Date: Fri, 29 Oct 2010 09:44:53 -0400 From: John Baldwin <jhb@freebsd.org> To: Attilio Rao <attilio@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r214457 - in head/sys: amd64/amd64 conf i386/i386 x86/x86 Message-ID: <201010290944.53628.jhb@freebsd.org> In-Reply-To: <AANLkTim0if81oH=S6LkCDDgpePD44NEPt%2BqSWHaOSK=C@mail.gmail.com> References: <201010281631.o9SGVdtZ014923@svn.freebsd.org> <201010281638.14043.jhb@freebsd.org> <AANLkTim0if81oH=S6LkCDDgpePD44NEPt%2BqSWHaOSK=C@mail.gmail.com>
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On Thursday, October 28, 2010 8:25:38 pm Attilio Rao wrote: > 2010/10/28 John Baldwin <jhb@freebsd.org>: > > On Thursday, October 28, 2010 4:28:12 pm Attilio Rao wrote: > >> 2010/10/28 John Baldwin <jhb@freebsd.org>: > >> > On Thursday, October 28, 2010 1:21:34 pm Attilio Rao wrote: > >> >> 2010/10/28 John Baldwin <jhb@freebsd.org>: > >> >> > On Thursday, October 28, 2010 12:31:39 pm Attilio Rao wrote: > >> >> >> Author: attilio > >> >> >> Date: Thu Oct 28 16:31:39 2010 > >> >> >> New Revision: 214457 > >> >> >> URL: http://svn.freebsd.org/changeset/base/214457 > >> >> >> > >> >> >> Log: > >> >> >> Merge nexus.c from amd64 and i386 to x86 subtree. > >> >> >> > >> >> >> Sponsored by: Sandvine Incorporated > >> >> >> Tested by: gianni > >> >> >> > >> >> > > >> >> > It would be better to merge these two routines. The loader now passes > > the > >> >> > smap to i386 kernels as well, so ram_attach() should probably be > > changed to > >> >> > try the amd64 approach first and if that fails fall back to using the > >> >> > phys_avail[] array instead. > >> >> > >> >> What do you think about this patch?: > >> >> Index: nexus.c > >> >> =================================================================== > >> >> --- nexus.c (revision 214457) > >> >> +++ nexus.c (working copy) > >> >> @@ -52,9 +52,7 @@ > >> >> #include <sys/systm.h> > >> >> #include <sys/bus.h> > >> >> #include <sys/kernel.h> > >> >> -#ifdef __amd64__ > >> >> #include <sys/linker.h> > >> >> -#endif > >> >> #include <sys/malloc.h> > >> >> #include <sys/module.h> > >> >> #include <machine/bus.h> > >> >> @@ -67,12 +65,10 @@ > >> >> #include <vm/pmap.h> > >> >> #include <machine/pmap.h> > >> >> > >> >> -#ifdef __amd64__ > >> >> #include <machine/metadata.h> > >> >> -#include <machine/pc/bios.h> > >> >> -#endif > >> >> #include <machine/nexusvar.h> > >> >> #include <machine/resource.h> > >> >> +#include <machine/pc/bios.h> > >> >> > >> >> #ifdef DEV_APIC > >> >> #include "pcib_if.h" > >> >> @@ -89,11 +85,13 @@ > >> >> #include <sys/rtprio.h> > >> >> > >> >> #ifdef __amd64__ > >> >> -#define RMAN_BUS_SPACE_IO AMD64_BUS_SPACE_IO > >> >> -#define RMAN_BUS_SPACE_MEM AMD64_BUS_SPACE_MEM > >> >> +#define X86_BUS_SPACE_IO AMD64_BUS_SPACE_IO > >> >> +#define X86_BUS_SPACE_MEM AMD64_BUS_SPACE_MEM > >> >> +#define ELF_KERN_STR "elf64 kernel" > >> >> #else > >> >> -#define RMAN_BUS_SPACE_IO I386_BUS_SPACE_IO > >> >> -#define RMAN_BUS_SPACE_MEM I386_BUS_SPACE_MEM > >> >> +#define X86_BUS_SPACE_IO I386_BUS_SPACE_IO > >> >> +#define X86_BUS_SPACE_MEM I386_BUS_SPACE_MEM > >> >> +#define ELF_KERN_STR "elf32 kernel" > >> >> #endif > >> >> @@ -701,16 +699,11 @@ > >> >> panic("ram_attach: resource %d failed to attach", > > rid); > >> >> rid++; > >> >> } > >> >> - return (0); > >> >> -} > >> >> -#else > >> >> -static int > >> >> -ram_attach(device_t dev) > >> >> -{ > >> >> - struct resource *res; > >> >> - vm_paddr_t *p; > >> >> - int error, i, rid; > >> >> > >> >> + /* If at least one smap attached, return. */ > >> >> + if (rid != 0) > >> >> + return (0); > >> >> + > >> > > >> > Perhaps this instead: > >> > > >> > /* If we found an SMAP, return. */ > >> > if (smapbase != NULL) > >> > return (0); > >> > >> No, I don't think this check is right, smapbase will always be != NULL > >> (otherwise the code panics). > > > > Oh, that needs to be fixed then. It can be NULL on i386 with an old loader > > (or on a really old machine without an SMAP). The amd64 nexus code could > > assume it would never be NULL, but i386 cannot. > > > > It should probably more closely match what i386 does during the memory probe > > which is: > > > > kmdp = search("elf kernel"); > > if (kmdp == NULL) > > kmdp = search("elfXX kernel"); > > if (kmdp != NULL) > > smapbase = preload_search(...); > > else > > smapbase = NULL; > > if (smapbase != NULL) { > > for (smap = ...) { > > } > > > > return (0); > > } > > > > /* fall through to old i386 code using phys_avail[] */ > > This further patch should address your concerns about nexus.c: > Index: nexus.c > =================================================================== > --- nexus.c (revision 214457) > +++ nexus.c (working copy) > @@ -52,9 +52,7 @@ > #include <sys/systm.h> > #include <sys/bus.h> > #include <sys/kernel.h> > -#ifdef __amd64__ > #include <sys/linker.h> > -#endif > #include <sys/malloc.h> > #include <sys/module.h> > #include <machine/bus.h> > @@ -67,12 +65,10 @@ > #include <vm/pmap.h> > #include <machine/pmap.h> > > -#ifdef __amd64__ > #include <machine/metadata.h> > -#include <machine/pc/bios.h> > -#endif > #include <machine/nexusvar.h> > #include <machine/resource.h> > +#include <machine/pc/bios.h> > > #ifdef DEV_APIC > #include "pcib_if.h" > @@ -89,13 +85,15 @@ > #include <sys/rtprio.h> > > #ifdef __amd64__ > -#define RMAN_BUS_SPACE_IO AMD64_BUS_SPACE_IO > -#define RMAN_BUS_SPACE_MEM AMD64_BUS_SPACE_MEM > +#define BUS_SPACE_IO AMD64_BUS_SPACE_IO > +#define BUS_SPACE_MEM AMD64_BUS_SPACE_MEM > #else > -#define RMAN_BUS_SPACE_IO I386_BUS_SPACE_IO > -#define RMAN_BUS_SPACE_MEM I386_BUS_SPACE_MEM > +#define BUS_SPACE_IO I386_BUS_SPACE_IO > +#define BUS_SPACE_MEM I386_BUS_SPACE_MEM > #endif > > +#define ELF_KERN_STR ("elf"__XSTRING(__ELF_WORD_SIZE)" kernel") > + > static MALLOC_DEFINE(M_NEXUSDEV, "nexusdev", "Nexus device"); > > #define DEVTONX(dev) ((struct nexus_device *)device_get_ivars(dev)) > @@ -435,7 +433,7 @@ > #else > rman_set_bushandle(r, rman_get_start(r)); > #endif > - rman_set_bustag(r, RMAN_BUS_SPACE_IO); > + rman_set_bustag(r, BUS_SPACE_IO); > break; > case SYS_RES_MEMORY: > #ifdef PC98 > @@ -446,7 +444,7 @@ > #endif > vaddr = pmap_mapdev(rman_get_start(r), rman_get_size(r)); > rman_set_virtual(r, vaddr); > - rman_set_bustag(r, RMAN_BUS_SPACE_MEM); > + rman_set_bustag(r, BUS_SPACE_MEM); > #ifdef PC98 > /* PC-98: the type of bus_space_handle_t is the structure. */ > bh->bsh_base = (bus_addr_t) vaddr; > @@ -668,48 +666,45 @@ > return (0); > } > > -#ifdef __amd64__ > static int > ram_attach(device_t dev) > { > struct bios_smap *smapbase, *smap, *smapend; > struct resource *res; > + vm_paddr_t *p; > caddr_t kmdp; > uint32_t smapsize; > - int error, rid; > + int error, i, rid; > > /* Retrieve the system memory map from the loader. */ > kmdp = preload_search_by_type("elf kernel"); > if (kmdp == NULL) > - kmdp = preload_search_by_type("elf64 kernel"); > - smapbase = (struct bios_smap *)preload_search_info(kmdp, > - MODINFO_METADATA | MODINFOMD_SMAP); > - smapsize = *((u_int32_t *)smapbase - 1); > - smapend = (struct bios_smap *)((uintptr_t)smapbase + smapsize); > + kmdp = preload_search_by_type(ELF_KERN_STR); > + if (kmdp != NULL) { > + smapbase = (struct bios_smap *)preload_search_info(kmdp, > + MODINFO_METADATA | MODINFOMD_SMAP); > + smapsize = *((u_int32_t *)smapbase - 1); > + smapend = (struct bios_smap *)((uintptr_t)smapbase + smapsize); I think this doesn't check for the case that smapbase is NULL. I would expect kmdp to always be non-NULL in practice (it just means we have a kernel). However, the preload_search_info() can fail when booting on an old machine without an SMAP or an old loader that doesn't pass the SMAP to i386. Hence the i386 approach of: if (kmdp! = NULL) smapbase = preload_search_info(); else smapbase = NULL; if (smapbase != NULL) { ... } You could do this as: if (kmdp != NULL) { smapbase = preload_search_info(); if (smapbase != NULL) { smapsize = ...; ... } } It just causes the code to indent further. -- John Baldwin
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