arm64: Cortex-A53 errata workaround: check for kernel addresses

[cascardo/linux.git] / arch / arm64 / kernel / traps.c

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 5ff020f..7255c9d 100644 (file)
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -434,18 +434,21 @@ void cpu_enable_cache_maint_trap(void *__unused)
 }
 
 #define __user_cache_maint(insn, address, res)                 \
-       asm volatile (                                          \
-               "1:     " insn ", %1\n"                         \
-               "       mov     %w0, #0\n"                      \
-               "2:\n"                                          \
-               "       .pushsection .fixup,\"ax\"\n"           \
-               "       .align  2\n"                            \
-               "3:     mov     %w0, %w2\n"                     \
-               "       b       2b\n"                           \
-               "       .popsection\n"                          \
-               _ASM_EXTABLE(1b, 3b)                            \
-               : "=r" (res)                                    \
-               : "r" (address), "i" (-EFAULT) )
+       if (untagged_addr(address) >= user_addr_max())          \
+               res = -EFAULT;                                  \
+       else                                                    \
+               asm volatile (                                  \
+                       "1:     " insn ", %1\n"                 \
+                       "       mov     %w0, #0\n"              \
+                       "2:\n"                                  \
+                       "       .pushsection .fixup,\"ax\"\n"   \
+                       "       .align  2\n"                    \
+                       "3:     mov     %w0, %w2\n"             \
+                       "       b       2b\n"                   \
+                       "       .popsection\n"                  \
+                       _ASM_EXTABLE(1b, 3b)                    \
+                       : "=r" (res)                            \
+                       : "r" (address), "i" (-EFAULT) )
 
 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
 {