Merge branch 'parisc-4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull more parisc updates from Helge Deller:

 - fix boot failure of 64-bit kernel. It got broken by the unwind
   optimization commit in merge window.

 - fix 64-bit userspace support (static 64-bit applications only, e.g.
   we don't yet have 64-bit userspace support in glibc).

 - consolidate unwind initialization code.

 - add machine model description to stack trace.

* 'parisc-4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Add hardware description to stack traces
  parisc: Fix boot failure of 64-bit kernel
  parisc: Consolidate unwind initialization calls
  parisc: Update comments in syscall.S regarding wide userland
  parisc: Fix ptraced 64-bit applications to call 64-bit syscalls
  parisc: Restore possibility to execute 64-bit applications

1 files changed, 21 insertions, 14 deletions

diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index 5f7e57fcaeef..f453997a7b8f 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -108,12 +108,8 @@ linux_gateway_entry:
 	mtsp	%r0,%sr6			/* get kernel space into sr6 */
 
 #ifdef CONFIG_64BIT
-	/* for now we can *always* set the W bit on entry to the syscall
-	 * since we don't support wide userland processes.  We could
-	 * also save the current SM other than in r0 and restore it on
-	 * exit from the syscall, and also use that value to know
-	 * whether to do narrow or wide syscalls. -PB
-	 */
+	/* Store W bit on entry to the syscall in case it's a wide userland
+	 * process. */
 	ssm	PSW_SM_W, %r1
 	extrd,u	%r1,PSW_W_BIT,1,%r1
 	/* sp must be aligned on 4, so deposit the W bit setting into
@@ -227,8 +223,7 @@ linux_gateway_entry:
 	or,=	%r2,%r2,%r2
 	ldo	R%sys_call_table64(%r1), %r19
 #else
-	ldil	L%sys_call_table, %r1
-	ldo     R%sys_call_table(%r1), %r19
+	load32	sys_call_table, %r19
 #endif	
 	comiclr,>>	__NR_Linux_syscalls, %r20, %r0
 	b,n	.Lsyscall_nosys
@@ -331,8 +326,6 @@ tracesys_next:
 	 *  task->thread.regs.gr[20] above.
 	 */
 	copy	%ret0,%r20
-	ldil	L%sys_call_table,%r1
-	ldo     R%sys_call_table(%r1), %r19
 
 	ldo     -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1      /* get task ptr */
 	LDREG	TI_TASK(%r1), %r1
@@ -354,6 +347,23 @@ tracesys_next:
 	comiclr,>>	__NR_Linux_syscalls, %r20, %r0
 	b,n	.Ltracesys_nosys
 
+	/* Note!  We cannot use the syscall table that is mapped
+	nearby since the gateway page is mapped execute-only. */
+
+#ifdef CONFIG_64BIT
+	LDREG	TASK_PT_GR30(%r1), %r19		/* get users sp back */
+	extrd,u	%r19,63,1,%r2			/* W hidden in bottom bit */
+
+	ldil	L%sys_call_table, %r1
+	or,=	%r2,%r2,%r2
+	addil	L%(sys_call_table64-sys_call_table), %r1
+	ldo	R%sys_call_table(%r1), %r19
+	or,=	%r2,%r2,%r2
+	ldo	R%sys_call_table64(%r1), %r19
+#else
+	load32	sys_call_table, %r19
+#endif
+
 	LDREGX  %r20(%r19), %r19
 
 	/* If this is a sys_rt_sigreturn call, and the signal was received
@@ -464,16 +474,13 @@ tracesys_sigexit:
 lws_start:
 
 #ifdef CONFIG_64BIT
-	/* FIXME: If we are a 64-bit kernel just
-	 *        turn this on unconditionally.
-	 */
 	ssm	PSW_SM_W, %r1
 	extrd,u	%r1,PSW_W_BIT,1,%r1
 	/* sp must be aligned on 4, so deposit the W bit setting into
 	 * the bottom of sp temporarily */
 	or,ev	%r1,%r30,%r30
 
-	/* Clip LWS number to a 32-bit value always */
+	/* Clip LWS number to a 32-bit value for 32-bit processes */
 	depdi	0, 31, 32, %r20
 #endif