Blackfin: add support for GENERIC_BUG

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

4 files changed, 99 insertions, 8 deletions

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index c56fd3eb7c10..74cdcf39b41c 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -28,6 +28,10 @@ config BLACKFIN
         select HAVE_OPROFILE
         select ARCH_WANT_OPTIONAL_GPIOLIB
 
+config GENERIC_BUG
+        def_bool y
+        depends on BUG
+
 config ZONE_DMA
         bool
         default y
diff --git a/arch/blackfin/include/asm/bug.h b/arch/blackfin/include/asm/bug.h
index 6d3e11b1fc57..655e49540e41 100644
--- a/arch/blackfin/include/asm/bug.h
+++ b/arch/blackfin/include/asm/bug.h
@@ -2,13 +2,58 @@
 #define _BLACKFIN_BUG_H
 
 #ifdef CONFIG_BUG
-#define HAVE_ARCH_BUG
 
-#define BUG() do { \
-        dump_bfin_trace_buffer(); \
-        printk(KERN_EMERG "BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
-        panic("BUG!"); \
-} while (0)
+#define BFIN_BUG_OPCODE 0xefcd
+
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+
+#define _BUG_OR_WARN(flags)                                             \
+        asm volatile(                                                   \
+                "1:     .hword  %0\n"                                   \
+                "       .section __bug_table,\"a\",@progbits\n"         \
+                "2:     .long   1b\n"                                   \
+                "       .long   %1\n"                                   \
+                "       .short  %2\n"                                   \
+                "       .short  %3\n"                                   \
+                "       .org    2b + %4\n"                              \
+                "       .previous"                                      \
+                :                                                       \
+                : "i"(BFIN_BUG_OPCODE), "i"(__FILE__),                  \
+                  "i"(__LINE__), "i"(flags),                            \
+                  "i"(sizeof(struct bug_entry)))
+
+#else
+
+#define _BUG_OR_WARN(flags)                                             \
+        asm volatile(                                                   \
+                "1:     .hword  %0\n"                                   \
+                "       .section __bug_table,\"a\",@progbits\n"         \
+                "2:     .long   1b\n"                                   \
+                "       .short  %1\n"                                   \
+                "       .org    2b + %2\n"                              \
+                "       .previous"                                      \
+                :                                                       \
+                : "i"(BFIN_BUG_OPCODE), "i"(flags),                     \
+                  "i"(sizeof(struct bug_entry)))
+
+#endif /* CONFIG_DEBUG_BUGVERBOSE */
+
+#define BUG()                                                           \
+        do {                                                            \
+                _BUG_OR_WARN(0);                                        \
+                for (;;);                                               \
+        } while (0)
+
+#define WARN_ON(condition)                                                      \
+        ({                                                              \
+                int __ret_warn_on = !!(condition);                      \
+                if (unlikely(__ret_warn_on))                            \
+                        _BUG_OR_WARN(BUGFLAG_WARNING);                  \
+                unlikely(__ret_warn_on);                                \
+        })
+
+#define HAVE_ARCH_BUG
+#define HAVE_ARCH_WARN_ON
 
 #endif
 
diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index aa76dfb0226e..2405f193224e 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -27,6 +27,7 @@
  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#include <linux/bug.h>
 #include <linux/uaccess.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
@@ -381,6 +382,23 @@ asmlinkage void trap_c(struct pt_regs *fp)
         /* 0x20 - Reserved, Caught by default */
         /* 0x21 - Undefined Instruction, handled here */
         case VEC_UNDEF_I:
+#ifdef CONFIG_BUG
+                if (kernel_mode_regs(fp)) {
+                        switch (report_bug(fp->pc, fp)) {
+                        case BUG_TRAP_TYPE_NONE:
+                                break;
+                        case BUG_TRAP_TYPE_WARN:
+                                dump_bfin_trace_buffer();
+                                fp->pc += 2;
+                                goto traps_done;
+                        case BUG_TRAP_TYPE_BUG:
+                                /* call to panic() will dump trace, and it is
+                                 * off at this point, so it won't be clobbered
+                                 */
+                                panic("BUG()");
+                        }
+                }
+#endif
                 info.si_code = ILL_ILLOPC;
                 sig = SIGILL;
                 verbose_printk(KERN_NOTICE EXC_0x21(KERN_NOTICE));
@@ -792,6 +810,18 @@ void dump_bfin_trace_buffer(void)
 }
 EXPORT_SYMBOL(dump_bfin_trace_buffer);
 
+#ifdef CONFIG_BUG
+int is_valid_bugaddr(unsigned long addr)
+{
+        unsigned short opcode;
+
+        if (!get_instruction(&opcode, (unsigned short *)addr))
+                return 0;
+
+        return opcode == BFIN_BUG_OPCODE;
+}
+#endif
+
 /*
  * Checks to see if the address pointed to is either a
  * 16-bit CALL instruction, or a 32-bit CALL instruction
diff --git a/arch/blackfin/kernel/vmlinux.lds.S b/arch/blackfin/kernel/vmlinux.lds.S
index 8b67167cb4f4..119fbdb46475 100644
--- a/arch/blackfin/kernel/vmlinux.lds.S
+++ b/arch/blackfin/kernel/vmlinux.lds.S
@@ -166,6 +166,20 @@ SECTIONS
         }
         PERCPU(4)
         SECURITY_INIT
+
+        /* we have to discard exit text and such at runtime, not link time, to
+         * handle embedded cross-section references (alt instructions, bug
+         * table, eh_frame, etc...)
+         */
+        .exit.text :
+        {
+                EXIT_TEXT
+        }
+        .exit.data :
+        {
+                EXIT_DATA
+        }
+
         .init.ramfs :
         {
                 . = ALIGN(4);
@@ -264,8 +278,6 @@ SECTIONS
 
         /DISCARD/ :
         {
-                EXIT_TEXT
-                EXIT_DATA
                 *(.exitcall.exit)
         }
 }