/*
 * Copyright (C) 2003 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/nls.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>


/**
 * usb_gadget_get_string - fill out a string descriptor 
 * @table: of c strings encoded using UTF-8
 * @id: string id, from low byte of wValue in get string descriptor
 * @buf: at least 256 bytes, must be 16-bit aligned
 *
 * Finds the UTF-8 string matching the ID, and converts it into a
 * string descriptor in utf16-le.
 * Returns length of descriptor (always even) or negative errno
 *
 * If your driver needs stings in multiple languages, you'll probably
 * "switch (wIndex) { ... }"  in your ep0 string descriptor logic,
 * using this routine after choosing which set of UTF-8 strings to use.
 * Note that US-ASCII is a strict subset of UTF-8; any string bytes with
 * the eighth bit set will be multibyte UTF-8 characters, not ISO-8859/1
 * characters (which are also widely used in C strings).
 */
int
usb_gadget_get_string (struct usb_gadget_strings *table, int id, u8 *buf)
{
	struct usb_string	*s;
	int			len;

	/* descriptor 0 has the language id */
	if (id == 0) {
		buf [0] = 4;
		buf [1] = USB_DT_STRING;
		buf [2] = (u8) table->language;
		buf [3] = (u8) (table->language >> 8);
		return 4;
	}
	for (s = table->strings; s && s->s; s++)
		if (s->id == id)
			break;

	/* unrecognized: stall. */
	if (!s || !s->s)
		return -EINVAL;

	/* string descriptors have length, tag, then UTF16-LE text */
	len = min ((size_t) 126, strlen (s->s));
	len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN,
			(wchar_t *) &buf[2], 126);
	if (len < 0)
		return -EINVAL;
	buf [0] = (len + 1) * 2;
	buf [1] = USB_DT_STRING;
	return buf [0];
}
EXPORT_SYMBOL_GPL(usb_gadget_get_string);
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/fs?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>fs</a>/<a href='/cgit.cgi/linux/net-next.git/commit/fs/affs?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>affs</a>/<a href='/cgit.cgi/linux/net-next.git/commit/fs/affs/file.c?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>file.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='c8f325a59cfc718d13a50fbc746ed9b415c25e92'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>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/fs/affs/file.c?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>c8f325a59cfc718d13a50fbc746ed9b415c25e92</a> (<a href='/cgit.cgi/linux/net-next.git/patch/fs/affs/file.c?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/fs/affs/file.c?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>fs/affs/file.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/fs/affs/file.c?id=bf29bddf0417a4783da3b24e8c9e017ac649326f'>bf29bddf0417a4783da3b24e8c9e017ac649326f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/fs/affs/file.c?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 'fs/affs/file.c')</div><table summary='diffstat' class='diffstat'>