On Sun, Oct 06, 2013 at 10:09:34AM -0400, Rob Clark wrote:
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.
Okay, the code I quoted is for __get_user() not get_user().
This is roughly what we (hpa/myself) came up with for ARM which did get things working, but itw as x86 which made us decide not to persue this. I've added the __get_user_8 implementation to this. The __inttype() thing was hpa's idea.
arch/arm/include/asm/uaccess.h | 17 +++++++++++++---- arch/arm/lib/getuser.S | 33 ++++++++++++++++++++++++++++++++- 2 files changed, 45 insertions(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 72abdc5..747f2cb 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -93,6 +93,9 @@ static inline void set_fs(mm_segment_t fs) : "cc"); \ flag; })
+#define __inttype(x) \ + __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) + /* * Single-value transfer routines. They automatically use the right * size if we just have the right pointer type. Note that the functions @@ -107,14 +110,16 @@ 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" +#define __GUP_CLOBBER_1 "lr", "cc" #ifdef CONFIG_CPU_USE_DOMAINS -#define __GUP_CLOBBER_2 "ip", "lr", "cc" +#define __GUP_CLOBBER_2 "ip", "lr", "cc" #else #define __GUP_CLOBBER_2 "lr", "cc" #endif -#define __GUP_CLOBBER_4 "lr", "cc" +#define __GUP_CLOBBER_4 "lr", "cc" +#define __GUP_CLOBBER_8 "lr", "cc"
#define __get_user_x(__r2,__p,__e,__l,__s) \ __asm__ __volatile__ ( \ @@ -129,7 +134,7 @@ extern int __get_user_4(void *); ({ \ 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 __inttype(*p) __r2 asm("r2"); \ register unsigned long __l asm("r1") = __limit; \ register int __e asm("r0"); \ switch (sizeof(*(__p))) { \ @@ -142,6 +147,9 @@ extern int __get_user_4(void *); case 4: \ __get_user_x(__r2, __p, __e, __l, 4); \ break; \ + case 8: \ + __get_user_x(__r2, __p, __e, __l, 8); \ + break; \ default: __e = __get_user_bad(); break; \ } \ x = (typeof(*(p))) __r2; \ @@ -150,6 +158,7 @@ extern int __get_user_4(void *);
#define get_user(x,p) \ ({ \ + __chk_user_ptr(ptr); \ might_fault(); \ __get_user_check(x,p); \ }) diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S index 9b06bb4..3583c83 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> @@ -32,6 +32,14 @@ #include <asm/errno.h> #include <asm/domain.h>
+#ifdef __ARMEB__ +#define rlo8 r3 +#define rhi8 r2 +#else +#define rlo8 r2 +#define rhi8 r3 +#endif + ENTRY(__get_user_1) check_uaccess r0, 1, r1, r2, __get_user_bad 1: TUSER(ldrb) r2, [r0] @@ -66,15 +74,38 @@ ENTRY(__get_user_4) mov pc, lr ENDPROC(__get_user_4)
+ENTRY(__get_user_8) + check_uaccess r0, 4, r1, r2, __get_user_bad8 +#ifdef CONFIG_CPU_USE_DOMAINS +#define GU8_FIXUPS 5b, 6b +5: ldrt rlo8, [r0], #4 +6: ldrt rhi8, [r0], #0 +#elif __LINUX_ARM_ARCH__ >= 6 +#define GU8_FIXUPS 5b +5: ldrd r2, [r0] +#else +#define GU8_FIXUPS 5b, 6b +5: ldr rlo8, [r0, #0] +6: ldr rhi8, [r0, #4] +#endif + mov r0, #0 + mov pc, lr + +__get_user_bad8: + mov r3, #0 __get_user_bad: mov r2, #0 mov r0, #-EFAULT mov pc, lr ENDPROC(__get_user_bad) +ENDPROC(__get_user_bad8)
.pushsection __ex_table, "a" .long 1b, __get_user_bad .long 2b, __get_user_bad .long 3b, __get_user_bad .long 4b, __get_user_bad + .irp param, GU8_FIXUPS + .long \param, __get_user_bad8 + .endr .popsection