cregit-Linux how code gets into the kernel

Release 4.7 include/asm-generic/futex.h

#ifndef _ASM_GENERIC_FUTEX_H

#define _ASM_GENERIC_FUTEX_H

#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/errno.h>

#ifndef CONFIG_SMP
/*
 * The following implementation only for uniprocessor machines.
 * It relies on preempt_disable() ensuring mutual exclusion.
 *
 */

/**
 * futex_atomic_op_inuser() - Atomic arithmetic operation with constant
 *                        argument and comparison of the previous
 *                        futex value with another constant.
 *
 * @encoded_op: encoded operation to execute
 * @uaddr:      pointer to user space address
 *
 * Return:
 * 0 - On success
 * <0 - On error
 */

static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) { int op = (encoded_op >> 28) & 7; int cmp = (encoded_op >> 24) & 15; int oparg = (encoded_op << 8) >> 20; int cmparg = (encoded_op << 20) >> 20; int oldval, ret; u32 tmp; if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) oparg = 1 << oparg; preempt_disable(); pagefault_disable(); ret = -EFAULT; if (unlikely(get_user(oldval, uaddr) != 0)) goto out_pagefault_enable; ret = 0; tmp = oldval; switch (op) { case FUTEX_OP_SET: tmp = oparg; break; case FUTEX_OP_ADD: tmp += oparg; break; case FUTEX_OP_OR: tmp |= oparg; break; case FUTEX_OP_ANDN: tmp &= ~oparg; break; case FUTEX_OP_XOR: tmp ^= oparg; break; default: ret = -ENOSYS; } if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0)) ret = -EFAULT; out_pagefault_enable: pagefault_enable(); preempt_enable(); if (ret == 0) { switch (cmp) { case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; default: ret = -ENOSYS; } } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
ley foon tanley foon tan29297.99%150.00%
david hildenbranddavid hildenbrand62.01%150.00%
Total298100.00%2100.00%

/** * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the * uaddr with newval if the current value is * oldval. * @uval: pointer to store content of @uaddr * @uaddr: pointer to user space address * @oldval: old value * @newval: new value to store to @uaddr * * Return: * 0 - On success * <0 - On error */
static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) { u32 val; preempt_disable(); if (unlikely(get_user(val, uaddr) != 0)) { preempt_enable(); return -EFAULT; } if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) { preempt_enable(); return -EFAULT; } *uval = val; preempt_enable(); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
ley foon tanley foon tan7382.02%133.33%
romain perierromain perier1011.24%133.33%
david hildenbranddavid hildenbrand66.74%133.33%
Total89100.00%3100.00%

#else
static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) { int op = (encoded_op >> 28) & 7; int cmp = (encoded_op >> 24) & 15; int oparg = (encoded_op << 8) >> 20; int cmparg = (encoded_op << 20) >> 20; int oldval = 0, ret; if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) oparg = 1 << oparg; if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32))) return -EFAULT; pagefault_disable(); switch (op) { case FUTEX_OP_SET: case FUTEX_OP_ADD: case FUTEX_OP_OR: case FUTEX_OP_ANDN: case FUTEX_OP_XOR: default: ret = -ENOSYS; } pagefault_enable(); if (!ret) { switch (cmp) { case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; default: ret = -ENOSYS; } } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
jeff dikejeff dike22498.25%133.33%
michel lespinassemichel lespinasse20.88%133.33%
peter zijlstrapeter zijlstra20.88%133.33%
Total228100.00%3100.00%


static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) { return -ENOSYS; }

Contributors

PersonTokensPropCommitsCommitProp
ingo molnaringo molnar1973.08%250.00%
michel lespinassemichel lespinasse726.92%250.00%
Total26100.00%4100.00%

#endif /* CONFIG_SMP */ #endif

Overall Contributors

PersonTokensPropCommitsCommitProp
ley foon tanley foon tan37556.05%19.09%
jeff dikejeff dike24136.02%218.18%
ingo molnaringo molnar192.84%218.18%
david hildenbranddavid hildenbrand131.94%218.18%
romain perierromain perier101.49%19.09%
michel lespinassemichel lespinasse91.35%218.18%
peter zijlstrapeter zijlstra20.30%19.09%
Total669100.00%11100.00%
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