[ARM] nommu: uaccess tweaks
MMUless systems have only one address space for all threads, so both the usual access_ok() checks, and the exception handling do not make much sense. Hence, discard the fixup and exception tables at link time, use memcpy/memset for the user copy/clearing functions, and define the permission check macros to be constants. Some of this patch was derived from the equivalent patch by Hyok S. Choi. Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King
Russell King
parent
002547b4f8
commit
9641c7cc5a
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@ -109,11 +109,13 @@ EXPORT_SYMBOL(memchr);
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EXPORT_SYMBOL(__memzero);
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/* user mem (segment) */
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EXPORT_SYMBOL(__strnlen_user);
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EXPORT_SYMBOL(__strncpy_from_user);
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#ifdef CONFIG_MMU
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EXPORT_SYMBOL(__copy_from_user);
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EXPORT_SYMBOL(__copy_to_user);
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EXPORT_SYMBOL(__clear_user);
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EXPORT_SYMBOL(__strnlen_user);
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EXPORT_SYMBOL(__strncpy_from_user);
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EXPORT_SYMBOL(__get_user_1);
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EXPORT_SYMBOL(__get_user_2);
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@ -123,6 +125,7 @@ EXPORT_SYMBOL(__put_user_1);
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EXPORT_SYMBOL(__put_user_2);
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EXPORT_SYMBOL(__put_user_4);
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EXPORT_SYMBOL(__put_user_8);
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#endif
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/* crypto hash */
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EXPORT_SYMBOL(sha_transform);
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@ -80,6 +80,10 @@ SECTIONS
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*(.exit.text)
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*(.exit.data)
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*(.exitcall.exit)
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#ifndef CONFIG_MMU
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*(.fixup)
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*(__ex_table)
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#endif
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}
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.text : { /* Real text segment */
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@ -87,7 +91,9 @@ SECTIONS
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*(.text)
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SCHED_TEXT
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LOCK_TEXT
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#ifdef CONFIG_MMU
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*(.fixup)
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#endif
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*(.gnu.warning)
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*(.rodata)
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*(.rodata.*)
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@ -142,7 +148,9 @@ SECTIONS
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*/
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. = ALIGN(32);
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__start___ex_table = .;
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#ifdef CONFIG_MMU
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*(__ex_table)
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#endif
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__stop___ex_table = .;
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/*
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@ -6,28 +6,31 @@
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lib-y := backtrace.o changebit.o csumipv6.o csumpartial.o \
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csumpartialcopy.o csumpartialcopyuser.o clearbit.o \
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copy_page.o delay.o findbit.o memchr.o memcpy.o \
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delay.o findbit.o memchr.o memcpy.o \
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memmove.o memset.o memzero.o setbit.o \
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strncpy_from_user.o strnlen_user.o \
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strchr.o strrchr.o \
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testchangebit.o testclearbit.o testsetbit.o \
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getuser.o putuser.o clear_user.o \
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ashldi3.o ashrdi3.o lshrdi3.o muldi3.o \
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ucmpdi2.o lib1funcs.o div64.o sha1.o \
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io-readsb.o io-writesb.o io-readsl.o io-writesl.o
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mmu-y := clear_user.o copy_page.o getuser.o putuser.o
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# the code in uaccess.S is not preemption safe and
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# probably faster on ARMv3 only
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ifeq ($(CONFIG_PREEMPT),y)
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lib-y += copy_from_user.o copy_to_user.o
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mmu-y += copy_from_user.o copy_to_user.o
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else
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ifneq ($(CONFIG_CPU_32v3),y)
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lib-y += copy_from_user.o copy_to_user.o
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mmu-y += copy_from_user.o copy_to_user.o
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else
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lib-y += uaccess.o
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mmu-y += uaccess.o
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endif
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endif
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lib-$(CONFIG_MMU) += $(mmu-y)
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ifeq ($(CONFIG_CPU_32v3),y)
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lib-y += io-readsw-armv3.o io-writesw-armv3.o
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else
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@ -40,16 +40,25 @@ struct exception_table_entry
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extern int fixup_exception(struct pt_regs *regs);
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/*
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* These two are intentionally not defined anywhere - if the kernel
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* code generates any references to them, that's a bug.
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*/
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extern int __get_user_bad(void);
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extern int __put_user_bad(void);
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/*
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* Note that this is actually 0x1,0000,0000
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*/
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#define KERNEL_DS 0x00000000
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#define USER_DS TASK_SIZE
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#define get_ds() (KERNEL_DS)
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#ifdef CONFIG_MMU
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#define USER_DS TASK_SIZE
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#define get_fs() (current_thread_info()->addr_limit)
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static inline void set_fs (mm_segment_t fs)
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static inline void set_fs(mm_segment_t fs)
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{
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current_thread_info()->addr_limit = fs;
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modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
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@ -75,8 +84,6 @@ static inline void set_fs (mm_segment_t fs)
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: "cc"); \
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flag; })
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#define access_ok(type,addr,size) (__range_ok(addr,size) == 0)
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/*
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* Single-value transfer routines. They automatically use the right
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* size if we just have the right pointer type. Note that the functions
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@ -87,20 +94,10 @@ static inline void set_fs (mm_segment_t fs)
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* fixup code, but there are a few places where it intrudes on the
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* main code path. When we only write to user space, there is no
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* problem.
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*
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* The "__xxx" versions of the user access functions do not verify the
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* address space - it must have been done previously with a separate
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* "access_ok()" call.
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*
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* The "xxx_error" versions set the third argument to EFAULT if an
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* error occurs, and leave it unchanged on success. Note that these
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* versions are void (ie, don't return a value as such).
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*/
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extern int __get_user_1(void *);
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extern int __get_user_2(void *);
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extern int __get_user_4(void *);
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extern int __get_user_bad(void);
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#define __get_user_x(__r2,__p,__e,__s,__i...) \
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__asm__ __volatile__ ( \
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@ -131,6 +128,74 @@ extern int __get_user_bad(void);
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__e; \
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})
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extern int __put_user_1(void *, unsigned int);
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extern int __put_user_2(void *, unsigned int);
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extern int __put_user_4(void *, unsigned int);
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extern int __put_user_8(void *, unsigned long long);
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#define __put_user_x(__r2,__p,__e,__s) \
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__asm__ __volatile__ ( \
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__asmeq("%0", "r0") __asmeq("%2", "r2") \
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"bl __put_user_" #__s \
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: "=&r" (__e) \
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: "0" (__p), "r" (__r2) \
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: "ip", "lr", "cc")
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#define put_user(x,p) \
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({ \
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const register typeof(*(p)) __r2 asm("r2") = (x); \
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const register typeof(*(p)) __user *__p asm("r0") = (p);\
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register int __e asm("r0"); \
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switch (sizeof(*(__p))) { \
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case 1: \
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__put_user_x(__r2, __p, __e, 1); \
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break; \
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case 2: \
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__put_user_x(__r2, __p, __e, 2); \
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break; \
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case 4: \
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__put_user_x(__r2, __p, __e, 4); \
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break; \
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case 8: \
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__put_user_x(__r2, __p, __e, 8); \
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break; \
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default: __e = __put_user_bad(); break; \
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} \
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__e; \
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})
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#else /* CONFIG_MMU */
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/*
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* uClinux has only one addr space, so has simplified address limits.
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*/
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#define USER_DS KERNEL_DS
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#define segment_eq(a,b) (1)
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#define __addr_ok(addr) (1)
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#define __range_ok(addr,size) (0)
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#define get_fs() (KERNEL_DS)
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static inline void set_fs(mm_segment_t fs)
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{
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}
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#define get_user(x,p) __get_user(x,p)
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#define put_user(x,p) __put_user(x,p)
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#endif /* CONFIG_MMU */
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#define access_ok(type,addr,size) (__range_ok(addr,size) == 0)
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/*
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* The "__xxx" versions of the user access functions do not verify the
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* address space - it must have been done previously with a separate
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* "access_ok()" call.
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*
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* The "xxx_error" versions set the third argument to EFAULT if an
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* error occurs, and leave it unchanged on success. Note that these
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* versions are void (ie, don't return a value as such).
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*/
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#define __get_user(x,ptr) \
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({ \
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long __gu_err = 0; \
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@ -212,43 +277,6 @@ do { \
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: "r" (addr), "i" (-EFAULT) \
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: "cc")
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extern int __put_user_1(void *, unsigned int);
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extern int __put_user_2(void *, unsigned int);
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extern int __put_user_4(void *, unsigned int);
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extern int __put_user_8(void *, unsigned long long);
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extern int __put_user_bad(void);
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#define __put_user_x(__r2,__p,__e,__s) \
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__asm__ __volatile__ ( \
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__asmeq("%0", "r0") __asmeq("%2", "r2") \
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"bl __put_user_" #__s \
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: "=&r" (__e) \
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: "0" (__p), "r" (__r2) \
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: "ip", "lr", "cc")
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#define put_user(x,p) \
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({ \
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const register typeof(*(p)) __r2 asm("r2") = (x); \
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const register typeof(*(p)) __user *__p asm("r0") = (p);\
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register int __e asm("r0"); \
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switch (sizeof(*(__p))) { \
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case 1: \
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__put_user_x(__r2, __p, __e, 1); \
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break; \
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case 2: \
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__put_user_x(__r2, __p, __e, 2); \
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break; \
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case 4: \
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__put_user_x(__r2, __p, __e, 4); \
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break; \
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case 8: \
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__put_user_x(__r2, __p, __e, 8); \
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break; \
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default: __e = __put_user_bad(); break; \
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} \
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__e; \
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})
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#define __put_user(x,ptr) \
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({ \
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long __pu_err = 0; \
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@ -354,9 +382,16 @@ do { \
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: "cc")
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#ifdef CONFIG_MMU
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extern unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n);
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extern unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n);
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extern unsigned long __clear_user(void __user *addr, unsigned long n);
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#else
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#define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0)
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#define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0)
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#define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0)
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#endif
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extern unsigned long __strncpy_from_user(char *to, const char __user *from, unsigned long count);
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extern unsigned long __strnlen_user(const char __user *s, long n);
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