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Diffstat (limited to 'arch/arm64/include/asm/uaccess.h')
-rw-r--r--arch/arm64/include/asm/uaccess.h363
1 files changed, 172 insertions, 191 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 32fc8061aa76..14be5000c5a0 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -18,50 +18,25 @@
#include <linux/kasan-checks.h>
#include <linux/string.h>
+#include <asm/asm-extable.h>
#include <asm/cpufeature.h>
+#include <asm/mmu.h>
+#include <asm/mte.h>
#include <asm/ptrace.h>
#include <asm/memory.h>
#include <asm/extable.h>
-#define get_fs() (current_thread_info()->addr_limit)
-
-static inline void set_fs(mm_segment_t fs)
-{
- current_thread_info()->addr_limit = fs;
-
- /*
- * Prevent a mispredicted conditional call to set_fs from forwarding
- * the wrong address limit to access_ok under speculation.
- */
- spec_bar();
-
- /* On user-mode return, check fs is correct */
- set_thread_flag(TIF_FSCHECK);
-
- /*
- * Enable/disable UAO so that copy_to_user() etc can access
- * kernel memory with the unprivileged instructions.
- */
- if (IS_ENABLED(CONFIG_ARM64_UAO) && fs == KERNEL_DS)
- asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO));
- else
- asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO,
- CONFIG_ARM64_UAO));
-}
-
-#define segment_eq(a, b) ((a) == (b))
+static inline int __access_ok(const void __user *ptr, unsigned long size);
/*
* Test whether a block of memory is a valid user space address.
* Returns 1 if the range is valid, 0 otherwise.
*
* This is equivalent to the following test:
- * (u65)addr + (u65)size <= (u65)current->addr_limit + 1
+ * (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 = current_thread_info()->addr_limit;
-
/*
* 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
@@ -71,35 +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)
-#define user_addr_max get_fs
-
-#define _ASM_EXTABLE(from, to) \
- " .pushsection __ex_table, \"a\"\n" \
- " .align 3\n" \
- " .long (" #from " - .), (" #to " - .)\n" \
- " .popsection\n"
+#include <asm-generic/access_ok.h>
/*
* User access enabling/disabling.
@@ -112,9 +63,8 @@ static inline void __uaccess_ttbr0_disable(void)
local_irq_save(flags);
ttbr = read_sysreg(ttbr1_el1);
ttbr &= ~TTBR_ASID_MASK;
- /* reserved_ttbr0 placed before swapper_pg_dir */
- write_sysreg(ttbr - RESERVED_TTBR0_SIZE, ttbr0_el1);
- isb();
+ /* reserved_pg_dir placed before swapper_pg_dir */
+ write_sysreg(ttbr - RESERVED_SWAPPER_OFFSET, ttbr0_el1);
/* Set reserved ASID */
write_sysreg(ttbr, ttbr1_el1);
isb();
@@ -138,7 +88,6 @@ static inline void __uaccess_ttbr0_enable(void)
ttbr1 &= ~TTBR_ASID_MASK; /* safety measure */
ttbr1 |= ttbr0 & TTBR_ASID_MASK;
write_sysreg(ttbr1, ttbr1_el1);
- isb();
/* Restore user page table */
write_sysreg(ttbr0, ttbr0_el1);
@@ -185,47 +134,32 @@ static inline void __uaccess_enable_hw_pan(void)
CONFIG_ARM64_PAN));
}
-#define __uaccess_disable(alt) \
-do { \
- if (!uaccess_ttbr0_disable()) \
- asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt, \
- CONFIG_ARM64_PAN)); \
-} while (0)
+static inline void uaccess_disable_privileged(void)
+{
+ mte_disable_tco();
-#define __uaccess_enable(alt) \
-do { \
- if (!uaccess_ttbr0_enable()) \
- asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), alt, \
- CONFIG_ARM64_PAN)); \
-} while (0)
+ if (uaccess_ttbr0_disable())
+ return;
-static inline void uaccess_disable(void)
-{
- __uaccess_disable(ARM64_HAS_PAN);
+ __uaccess_enable_hw_pan();
}
-static inline void uaccess_enable(void)
+static inline void uaccess_enable_privileged(void)
{
- __uaccess_enable(ARM64_HAS_PAN);
-}
+ mte_enable_tco();
-/*
- * These functions are no-ops when UAO is present.
- */
-static inline void uaccess_disable_not_uao(void)
-{
- __uaccess_disable(ARM64_ALT_PAN_NOT_UAO);
-}
+ if (uaccess_ttbr0_enable())
+ return;
-static inline void uaccess_enable_not_uao(void)
-{
- __uaccess_enable(ARM64_ALT_PAN_NOT_UAO);
+ __uaccess_disable_hw_pan();
}
/*
- * Sanitise a uaccess pointer such that it becomes NULL if above the
- * current addr_limit. 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)
@@ -233,14 +167,12 @@ 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" (current_thread_info()->addr_limit),
- "r" (untagged_addr(ptr))
- : "cc");
-
- csdb();
+ " bic %0, %1, %2\n"
+ : "=r" (safe_ptr)
+ : "r" (ptr),
+ "i" (BIT(55))
+ );
+
return safe_ptr;
}
@@ -252,48 +184,52 @@ 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_user_asm(instr, alt_instr, reg, x, addr, err, feature) \
+#define __get_mem_asm(load, reg, x, addr, err, type) \
asm volatile( \
- "1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \
- alt_instr " " reg "1, [%2]\n", feature) \
+ "1: " load " " reg "1, [%2]\n" \
"2:\n" \
- " .section .fixup, \"ax\"\n" \
- " .align 2\n" \
- "3: mov %w0, %3\n" \
- " mov %1, #0\n" \
- " b 2b\n" \
- " .previous\n" \
- _ASM_EXTABLE(1b, 3b) \
- : "+r" (err), "=&r" (x) \
- : "r" (addr), "i" (-EFAULT))
+ _ASM_EXTABLE_##type##ACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \
+ : "+r" (err), "=r" (x) \
+ : "r" (addr))
+
+#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)
+/*
+ * We must not call into the scheduler between uaccess_ttbr0_enable() and
+ * uaccess_ttbr0_disable(). As `x` and `ptr` could contain blocking functions,
+ * we must evaluate these outside of the critical section.
+ */
#define __raw_get_user(x, ptr, err) \
do { \
- unsigned long __gu_val; \
+ __typeof__(*(ptr)) __user *__rgu_ptr = (ptr); \
+ __typeof__(x) __rgu_val; \
__chk_user_ptr(ptr); \
- uaccess_enable_not_uao(); \
- switch (sizeof(*(ptr))) { \
- case 1: \
- __get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \
- (err), ARM64_HAS_UAO); \
- break; \
- case 2: \
- __get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr), \
- (err), ARM64_HAS_UAO); \
- break; \
- case 4: \
- __get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr), \
- (err), ARM64_HAS_UAO); \
- break; \
- case 8: \
- __get_user_asm("ldr", "ldtr", "%x", __gu_val, (ptr), \
- (err), ARM64_HAS_UAO); \
- break; \
- default: \
- BUILD_BUG(); \
- } \
- uaccess_disable_not_uao(); \
- (x) = (__force __typeof__(*(ptr)))__gu_val; \
+ \
+ uaccess_ttbr0_enable(); \
+ __raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err, U); \
+ uaccess_ttbr0_disable(); \
+ \
+ (x) = __rgu_val; \
} while (0)
#define __get_user_error(x, ptr, err) \
@@ -304,7 +240,7 @@ do { \
__p = uaccess_mask_ptr(__p); \
__raw_get_user((x), __p, (err)); \
} else { \
- (x) = 0; (err) = -EFAULT; \
+ (x) = (__force __typeof__(x))0; (err) = -EFAULT; \
} \
} while (0)
@@ -317,46 +253,69 @@ do { \
#define get_user __get_user
-#define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature) \
+/*
+ * We must not call into the scheduler between __mte_enable_tco_async() and
+ * __mte_disable_tco_async(). As `dst` and `src` may contain blocking
+ * functions, we must evaluate these outside of the critical section.
+ */
+#define __get_kernel_nofault(dst, src, type, err_label) \
+do { \
+ __typeof__(dst) __gkn_dst = (dst); \
+ __typeof__(src) __gkn_src = (src); \
+ int __gkn_err = 0; \
+ \
+ __mte_enable_tco_async(); \
+ __raw_get_mem("ldr", *((type *)(__gkn_dst)), \
+ (__force type *)(__gkn_src), __gkn_err, K); \
+ __mte_disable_tco_async(); \
+ \
+ if (unlikely(__gkn_err)) \
+ goto err_label; \
+} while (0)
+
+#define __put_mem_asm(store, reg, x, addr, err, type) \
asm volatile( \
- "1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \
- alt_instr " " reg "1, [%2]\n", feature) \
+ "1: " store " " reg "1, [%2]\n" \
"2:\n" \
- " .section .fixup,\"ax\"\n" \
- " .align 2\n" \
- "3: mov %w0, %3\n" \
- " b 2b\n" \
- " .previous\n" \
- _ASM_EXTABLE(1b, 3b) \
+ _ASM_EXTABLE_##type##ACCESS_ERR(1b, 2b, %w0) \
: "+r" (err) \
- : "r" (x), "r" (addr), "i" (-EFAULT))
+ : "rZ" (x), "r" (addr))
+
+#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)
+/*
+ * We must not call into the scheduler between uaccess_ttbr0_enable() and
+ * uaccess_ttbr0_disable(). As `x` and `ptr` could contain blocking functions,
+ * we must evaluate these outside of the critical section.
+ */
#define __raw_put_user(x, ptr, err) \
do { \
- __typeof__(*(ptr)) __pu_val = (x); \
- __chk_user_ptr(ptr); \
- uaccess_enable_not_uao(); \
- switch (sizeof(*(ptr))) { \
- case 1: \
- __put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \
- (err), ARM64_HAS_UAO); \
- break; \
- case 2: \
- __put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr), \
- (err), ARM64_HAS_UAO); \
- break; \
- case 4: \
- __put_user_asm("str", "sttr", "%w", __pu_val, (ptr), \
- (err), ARM64_HAS_UAO); \
- break; \
- case 8: \
- __put_user_asm("str", "sttr", "%x", __pu_val, (ptr), \
- (err), ARM64_HAS_UAO); \
- break; \
- default: \
- BUILD_BUG(); \
- } \
- uaccess_disable_not_uao(); \
+ __typeof__(*(ptr)) __user *__rpu_ptr = (ptr); \
+ __typeof__(*(ptr)) __rpu_val = (x); \
+ __chk_user_ptr(__rpu_ptr); \
+ \
+ uaccess_ttbr0_enable(); \
+ __raw_put_mem("sttr", __rpu_val, __rpu_ptr, err, U); \
+ uaccess_ttbr0_disable(); \
} while (0)
#define __put_user_error(x, ptr, err) \
@@ -380,14 +339,34 @@ do { \
#define put_user __put_user
+/*
+ * We must not call into the scheduler between __mte_enable_tco_async() and
+ * __mte_disable_tco_async(). As `dst` and `src` may contain blocking
+ * functions, we must evaluate these outside of the critical section.
+ */
+#define __put_kernel_nofault(dst, src, type, err_label) \
+do { \
+ __typeof__(dst) __pkn_dst = (dst); \
+ __typeof__(src) __pkn_src = (src); \
+ int __pkn_err = 0; \
+ \
+ __mte_enable_tco_async(); \
+ __raw_put_mem("str", *((type *)(__pkn_src)), \
+ (__force type *)(__pkn_dst), __pkn_err, K); \
+ __mte_disable_tco_async(); \
+ \
+ if (unlikely(__pkn_err)) \
+ goto err_label; \
+} while(0)
+
extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
#define raw_copy_from_user(to, from, n) \
({ \
unsigned long __acfu_ret; \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__acfu_ret = __arch_copy_from_user((to), \
__uaccess_mask_ptr(from), (n)); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
__acfu_ret; \
})
@@ -395,24 +374,13 @@ extern unsigned long __must_check __arch_copy_to_user(void __user *to, const voi
#define raw_copy_to_user(to, from, n) \
({ \
unsigned long __actu_ret; \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__actu_ret = __arch_copy_to_user(__uaccess_mask_ptr(to), \
(from), (n)); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
__actu_ret; \
})
-extern unsigned long __must_check __arch_copy_in_user(void __user *to, const void __user *from, unsigned long n);
-#define raw_copy_in_user(to, from, n) \
-({ \
- unsigned long __aciu_ret; \
- uaccess_enable_not_uao(); \
- __aciu_ret = __arch_copy_in_user(__uaccess_mask_ptr(to), \
- __uaccess_mask_ptr(from), (n)); \
- uaccess_disable_not_uao(); \
- __aciu_ret; \
-})
-
#define INLINE_COPY_TO_USER
#define INLINE_COPY_FROM_USER
@@ -420,9 +388,9 @@ extern unsigned long __must_check __arch_clear_user(void __user *to, unsigned lo
static inline unsigned long __must_check __clear_user(void __user *to, unsigned long n)
{
if (access_ok(to, n)) {
- uaccess_enable_not_uao();
+ uaccess_ttbr0_enable();
n = __arch_clear_user(__uaccess_mask_ptr(to), n);
- uaccess_disable_not_uao();
+ uaccess_ttbr0_disable();
}
return n;
}
@@ -433,8 +401,6 @@ extern long strncpy_from_user(char *dest, const char __user *src, long count);
extern __must_check long strnlen_user(const char __user *str, long n);
#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
-struct page;
-void memcpy_page_flushcache(char *to, struct page *page, size_t offset, size_t len);
extern unsigned long __must_check __copy_user_flushcache(void *to, const void __user *from, unsigned long n);
static inline int __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size)
@@ -444,4 +410,19 @@ 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 */
generated by cgit (git 2.34.1) at 2024-05-09 08:35:37 +0000