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Date:      Sat, 2 Jun 2018 19:17:11 +0000 (UTC)
From:      Justin Hibbits <jhibbits@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r334535 - in head: lib/libc/sys sys/powerpc/include sys/powerpc/powerpc
Message-ID:  <201806021917.w52JHBLE034369@repo.freebsd.org>

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Author: jhibbits
Date: Sat Jun  2 19:17:11 2018
New Revision: 334535
URL: https://svnweb.freebsd.org/changeset/base/334535

Log:
  Added ptrace support for reading/writing powerpc VSX registers
  
  Summary:
  Added ptrace support for getting/setting the remaining part of the VSX registers
  (the part that's not already covered by FPR or VR registers).
  
  This is necessary to add support for VSX registers in debuggers.
  
  Submitted by:	Luis Pires
  Differential Revision: https://reviews.freebsd.org/D15458

Modified:
  head/lib/libc/sys/ptrace.2
  head/sys/powerpc/include/fpu.h
  head/sys/powerpc/include/ptrace.h
  head/sys/powerpc/powerpc/fpu.c
  head/sys/powerpc/powerpc/ptrace_machdep.c

Modified: head/lib/libc/sys/ptrace.2
==============================================================================
--- head/lib/libc/sys/ptrace.2	Sat Jun  2 18:03:35 2018	(r334534)
+++ head/lib/libc/sys/ptrace.2	Sat Jun  2 19:17:11 2018	(r334535)
@@ -2,7 +2,7 @@
 .\"	$NetBSD: ptrace.2,v 1.2 1995/02/27 12:35:37 cgd Exp $
 .\"
 .\" This file is in the public domain.
-.Dd May 22, 2018
+.Dd June 2, 2018
 .Dt PTRACE 2
 .Os
 .Sh NAME
@@ -934,6 +934,24 @@ argument is ignored.
 Set the thread's
 .Dv ALTIVEC
 machine state from the buffer pointed to by
+.Fa addr .
+.Pp
+The
+.Fa data
+argument is ignored.
+.It Dv PT_GETVSRREGS
+Return doubleword 1 of the thread's
+.Dv VSX
+registers VSR0-VSR31 in the buffer pointed to by
+.Fa addr .
+.Pp
+The
+.Fa data
+argument is ignored.
+.It Dv PT_SETVSRREGS
+Set doubleword 1 of the thread's
+.Dv VSX
+registers VSR0-VSR31 from the buffer pointed to by
 .Fa addr .
 .Pp
 The

Modified: head/sys/powerpc/include/fpu.h
==============================================================================
--- head/sys/powerpc/include/fpu.h	Sat Jun  2 18:03:35 2018	(r334534)
+++ head/sys/powerpc/include/fpu.h	Sat Jun  2 19:17:11 2018	(r334535)
@@ -74,6 +74,7 @@
 
 void    enable_fpu(struct thread *);
 void    save_fpu(struct thread *);
+void    save_fpu_nodrop(struct thread *);
 
 #endif /* _KERNEL */
 

Modified: head/sys/powerpc/include/ptrace.h
==============================================================================
--- head/sys/powerpc/include/ptrace.h	Sat Jun  2 18:03:35 2018	(r334534)
+++ head/sys/powerpc/include/ptrace.h	Sat Jun  2 19:17:11 2018	(r334535)
@@ -39,5 +39,7 @@
 
 #define PT_GETVRREGS	(PT_FIRSTMACH + 0)
 #define PT_SETVRREGS	(PT_FIRSTMACH + 1)
+#define PT_GETVSRREGS	(PT_FIRSTMACH + 2)
+#define PT_SETVSRREGS	(PT_FIRSTMACH + 3)
 
 #endif

Modified: head/sys/powerpc/powerpc/fpu.c
==============================================================================
--- head/sys/powerpc/powerpc/fpu.c	Sat Jun  2 18:03:35 2018	(r334534)
+++ head/sys/powerpc/powerpc/fpu.c	Sat Jun  2 19:17:11 2018	(r334535)
@@ -45,6 +45,60 @@ __FBSDID("$FreeBSD$");
 #include <machine/pcb.h>
 #include <machine/psl.h>
 
+static void
+save_fpu_int(struct thread *td)
+{
+	int	msr;
+	struct	pcb *pcb;
+
+	pcb = td->td_pcb;
+
+	/*
+	 * Temporarily re-enable floating-point during the save
+	 */
+	msr = mfmsr();
+	if (pcb->pcb_flags & PCB_VSX)
+		mtmsr(msr | PSL_FP | PSL_VSX);
+	else
+		mtmsr(msr | PSL_FP);
+
+	/*
+	 * Save the floating-point registers and FPSCR to the PCB
+	 */
+	if (pcb->pcb_flags & PCB_VSX) {
+	#define SFP(n)   __asm ("stxvw4x " #n ", 0,%0" \
+			:: "b"(&pcb->pcb_fpu.fpr[n]));
+		SFP(0);		SFP(1);		SFP(2);		SFP(3);
+		SFP(4);		SFP(5);		SFP(6);		SFP(7);
+		SFP(8);		SFP(9);		SFP(10);	SFP(11);
+		SFP(12);	SFP(13);	SFP(14);	SFP(15);
+		SFP(16);	SFP(17);	SFP(18);	SFP(19);
+		SFP(20);	SFP(21);	SFP(22);	SFP(23);
+		SFP(24);	SFP(25);	SFP(26);	SFP(27);
+		SFP(28);	SFP(29);	SFP(30);	SFP(31);
+	#undef SFP
+	} else {
+	#define SFP(n)   __asm ("stfd " #n ", 0(%0)" \
+			:: "b"(&pcb->pcb_fpu.fpr[n]));
+		SFP(0);		SFP(1);		SFP(2);		SFP(3);
+		SFP(4);		SFP(5);		SFP(6);		SFP(7);
+		SFP(8);		SFP(9);		SFP(10);	SFP(11);
+		SFP(12);	SFP(13);	SFP(14);	SFP(15);
+		SFP(16);	SFP(17);	SFP(18);	SFP(19);
+		SFP(20);	SFP(21);	SFP(22);	SFP(23);
+		SFP(24);	SFP(25);	SFP(26);	SFP(27);
+		SFP(28);	SFP(29);	SFP(30);	SFP(31);
+	#undef SFP
+	}
+	__asm __volatile ("mffs 0; stfd 0,0(%0)" :: "b"(&pcb->pcb_fpu.fpscr));
+
+	/*
+	 * Disable floating-point again
+	 */
+	isync();
+	mtmsr(msr);
+}
+
 void
 enable_fpu(struct thread *td)
 {
@@ -129,57 +183,13 @@ enable_fpu(struct thread *td)
 void
 save_fpu(struct thread *td)
 {
-	int	msr;
 	struct	pcb *pcb;
 
 	pcb = td->td_pcb;
 
-	/*
-	 * Temporarily re-enable floating-point during the save
-	 */
-	msr = mfmsr();
-	if (pcb->pcb_flags & PCB_VSX)
-		mtmsr(msr | PSL_FP | PSL_VSX);
-	else
-		mtmsr(msr | PSL_FP);
+	save_fpu_int(td);
 
 	/*
-	 * Save the floating-point registers and FPSCR to the PCB
-	 */
-	if (pcb->pcb_flags & PCB_VSX) {
-	#define SFP(n)   __asm ("stxvw4x " #n ", 0,%0" \
-			:: "b"(&pcb->pcb_fpu.fpr[n]));
-		SFP(0);		SFP(1);		SFP(2);		SFP(3);
-		SFP(4);		SFP(5);		SFP(6);		SFP(7);
-		SFP(8);		SFP(9);		SFP(10);	SFP(11);
-		SFP(12);	SFP(13);	SFP(14);	SFP(15);
-		SFP(16);	SFP(17);	SFP(18);	SFP(19);
-		SFP(20);	SFP(21);	SFP(22);	SFP(23);
-		SFP(24);	SFP(25);	SFP(26);	SFP(27);
-		SFP(28);	SFP(29);	SFP(30);	SFP(31);
-	#undef SFP
-	} else {
-	#define SFP(n)   __asm ("stfd " #n ", 0(%0)" \
-			:: "b"(&pcb->pcb_fpu.fpr[n]));
-		SFP(0);		SFP(1);		SFP(2);		SFP(3);
-		SFP(4);		SFP(5);		SFP(6);		SFP(7);
-		SFP(8);		SFP(9);		SFP(10);	SFP(11);
-		SFP(12);	SFP(13);	SFP(14);	SFP(15);
-		SFP(16);	SFP(17);	SFP(18);	SFP(19);
-		SFP(20);	SFP(21);	SFP(22);	SFP(23);
-		SFP(24);	SFP(25);	SFP(26);	SFP(27);
-		SFP(28);	SFP(29);	SFP(30);	SFP(31);
-	#undef SFP
-	}
-	__asm __volatile ("mffs 0; stfd 0,0(%0)" :: "b"(&pcb->pcb_fpu.fpscr));
-
-	/*
-	 * Disable floating-point again
-	 */
-	isync();
-	mtmsr(msr);
-
-	/*
 	 * Clear the current fp thread and pcb's CPU id
 	 * XXX should this be left clear to allow lazy save/restore ?
 	 */
@@ -187,3 +197,19 @@ save_fpu(struct thread *td)
 	PCPU_SET(fputhread, NULL);
 }
 
+/*
+ * Save fpu state without dropping ownership.  This will only save state if
+ * the current fpu thread is `td'.
+ */
+void
+save_fpu_nodrop(struct thread *td)
+{
+	struct thread *ftd;
+
+	ftd = PCPU_GET(fputhread);
+	if (td != ftd) {
+		return;
+	}
+
+	save_fpu_int(td);
+}

Modified: head/sys/powerpc/powerpc/ptrace_machdep.c
==============================================================================
--- head/sys/powerpc/powerpc/ptrace_machdep.c	Sat Jun  2 18:03:35 2018	(r334534)
+++ head/sys/powerpc/powerpc/ptrace_machdep.c	Sat Jun  2 19:17:11 2018	(r334535)
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/ptrace.h>
 #include <sys/sysent.h>
 #include <machine/altivec.h>
+#include <machine/fpu.h>
 #include <machine/cpu.h>
 #include <machine/md_var.h>
 #include <machine/pcb.h>
@@ -45,10 +46,14 @@ cpu_ptrace(struct thread *td, int req, void *addr, int
 	int error;
 	struct pcb *pcb;
 	struct vec vec;
+	uint64_t vsr[32];
+	uint64_t *vsr_dw1;
+	int vsr_idx;
 
 	pcb = td->td_pcb;
 
 	bzero(&vec, sizeof(vec));
+	bzero(vsr, sizeof(vsr));
 
 	error = EINVAL;
 	switch (req) {
@@ -69,6 +74,43 @@ cpu_ptrace(struct thread *td, int req, void *addr, int
 		if (error == 0) {
 			pcb->pcb_flags |= PCB_VEC;
 			memcpy(&pcb->pcb_vec, &vec, sizeof(vec));
+		}
+		break;
+	case PT_GETVSRREGS:
+		if (!(cpu_features & PPC_FEATURE_HAS_VSX))
+			break;
+
+		if (pcb->pcb_flags & PCB_VSX) {
+			save_fpu_nodrop(td);
+
+			/*
+			 * Doubleword 0 of VSR0-VSR31 overlap with FPR0-FPR31 and
+			 * VSR32-VSR63 overlap with VR0-VR31, so we only copy
+			 * the non-overlapping data, which is doubleword 1 of VSR0-VSR31.
+			 */
+			for (vsr_idx = 0; vsr_idx < nitems(vsr); vsr_idx++) {
+				vsr_dw1 = (uint64_t *)&pcb->pcb_fpu.fpr[vsr_idx].vsr[2];
+				vsr[vsr_idx] = *vsr_dw1;
+			}
+		}
+		error = copyout(&vsr, addr, sizeof(vsr));
+		break;
+	case PT_SETVSRREGS:
+		if (!(cpu_features & PPC_FEATURE_HAS_VSX))
+			break;
+		error = copyin(addr, &vsr, sizeof(vsr));
+		if (error == 0) {
+			pcb->pcb_flags |= PCB_VSX;
+
+			/*
+			 * Doubleword 0 of VSR0-VSR31 overlap with FPR0-FPR31 and
+			 * VSR32-VSR63 overlap with VR0-VR31, so we only copy
+			 * the non-overlapping data, which is doubleword 1 of VSR0-VSR31.
+			 */
+			for (vsr_idx = 0; vsr_idx < nitems(vsr); vsr_idx++) {
+				vsr_dw1 = (uint64_t *)&pcb->pcb_fpu.fpr[vsr_idx].vsr[2];
+				*vsr_dw1 = vsr[vsr_idx];
+			}
 		}
 		break;
 



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