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Differential D31990 Diff 98542 sys/amd64/amd64/minidump_machdep.c

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sys/amd64/amd64/minidump_machdep.c

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#include <vm/vm_page.h> #include <vm/vm_page.h>
#include <vm/vm_phys.h> #include <vm/vm_phys.h>
#include <vm/vm_dumpset.h> #include <vm/vm_dumpset.h>
#include <vm/pmap.h> #include <vm/pmap.h>
#include <machine/atomic.h> #include <machine/atomic.h>
#include <machine/elf.h> #include <machine/elf.h>
#include <machine/md_var.h> #include <machine/md_var.h>
#include <machine/minidump.h> #include <machine/minidump.h>
#include <machine/vmparam.h>
CTASSERT(sizeof(struct kerneldumpheader) == 512); CTASSERT(sizeof(struct kerneldumpheader) == 512);
static struct kerneldumpheader kdh; static struct kerneldumpheader kdh;
/* Handle chunked writes. */ /* Handle chunked writes. */
static size_t fragsz; static size_t fragsz;
static void *dump_va; static void *dump_va;
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/* A fake page table page, to avoid having to handle both 4K and 2M pages */ /* A fake page table page, to avoid having to handle both 4K and 2M pages */
static pd_entry_t fakepd[NPDEPG]; static pd_entry_t fakepd[NPDEPG];
int int
cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state) cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
{ {
uint32_t pmapsize; uint32_t pmapsize;
vm_offset_t va; vm_offset_t va, kva_end;
int error; int error;
uint64_t *pml4, *pdp, *pd, *pt, pa; uint64_t *pml4, *pdp, *pd, *pt, pa;
int i, ii, j, k, n; uint64_t pdpe, pde, pte;
int ii, j, k, n;
int retry_count; int retry_count;
struct minidumphdr mdhdr; struct minidumphdr mdhdr;
retry_count = 0; retry_count = 0;
retry: retry:
retry_count++; retry_count++;
/* Walk page table pages, set bits in vm_page_dump */ /* Snapshot the KVA upper bound in case it grows. */
kva_end = MAX(KERNBASE + nkpt * NBPDR, kernel_vm_end);
/*
* Walk the kernel page table pages, setting the active entries in the
* dump bitmap.
*
* NB: for a live dump, we may be racing with updates to the page
* tables, so care must be taken to read each entry only once.
*/
pmapsize = 0; pmapsize = 0;
for (va = VM_MIN_KERNEL_ADDRESS; va < MAX(KERNBASE + nkpt * NBPDR, for (va = VM_MIN_KERNEL_ADDRESS; va < kva_end; ) {
kernel_vm_end); ) {
/* /*
* We always write a page, even if it is zero. Each * We always write a page, even if it is zero. Each
* page written corresponds to 1GB of space * page written corresponds to 1GB of space
*/ */
pmapsize += PAGE_SIZE; pmapsize += PAGE_SIZE;
ii = pmap_pml4e_index(va); ii = pmap_pml4e_index(va);
pml4 = (uint64_t *)PHYS_TO_DMAP(KPML4phys) + ii; pml4 = (uint64_t *)PHYS_TO_DMAP(KPML4phys) + ii;
pdp = (uint64_t *)PHYS_TO_DMAP(*pml4 & PG_FRAME); pdp = (uint64_t *)PHYS_TO_DMAP(*pml4 & PG_FRAME);
i = pmap_pdpe_index(va); pdpe = atomic_load_64(&pdp[pmap_pdpe_index(va)]);
if ((pdp[i] & PG_V) == 0) { if ((pdpe & PG_V) == 0) {
markjUnsubmitted
Not Done
Inline Actions

There is no guarantee in general that the compiled code will load PTEs only once. atomic_load_* is needed, I believe.

markj: There is no guarantee in general that the compiled code will load PTEs only once. atomic_load_*…
mhorneAuthorUnsubmitted
Done
Inline Actions

Right, I should have realized this. Will update shortly.

mhorne: Right, I should have realized this. Will update shortly.
va += NBPDP; va += NBPDP;
continue; continue;
} }
/* /*
* 1GB page is represented as 512 2MB pages in a dump. * 1GB page is represented as 512 2MB pages in a dump.
*/ */
if ((pdp[i] & PG_PS) != 0) { if ((pdpe & PG_PS) != 0) {
va += NBPDP; va += NBPDP;
pa = pdp[i] & PG_PS_FRAME; pa = pdpe & PG_PS_FRAME;
for (n = 0; n < NPDEPG * NPTEPG; n++) { for (n = 0; n < NPDEPG * NPTEPG; n++) {
if (vm_phys_is_dumpable(pa)) if (vm_phys_is_dumpable(pa))
dump_add_page(pa); dump_add_page(pa);
pa += PAGE_SIZE; pa += PAGE_SIZE;
} }
continue; continue;
} }
pd = (uint64_t *)PHYS_TO_DMAP(pdp[i] & PG_FRAME); pd = (uint64_t *)PHYS_TO_DMAP(pdpe & PG_FRAME);
for (n = 0; n < NPDEPG; n++, va += NBPDR) { for (n = 0; n < NPDEPG; n++, va += NBPDR) {
j = pmap_pde_index(va); pde = atomic_load_64(pd[pmap_pde_index(va)]);
if ((pd[j] & PG_V) == 0) if ((pde & PG_V) == 0)
continue; continue;
if ((pd[j] & PG_PS) != 0) { if ((pde & PG_PS) != 0) {
/* This is an entire 2M page. */ /* This is an entire 2M page. */
pa = pd[j] & PG_PS_FRAME; pa = pde & PG_PS_FRAME;
for (k = 0; k < NPTEPG; k++) { for (k = 0; k < NPTEPG; k++) {
if (vm_phys_is_dumpable(pa)) if (vm_phys_is_dumpable(pa))
dump_add_page(pa); dump_add_page(pa);
pa += PAGE_SIZE; pa += PAGE_SIZE;
} }
continue; continue;
} }
pa = pd[j] & PG_FRAME; pa = pde & PG_FRAME;
/* set bit for this PTE page */ /* set bit for this PTE page */
if (vm_phys_is_dumpable(pa)) if (vm_phys_is_dumpable(pa))
dump_add_page(pa); dump_add_page(pa);
/* and for each valid page in this 2MB block */ /* and for each valid page in this 2MB block */
pt = (uint64_t *)PHYS_TO_DMAP(pd[j] & PG_FRAME); pt = (uint64_t *)PHYS_TO_DMAP(pde & PG_FRAME);
for (k = 0; k < NPTEPG; k++) { for (k = 0; k < NPTEPG; k++) {
if ((pt[k] & PG_V) == 0) pte = atomic_load_64(&pt[k]);
if ((pte & PG_V) == 0)
continue; continue;
pa = pt[k] & PG_FRAME; pa = pte & PG_FRAME;
if (vm_phys_is_dumpable(pa)) if (PHYS_IN_DMAP(pa) && vm_phys_is_dumpable(pa))
dump_add_page(pa); dump_add_page(pa);
} }
} }
} }
/* Calculate dump size. */ /* Calculate dump size. */
dumpsize = pmapsize; dumpsize = pmapsize;
dumpsize += round_page(msgbufp->msg_size); dumpsize += round_page(msgbufp->msg_size);
dumpsize += round_page(sizeof(dump_avail)); dumpsize += round_page(sizeof(dump_avail));
dumpsize += round_page(BITSET_SIZE(vm_page_dump_pages)); dumpsize += round_page(BITSET_SIZE(vm_page_dump_pages));
VM_PAGE_DUMP_FOREACH(pa) { VM_PAGE_DUMP_FOREACH(pa) {
/* Clear out undumpable pages now if needed */ /* Clear out undumpable pages now if needed */
if (vm_phys_is_dumpable(pa)) { if (PHYS_IN_DMAP(pa) && vm_phys_is_dumpable(pa)) {
dumpsize += PAGE_SIZE; dumpsize += PAGE_SIZE;
} else { } else {
dump_drop_page(pa); dump_drop_page(pa);
} }
} }
dumpsize += PAGE_SIZE; dumpsize += PAGE_SIZE;
wdog_next = progress = dumpsize; wdog_next = progress = dumpsize;
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/* Dump bitmap */ /* Dump bitmap */
error = blk_write(di, (char *)vm_page_dump, 0, error = blk_write(di, (char *)vm_page_dump, 0,
round_page(BITSET_SIZE(vm_page_dump_pages))); round_page(BITSET_SIZE(vm_page_dump_pages)));
if (error) if (error)
goto fail; goto fail;
/* Dump kernel page directory pages */ /* Dump kernel page directory pages */
bzero(fakepd, sizeof(fakepd)); bzero(fakepd, sizeof(fakepd));
for (va = VM_MIN_KERNEL_ADDRESS; va < MAX(KERNBASE + nkpt * NBPDR, for (va = VM_MIN_KERNEL_ADDRESS; va < kva_end; va += NBPDP) {
kernel_vm_end); va += NBPDP) {
ii = pmap_pml4e_index(va); ii = pmap_pml4e_index(va);
pml4 = (uint64_t *)PHYS_TO_DMAP(KPML4phys) + ii; pml4 = (uint64_t *)PHYS_TO_DMAP(KPML4phys) + ii;
pdp = (uint64_t *)PHYS_TO_DMAP(*pml4 & PG_FRAME); pdp = (uint64_t *)PHYS_TO_DMAP(*pml4 & PG_FRAME);
i = pmap_pdpe_index(va); pdpe = atomic_load_64(&pdp[pmap_pdpe_index(va)]);
/* We always write a page, even if it is zero */ /* We always write a page, even if it is zero */
if ((pdp[i] & PG_V) == 0) { if ((pdpe & PG_V) == 0) {
error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE); error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
if (error) if (error)
goto fail; goto fail;
/* flush, in case we reuse fakepd in the same block */ /* flush, in case we reuse fakepd in the same block */
error = blk_flush(di); error = blk_flush(di);
if (error) if (error)
goto fail; goto fail;
continue; continue;
} }
/* 1GB page is represented as 512 2MB pages in a dump */ /* 1GB page is represented as 512 2MB pages in a dump */
if ((pdp[i] & PG_PS) != 0) { if ((pdpe & PG_PS) != 0) {
/* PDPE and PDP have identical layout in this case */ /* PDPE and PDP have identical layout in this case */
fakepd[0] = pdp[i]; fakepd[0] = pdpe;
for (j = 1; j < NPDEPG; j++) for (j = 1; j < NPDEPG; j++)
fakepd[j] = fakepd[j - 1] + NBPDR; fakepd[j] = fakepd[j - 1] + NBPDR;
error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE); error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
if (error) if (error)
goto fail; goto fail;
/* flush, in case we reuse fakepd in the same block */ /* flush, in case we reuse fakepd in the same block */
error = blk_flush(di); error = blk_flush(di);
if (error) if (error)
goto fail; goto fail;
bzero(fakepd, sizeof(fakepd)); bzero(fakepd, sizeof(fakepd));
continue; continue;
} }
pd = (uint64_t *)PHYS_TO_DMAP(pdp[i] & PG_FRAME); pa = pdpe & PG_FRAME;
if (PHYS_IN_DMAP(pa) && vm_phys_is_dumpable(pa)) {
pd = (uint64_t *)PHYS_TO_DMAP(pa);
error = blk_write(di, (char *)pd, 0, PAGE_SIZE); error = blk_write(di, (char *)pd, 0, PAGE_SIZE);
} else {
/* Malformed pa, write the zeroed fakepd. */
error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
}
if (error) if (error)
goto fail; goto fail;
error = blk_flush(di); error = blk_flush(di);
if (error) if (error)
goto fail; goto fail;
} }
/* Dump memory chunks */ /* Dump memory chunks */
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