/*
 * helpers for managing a buffer for many packets
 *
 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
 * Licensed under the terms of the GNU General Public License, version 2.
 */

#include <linux/firewire.h>
#include <linux/export.h>
#include <linux/slab.h>
#include "packets-buffer.h"

/**
 * iso_packets_buffer_init - allocates the memory for packets
 * @b: the buffer structure to initialize
 * @unit: the device at the other end of the stream
 * @count: the number of packets
 * @packet_size: the (maximum) size of a packet, in bytes
 * @direction: %DMA_TO_DEVICE or %DMA_FROM_DEVICE
 */
int iso_packets_buffer_init(struct iso_packets_buffer *b, struct fw_unit *unit,
			    unsigned int count, unsigned int packet_size,
			    enum dma_data_direction direction)
{
	unsigned int packets_per_page, pages;
	unsigned int i, page_index, offset_in_page;
	void *p;
	int err;

	b->packets = kmalloc(count * sizeof(*b->packets), GFP_KERNEL);
	if (!b->packets) {
		err = -ENOMEM;
		goto error;
	}

	packet_size = L1_CACHE_ALIGN(packet_size);
	packets_per_page = PAGE_SIZE / packet_size;
	if (WARN_ON(!packets_per_page)) {
		err = -EINVAL;
		goto error;
	}
	pages = DIV_ROUND_UP(count, packets_per_page);

	err = fw_iso_buffer_init(&b->iso_buffer, fw_parent_device(unit)->card,
				 pages, direction);
	if (err < 0)
		goto err_packets;

	for (i = 0; i < count; ++i) {
		page_index = i / packets_per_page;
		p = page_address(b->iso_buffer.pages[page_index]);
		offset_in_page = (i % packets_per_page) * packet_size;
		b->packets[i].buffer = p + offset_in_page;
		b->packets[i].offset = page_index * PAGE_SIZE + offset_in_page;
	}

	return 0;

err_packets:
	kfree(b->packets);
error:
	return err;
}
EXPORT_SYMBOL(iso_packets_buffer_init);

/**
 * iso_packets_buffer_destroy - frees packet buffer resources
 * @b: the buffer structure to free
 * @unit: the device at the other end of the stream
 */
void iso_packets_buffer_destroy(struct iso_packets_buffer *b,
				struct fw_unit *unit)
{
	fw_iso_buffer_destroy(&b->iso_buffer, fw_parent_device(unit)->card);
	kfree(b->packets);
}
EXPORT_SYMBOL(iso_packets_buffer_destroy);
pf.c?h=nds-private-remove&amp;id=16a16cd35ee29d9bea54dd60e55d9c1cc685a37d'>diff</a></td><td class='form'><form class='right' method='get' action='/cgit.cgi/linux/net-next.git/log/tools/lib/bpf/bpf.c'>
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/log/?h=nds-private-remove&amp;id=16a16cd35ee29d9bea54dd60e55d9c1cc685a37d'>root</a>/<a href='/cgit.cgi/linux/net-next.git/log/tools?h=nds-private-remove&amp;id=16a16cd35ee29d9bea54dd60e55d9c1cc685a37d'>tools</a>/<a href='/cgit.cgi/linux/net-next.git/log/tools/lib?h=nds-private-remove&amp;id=16a16cd35ee29d9bea54dd60e55d9c1cc685a37d'>lib</a>/<a href='/cgit.cgi/linux/net-next.git/log/tools/lib/bpf?h=nds-private-remove&amp;id=16a16cd35ee29d9bea54dd60e55d9c1cc685a37d'>bpf</a>/<a href='/cgit.cgi/linux/net-next.git/log/tools/lib/bpf/bpf.c?h=nds-private-remove&amp;id=16a16cd35ee29d9bea54dd60e55d9c1cc685a37d'>bpf.c</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/tools/lib/bpf/bpf.c?h=nds-private-remove&amp;id=16a16cd35ee29d9bea54dd60e55d9c1cc685a37d&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;</td><td class='right'>2017-02-01 17:45:02 +0000</td></tr>
<tr><th>committer</th><td>Ingo Molnar &lt;mingo@kernel.org&gt;</td><td class='right'>2017-02-01 21:17:49 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/core/Kconfig?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>c8f325a59cfc718d13a50fbc746ed9b415c25e92</a> (<a href='/cgit.cgi/linux/net-next.git/patch/sound/core/Kconfig?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>d53fbdac9d0781e39a13b2ac6b2bd258cf3b4140</a> /<a href='/cgit.cgi/linux/net-next.git/tree/sound/core/Kconfig?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>sound/core/Kconfig</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/core/Kconfig?id=bf29bddf0417a4783da3b24e8c9e017ac649326f'>bf29bddf0417a4783da3b24e8c9e017ac649326f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/core/Kconfig?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92&amp;id2=bf29bddf0417a4783da3b24e8c9e017ac649326f'>diff</a>)</td></tr></table>
<div class='commit-subject'>efi/fdt: Avoid FDT manipulation after ExitBootServices()</div><div class='commit-msg'>Some AArch64 UEFI implementations disable the MMU in ExitBootServices(),
after which unaligned accesses to RAM are no longer supported.

Commit:

  abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")

fixed an issue in the memory map handling of the stub FDT code, but
inadvertently created an issue with such firmware, by moving some
of the FDT manipulation to after the invocation of ExitBootServices().

Given that the stub's libfdt implementation uses the ordinary, accelerated
string functions, which rely on hardware handling of unaligned accesses,
manipulating the FDT with the MMU off may result in alignment faults.

So fix the situation by moving the update_fdt_memmap() call into the
callback function invoked by efi_exit_boot_services() right before it
calls the ExitBootServices() UEFI service (which is arguably a better
place for it anyway)

Note that disabling the MMU in ExitBootServices() is not compliant with
the UEFI spec, and carries great risk due to the fact that switching from
cached to uncached memory accesses halfway through compiler generated code
(i.e., involving a stack) can never be done in a way that is architecturally
safe.

Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")
Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Tested-by: Riku Voipio &lt;riku.voipio@linaro.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Cc: mark.rutland@arm.com
Cc: linux-efi@vger.kernel.org
Cc: matt@codeblueprint.co.uk
Cc: leif.lindholm@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>Diffstat</a> (limited to 'sound/core/Kconfig')</div><table summary='diffstat' class='diffstat'>