svn commit: r345402 - head/sys/powerpc/aim

[Justin Hibbits]

Author: jhibbits
Date: Fri Mar 22 01:43:31 2019
New Revision: 345402
URL: https://svnweb.freebsd.org/changeset/base/345402

Log:
  powerpc64: Handle the modern (2.05+) implementaiton of tlbie
  
  By happenstance gcc4 puts 'vpn' into r0 in all uses of TLBIE(), but modern
  gcc does not.  Also, the single-argument form of tlbie zeros all unused
  arguments, making the modern tlbie instruction use r0 as the RS field
  (LPID).
  
  The vpn argument has the bottom 12 bits cleared (the input having been
  left-shifted by 12 bits), which just so happens, on the POWER9 and previous
  incarnations, to be the number of LPID bits supported.  With those bits
  being zero, the instruction:
  
  	tlbie r0, r0
  
  will invalidate the VPN in r0, in LPAR 0 (ignoring the upper bits of r0 for
  the RS field).  One build with gcc8 yields:
  
  	tlbie r9, r0
  
  with r0 having arbitrary contents, not equal to r9.  This leads to strange
  crashes, behaviors, and panics, due to the requested TLB entry not actually
  being invalidated.
  
  As the moea64_native must work on both old and new, we explicitly zero out
  r0 so that it can work with only the single argument, built with base gcc
  and modern gcc.  isa3_hashtb takes a different approach, encoding the
  two-argument form, soas not to explicitly clobber r0, and instead let the
  compiler decide.
  
  Reported by:	Brandon Bergren
  Tested by:	Brandon Bergren
  MFC after:	1 week

Modified:
  head/sys/powerpc/aim/isa3_hashtb.c
  head/sys/powerpc/aim/moea64_native.c

Modified: head/sys/powerpc/aim/isa3_hashtb.c
==============================================================================
--- head/sys/powerpc/aim/isa3_hashtb.c	Fri Mar 22 01:42:27 2019	(r345401)
+++ head/sys/powerpc/aim/isa3_hashtb.c	Fri Mar 22 01:43:31 2019	(r345402)
@@ -139,7 +139,8 @@ TLBIE(uint64_t vpn)
 {
 	vpn <<= ADDR_PIDX_SHFT;
 
-	__asm __volatile("tlbie %0" :: "r"(vpn) : "memory");
+	__asm __volatile(".long 0x7c000264 | (%0 << 11) | (%1 << 21)"
+	    :: "r"(vpn), "r"(0) : "memory");
 	__asm __volatile("eieio; tlbsync; ptesync" ::: "memory");
 }
 

Modified: head/sys/powerpc/aim/moea64_native.c
==============================================================================
--- head/sys/powerpc/aim/moea64_native.c	Fri Mar 22 01:42:27 2019	(r345401)
+++ head/sys/powerpc/aim/moea64_native.c	Fri Mar 22 01:43:31 2019	(r345402)
@@ -156,7 +156,7 @@ TLBIE(uint64_t vpn) {
 		vpn &= ~(0xffffULL << 48);
 
 #ifdef __powerpc64__
-	__asm __volatile("tlbie %0" :: "r"(vpn) : "memory");
+	__asm __volatile("li 0, 0; tlbie %0" :: "r"(vpn) : "0","memory");
 	__asm __volatile("eieio; tlbsync; ptesync" ::: "memory");
 #else
 	vpn_hi = (uint32_t)(vpn >> 32);