diff options
Diffstat (limited to 'arch/arm64/include/asm/uaccess.h')
| -rw-r--r-- | arch/arm64/include/asm/uaccess.h | 160 |
1 files changed, 78 insertions, 82 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 3a5ff5e20586..5c7b2f9d5913 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -26,7 +26,7 @@ #include <asm/memory.h> #include <asm/extable.h> -#define HAVE_GET_KERNEL_NOFAULT +static inline int __access_ok(const void __user *ptr, unsigned long size); /* * Test whether a block of memory is a valid user space address. @@ -35,10 +35,8 @@ * This is equivalent to the following test: * (u65)addr + (u65)size <= (u65)TASK_SIZE_MAX */ -static inline unsigned long __range_ok(const void __user *addr, unsigned long size) +static inline int access_ok(const void __user *addr, unsigned long size) { - unsigned long ret, limit = TASK_SIZE_MAX - 1; - /* * Asynchronous I/O running in a kernel thread does not have the * TIF_TAGGED_ADDR flag of the process owning the mm, so always untag @@ -48,28 +46,11 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si (current->flags & PF_KTHREAD || test_thread_flag(TIF_TAGGED_ADDR))) addr = untagged_addr(addr); - __chk_user_ptr(addr); - asm volatile( - // A + B <= C + 1 for all A,B,C, in four easy steps: - // 1: X = A + B; X' = X % 2^64 - " adds %0, %3, %2\n" - // 2: Set C = 0 if X > 2^64, to guarantee X' > C in step 4 - " csel %1, xzr, %1, hi\n" - // 3: Set X' = ~0 if X >= 2^64. For X == 2^64, this decrements X' - // to compensate for the carry flag being set in step 4. For - // X > 2^64, X' merely has to remain nonzero, which it does. - " csinv %0, %0, xzr, cc\n" - // 4: For X < 2^64, this gives us X' - C - 1 <= 0, where the -1 - // comes from the carry in being clear. Otherwise, we are - // testing X' - C == 0, subject to the previous adjustments. - " sbcs xzr, %0, %1\n" - " cset %0, ls\n" - : "=&r" (ret), "+r" (limit) : "Ir" (size), "0" (addr) : "cc"); - - return ret; + return likely(__access_ok(addr, size)); } +#define access_ok access_ok -#define access_ok(addr, size) __range_ok(addr, size) +#include <asm-generic/access_ok.h> /* * User access enabling/disabling. @@ -222,9 +203,11 @@ static inline void uaccess_enable_privileged(void) } /* - * Sanitise a uaccess pointer such that it becomes NULL if above the maximum - * user address. In case the pointer is tagged (has the top byte set), untag - * the pointer before checking. + * Sanitize a uaccess pointer such that it cannot reach any kernel address. + * + * Clearing bit 55 ensures the pointer cannot address any portion of the TTBR1 + * address range (i.e. any kernel address), and either the pointer falls within + * the TTBR0 address range or must cause a fault. */ #define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr) static inline void __user *__uaccess_mask_ptr(const void __user *ptr) @@ -232,14 +215,12 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) void __user *safe_ptr; asm volatile( - " bics xzr, %3, %2\n" - " csel %0, %1, xzr, eq\n" - : "=&r" (safe_ptr) - : "r" (ptr), "r" (TASK_SIZE_MAX - 1), - "r" (untagged_addr(ptr)) - : "cc"); - - csdb(); + " bic %0, %1, %2\n" + : "=r" (safe_ptr) + : "r" (ptr), + "i" (BIT(55)) + ); + return safe_ptr; } @@ -251,34 +232,34 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) * The "__xxx_error" versions set the third argument to -EFAULT if an error * occurs, and leave it unchanged on success. */ -#define __get_mem_asm(load, reg, x, addr, err) \ +#define __get_mem_asm(load, reg, x, addr, err, type) \ asm volatile( \ "1: " load " " reg "1, [%2]\n" \ "2:\n" \ - _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \ + _ASM_EXTABLE_##type##ACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \ : "+r" (err), "=&r" (x) \ : "r" (addr)) -#define __raw_get_mem(ldr, x, ptr, err) \ -do { \ - unsigned long __gu_val; \ - switch (sizeof(*(ptr))) { \ - case 1: \ - __get_mem_asm(ldr "b", "%w", __gu_val, (ptr), (err)); \ - break; \ - case 2: \ - __get_mem_asm(ldr "h", "%w", __gu_val, (ptr), (err)); \ - break; \ - case 4: \ - __get_mem_asm(ldr, "%w", __gu_val, (ptr), (err)); \ - break; \ - case 8: \ - __get_mem_asm(ldr, "%x", __gu_val, (ptr), (err)); \ - break; \ - default: \ - BUILD_BUG(); \ - } \ - (x) = (__force __typeof__(*(ptr)))__gu_val; \ +#define __raw_get_mem(ldr, x, ptr, err, type) \ +do { \ + unsigned long __gu_val; \ + switch (sizeof(*(ptr))) { \ + case 1: \ + __get_mem_asm(ldr "b", "%w", __gu_val, (ptr), (err), type); \ + break; \ + case 2: \ + __get_mem_asm(ldr "h", "%w", __gu_val, (ptr), (err), type); \ + break; \ + case 4: \ + __get_mem_asm(ldr, "%w", __gu_val, (ptr), (err), type); \ + break; \ + case 8: \ + __get_mem_asm(ldr, "%x", __gu_val, (ptr), (err), type); \ + break; \ + default: \ + BUILD_BUG(); \ + } \ + (x) = (__force __typeof__(*(ptr)))__gu_val; \ } while (0) /* @@ -293,7 +274,7 @@ do { \ __chk_user_ptr(ptr); \ \ uaccess_ttbr0_enable(); \ - __raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err); \ + __raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err, U); \ uaccess_ttbr0_disable(); \ \ (x) = __rgu_val; \ @@ -333,40 +314,40 @@ do { \ \ __uaccess_enable_tco_async(); \ __raw_get_mem("ldr", *((type *)(__gkn_dst)), \ - (__force type *)(__gkn_src), __gkn_err); \ + (__force type *)(__gkn_src), __gkn_err, K); \ __uaccess_disable_tco_async(); \ \ if (unlikely(__gkn_err)) \ goto err_label; \ } while (0) -#define __put_mem_asm(store, reg, x, addr, err) \ +#define __put_mem_asm(store, reg, x, addr, err, type) \ asm volatile( \ "1: " store " " reg "1, [%2]\n" \ "2:\n" \ - _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) \ + _ASM_EXTABLE_##type##ACCESS_ERR(1b, 2b, %w0) \ : "+r" (err) \ : "r" (x), "r" (addr)) -#define __raw_put_mem(str, x, ptr, err) \ -do { \ - __typeof__(*(ptr)) __pu_val = (x); \ - switch (sizeof(*(ptr))) { \ - case 1: \ - __put_mem_asm(str "b", "%w", __pu_val, (ptr), (err)); \ - break; \ - case 2: \ - __put_mem_asm(str "h", "%w", __pu_val, (ptr), (err)); \ - break; \ - case 4: \ - __put_mem_asm(str, "%w", __pu_val, (ptr), (err)); \ - break; \ - case 8: \ - __put_mem_asm(str, "%x", __pu_val, (ptr), (err)); \ - break; \ - default: \ - BUILD_BUG(); \ - } \ +#define __raw_put_mem(str, x, ptr, err, type) \ +do { \ + __typeof__(*(ptr)) __pu_val = (x); \ + switch (sizeof(*(ptr))) { \ + case 1: \ + __put_mem_asm(str "b", "%w", __pu_val, (ptr), (err), type); \ + break; \ + case 2: \ + __put_mem_asm(str "h", "%w", __pu_val, (ptr), (err), type); \ + break; \ + case 4: \ + __put_mem_asm(str, "%w", __pu_val, (ptr), (err), type); \ + break; \ + case 8: \ + __put_mem_asm(str, "%x", __pu_val, (ptr), (err), type); \ + break; \ + default: \ + BUILD_BUG(); \ + } \ } while (0) /* @@ -381,7 +362,7 @@ do { \ __chk_user_ptr(__rpu_ptr); \ \ uaccess_ttbr0_enable(); \ - __raw_put_mem("sttr", __rpu_val, __rpu_ptr, err); \ + __raw_put_mem("sttr", __rpu_val, __rpu_ptr, err, U); \ uaccess_ttbr0_disable(); \ } while (0) @@ -419,7 +400,7 @@ do { \ \ __uaccess_enable_tco_async(); \ __raw_put_mem("str", *((type *)(__pkn_src)), \ - (__force type *)(__pkn_dst), __pkn_err); \ + (__force type *)(__pkn_dst), __pkn_err, K); \ __uaccess_disable_tco_async(); \ \ if (unlikely(__pkn_err)) \ @@ -479,4 +460,19 @@ static inline int __copy_from_user_flushcache(void *dst, const void __user *src, } #endif +#ifdef CONFIG_ARCH_HAS_SUBPAGE_FAULTS + +/* + * Return 0 on success, the number of bytes not probed otherwise. + */ +static inline size_t probe_subpage_writeable(const char __user *uaddr, + size_t size) +{ + if (!system_supports_mte()) + return 0; + return mte_probe_user_range(uaddr, size); +} + +#endif /* CONFIG_ARCH_HAS_SUBPAGE_FAULTS */ + #endif /* __ASM_UACCESS_H */ |