2 files changed, 20 insertions, 6 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index cf006d40342c..36586dba6fa6 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1186,6 +1186,15 @@ if !MMU
 source "arch/arm/Kconfig-nommu"
 endif
 
+config ARM_ERRATA_326103
+        bool "ARM errata: FSR write bit incorrect on a SWP to read-only memory"
+        depends on CPU_V6
+        help
+          Executing a SWP instruction to read-only memory does not set bit 11
+          of the FSR on the ARM 1136 prior to r1p0. This causes the kernel to
+          treat the access as a read, preventing a COW from occurring and
+          causing the faulting task to livelock.
+
 config ARM_ERRATA_411920
         bool "ARM errata: Invalidation of the Instruction Cache operation can fail"
         depends on CPU_V6 || CPU_V6K
diff --git a/arch/arm/mm/abort-ev6.S b/arch/arm/mm/abort-ev6.S
index ff1f7cc11f87..80741992a9fc 100644
--- a/arch/arm/mm/abort-ev6.S
+++ b/arch/arm/mm/abort-ev6.S
@@ -26,18 +26,23 @@ 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 (erratum 326103).
- * The test below covers all the write situations, including Java bytecodes
+ * Faulty SWP instruction on 1136 doesn't set bit 11 in DFSR.
  */
-        bic     r1, r1, #1 << 11                @ clear bit 11 of FSR
+#ifdef CONFIG_ARM_ERRATA_326103
+        ldr     ip, =0x4107b36
+        mrc     p15, 0, r3, c0, c0, 0           @ get processor id
+        teq     ip, r3, lsr #4                  @ r0 ARM1136?
+        bne     do_DataAbort
         tst     r5, #PSR_J_BIT                  @ Java?
+        tsteq   r5, #PSR_T_BIT                  @ Thumb?
         bne     do_DataAbort
-        do_thumb_abort fsr=r1, pc=r4, psr=r5, tmp=r3
-        ldreq   r3, [r4]                        @ read aborted ARM instruction
+        bic     r1, r1, #1 << 11                @ clear bit 11 of FSR
+        ldr     r3, [r4]                        @ read aborted ARM instruction
 #ifdef CONFIG_CPU_ENDIAN_BE8
-        reveq   r3, r3
+        rev     r3, r3
 #endif
         do_ldrd_abort tmp=ip, insn=r3
         tst     r3, #1 << 20                    @ L = 0 -> write
         orreq   r1, r1, #1 << 11                @ yes.
+#endif
         b       do_DataAbort