Date: Wed, 24 Dec 2014 17:05:59 -0800 From: Rui Paulo <rpaulo@me.com> To: Ian Lepore <ian@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Andrew Turner <andrew@fubar.geek.nz> Subject: Re: svn commit: r276187 - head/sys/arm/arm Message-ID: <8E8B7FE3-0C97-4A84-BC1D-1C5A0E732D0C@me.com> In-Reply-To: <1419460812.1018.157.camel@freebsd.org> References: <201412241712.sBOHCqvW039381@svn.freebsd.org> <20141224222637.03a19e57@bender> <1419460812.1018.157.camel@freebsd.org>
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On Dec 24, 2014, at 14:40, Ian Lepore <ian@FreeBSD.org> wrote: > > 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@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@gmail.com>, >>> Michal Meloun <meloun@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. I'm a bit surprised about this. This most likely warrants a comment. -- Rui Paulohelp
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