ref: a5db044fd3ccb8f021d4deb07b3dc732ed41d699
dir: /sys/src/9/imx8/sysreg.c/
/*
* ARMv8 system registers
* mainly to cope with arm hard-wiring register numbers into instructions.
*
* these routines must be callable from KZERO.
*
* on a multiprocessor, process switching to another cpu is assumed
* to be inhibited by the caller as these registers are local to the cpu.
*/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
static void*
mkinstr(ulong wd)
{
static ulong ib[256], *ep[MAXMACH+1];
static Lock lk;
ulong *ip, *ie;
ie = ep[m->machno];
for(ip = ib; ip < ie; ip += 2)
if(*ip == wd)
return ip;
ilock(&lk);
ie = ep[MAXMACH];
for(; ip < ie; ip += 2)
if(*ip == wd)
goto Found;
if(ip >= &ib[nelem(ib)])
panic("mkinstr: out of instrucuction buffer");
ip[0] = wd;
ip[1] = 0xd65f03c0; // RETURN
ep[MAXMACH] = ie = ip + 2;
cachedwbinvse(ip, 2*sizeof(*ip));
Found:
iunlock(&lk);
cacheiinv();
ep[m->machno] = ie;
return ip;
}
uvlong
sysrd(ulong spr)
{
uvlong (*fp)(void) = mkinstr(0xd5380000UL | spr);
return fp();
}
void
syswr(ulong spr, uvlong val)
{
void (*fp)(uvlong) = mkinstr(0xd5180000UL | spr);
fp(val);
}