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authorStafford Horne <shorne@gmail.com>2020-06-25 20:29:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-26 00:27:36 -0700
commit313a5257b84c26b7f080c5d294aabe7d38ca439c (patch)
treec8fbf539166e30ae59f4257d74cf8bf88ac58a89 /arch/openrisc/kernel
parent908f7d12d3ba51dfe0449b9723199b423f97ca9a (diff)
openrisc: fix boot oops when DEBUG_VM is enabled
Since v5.8-rc1 OpenRISC Linux fails to boot when DEBUG_VM is enabled. This has been bisected to commit 42fc541404f2 ("mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked()"). The added locking checks exposed the issue that OpenRISC was not taking this mmap lock when during page walks for DMA operations. This patch locks and unlocks the mmap lock for page walking. Link: http://lkml.kernel.org/r/20200617090247.1680188-1-shorne@gmail.com Fixes: 42fc541404f2 ("mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked()" Signed-off-by: Stafford Horne <shorne@gmail.com> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Steven Price <steven.price@arm.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/openrisc/kernel')
-rw-r--r--arch/openrisc/kernel/dma.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
index c152a68811dd..345727638d52 100644
--- a/arch/openrisc/kernel/dma.c
+++ b/arch/openrisc/kernel/dma.c
@@ -74,8 +74,11 @@ void *arch_dma_set_uncached(void *cpu_addr, size_t size)
* We need to iterate through the pages, clearing the dcache for
* them and setting the cache-inhibit bit.
*/
+ mmap_read_lock(&init_mm);
error = walk_page_range(&init_mm, va, va + size, &set_nocache_walk_ops,
NULL);
+ mmap_read_unlock(&init_mm);
+
if (error)
return ERR_PTR(error);
return cpu_addr;
@@ -85,9 +88,11 @@ void arch_dma_clear_uncached(void *cpu_addr, size_t size)
{
unsigned long va = (unsigned long)cpu_addr;
+ mmap_read_lock(&init_mm);
/* walk_page_range shouldn't be able to fail here */
WARN_ON(walk_page_range(&init_mm, va, va + size,
&clear_nocache_walk_ops, NULL));
+ mmap_read_unlock(&init_mm);
}
void arch_sync_dma_for_device(phys_addr_t addr, size_t size,