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Added ptrace support for reading/writing powerpc VSX registers

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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
This commit is contained in:
Justin Hibbits 2018-06-02 19:17:11 +00:00
parent ba96f37758
commit 2e65567500
5 changed files with 135 additions and 46 deletions
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20
lib/libc/sys/ptrace.2
View File

@ -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
@ -939,6 +939,24 @@ machine state from the buffer pointed to by
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
.Fa data
argument is ignored.
.El
.Pp
Additionally, other machine-specific requests can exist.

1
sys/powerpc/include/fpu.h
View File

@ -74,6 +74,7 @@
void enable_fpu(struct thread *);
void save_fpu(struct thread *);
void save_fpu_nodrop(struct thread *);
#endif /* _KERNEL */

2
sys/powerpc/include/ptrace.h
View File

@ -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

116
sys/powerpc/powerpc/fpu.c
View File

@ -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)
{
@ -129,55 +183,11 @@ 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 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);
save_fpu_int(td);
/*
* Clear the current fp thread and pcb's CPU id
@ -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);
}

42
sys/powerpc/powerpc/ptrace_machdep.c
View File

@ -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 data)
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) {
@ -71,6 +76,43 @@ cpu_ptrace(struct thread *td, int req, void *addr, int data)
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;
default:
break;