From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/include/linux/uaccess.h | 134 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 kernel/include/linux/uaccess.h (limited to 'kernel/include/linux/uaccess.h') diff --git a/kernel/include/linux/uaccess.h b/kernel/include/linux/uaccess.h new file mode 100644 index 000000000..941b2dab5 --- /dev/null +++ b/kernel/include/linux/uaccess.h @@ -0,0 +1,134 @@ +#ifndef __LINUX_UACCESS_H__ +#define __LINUX_UACCESS_H__ + +#include +#include + +static __always_inline void pagefault_disabled_inc(void) +{ + current->pagefault_disabled++; +} + +static __always_inline void pagefault_disabled_dec(void) +{ + current->pagefault_disabled--; + WARN_ON(current->pagefault_disabled < 0); +} + +/* + * These routines enable/disable the pagefault handler. If disabled, it will + * not take any locks and go straight to the fixup table. + * + * User access methods will not sleep when called from a pagefault_disabled() + * environment. + */ +static inline void pagefault_disable(void) +{ + migrate_disable(); + pagefault_disabled_inc(); + /* + * make sure to have issued the store before a pagefault + * can hit. + */ + barrier(); +} + +static inline void pagefault_enable(void) +{ + /* + * make sure to issue those last loads/stores before enabling + * the pagefault handler again. + */ + barrier(); + pagefault_disabled_dec(); + migrate_enable(); +} + +/* + * Is the pagefault handler disabled? If so, user access methods will not sleep. + */ +#define pagefault_disabled() (current->pagefault_disabled != 0) + +/* + * The pagefault handler is in general disabled by pagefault_disable() or + * when in irq context (via in_atomic()). + * + * This function should only be used by the fault handlers. Other users should + * stick to pagefault_disabled(). + * Please NEVER use preempt_disable() to disable the fault handler. With + * !CONFIG_PREEMPT_COUNT, this is like a NOP. So the handler won't be disabled. + * in_atomic() will report different values based on !CONFIG_PREEMPT_COUNT. + */ +#define faulthandler_disabled() (pagefault_disabled() || in_atomic()) + +#ifndef ARCH_HAS_NOCACHE_UACCESS + +static inline unsigned long __copy_from_user_inatomic_nocache(void *to, + const void __user *from, unsigned long n) +{ + return __copy_from_user_inatomic(to, from, n); +} + +static inline unsigned long __copy_from_user_nocache(void *to, + const void __user *from, unsigned long n) +{ + return __copy_from_user(to, from, n); +} + +#endif /* ARCH_HAS_NOCACHE_UACCESS */ + +/** + * probe_kernel_address(): safely attempt to read from a location + * @addr: address to read from - its type is type typeof(retval)* + * @retval: read into this variable + * + * Safely read from address @addr into variable @revtal. If a kernel fault + * happens, handle that and return -EFAULT. + * We ensure that the __get_user() is executed in atomic context so that + * do_page_fault() doesn't attempt to take mmap_sem. This makes + * probe_kernel_address() suitable for use within regions where the caller + * already holds mmap_sem, or other locks which nest inside mmap_sem. + * This must be a macro because __get_user() needs to know the types of the + * args. + * + * We don't include enough header files to be able to do the set_fs(). We + * require that the probe_kernel_address() caller will do that. + */ +#define probe_kernel_address(addr, retval) \ + ({ \ + long ret; \ + mm_segment_t old_fs = get_fs(); \ + \ + set_fs(KERNEL_DS); \ + pagefault_disable(); \ + ret = __copy_from_user_inatomic(&(retval), (__force typeof(retval) __user *)(addr), sizeof(retval)); \ + pagefault_enable(); \ + set_fs(old_fs); \ + ret; \ + }) + +/* + * probe_kernel_read(): safely attempt to read from a location + * @dst: pointer to the buffer that shall take the data + * @src: address to read from + * @size: size of the data chunk + * + * Safely read from address @src to the buffer at @dst. If a kernel fault + * happens, handle that and return -EFAULT. + */ +extern long probe_kernel_read(void *dst, const void *src, size_t size); +extern long __probe_kernel_read(void *dst, const void *src, size_t size); + +/* + * probe_kernel_write(): safely attempt to write to a location + * @dst: address to write to + * @src: pointer to the data that shall be written + * @size: size of the data chunk + * + * Safely write to address @dst from the buffer at @src. If a kernel fault + * happens, handle that and return -EFAULT. + */ +extern long notrace probe_kernel_write(void *dst, const void *src, size_t size); +extern long notrace __probe_kernel_write(void *dst, const void *src, size_t size); + +#endif /* __LINUX_UACCESS_H__ */ -- cgit 1.2.3-korg