Date: Thu, 1 May 2008 17:38:21 GMT From: Peter Wemm <peter@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 140994 for review Message-ID: <200805011738.m41HcLq2038321@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=140994 Change 140994 by peter@peter_daintree on 2008/05/01 17:37:28 Update. Use the correct fields. Look for pcpu_size in the kernel to adapt to any layout changes. (Let the consumer deal with variance rather than guaranteeing that libkvm breaks first) Affected files ... .. //depot/projects/hammer/lib/libkvm/kvm_amd64.c#24 edit Differences ... ==== //depot/projects/hammer/lib/libkvm/kvm_amd64.c#24 (text+ko) ==== @@ -76,7 +76,8 @@ size_t mmapsize; pml4_entry_t *PML4; int mp_maxcpus; - struct pcpu *pcpu; + int pcpu_recsize; + char *pcpu; }; /* @@ -375,9 +376,23 @@ /* UP system; symbol doesn't exist */ vmst->mp_maxcpus = 1; } - vm->pcpu = _kvm_malloc(kd, sizeof(struct pcpu) * vm->mp_maxcpus); + /* + * The __pcpu array may have different inter-record padding or may + * grow additional fields. We have to adapt the best we can. + */ + nlist[0].n_name = "pcpu_size"; + nlist[1].n_name = 0; + if (kvm_nlist(kd, nlist) == 0) { + if (kvm_read(kd, nlist[0].n_value, &vm->pcpu_recsize, + sizeof(vm->pcpu_recsize)) != sizeof(vm->pcpu_recsize)) { + _kvm_err(kd, kd->program, "cannot read pcpu_size"); + } else { + /* Older kernel's dont have it. Hope for the best. */ + vmst->pcpu_recsize = sizeof(struct pcpu); + } + vm->pcpu = _kvm_malloc(kd, vm->pcpu_recsize * vm->mp_maxcpus); - nlist[0].n_name = "pcpu"; + nlist[0].n_name = "__pcpu"; nlist[1].n_name = 0; if (kvm_nlist(kd, nlist) != 0) { @@ -385,8 +400,8 @@ return (-1); } if (kvm_read(kd, nlist[0].n_value, vm->pcpu, - sizeof(struct pcpu) * vm->mp_maxcpus) != - sizeof(struct pcpu) * vm->mp_maxcpus) { + vm->pcpu_recsize * vm->mp_maxcpus) != + vm->pcpu_recsize * vm->mp_maxcpus) { _kvm_err(kd, kd->program, "cannot read pcpu chunk"); return (-1); } @@ -407,8 +422,8 @@ return (NULL); } - if (cpu < 0 || cpu > vm->vm_maxcpus) + if (cpu < 0 || cpu > vm->vm_maxcpus) _kvm_err(kd, kd->program, " return (NULL); /* EDOOFUS actually */ - return (&vm->pcpu[cpu]); + return ((struct pcpu *)&vm->pcpu[cpu * vm->pcpu_recsize]); }
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