svn commit: r347496 - in stable/12/sys/powerpc: fpu include powerpc
Justin Hibbits
jhibbits at FreeBSD.org
Sat May 11 18:31:07 UTC 2019
Author: jhibbits
Date: Sat May 11 18:31:05 2019
New Revision: 347496
URL: https://svnweb.freebsd.org/changeset/base/347496
Log:
MFC r345829, r345831
r345829:
powerpc: Apply r178139 from sparc64 to powerpc's fpu_sqrt
This fix was committed less than 2 months after the code was forked into the
powerpc kernel. Though powerpc doesn't use quad-precision floating point,
or need it for emulation, the changes do look like correctness fixes
overall.
This was found while trying to get fsqrt emulation working on e5500, which
does have a real FPU, but lacks the fsqrt instruction. This is not the
complete fix, the rest is to be committed separately.
r345831:
powerpc: Allow emulating optional FPU instructions on CPUs with an FPU
The e5500 has an FPU, but lacks the optional fsqrt instruction. This
instruction gets emulated in the kernel, but the emulation uses stale data,
from the last switch out, and does not return the result of the operation
immediately. Fix both of these conditions by saving and restoring the FPRs
around the emulation point.
Modified:
stable/12/sys/powerpc/fpu/fpu_sqrt.c
stable/12/sys/powerpc/include/trap.h
stable/12/sys/powerpc/powerpc/exec_machdep.c
stable/12/sys/powerpc/powerpc/trap.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/sys/powerpc/fpu/fpu_sqrt.c
==============================================================================
--- stable/12/sys/powerpc/fpu/fpu_sqrt.c Sat May 11 18:25:15 2019 (r347495)
+++ stable/12/sys/powerpc/fpu/fpu_sqrt.c Sat May 11 18:31:05 2019 (r347496)
@@ -353,7 +353,7 @@ fpu_sqrt(struct fpemu *fe)
FPU_SUBC(d0, x0, t0);
if ((int)d0 >= 0) {
x0 = d0, x1 = d1, x2 = d2;
- q |= bit;
+ q = bit;
y1 |= 1; /* now t1, y1 are set in concrete */
}
ODD_DOUBLE;
@@ -385,12 +385,12 @@ fpu_sqrt(struct fpemu *fe)
FPU_SUBCS(d2, x2, t2);
FPU_SUBCS(d1, x1, t1);
FPU_SUBC(d0, x0, t0);
- ODD_DOUBLE;
if ((int)d0 >= 0) {
- x0 = d0, x1 = d1, x2 = d2;
- q |= bit;
+ x0 = d0, x1 = d1, x2 = d2; x3 = d3;
+ q = bit;
y2 |= 1;
}
+ ODD_DOUBLE;
while ((bit >>= 1) != 0) {
EVEN_DOUBLE;
t3 = y3 | bit;
@@ -399,7 +399,7 @@ fpu_sqrt(struct fpemu *fe)
FPU_SUBCS(d1, x1, t1);
FPU_SUBC(d0, x0, t0);
if ((int)d0 >= 0) {
- x0 = d0, x1 = d1, x2 = d2;
+ x0 = d0, x1 = d1, x2 = d2; x3 = d3;
q |= bit;
y3 |= bit << 1;
}
Modified: stable/12/sys/powerpc/include/trap.h
==============================================================================
--- stable/12/sys/powerpc/include/trap.h Sat May 11 18:25:15 2019 (r347495)
+++ stable/12/sys/powerpc/include/trap.h Sat May 11 18:31:05 2019 (r347496)
@@ -149,10 +149,10 @@
#ifndef LOCORE
struct trapframe;
-struct pcb;
+struct thread;
extern int (*hmi_handler)(struct trapframe *);
void trap(struct trapframe *);
-int ppc_instr_emulate(struct trapframe *, struct pcb *);
+int ppc_instr_emulate(struct trapframe *, struct thread *);
#endif
#endif /* _POWERPC_TRAP_H_ */
Modified: stable/12/sys/powerpc/powerpc/exec_machdep.c
==============================================================================
--- stable/12/sys/powerpc/powerpc/exec_machdep.c Sat May 11 18:25:15 2019 (r347495)
+++ stable/12/sys/powerpc/powerpc/exec_machdep.c Sat May 11 18:31:05 2019 (r347496)
@@ -1066,8 +1066,9 @@ emulate_mtspr(int spr, int reg, struct trapframe *fram
#define XFX 0xFC0007FF
int
-ppc_instr_emulate(struct trapframe *frame, struct pcb *pcb)
+ppc_instr_emulate(struct trapframe *frame, struct thread *td)
{
+ struct pcb *pcb;
uint32_t instr;
int reg, sig;
int rs, spr;
@@ -1094,12 +1095,16 @@ ppc_instr_emulate(struct trapframe *frame, struct pcb
return (0);
}
+ pcb = td->td_pcb;
#ifdef FPU_EMU
if (!(pcb->pcb_flags & PCB_FPREGS)) {
bzero(&pcb->pcb_fpu, sizeof(pcb->pcb_fpu));
pcb->pcb_flags |= PCB_FPREGS;
- }
+ } else if (pcb->pcb_flags & PCB_FPU)
+ save_fpu(td);
sig = fpu_emulate(frame, &pcb->pcb_fpu);
+ if ((sig == 0 || sig == SIGFPE) && pcb->pcb_flags & PCB_FPU)
+ enable_fpu(td);
#endif
return (sig);
Modified: stable/12/sys/powerpc/powerpc/trap.c
==============================================================================
--- stable/12/sys/powerpc/powerpc/trap.c Sat May 11 18:25:15 2019 (r347495)
+++ stable/12/sys/powerpc/powerpc/trap.c Sat May 11 18:31:05 2019 (r347496)
@@ -361,7 +361,7 @@ trap(struct trapframe *frame)
sig = SIGTRAP;
ucode = TRAP_BRKPT;
} else {
- sig = ppc_instr_emulate(frame, td->td_pcb);
+ sig = ppc_instr_emulate(frame, td);
if (sig == SIGILL) {
if (frame->srr1 & EXC_PGM_PRIV)
ucode = ILL_PRVOPC;
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