From: Roman Zippel <zippel@linux-m68k.org>
Date: Mon, 5 May 2008 19:25:48 +0000 (+0200)
Subject: m68k: Handle 68040 bus faults
X-Git-Tag: v2.6.26-rc2~68
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3b17f136bf32984eb0faeb116bcd44ffe3503782;p=linux-2.6

m68k: Handle 68040 bus faults

Fix 68040 bus fault handling, so the standard kernel exception handling
can be used for i/o probing.

Contrary to normal access faults there is nothing to fix, but at least
we have to disable writebacks to avoid recursive faults.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c
index fd4858e2dd..75b8340b25 100644
--- a/arch/m68k/kernel/traps.c
+++ b/arch/m68k/kernel/traps.c
@@ -468,15 +468,26 @@ static inline void access_error040(struct frame *fp)
 			 * (if do_page_fault didn't fix the mapping,
                          * the writeback won't do good)
 			 */
+disable_wb:
 #ifdef DEBUG
 			printk(".. disabling wb2\n");
 #endif
 			if (fp->un.fmt7.wb2a == fp->un.fmt7.faddr)
 				fp->un.fmt7.wb2s &= ~WBV_040;
+			if (fp->un.fmt7.wb3a == fp->un.fmt7.faddr)
+				fp->un.fmt7.wb3s &= ~WBV_040;
 		}
-	} else if (send_fault_sig(&fp->ptregs) > 0) {
-		printk("68040 access error, ssw=%x\n", ssw);
-		trap_c(fp);
+	} else {
+		/* In case of a bus error we either kill the process or expect
+		 * the kernel to catch the fault, which then is also responsible
+		 * for cleaning up the mess.
+		 */
+		current->thread.signo = SIGBUS;
+		current->thread.faddr = fp->un.fmt7.faddr;
+		if (send_fault_sig(&fp->ptregs) >= 0)
+			printk("68040 bus error (ssw=%x, faddr=%lx)\n", ssw,
+			       fp->un.fmt7.faddr);
+		goto disable_wb;
 	}
 
 	do_040writebacks(fp);