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i386: Always bounce DMA requests above 4G for !PAE kernels

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i386 kernels without 'options PAE' will still use PAE page tables if
the CPU supports PAE both to support larger amounts of RAM and for
PG_NX permissions.  However, to avoid changing the API, bus_addr_t and
related constants (e.g. BUS_SPACE_MAXADDR) are still limited to
32 bits.

To cope with this, the x86 bus_dma code included an extra check to
bounce requests for addresses above BUS_SPACE_MAXADDR.  This check was
elided (probably because it looks always-true on its face and had no
comment explaining its purpose) in recent refactoring.  To fix,
restore a custom address-validation function for i386 kernels without
options PAE that includes this check.

Reported by:	ci.freebsd.org
Reviewed by:	markj
Fixes:		3933ff56f9 busdma: tidy bus_dma_run_filter() functions
Differential Revision:	https://reviews.freebsd.org/D43277
This commit is contained in:
John Baldwin 2024-01-02 13:15:13 -08:00
parent 025007f391
commit 67b0b90785
1 changed files with 23 additions and 6 deletions
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29
sys/x86/x86/busdma_bounce.c
View file

@ -117,6 +117,23 @@ static MALLOC_DEFINE(M_BUSDMA, "busdma", "busdma metadata");
#include "../../kern/subr_busdma_bounce.c"
/*
* On i386 kernels without 'options PAE' we need to also bounce any
* physical addresses above 4G.
*
* NB: vm_paddr_t is required here since bus_addr_t is only 32 bits in
* i386 kernels without 'options PAE'.
*/
static __inline bool
must_bounce(bus_dma_tag_t dmat, vm_paddr_t paddr)
{
#if defined(__i386__) && !defined(PAE)
if (paddr > BUS_SPACE_MAXADDR)
return (true);
#endif
return (addr_needs_bounce(dmat, paddr));
}
static int
bounce_bus_dma_zone_setup(bus_dma_tag_t dmat)
{
@ -491,7 +508,7 @@ _bus_dmamap_pagesneeded(bus_dma_tag_t dmat, vm_paddr_t buf, bus_size_t buflen,
curaddr = buf;
while (buflen != 0) {
sgsize = MIN(buflen, dmat->common.maxsegsz);
if (addr_needs_bounce(dmat, curaddr)) {
if (must_bounce(dmat, curaddr)) {
sgsize = MIN(sgsize,
PAGE_SIZE - (curaddr & PAGE_MASK));
if (pagesneeded == NULL)
@ -547,7 +564,7 @@ _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, pmap_t pmap,
paddr = pmap_kextract(vaddr);
else
paddr = pmap_extract(pmap, vaddr);
if (addr_needs_bounce(dmat, paddr)) {
if (must_bounce(dmat, paddr)) {
sg_len = roundup2(sg_len,
dmat->common.alignment);
map->pagesneeded++;
@ -584,7 +601,7 @@ _bus_dmamap_count_ma(bus_dma_tag_t dmat, bus_dmamap_t map, struct vm_page **ma,
sg_len = PAGE_SIZE - ma_offs;
max_sgsize = MIN(buflen, dmat->common.maxsegsz);
sg_len = MIN(sg_len, max_sgsize);
if (addr_needs_bounce(dmat, paddr)) {
if (must_bounce(dmat, paddr)) {
sg_len = roundup2(sg_len,
dmat->common.alignment);
sg_len = MIN(sg_len, max_sgsize);
@ -685,7 +702,7 @@ bounce_bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
sgsize = MIN(buflen, dmat->common.maxsegsz);
if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0 &&
map->pagesneeded != 0 &&
addr_needs_bounce(dmat, curaddr)) {
must_bounce(dmat, curaddr)) {
sgsize = MIN(sgsize, PAGE_SIZE - (curaddr & PAGE_MASK));
curaddr = add_bounce_page(dmat, map, 0, curaddr, 0,
sgsize);
@ -753,7 +770,7 @@ bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0 &&
map->pagesneeded != 0 &&
addr_needs_bounce(dmat, curaddr)) {
must_bounce(dmat, curaddr)) {
sgsize = roundup2(sgsize, dmat->common.alignment);
sgsize = MIN(sgsize, max_sgsize);
curaddr = add_bounce_page(dmat, map, kvaddr, curaddr, 0,
@ -820,7 +837,7 @@ bounce_bus_dmamap_load_ma(bus_dma_tag_t dmat, bus_dmamap_t map,
sgsize = PAGE_SIZE - ma_offs;
if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0 &&
map->pagesneeded != 0 &&
addr_needs_bounce(dmat, paddr)) {
must_bounce(dmat, paddr)) {
sgsize = roundup2(sgsize, dmat->common.alignment);
sgsize = MIN(sgsize, max_sgsize);
KASSERT(vm_addr_align_ok(sgsize,