ARM: fix "bad mode in ... handler" message for undefined instructions

[firefly-linux-kernel-4.4.55.git] / arch / arm / kernel / traps.c

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 18b32e8e4497f4c1966f43ac6fbb4963315fb968..d6a0fdb6c2eebcc3a026a47c5ce62bbedb06a67a 100644 (file)
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -35,9 +35,13 @@
 #include <asm/tls.h>
 #include <asm/system_misc.h>
 
-#include "signal.h"
-
-static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
+static const char *handler[]= {
+       "prefetch abort",
+       "data abort",
+       "address exception",
+       "interrupt",
+       "undefined instruction",
+};
 
 void *vectors_page;
 
@@ -800,47 +804,55 @@ void __init trap_init(void)
        return;
 }
 
-static void __init kuser_get_tls_init(unsigned long vectors)
+#ifdef CONFIG_KUSER_HELPERS
+static void __init kuser_init(void *vectors)
 {
+       extern char __kuser_helper_start[], __kuser_helper_end[];
+       int kuser_sz = __kuser_helper_end - __kuser_helper_start;
+
+       memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
+
        /*
         * vectors + 0xfe0 = __kuser_get_tls
         * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
         */
        if (tls_emu || has_tls_reg)
-               memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4);
+               memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
 }
+#else
+static void __init kuser_init(void *vectors)
+{
+}
+#endif
 
 void __init early_trap_init(void *vectors_base)
 {
        unsigned long vectors = (unsigned long)vectors_base;
        extern char __stubs_start[], __stubs_end[];
        extern char __vectors_start[], __vectors_end[];
-       extern char __kuser_helper_start[], __kuser_helper_end[];
-       int kuser_sz = __kuser_helper_end - __kuser_helper_start;
+       unsigned i;
 
        vectors_page = vectors_base;
 
+       /*
+        * Poison the vectors page with an undefined instruction.  This
+        * instruction is chosen to be undefined for both ARM and Thumb
+        * ISAs.  The Thumb version is an undefined instruction with a
+        * branch back to the undefined instruction.
+        */
+       for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
+               ((u32 *)vectors_base)[i] = 0xe7fddef1;
+
        /*
         * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
         * into the vector page, mapped at 0xffff0000, and ensure these
         * are visible to the instruction stream.
         */
        memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
-       memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);
-       memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
+       memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
 
-       /*
-        * Do processor specific fixups for the kuser helpers
-        */
-       kuser_get_tls_init(vectors);
-
-       /*
-        * Copy signal return handlers into the vector page, and
-        * set sigreturn to be a pointer to these.
-        */
-       memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
-              sigreturn_codes, sizeof(sigreturn_codes));
+       kuser_init(vectors_base);
 
-       flush_icache_range(vectors, vectors + PAGE_SIZE);
+       flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
        modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
 }