BACKPORT: arm64: Factor out PAN enabling/disabling into separate uaccess_* macros

[firefly-linux-kernel-4.4.55.git] / arch / arm64 / include / asm / uaccess.h

diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index c3d445b42351e1a529d94c4ba44e9c4d37544821..8259eded53dca542336ed5a352be5c6961e5086d 100644 (file)
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -18,16 +18,19 @@
 #ifndef __ASM_UACCESS_H
 #define __ASM_UACCESS_H
 
+#include <asm/alternative.h>
+#include <asm/sysreg.h>
+
+#ifndef __ASSEMBLY__
+
 /*
  * User space memory access functions
  */
 #include <linux/string.h>
 #include <linux/thread_info.h>
 
-#include <asm/alternative.h>
 #include <asm/cpufeature.h>
 #include <asm/ptrace.h>
-#include <asm/sysreg.h>
 #include <asm/errno.h>
 #include <asm/memory.h>
 #include <asm/compiler.h>
@@ -123,6 +126,44 @@ static inline void set_fs(mm_segment_t fs)
        "       .long           (" #from " - .), (" #to " - .)\n"       \
        "       .popsection\n"
 
+/*
+ * User access enabling/disabling.
+ */
+#define __uaccess_disable(alt)                                         \
+do {                                                                   \
+       asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt,                  \
+                       CONFIG_ARM64_PAN));                             \
+} while (0)
+
+#define __uaccess_enable(alt)                                          \
+do {                                                                   \
+       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);
+}
+
 /*
  * 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()"
@@ -150,8 +191,7 @@ static inline void set_fs(mm_segment_t fs)
 do {                                                                   \
        unsigned long __gu_val;                                         \
        __chk_user_ptr(ptr);                                            \
-       asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
-                       CONFIG_ARM64_PAN));                             \
+       uaccess_enable_not_uao();                                       \
        switch (sizeof(*(ptr))) {                                       \
        case 1:                                                         \
                __get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr),  \
@@ -172,9 +212,8 @@ do {                                                                        \
        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)                                             \
@@ -219,8 +258,7 @@ do {                                                                        \
 do {                                                                   \
        __typeof__(*(ptr)) __pu_val = (x);                              \
        __chk_user_ptr(ptr);                                            \
-       asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
-                       CONFIG_ARM64_PAN));                             \
+       uaccess_enable_not_uao();                                       \
        switch (sizeof(*(ptr))) {                                       \
        case 1:                                                         \
                __put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr),  \
@@ -241,8 +279,7 @@ do {                                                                        \
        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)                                             \
@@ -327,4 +364,26 @@ extern long strncpy_from_user(char *dest, const char __user *src, long count);
 extern __must_check long strlen_user(const char __user *str);
 extern __must_check long strnlen_user(const char __user *str, long n);
 
+#else  /* __ASSEMBLY__ */
+
+#include <asm/assembler.h>
+
+/*
+ * User access enabling/disabling macros. These are no-ops when UAO is
+ * present.
+ */
+       .macro  uaccess_disable_not_uao, tmp1
+alternative_if ARM64_ALT_PAN_NOT_UAO
+       SET_PSTATE_PAN(1)
+alternative_else_nop_endif
+       .endm
+
+       .macro  uaccess_enable_not_uao, tmp1, tmp2
+alternative_if ARM64_ALT_PAN_NOT_UAO
+       SET_PSTATE_PAN(0)
+alternative_else_nop_endif
+       .endm
+
+#endif /* __ASSEMBLY__ */
+
 #endif /* __ASM_UACCESS_H */