diff options
| -rw-r--r-- | arch/arm/mm/alignment.c | 2 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/fsl_pci.c | 2 | ||||
| -rw-r--r-- | include/linux/uaccess.h | 40 | ||||
| -rw-r--r-- | mm/maccess.c | 5 |
4 files changed, 17 insertions, 32 deletions
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c index 00b7f7de28a1..7d5f4c736a16 100644 --- a/arch/arm/mm/alignment.c +++ b/arch/arm/mm/alignment.c @@ -803,7 +803,7 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs) } } } else { - fault = probe_kernel_address(instrptr, instr); + fault = probe_kernel_address((void *)instrptr, instr); instr = __mem_to_opcode_arm(instr); } diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c index ebc1f412cf49..13b9bcf5485e 100644 --- a/arch/powerpc/sysdev/fsl_pci.c +++ b/arch/powerpc/sysdev/fsl_pci.c @@ -999,7 +999,7 @@ int fsl_pci_mcheck_exception(struct pt_regs *regs) ret = get_user(regs->nip, &inst); pagefault_enable(); } else { - ret = probe_kernel_address(regs->nip, inst); + ret = probe_kernel_address((void *)regs->nip, inst); } if (mcheck_handle_load(regs, inst)) { diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index d6f2c2c5b043..558129af828a 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -75,36 +75,6 @@ static inline unsigned long __copy_from_user_nocache(void *to, #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 @@ -131,4 +101,14 @@ extern long notrace __probe_kernel_write(void *dst, const void *src, size_t size extern long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count); +/** + * probe_kernel_address(): safely attempt to read from a location + * @addr: address to read from + * @retval: read into this variable + * + * Returns 0 on success, or -EFAULT. + */ +#define probe_kernel_address(addr, retval) \ + probe_kernel_read(&retval, addr, sizeof(retval)) + #endif /* __LINUX_UACCESS_H__ */ diff --git a/mm/maccess.c b/mm/maccess.c index 34fe24759ed1..1b13638d238d 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -13,6 +13,11 @@ * * Safely read from address @src to the buffer at @dst. If a kernel fault * happens, handle that and return -EFAULT. + * + * We ensure that the copy_from_user is executed in atomic context so that + * do_page_fault() doesn't attempt to take mmap_sem. This makes + * probe_kernel_read() suitable for use within regions where the caller + * already holds mmap_sem, or other locks which nest inside mmap_sem. */ long __weak probe_kernel_read(void *dst, const void *src, size_t size) |