#endif`
80			`return ret;`
81			`}`
82
83			`u8 l4_atomic_dest_readb(unsigned long *location)`
84			`{`
85			`unsigned int tmp, res;`
86			`__asm__ __volatile__ (`
87			`"1: \n"`
88			`" ldrex %0, [%2] \n"`
89			`" strex %1, %3, [%2] \n"`
90			`" teq %1, #0 \n"`
91			`" bne 1b \n"`
92			`: "=&r"(tmp), "=&r"(res)`
93			`: "r"(location), "r"(0)`
94			`: "cc", "memory"`
95			`);`
96
97			`return (u8)tmp;`
98			`}`

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[/] [c0or1k/] [trunk/] [conts/] [libl4/] [src/] [arch/] [arm/] [v6/] [mutex.c] - Blame information for rev 2