ARM: 7396/1: errata: only handle ARM erratum #326103 on affected cores
Erratum #326103 ("FSR write bit incorrect on a SWP to read-only memory")
only affects the ARM 1136 core prior to r1p0. The workaround
disassembles the faulting instruction to determine whether it was a read
or write access on all v6 cores.
An issue has been reported on the ARM 11MPCore whereby loading the
faulting instruction may happen in parallel with that page being
unmapped, resulting in a deadlock due to the lack of TLB broadcasting
in hardware:
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-March/091561.html
This patch limits the workaround so that it is only used on affected
cores, which are known to be UP only. Other v6 cores can rely on the
FSR to indicate the access type correctly.
Cc: stable@vger.kernel.org
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/abort-ev6.S b/arch/arm/mm/abort-ev6.S
index ff1f7cc..8074199 100644
--- a/arch/arm/mm/abort-ev6.S
+++ b/arch/arm/mm/abort-ev6.S
@@ -26,18 +26,23 @@
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
- tst r5, #PSR_J_BIT @ Java?
+#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
- do_thumb_abort fsr=r1, pc=r4, psr=r5, tmp=r3
- ldreq r3, [r4] @ read aborted ARM instruction
+ tst r5, #PSR_J_BIT @ Java?
+ tsteq r5, #PSR_T_BIT @ Thumb?
+ bne do_DataAbort
+ 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