3 files changed, 36 insertions, 2 deletions

diff --git a/Documentation/powerpc/transactional_memory.txt b/Documentation/powerpc/transactional_memory.txt
index 84e04a0db0f8..c54bf3127651 100644
--- a/Documentation/powerpc/transactional_memory.txt
+++ b/Documentation/powerpc/transactional_memory.txt
@@ -161,9 +161,12 @@ kernel aborted a transaction:
                         transactions for consistency will use this.
  TM_CAUSE_SIGNAL        Signal delivered.
  TM_CAUSE_MISC          Currently unused.
+ TM_CAUSE_ALIGNMENT     Alignment fault.
+ TM_CAUSE_EMULATE       Emulation that touched memory.
 
-These can be checked by the user program's abort handler as TEXASR[0:7].
-
+These can be checked by the user program's abort handler as TEXASR[0:7].  If
+bit 7 is set, it indicates that the error is consider persistent.  For example
+a TM_CAUSE_ALIGNMENT will be persistent while a TM_CAUSE_RESCHED will not.q
 
 GDB
 ===
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 8f6a94b2dc99..d0528e0d6db8 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -122,6 +122,8 @@
 #define TM_CAUSE_SYSCALL        0xd8  /* future use */
 #define TM_CAUSE_MISC           0xd6  /* future use */
 #define TM_CAUSE_SIGNAL         0xd4
+#define TM_CAUSE_ALIGNMENT      0xd2
+#define TM_CAUSE_EMULATE        0xd0
 
 #if defined(CONFIG_PPC_BOOK3S_64)
 #define MSR_64BIT       MSR_SF
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index a7a648f6b750..f18c79c324ef 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -53,6 +53,7 @@
 #ifdef CONFIG_PPC64
 #include <asm/firmware.h>
 #include <asm/processor.h>
+#include <asm/tm.h>
 #endif
 #include <asm/kexec.h>
 #include <asm/ppc-opcode.h>
@@ -932,6 +933,28 @@ static int emulate_isel(struct pt_regs *regs, u32 instword)
         return 0;
 }
 
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+static inline bool tm_abort_check(struct pt_regs *regs, int cause)
+{
+        /* If we're emulating a load/store in an active transaction, we cannot
+         * emulate it as the kernel operates in transaction suspended context.
+         * We need to abort the transaction.  This creates a persistent TM
+         * abort so tell the user what caused it with a new code.
+         */
+        if (MSR_TM_TRANSACTIONAL(regs->msr)) {
+                tm_enable();
+                tm_abort(cause);
+                return true;
+        }
+        return false;
+}
+#else
+static inline bool tm_abort_check(struct pt_regs *regs, int reason)
+{
+        return false;
+}
+#endif
+
 static int emulate_instruction(struct pt_regs *regs)
 {
         u32 instword;
@@ -971,6 +994,9 @@ static int emulate_instruction(struct pt_regs *regs)
 
         /* Emulate load/store string insn. */
         if ((instword & PPC_INST_STRING_GEN_MASK) == PPC_INST_STRING) {
+                if (tm_abort_check(regs,
+                                   TM_CAUSE_EMULATE | TM_CAUSE_PERSISTENT))
+                        return -EINVAL;
                 PPC_WARN_EMULATED(string, regs);
                 return emulate_string_inst(regs, instword);
         }
@@ -1148,6 +1174,9 @@ void alignment_exception(struct pt_regs *regs)
         if (!arch_irq_disabled_regs(regs))
                 local_irq_enable();
 
+        if (tm_abort_check(regs, TM_CAUSE_ALIGNMENT | TM_CAUSE_PERSISTENT))
+                goto bail;
+
         /* we don't implement logging of alignment exceptions */
         if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
                 fixed = fix_alignment(regs);