[PATCH] ARM: 2655/1: ARM1136 SWP instruction abort handler fix

Patch from George G. Davis

As noted in http://www.arm.com/linux/patch-2.6.9-arm1.gz, the "Faulty SWP instruction on 1136 doesn't set bit 11 in DFSR." So the v6_early_abort handler does not report the correct rd/wr direction for the SWP instruction which may result in SEGVS or hangs. In order to work around this problem, this patch merely updates the fix contained in the ARM Ltd. patch to use the macroised abort handler fixups.

Signed-off-by: George G. Davis
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/abort-ev6.S

@@ -1,5 +1,6 @@
 #include <linux/linkage.h>
 #include <asm/assembler.h>
+#include "abort-macro.S"
 /*
  * Function: v6_early_abort
  *
@@ -13,11 +14,26 @@
  *	   : sp = pointer to registers
  *
  * Purpose : obtain information about current aborted instruction.
+ * Note: we read user space.  This means we might cause a data
+ * abort here if the I-TLB and D-TLB aren't seeing the same
+ * picture.  Unfortunately, this does happen.  We live with it.
  */
 	.align	5
 ENTRY(v6_early_abort)
 	mrc	p15, 0, r1, c5, c0, 0		@ get FSR
 	mrc	p15, 0, r0, c6, c0, 0		@ get FAR
+/*
+ * Faulty SWP instruction on 1136 doesn't set bit 11 in DFSR.
+ * The test below covers all the write situations, including Java bytecodes
+ */
+	bic	r1, r1, #1 << 11 | 1 << 10	@ clear bits 11 and 10 of FSR
+	tst	r3, #PSR_J_BIT			@ Java?
+	movne	pc, lr
+	do_thumb_abort
+	ldreq	r3, [r2]			@ read aborted ARM instruction
+	do_ldrd_abort
+	tst	r3, #1 << 20			@ L = 0 -> write
+	orreq	r1, r1, #1 << 11		@ yes.
 	mov	pc, lr