/*
 * DMA memory management for framework level HCD code (hc_driver)
 *
 * This implementation plugs in through generic "usb_bus" level methods,
 * and should work with all USB controllers, regardless of bus type.
 *
 * Released under the GPLv2 only.
 * SPDX-License-Identifier: GPL-2.0
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/mm.h>
#include <linux/io.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>


/*
 * DMA-Coherent Buffers
 */

/* FIXME tune these based on pool statistics ... */
static size_t pool_max[HCD_BUFFER_POOLS] = {
	32, 128, 512, 2048,
};

void __init usb_init_pool_max(void)
{
	/*
	 * The pool_max values must never be smaller than
	 * ARCH_KMALLOC_MINALIGN.
	 */
	if (ARCH_KMALLOC_MINALIGN <= 32)
		;			/* Original value is okay */
	else if (ARCH_KMALLOC_MINALIGN <= 64)
		pool_max[0] = 64;
	else if (ARCH_KMALLOC_MINALIGN <= 128)
		pool_max[0] = 0;	/* Don't use this pool */
	else
		BUILD_BUG();		/* We don't allow this */
}

/* SETUP primitives */

/**
 * hcd_buffer_create - initialize buffer pools
 * @hcd: the bus whose buffer pools are to be initialized
 * Context: !in_interrupt()
 *
 * Call this as part of initializing a host controller that uses the dma
 * memory allocators.  It initializes some pools of dma-coherent memory that
 * will be shared by all drivers using that controller.
 *
 * Call hcd_buffer_destroy() to clean up after using those pools.
 *
 * Return: 0 if successful. A negative errno value otherwise.
 */
int hcd_buffer_create(struct usb_hcd *hcd)
{
	char		name[16];
	int		i, size;

	if (!IS_ENABLED(CONFIG_HAS_DMA) ||
	    (!hcd->self.controller->dma_mask &&
	     !(hcd->driver->flags & HCD_LOCAL_MEM)))
		return 0;

	for (i = 0; i < HCD_BUFFER_POOLS; i++) {
		size = pool_max[i];
		if (!size)
			continue;
		snprintf(name, sizeof(name), "buffer-%d", size);
		hcd->pool[i] = dma_pool_create(name, hcd->self.controller,
				size, size, 0);
		if (!hcd->pool[i]) {
			hcd_buffer_destroy(hcd);
			return -ENOMEM;
		}
	}
	return 0;
}


/**
 * hcd_buffer_destroy - deallocate buffer pools
 * @hcd: the bus whose buffer pools are to be destroyed
 * Context: !in_interrupt()
 *
 * This frees the buffer pools created by hcd_buffer_create().
 */
void hcd_buffer_destroy(struct usb_hcd *hcd)
{
	int i;

	if (!IS_ENABLED(CONFIG_HAS_DMA))
		return;

	for (i = 0; i < HCD_BUFFER_POOLS; i++) {
		struct dma_pool *pool = hcd->pool[i];

		if (pool) {
			dma_pool_destroy(pool);
			hcd->pool[i] = NULL;
		}
	}
}


/* sometimes alloc/free could use kmalloc with GFP_DMA, for
 * better sharing and to leverage mm/slab.c intelligence.
 */

void *hcd_buffer_alloc(
	struct usb_bus		*bus,
	size_t			size,
	gfp_t			mem_flags,
	dma_addr_t		*dma
)
{
	struct usb_hcd		*hcd = bus_to_hcd(bus);
	int			i;

	if (size == 0)
		return NULL;

	/* some USB hosts just use PIO */
	if (!IS_ENABLED(CONFIG_HAS_DMA) ||
	    (!bus->controller->dma_mask &&
	     !(hcd->driver->flags & HCD_LOCAL_MEM))) {
		*dma = ~(dma_addr_t) 0;
		return kmalloc(size, mem_flags);
	}

	for (i = 0; i < HCD_BUFFER_POOLS; i++) {
		if (size <= pool_max[i])
			return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
	}
	return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);
}

void hcd_buffer_free(
	struct usb_bus		*bus,
	size_t			size,
	void			*addr,
	dma_addr_t		dma
)
{
	struct usb_hcd		*hcd = bus_to_hcd(bus);
	int			i;

	if (!addr)
		return;

	if (!IS_ENABLED(CONFIG_HAS_DMA) ||
	    (!bus->controller->dma_mask &&
	     !(hcd->driver->flags & HCD_LOCAL_MEM))) {
		kfree(addr);
		return;
	}

	for (i = 0; i < HCD_BUFFER_POOLS; i++) {
		if (size <= pool_max[i]) {
			dma_pool_free(hcd->pool[i], addr, dma);
			return;
		}
	}
	dma_free_coherent(hcd->self.controller, size, addr, dma);
}
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/include/trace/events/vmscan.h?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>c8f325a59cfc718d13a50fbc746ed9b415c25e92</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/trace/events/vmscan.h?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/include/trace/events/vmscan.h?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>include/trace/events/vmscan.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/trace/events/vmscan.h?id=bf29bddf0417a4783da3b24e8c9e017ac649326f'>bf29bddf0417a4783da3b24e8c9e017ac649326f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/trace/events/vmscan.h?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 'include/trace/events/vmscan.h')</div><table summary='diffstat' class='diffstat'>