#include <linux/string.h>
#include <linux/thread_info.h>
-#include <asm/alternative.h>
#include <asm/cpufeature.h>
+ #include <asm/processor.h>
#include <asm/ptrace.h>
-#include <asm/sysreg.h>
#include <asm/errno.h>
#include <asm/memory.h>
#include <asm/compiler.h>
" .popsection\n"
/*
+ * User access enabling/disabling.
+ */
+#ifdef CONFIG_ARM64_SW_TTBR0_PAN
+static inline void __uaccess_ttbr0_disable(void)
+{
+ unsigned long flags, ttbr;
+
+ local_irq_save(flags);
+ ttbr = read_sysreg(ttbr1_el1);
+ ttbr &= ~TTBR_ASID_MASK;
+ /* reserved_ttbr0 placed at the end of swapper_pg_dir */
+ write_sysreg(ttbr + SWAPPER_DIR_SIZE, ttbr0_el1);
+ isb();
+ /* Set reserved ASID */
+ write_sysreg(ttbr, ttbr1_el1);
+ isb();
+ local_irq_restore(flags);
+}
+
+static inline void __uaccess_ttbr0_enable(void)
+{
+ unsigned long flags, ttbr0, ttbr1;
+
+ /*
+ * Disable interrupts to avoid preemption between reading the 'ttbr0'
+ * variable and the MSR. A context switch could trigger an ASID
+ * roll-over and an update of 'ttbr0'.
+ */
+ local_irq_save(flags);
+ ttbr0 = READ_ONCE(current_thread_info()->ttbr0);
+
+ /* Restore active ASID */
+ ttbr1 = read_sysreg(ttbr1_el1);
+ 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);
+ isb();
+ local_irq_restore(flags);
+}
+
+static inline bool uaccess_ttbr0_disable(void)
+{
+ if (!system_uses_ttbr0_pan())
+ return false;
+ __uaccess_ttbr0_disable();
+ return true;
+}
+
+static inline bool uaccess_ttbr0_enable(void)
+{
+ if (!system_uses_ttbr0_pan())
+ return false;
+ __uaccess_ttbr0_enable();
+ return true;
+}
+#else
+static inline bool uaccess_ttbr0_disable(void)
+{
+ return false;
+}
+
+static inline bool uaccess_ttbr0_enable(void)
+{
+ return false;
+}
+#endif
+
+#define __uaccess_disable(alt) \
+do { \
+ if (!uaccess_ttbr0_disable()) \
+ asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt, \
+ CONFIG_ARM64_PAN)); \
+} while (0)
+
+#define __uaccess_enable(alt) \
+do { \
+ if (!uaccess_ttbr0_enable()) \
+ asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), alt, \
+ CONFIG_ARM64_PAN)); \
+} while (0)
+
+static inline void uaccess_disable(void)
+{
+ __uaccess_disable(ARM64_HAS_PAN);
+}
+
+static inline void uaccess_enable(void)
+{
+ __uaccess_enable(ARM64_HAS_PAN);
+}
+
+/*
+ * These functions are no-ops when UAO is present.
+ */
+static inline void uaccess_disable_not_uao(void)
+{
+ __uaccess_disable(ARM64_ALT_PAN_NOT_UAO);
+}
+
+static inline void uaccess_enable_not_uao(void)
+{
+ __uaccess_enable(ARM64_ALT_PAN_NOT_UAO);
+}
+
+/*
+ * Sanitise a uaccess pointer such that it becomes NULL if above the
+ * current addr_limit.
+ */
+ #define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr)
+ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
+ {
+ void __user *safe_ptr;
+
+ asm volatile(
+ " bics xzr, %1, %2\n"
+ " csel %0, %1, xzr, eq\n"
+ : "=&r" (safe_ptr)
+ : "r" (ptr), "r" (current_thread_info()->addr_limit)
+ : "cc");
+
+ csdb();
+ return safe_ptr;
+ }
+
+ /*
* The "__xxx" versions of the user access functions do not verify the address
* space - it must have been done previously with a separate "access_ok()"
* call.
default: \
BUILD_BUG(); \
} \
+ uaccess_disable_not_uao(); \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
- asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
- CONFIG_ARM64_PAN)); \
} while (0)
- #define __get_user(x, ptr) \
+ #define __get_user_check(x, ptr, err) \
({ \
- int __gu_err = 0; \
- __get_user_err((x), (ptr), __gu_err); \
- __gu_err; \
+ __typeof__(*(ptr)) __user *__p = (ptr); \
+ might_fault(); \
+ if (access_ok(VERIFY_READ, __p, sizeof(*__p))) { \
+ __p = uaccess_mask_ptr(__p); \
+ __get_user_err((x), __p, (err)); \
+ } else { \
+ (x) = 0; (err) = -EFAULT; \
+ } \
})
#define __get_user_error(x, ptr, err) \
default: \
BUILD_BUG(); \
} \
- asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
- CONFIG_ARM64_PAN)); \
+ uaccess_disable_not_uao(); \
} while (0)
- #define __put_user(x, ptr) \
+ #define __put_user_check(x, ptr, err) \
({ \
- int __pu_err = 0; \
- __put_user_err((x), (ptr), __pu_err); \
- __pu_err; \
+ __typeof__(*(ptr)) __user *__p = (ptr); \
+ might_fault(); \
+ if (access_ok(VERIFY_WRITE, __p, sizeof(*__p))) { \
+ __p = uaccess_mask_ptr(__p); \
+ __put_user_err((x), __p, (err)); \
+ } else { \
+ (err) = -EFAULT; \
+ } \
})
#define __put_user_error(x, ptr, err) \
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