Here's a proposal for implementing cpu_rnd_messybits() as a read of
the cycle counter on alpha, powerpc, and sparc64. Since I don't have
those archs, the diff is not even compile-tested.
* alpha: RPCC is a 32-bit counter (in a 64-bit register)
* powerpc: TB is a 64-bit counter split into two registers
* sparc64: TICK is a(n implementation-defined, up to) 63-bit counter
Index: sys/arch/alpha/alpha/machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/alpha/alpha/machdep.c,v
retrieving revision 1.191
diff -u -p -r1.191 machdep.c
--- sys/arch/alpha/alpha/machdep.c 31 May 2020 06:23:56 -0000 1.191
+++ sys/arch/alpha/alpha/machdep.c 4 Jun 2020 17:57:45 -0000
@@ -1854,12 +1854,3 @@ alpha_XXX_dmamap(v)
/* XXX */
return (vtophys(v) | alpha_XXX_dmamap_or); /* XXX */
} /* XXX */
/* XXX XXX END XXX XXX */
-
-unsigned int
-cpu_rnd_messybits(void)
-{
- struct timespec ts;
-
- nanotime(&ts);
- return (ts.tv_nsec ^ (ts.tv_sec << 20));
-}
Index: sys/arch/alpha/include/cpu.h
===================================================================
RCS file: /cvs/src/sys/arch/alpha/include/cpu.h,v
retrieving revision 1.62
diff -u -p -r1.62 cpu.h
--- sys/arch/alpha/include/cpu.h 31 May 2020 06:23:56 -0000 1.62
+++ sys/arch/alpha/include/cpu.h 4 Jun 2020 17:59:25 -0000
@@ -288,7 +288,11 @@ do {
\
*/
#define cpu_number() alpha_pal_whami()
-unsigned int cpu_rnd_messybits(void);
+static inline unsigned int
+cpu_rnd_messybits(void)
+{
+ return alpha_rpcc();
+}
/*
* Arguments to hardclock and gatherstats encapsulate the previous
Index: sys/arch/macppc/macppc/machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/macppc/macppc/machdep.c,v
retrieving revision 1.191
diff -u -p -r1.191 machdep.c
--- sys/arch/macppc/macppc/machdep.c 31 May 2020 06:23:57 -0000 1.191
+++ sys/arch/macppc/macppc/machdep.c 4 Jun 2020 18:07:31 -0000
@@ -913,12 +913,3 @@ cpu_switchto(struct proc *oldproc, struc
cpu_switchto_asm(oldproc, newproc);
}
-
-unsigned int
-cpu_rnd_messybits(void)
-{
- struct timespec ts;
-
- nanotime(&ts);
- return (ts.tv_nsec ^ (ts.tv_sec << 20));
-}
Index: sys/arch/powerpc/include/cpu.h
===================================================================
RCS file: /cvs/src/sys/arch/powerpc/include/cpu.h,v
retrieving revision 1.67
diff -u -p -r1.67 cpu.h
--- sys/arch/powerpc/include/cpu.h 31 May 2020 06:23:58 -0000 1.67
+++ sys/arch/powerpc/include/cpu.h 4 Jun 2020 18:13:07 -0000
@@ -161,7 +161,15 @@ extern int ppc_nobat;
void cpu_bootstrap(void);
-unsigned int cpu_rnd_messybits(void);
+static inline unsigned int
+cpu_rnd_messybits(void)
+{
+ unsigned int hi, lo;
+
+ __asm volatile("mftbu %0; mftb %1" : "=r" (hi), "=r" (lo));
+
+ return (hi ^ lo);
+}
/*
* This is used during profiling to integrate system time.
Index: sys/arch/sparc64/include/cpu.h
===================================================================
RCS file: /cvs/src/sys/arch/sparc64/include/cpu.h,v
retrieving revision 1.94
diff -u -p -r1.94 cpu.h
--- sys/arch/sparc64/include/cpu.h 31 May 2020 06:23:58 -0000 1.94
+++ sys/arch/sparc64/include/cpu.h 4 Jun 2020 18:05:18 -0000
@@ -211,7 +211,15 @@ void cpu_unidle(struct cpu_info *);
#define curpcb __curcpu->ci_cpcb
#define fpproc __curcpu->ci_fpproc
-unsigned int cpu_rnd_messybits(void);
+static inline unsigned int
+cpu_rnd_messybits(void)
+{
+ u_int64_t tick;
+
+ __asm volatile("rd %%tick, %0" : "=r" (tick) :);
+
+ return ((tick >> 32) ^ tick);
+}
/*
* On processors with multiple threads we force a thread switch.
Index: sys/arch/sparc64/sparc64/machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/sparc64/sparc64/machdep.c,v
retrieving revision 1.196
diff -u -p -r1.196 machdep.c
--- sys/arch/sparc64/sparc64/machdep.c 31 May 2020 06:23:58 -0000 1.196
+++ sys/arch/sparc64/sparc64/machdep.c 4 Jun 2020 18:01:16 -0000
@@ -2114,12 +2114,3 @@ blink_led_timeout(void *vsc)
t = (((averunnable.ldavg[0] + FSCALE) * hz) >> (FSHIFT + 1));
timeout_add(&sc->bls_to, t);
}
-
-unsigned int
-cpu_rnd_messybits(void)
-{
- struct timespec ts;
-
- nanotime(&ts);
- return (ts.tv_nsec ^ (ts.tv_sec << 20));
-}
--
Christian "naddy" Weisgerber [email protected]
