The following warning occurred sporadically on s390:
DMA-API: nvme 0006:00:00.0: device driver maps memory from kernel text or rodata [addr=0000000048cc5e2f] [len=131072]
WARNING: CPU: 4 PID: 825 at kernel/dma/debug.c:1083 check_for_illegal_area+0xa8/0x138

It is a false-positive warning, due to broken logic in debug_dma_map_sg().
check_for_illegal_area() checks for overlay of sg elements with kernel text
or rodata. It is called with sg_dma_len(s) instead of s->length as
parameter. After the call to ->map_sg(), sg_dma_len() will contain the
length of possibly combined sg elements in the DMA address space, and not
the individual sg element length, which would be s->length.

The check will then use the physical start address of an sg element, and
add the DMA length for the overlap check, which could result in the false
warning, because the DMA length can be larger than the actual single sg
element length.

In addition, the call to check_for_illegal_area() happens in the iteration
over mapped_ents, which will not include all individual sg elements if
any of them were combined in ->map_sg().

Fix this by using s->length instead of sg_dma_len(s). Also put the call to
check_for_illegal_area() in a separate loop, iterating over all the
individual sg elements ("nents" instead of "mapped_ents").

While at it, as suggested by Robin Murphy, also move check_for_stack()
inside the new loop, as it is similarly concerned with validating the
individual sg elements.

Link: https://lore.kernel.org/lkml/20210705185252.4074653-1-gerald.schaefer@linux.ibm.com
Fixes: 884d0597 ("dma-debug: use sg_dma_len accessor")
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

htmldocs began producing the following warnings:

  kernel/dma/mapping.c:256: WARNING: Definition list ends without a
             blank line; unexpected unindent.
  kernel/dma/mapping.c:257: WARNING: Bullet list ends without a blank
             line; unexpected unindent.

Reformatting the list without hyphens fixes the warnings and produces
both a readable text and HTML output.

Fixes: fffe3cc8 ("dma-mapping: allow map_sg() ops to return negative error code")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Commit 53b7670e ("sparc: factor the dma coherent mapping into
helper") lost the page align for the calls to dma_make_coherent and
srmmu_unmapiorange. The latter cannot handle a non page aligned len
argument.
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

For some drivers, that use the DMA API. This error message can be reached
several millions of times per second, causing spam to the kernel's printk
buffer and bringing the CPU usage up to 100% (so, it should be rate
limited). However, since there is at least one driver that is in the
mainline and suffers from the error condition, it is more useful to
err_printk() here instead of just rate limiting the error message (in hopes
that it will make it easier for other drivers that suffer from this issue
to be spotted).

Link: https://lkml.kernel.org/r/fd67fbac-64bf-f0ea-01e1-5938ccfab9d0@arm.comReported-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Hamza Mahfooz <someguy@effective-light.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Add the missing description for the nents parameter, and fix a trivial
misalignment.

Fixes: fffe3cc8 ("dma-mapping: allow map_sg() ops to return negative error codes")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Switch hexagon to use the generic code for dma_alloc_coherent from
a global pre-filled pool.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Cain <bcain@codeaurora.org>

Only build the code to support the global coherent pool if support for
it is enabled.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dillon Min <dillon.minfei@gmail.com>

Add a new helper to initialize the global coherent pool.  This both
cleans up the existing initialization which indirects through the
reserved_mem_ops that are normally only used for struct device, and
also allows using the global pool for non-devicetree architectures.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dillon Min <dillon.minfei@gmail.com>

Return the allocated dma_coherent_mem structure, set the
use_dma_pfn_offset and print the failure warning inside of
dma_init_coherent_memory instead of leaving that to the callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dillon Min <dillon.minfei@gmail.com>

Switch an ifdef so that the global coherent pool is initialized for
any architecture that selects the DMA_GLOBAL_POOL symbol insted of
hardcoding ARM.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dillon Min <dillon.minfei@gmail.com>

Select the right options to just use the generic dma-direct code
instead of reimplementing it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dillon Min <dillon.minfei@gmail.com>

Add an option to allocate uncached memory for dma_alloc_coherent from
the global dma_coherent_default_memory.  This will allow to move
arm-nommu (and eventually other platforms) to use generic code for
allocating uncached memory from a pre-populated pool.

Note that this is a different pool from the one that platforms that
can remap at runtime use for GFP_ATOMIC allocations for now, although
there might be opportunities to eventually end up with a common codebase
for the two use cases.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dillon Min <dillon.minfei@gmail.com>

These can only return 0 for failure or the number of entries, so turn
the return value into an unsigned int.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>

Now that all the .map_sg operations have been converted to returning
proper error codes, drop the code to handle a zero return value,
add a warning if a zero is returned.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.

The only errno to return is -EINVAL in the case when DMA is not
supported.
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Setting the ->dma_address to DMA_MAPPING_ERROR is not part of
the ->map_sg calling convention, so remove it.

Link: https://lore.kernel.org/linux-mips/20210716063241.GC13345@lst.de/Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.

So make __dma_map_cont() return a valid errno (which is then propagated
to gart_map_sg() via dma_map_cont()) and return it in case of failure.

Also, return -EINVAL in case of invalid nents.
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.

xen_swiotlb_map_sg() may only fail if xen_swiotlb_map_page() fails, but
xen_swiotlb_map_page() only supports returning errors as
DMA_MAPPING_ERROR. So coalesce all errors into EIO per the documentation
for dma_map_sgtable().
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.
Return -EINVAL if the ioc cannot be obtained.
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Setting the ->dma_address to DMA_MAPPING_ERROR is not part of
the ->map_sg calling convention, so remove it.

Link: https://lore.kernel.org/linux-mips/20210716063241.GC13345@lst.de/Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.

Returning an errno from __sbus_iommu_map_sg() results in
sbus_iommu_map_sg_gflush() and sbus_iommu_map_sg_pflush() returning an
errno, as those functions are wrappers around __sbus_iommu_map_sg().
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Setting the ->dma_address to DMA_MAPPING_ERROR is not part of
the ->map_sg calling convention, so remove it.

Link: https://lore.kernel.org/linux-mips/20210716063241.GC13345@lst.de/Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.

So propagate the error from __s390_dma_map_sg() up. __s390_dma_map_sg()
returns either -ENOMEM on allocation failure or -EINVAL which is
the same as what's expected by dma_map_sgtable().
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Setting the ->dma_address to DMA_MAPPING_ERROR is not part of
the ->map_sg calling convention, so remove it.

Link: https://lore.kernel.org/linux-mips/20210716063241.GC13345@lst.de/Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Geoff Levand <geoff@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.

Propagate the error up if vio_dma_iommu_map_sg() fails.

ppc_iommu_map_sg() may fail either because of iommu_range_alloc() or
because of tbl->it_ops->set(). The former only supports returning an
error with DMA_MAPPING_ERROR and an examination of the latter indicates
that it may return arch-specific errors (for example,
tce_buildmulti_pSeriesLP()). Hence, coalesce all of those errors into
-EIO, per the documentation on dma_map_sgtable().
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Geoff Levand <geoff@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.

vdma_alloc() may fail for different reasons, but since it only supports
indicating an error via a return of DMA_MAPPING_ERROR, we coalesce the
different reasons into -EIO as is documented on dma_map_sgtable().
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.

In the case of a dma_mapping_error() return -EIO as the actual cause
is opaque here.

sba_coalesce_chunks() may only presently fail if sba_alloc_range()
fails, which in turn only fails if the iommu is out of mapping
resources, hence a -ENOMEM is used in that case.
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Setting the ->dma_address to DMA_MAPPING_ERROR is not part of the
->map_sg calling convention, so remove it.

Link: https://lore.kernel.org/linux-mips/20210716063241.GC13345@lst.de/Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.
In the case of a DMA_MAPPING_ERROR, -EIO is returned. Otherwise,
-ENOMEM or -EINVAL is returned depending on the error from
__map_sg_chunk().
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The .map_sg() op now expects an error code instead of zero on failure.

pci_map_single_1() can fail for different reasons, but since the only
supported type of error return is DMA_MAPPING_ERROR, we coalesce those
errors into EIO.

ENOMEM is returned when no page tables can be allocated.
Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Return appropriate error codes EINVAL or ENOMEM from
iommup_dma_map_sg(). If lower level code returns ENOMEM, then we
return it, other errors are coalesced into EINVAL.

iommu_dma_map_sg_swiotlb() returns -EIO as its an unknown error
from a call that returns DMA_MAPPING_ERROR.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Convert to ssize_t return code so the return code from __iommu_map()
can be returned all the way down through dma_iommu_map_sg().
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Now that the map_sg() op expects error codes instead of return zero on
error, convert dma_direct_map_sg() to return an error code. Per the
documentation for dma_map_sgtable(), -EIO is returned due to an
DMA_MAPPING_ERROR with unknown cause.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Allow dma_map_sgtable() to pass errors from the map_sg() ops. This
will be required for returning appropriate error codes when mapping
P2PDMA memory.

Introduce __dma_map_sg_attrs() which will return the raw error code
from the map_sg operation (whether it be negative or zero). Then add a
dma_map_sg_attrs() wrapper to convert any negative errors to zero to
satisfy the existing calling convention.

dma_map_sgtable() defines three error codes that .map_sg implementations
are allowed to return: -EINVAL, -ENOMEM and -EIO. The latter of which
is a generic return for cases that are passing DMA_MAPPING_ERROR
through.

dma_map_sgtable() will convert a zero error return for old map_sg() ops
into a -EIO return and return any negative errors as reported.

This allows map_sg implementations to start returning multiple
negative error codes. Legacy map_sg implementations can continue
to return zero until they are all converted.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Due to link order, dma_debug_init is called before debugfs has a chance
to initialize (via debugfs_init which also happens in the core initcall
stage), so the directories for dma-debug are never created.

Decouple dma_debug_fs_init from dma_debug_init and defer its init until
core_initcall_sync (after debugfs has been initialized) while letting
dma-debug initialization occur as soon as possible to catch any early
mappings, as suggested in [1].

[1] https://lore.kernel.org/linux-iommu/YIgGa6yF%2Fadg8OSN@kroah.com/

Fixes: 15b28bbc ("dma-debug: move initialization to common code")
Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

There is already a memory_intersects() helper in sections.h,
use memory_intersects() directly instead of private overlap().
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Pull timer fix from Thomas Gleixner:
 "A single timer fix:

   - Prevent a memory ordering issue in the timer expiry code which
     makes it possible to observe falsely that the callback has been
     executed already while that's not the case, which violates the
     guarantee of del_timer_sync()"

* tag 'timers-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers: Move clearing of base::timer_running under base:: Lock

Pull scheduler fix from Thomas Gleixner:
 "A single scheduler fix:

   - Prevent a double enqueue caused by rt_effective_prio() being
     invoked twice in __sched_setscheduler()"

* tag 'sched-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/rt: Fix double enqueue caused by rt_effective_prio

Pull perf fixes from Thomas Gleixner:
 "A set of perf fixes:

   - Correct the permission checks for perf event which send SIGTRAP to
     a different process and clean up that code to be more readable.

   - Prevent an out of bound MSR access in the x86 perf code which
     happened due to an incomplete limiting to the actually available
     hardware counters.

   - Prevent access to the AMD64_EVENTSEL_HOSTONLY bit when running
     inside a guest.

   - Handle small core counter re-enabling correctly by issuing an ACK
     right before reenabling it to prevent a stale PEBS record being
     kept around"

* tag 'perf-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Apply mid ACK for small core
  perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest
  perf/x86: Fix out of bound MSR access
  perf: Refactor permissions check into perf_check_permission()
  perf: Fix required permissions if sigtrap is requested