svn commit: r325525 - in head/sys/powerpc: booke powerpc

[Justin Hibbits]

Author: jhibbits
Date: Wed Nov  8 01:23:37 2017
New Revision: 325525
URL: https://svnweb.freebsd.org/changeset/base/325525

Log:
  Clear the WE bit in C code rather than the asm
  
  According to EREF rlwinm is supposed to clear the upper 32 bits of the
  register of 64-bit cores.  However, from experience it seems there's a bug
  in the e5500 which causes the result to be duplicated in the upper bits of
  the register.  This causes problems when applied to stashed SRR1 accessed
  to retrieve context, as the upper bits are not masked out, so a
  set_mcontext() fails.  This causes sigreturn() to in turn return with
  EINVAL, causing make(1) to exit with error.
  
  This bit is unused in e500mc derivatives (including e5500), so could just be
  conditional on non-powerpc64, but there may be other non-Freescale cores
  which do use it.  This is also the same as the POW bit on Book-S, so could
  be cleared unconditionally with the only penalty being a few clock cycles
  for these two interrupts.

Modified:
  head/sys/powerpc/booke/trap_subr.S
  head/sys/powerpc/powerpc/interrupt.c

Modified: head/sys/powerpc/booke/trap_subr.S
==============================================================================
--- head/sys/powerpc/booke/trap_subr.S	Wed Nov  8 01:00:59 2017	(r325524)
+++ head/sys/powerpc/booke/trap_subr.S	Wed Nov  8 01:23:37 2017	(r325525)
@@ -567,7 +567,7 @@ INTERRUPT(int_external_input)
 	addi	%r3, %r1, CALLSIZE
 	bl	CNAME(powerpc_interrupt)
 	TOC_RESTORE
-	b	clear_we
+	b	trapexit
 
 
 INTERRUPT(int_alignment)
@@ -607,7 +607,7 @@ INTERRUPT(int_decrementer)
 	addi	%r3, %r1, CALLSIZE
 	bl	CNAME(powerpc_interrupt)
 	TOC_RESTORE
-	b	clear_we
+	b	trapexit
 
 
 /*****************************************************************************
@@ -1090,12 +1090,6 @@ dbleave:
 	FRAME_LEAVE(SPR_SRR0, SPR_SRR1)
 	rfi
 #endif /* KDB */
-
-clear_we:
-	LOAD	%r3, (FRAME_SRR1+CALLSIZE)(%r1)
-	rlwinm	%r3, %r3, 0, 14, 12
-	STORE	%r3, (FRAME_SRR1+CALLSIZE)(%r1)
-	b	trapexit
 
 #ifdef SMP
 ENTRY(tlb_lock)

Modified: head/sys/powerpc/powerpc/interrupt.c
==============================================================================
--- head/sys/powerpc/powerpc/interrupt.c	Wed Nov  8 01:00:59 2017	(r325524)
+++ head/sys/powerpc/powerpc/interrupt.c	Wed Nov  8 01:23:37 2017	(r325525)
@@ -89,6 +89,9 @@ powerpc_interrupt(struct trapframe *framep)
 		critical_enter();
 		PIC_DISPATCH(root_pic, framep);
 		critical_exit();
+#ifdef BOOKE
+		framep->srr1 &= ~PSL_WE;
+#endif
 		break;
 
 	case EXC_DECR:
@@ -100,6 +103,9 @@ powerpc_interrupt(struct trapframe *framep)
 		td->td_intr_frame = oldframe;
 		atomic_subtract_int(&td->td_intr_nesting_level, 1);
 		critical_exit();
+#ifdef BOOKE
+		framep->srr1 &= ~PSL_WE;
+#endif
 		break;
 #ifdef HWPMC_HOOKS
 	case EXC_PERF: