diff options
| author | Shawn Anastasio <shawn@anastas.io> | 2019-07-17 18:54:37 -0500 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-07-19 21:29:49 +1000 |
| commit | b4fc36e60f25cf22bf8b7b015a701015740c3743 (patch) | |
| tree | 1db70e710b251f20a845176881c3274c1cb307e3 /arch/powerpc/kernel | |
| parent | 9798f4ea71eaf8eaad7e688c5b298528089c7bf8 (diff) | |
powerpc/dma: Fix invalid DMA mmap behavior
The refactor of powerpc DMA functions in commit 6666cc17d780
("powerpc/dma: remove dma_nommu_mmap_coherent") incorrectly
changes the way DMA mappings are handled on powerpc.
Since this change, all mapped pages are marked as cache-inhibited
through the default implementation of arch_dma_mmap_pgprot.
This differs from the previous behavior of only marking pages
in noncoherent mappings as cache-inhibited and has resulted in
sporadic system crashes in certain hardware configurations and
workloads (see Bugzilla).
This commit restores the previous correct behavior by providing
an implementation of arch_dma_mmap_pgprot that only marks
pages in noncoherent mappings as cache-inhibited. As this behavior
should be universal for all powerpc platforms a new file,
dma-generic.c, was created to store it.
Fixes: 6666cc17d780 ("powerpc/dma: remove dma_nommu_mmap_coherent")
# NOTE: fixes commit 6666cc17d780 released in v5.1.
# Consider a stable tag:
# Cc: stable@vger.kernel.org # v5.1+
# NOTE: fixes commit 6666cc17d780 released in v5.1.
# Consider a stable tag:
# Cc: stable@vger.kernel.org # v5.1+
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Shawn Anastasio <shawn@anastas.io>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190717235437.12908-1-shawn@anastas.io
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/Makefile | 3 | ||||
| -rw-r--r-- | arch/powerpc/kernel/dma-common.c | 17 |
2 files changed, 19 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 56dfa7a2a6f2..ea0c69236789 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -49,7 +49,8 @@ obj-y := cputable.o ptrace.o syscalls.o \ signal.o sysfs.o cacheinfo.o time.o \ prom.o traps.o setup-common.o \ udbg.o misc.o io.o misc_$(BITS).o \ - of_platform.o prom_parse.o + of_platform.o prom_parse.o \ + dma-common.o obj-$(CONFIG_PPC64) += setup_64.o sys_ppc32.o \ signal_64.o ptrace32.o \ paca.o nvram_64.o firmware.o diff --git a/arch/powerpc/kernel/dma-common.c b/arch/powerpc/kernel/dma-common.c new file mode 100644 index 000000000000..dc7ef6b17b69 --- /dev/null +++ b/arch/powerpc/kernel/dma-common.c @@ -0,0 +1,17 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Contains common dma routines for all powerpc platforms. + * + * Copyright (C) 2019 Shawn Anastasio. + */ + +#include <linux/mm.h> +#include <linux/dma-noncoherent.h> + +pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot, + unsigned long attrs) +{ + if (!dev_is_dma_coherent(dev)) + return pgprot_noncached(prot); + return prot; +} |