Messages in this thread | | | Date | Wed, 23 Feb 2022 17:30:53 -0600 | Subject | Re: [PATCH v2 07/18] nios2: drop access_ok() check from __put_user() | From | Dinh Nguyen <> |
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On 2/16/22 07:13, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > Unlike other architectures, the nios2 version of __put_user() has an > extra check for access_ok(), preventing it from being used to implement > __put_kernel_nofault(). > > Split up put_user() along the same lines as __get_user()/get_user() > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > arch/nios2/include/asm/uaccess.h | 56 +++++++++++++++++++------------- > 1 file changed, 33 insertions(+), 23 deletions(-) > > diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h > index ca9285a915ef..a5cbe07cf0da 100644 > --- a/arch/nios2/include/asm/uaccess.h > +++ b/arch/nios2/include/asm/uaccess.h > @@ -167,34 +167,44 @@ do { \ > : "r" (val), "r" (ptr), "i" (-EFAULT)); \ > } > > -#define put_user(x, ptr) \ > +#define __put_user_common(__pu_val, __pu_ptr) \ > ({ \ > long __pu_err = -EFAULT; \ > - __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \ > - __typeof__(*(ptr)) __pu_val = (__typeof(*ptr))(x); \ > - if (access_ok(__pu_ptr, sizeof(*__pu_ptr))) { \ > - switch (sizeof(*__pu_ptr)) { \ > - case 1: \ > - __put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \ > - break; \ > - case 2: \ > - __put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \ > - break; \ > - case 4: \ > - __put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \ > - break; \ > - default: \ > - /* XXX: This looks wrong... */ \ > - __pu_err = 0; \ > - if (copy_to_user(__pu_ptr, &(__pu_val), \ > - sizeof(*__pu_ptr))) \ > - __pu_err = -EFAULT; \ > - break; \ > - } \ > + switch (sizeof(*__pu_ptr)) { \ > + case 1: \ > + __put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \ > + break; \ > + case 2: \ > + __put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \ > + break; \ > + case 4: \ > + __put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \ > + break; \ > + default: \ > + /* XXX: This looks wrong... */ \ > + __pu_err = 0; \ > + if (__copy_to_user(__pu_ptr, &(__pu_val), \ > + sizeof(*__pu_ptr))) \ > + __pu_err = -EFAULT; \ > + break; \ > } \ > __pu_err; \ > }) > > -#define __put_user(x, ptr) put_user(x, ptr) > +#define __put_user(x, ptr) \ > +({ \ > + __auto_type __pu_ptr = (ptr); \ > + typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x); \ > + __put_user_common(__pu_val, __pu_ptr); \ > +}) > + > +#define put_user(x, ptr) \ > +({ \ > + __auto_type __pu_ptr = (ptr); \ > + typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x); \ > + access_ok(__pu_ptr, sizeof(*__pu_ptr)) ? \ > + __put_user_common(__pu_val, __pu_ptr) : \ > + -EFAULT; \ > +}) > > #endif /* _ASM_NIOS2_UACCESS_H */
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
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