svn commit: r276187 - head/sys/arm/arm

[Ian Lepore]

On Wed, 2014-12-24 at 22:26 +0000, Andrew Turner wrote:
> On Wed, 24 Dec 2014 17:12:52 +0000 (UTC)
> Ian Lepore <ian at FreeBSD.org> wrote:
> 
> > Author: ian
> > Date: Wed Dec 24 17:12:51 2014
> > New Revision: 276187
> > URL: https://svnweb.freebsd.org/changeset/base/276187
> > 
> > Log:
> >   Eliminate unnecessary references to pte.h internals by using the
> > standard pmap_kenter_temporary() to map pages while dumping.
> >   
> >   Submitted by:	Svatopluk Kraus <onwahe at gmail.com>,
> >   		Michal Meloun <meloun at miracle.cz>
> > 
> > Modified:
> >   head/sys/arm/arm/dump_machdep.c
> > 
> > Modified: head/sys/arm/arm/dump_machdep.c
> > ==============================================================================
> > --- head/sys/arm/arm/dump_machdep.c	Wed Dec 24 16:11:15
> > 2014	(r276186) +++ head/sys/arm/arm/dump_machdep.c	Wed
> > Dec 24 17:12:51 2014	(r276187) @@ -160,11 +160,13 @@ static int
> >  cb_dumpdata(struct md_pa *mdp, int seqnr, void *arg)
> >  {
> >  	struct dumperinfo *di = (struct dumperinfo*)arg;
> > -	vm_paddr_t pa;
> > +	vm_paddr_t a, pa;
> > +	void *va;
> >  	uint32_t pgs;
> >  	size_t counter, sz, chunk;
> > -	int c, error;
> > +	int i, c, error;
> >  
> > +	va = 0;
> >  	error = 0;	/* catch case in which chunk size is 0 */
> >  	counter = 0;
> >  	pgs = mdp->md_size / PAGE_SIZE;
> > @@ -194,16 +196,14 @@ cb_dumpdata(struct md_pa *mdp, int seqnr
> >  			printf(" %d", pgs * PAGE_SIZE);
> >  			counter &= (1<<24) - 1;
> >  		}
> > -		if (pa == (pa & L1_ADDR_BITS)) {
> > -			pmap_kenter_section(0, pa & L1_ADDR_BITS, 0);
> > -			cpu_tlb_flushID_SE(0);
> > -			cpu_cpwait();
> > +		for (i = 0; i < chunk; i++) {
> > +			a = pa + i * PAGE_SIZE;
> > +			va = pmap_kenter_temporary(trunc_page(a), i);
> 
> Is this correct? It may map multiple chunks here.
> >  		}
> >  #ifdef SW_WATCHDOG
> >  		wdog_kern_pat(WD_LASTVAL);
> >  #endif
> > -		error = dump_write(di,
> > -		    (void *)(pa - (pa & L1_ADDR_BITS)),0, dumplo,
> > sz);
> > +		error = dump_write(di, va, 0, dumplo, sz);
> 
> Then uses the last virtual address to dump the data here. Wouldn't this
> miss the chunks mapped other than the last one?

Yeah, but a quirk of pmap_kenter_temporary() is that its return value is
constant, so this wrong-looking code is actually right.

-- Ian