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 na...@mips.inka.de