| Message ID | 1381020350-1125-13-git-send-email-robdclark@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, Oct 05, 2013 at 08:45:50PM -0400, Rob Clark wrote: > A new atomic modeset/pageflip ioctl being developed in DRM requires > get_user() to work for 64bit types (in addition to just put_user()). > > v1: original > v2: pass correct size to check_uaccess, and better handling of narrowing > double word read with __get_user_xb() (Russell King's suggestion) I thought we had decided not to support this for 32-bit because x86_32 had problems here as well: #ifdef CONFIG_X86_32 #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() #else #define __get_user_asm_u64(x, ptr, retval, errret) \ __get_user_asm(x, ptr, retval, "q", "", "=r", errret) #define __get_user_asm_ex_u64(x, ptr) \ __get_user_asm_ex(x, ptr, "q", "", "=r") #endif
On Sun, Oct 6, 2013 at 4:53 AM, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > On Sat, Oct 05, 2013 at 08:45:50PM -0400, Rob Clark wrote: >> A new atomic modeset/pageflip ioctl being developed in DRM requires >> get_user() to work for 64bit types (in addition to just put_user()). >> >> v1: original >> v2: pass correct size to check_uaccess, and better handling of narrowing >> double word read with __get_user_xb() (Russell King's suggestion) > > I thought we had decided not to support this for 32-bit because x86_32 > had problems here as well: I don't remember.. actually I didn't even realize it wasn't merged until I tried to build with the atomic modeset ioctl. Ville did have a patch to add it for x86_32, and that patch appears to be merged (96477b4c), so I just assume it wasn't removed since then. BR, -R > #ifdef CONFIG_X86_32 > #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() > #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() > #else > #define __get_user_asm_u64(x, ptr, retval, errret) \ > __get_user_asm(x, ptr, retval, "q", "", "=r", errret) > #define __get_user_asm_ex_u64(x, ptr) \ > __get_user_asm_ex(x, ptr, "q", "", "=r") > #endif >
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 72abdc5..c54fdce 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -107,6 +107,7 @@ static inline void set_fs(mm_segment_t fs) extern int __get_user_1(void *); extern int __get_user_2(void *); extern int __get_user_4(void *); +extern int __get_user_8(void *); #define __GUP_CLOBBER_1 "lr", "cc" #ifdef CONFIG_CPU_USE_DOMAINS @@ -115,6 +116,7 @@ extern int __get_user_4(void *); #define __GUP_CLOBBER_2 "lr", "cc" #endif #define __GUP_CLOBBER_4 "lr", "cc" +#define __GUP_CLOBBER_8 "lr", "cc" #define __get_user_x(__r2,__p,__e,__l,__s) \ __asm__ __volatile__ ( \ @@ -125,11 +127,19 @@ extern int __get_user_4(void *); : "0" (__p), "r" (__l) \ : __GUP_CLOBBER_##__s) +/* narrowing a double-word get into a single 32bit word register: */ +#ifdef BIG_ENDIAN +#define __get_user_xb(__r2,__p,__e,__l,__s) \ + __get_user_x(__r2,(uintptr_t)__p + 4,__e,__l,__s) +#else +#define __get_user_xb __get_user_x +#endif + #define __get_user_check(x,p) \ ({ \ unsigned long __limit = current_thread_info()->addr_limit - 1; \ register const typeof(*(p)) __user *__p asm("r0") = (p);\ - register unsigned long __r2 asm("r2"); \ + register typeof(x) __r2 asm("r2"); \ register unsigned long __l asm("r1") = __limit; \ register int __e asm("r0"); \ switch (sizeof(*(__p))) { \ @@ -142,6 +152,12 @@ extern int __get_user_4(void *); case 4: \ __get_user_x(__r2, __p, __e, __l, 4); \ break; \ + case 8: \ + if (sizeof((x)) < 8) \ + __get_user_xb(__r2, __p, __e, __l, 4); \ + else \ + __get_user_x(__r2, __p, __e, __l, 8); \ + break; \ default: __e = __get_user_bad(); break; \ } \ x = (typeof(*(p))) __r2; \ diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S index 9b06bb4..ed98707 100644 --- a/arch/arm/lib/getuser.S +++ b/arch/arm/lib/getuser.S @@ -18,7 +18,7 @@ * Inputs: r0 contains the address * r1 contains the address limit, which must be preserved * Outputs: r0 is the error code - * r2 contains the zero-extended value + * r2, r3 contains the zero-extended value * lr corrupted * * No other registers must be altered. (see <asm/uaccess.h> @@ -66,6 +66,19 @@ ENTRY(__get_user_4) mov pc, lr ENDPROC(__get_user_4) +ENTRY(__get_user_8) + check_uaccess r0, 8, r1, r2, __get_user_bad +#ifdef CONFIG_THUMB2_KERNEL +5: TUSER(ldr) r2, [r0] +6: TUSER(ldr) r3, [r0, #4] +#else +5: TUSER(ldr) r2, [r0], #4 +6: TUSER(ldr) r3, [r0] +#endif + mov r0, #0 + mov pc, lr +ENDPROC(__get_user_8) + __get_user_bad: mov r2, #0 mov r0, #-EFAULT @@ -77,4 +90,6 @@ ENDPROC(__get_user_bad) .long 2b, __get_user_bad .long 3b, __get_user_bad .long 4b, __get_user_bad + .long 5b, __get_user_bad + .long 6b, __get_user_bad .popsection
A new atomic modeset/pageflip ioctl being developed in DRM requires get_user() to work for 64bit types (in addition to just put_user()). v1: original v2: pass correct size to check_uaccess, and better handling of narrowing double word read with __get_user_xb() (Russell King's suggestion) Signed-off-by: Rob Clark <robdclark@gmail.com> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> --- arch/arm/include/asm/uaccess.h | 18 +++++++++++++++++- arch/arm/lib/getuser.S | 17 ++++++++++++++++- 2 files changed, 33 insertions(+), 2 deletions(-)