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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
commitf4cdf7ca9a1fdcca413157df19753f388a5a224e (patch)
tree60a31895b2446cd7fa27514e8c2843534a0de0da /include/crypto/scatterwalk.h
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Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab: - v4l2-core: added ISP statistics support and per-block validation - v4l2-core: Allow unknown HDR10 white point and luminance - New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor - New codec: Milos: VPU v2.0 codec support - isp driver: gained support for Dreamchip RPPX1 ISP framework - vsp1 driver: gained support for RZ/T2H and RZ/N2H - Novalake driver: gained CVS support for new NVL hardware - dvb-core: fix feed leak on failed DMX_ADD_PID - several driver fixes, cleanups and minor improvements * tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits) media: ipu-bridge: check all DMI entries when overriding sensor rotation media: v4l2-async: avoid deleting unlinked ASC entry on link error media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement media: intel/ipu6: fix async notifier cleanup leak on parse error media: staging/ipu7: fix async notifier UAF on probe error path media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem() media: rcar-isp: Fix VSPX reference leaks media: rcar-isp: Release ISPCORE resources media: i2c: imx415: Release runtime PM reference on VBLANK error media: i2c: imx415: Return test pattern write errors media: renesas: vsp1: Declare index variables in for loop statement media: renesas: vsp1: Make reset control optional to support platforms without a reset line media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs media: nxp: imx8-isi: Add additional 32-bit RGB format support media: nxp: imx8-isi: Add 16-bit raw Bayer format support media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks media: nxp: imx8-isi: Correct color map between V4L2 and ISI ...
Diffstat (limited to 'include/crypto/scatterwalk.h')
-rw-r--r--include/crypto/scatterwalk.h256
1 files changed, 256 insertions, 0 deletions
diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
new file mode 100644
index 000000000..624fab589
--- /dev/null
+++ b/include/crypto/scatterwalk.h
@@ -0,0 +1,256 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Cryptographic scatter and gather helpers.
+ *
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
+ * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
+ * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#ifndef _CRYPTO_SCATTERWALK_H
+#define _CRYPTO_SCATTERWALK_H
+
+#include <crypto/algapi.h>
+
+#include <linux/highmem.h>
+#include <linux/mm.h>
+#include <linux/scatterlist.h>
+
+static inline void scatterwalk_crypto_chain(struct scatterlist *head,
+ struct scatterlist *sg, int num)
+{
+ if (sg)
+ sg_chain(head, num, sg);
+ else
+ sg_mark_end(head);
+}
+
+static inline void scatterwalk_start(struct scatter_walk *walk,
+ struct scatterlist *sg)
+{
+ walk->sg = sg;
+ walk->offset = sg->offset;
+}
+
+/*
+ * This is equivalent to scatterwalk_start(walk, sg) followed by
+ * scatterwalk_skip(walk, pos).
+ */
+static inline void scatterwalk_start_at_pos(struct scatter_walk *walk,
+ struct scatterlist *sg,
+ unsigned int pos)
+{
+ while (pos > sg->length) {
+ pos -= sg->length;
+ sg = sg_next(sg);
+ }
+ walk->sg = sg;
+ walk->offset = sg->offset + pos;
+}
+
+static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
+ unsigned int nbytes)
+{
+ unsigned int len_this_sg;
+ unsigned int limit;
+
+ if (walk->offset >= walk->sg->offset + walk->sg->length)
+ scatterwalk_start(walk, sg_next(walk->sg));
+ len_this_sg = walk->sg->offset + walk->sg->length - walk->offset;
+
+ /*
+ * HIGHMEM case: the page may have to be mapped into memory. To avoid
+ * the complexity of having to map multiple pages at once per sg entry,
+ * clamp the returned length to not cross a page boundary.
+ *
+ * !HIGHMEM case: no mapping is needed; all pages of the sg entry are
+ * already mapped contiguously in the kernel's direct map. For improved
+ * performance, allow the walker to return data segments that cross a
+ * page boundary. Do still cap the length to PAGE_SIZE, since some
+ * users rely on that to avoid disabling preemption for too long when
+ * using SIMD. It's also needed for when skcipher_walk uses a bounce
+ * page due to the data not being aligned to the algorithm's alignmask.
+ */
+ if (IS_ENABLED(CONFIG_HIGHMEM))
+ limit = PAGE_SIZE - offset_in_page(walk->offset);
+ else
+ limit = PAGE_SIZE;
+
+ return min3(nbytes, len_this_sg, limit);
+}
+
+/*
+ * Create a scatterlist that represents the remaining data in a walk. Uses
+ * chaining to reference the original scatterlist, so this uses at most two
+ * entries in @sg_out regardless of the number of entries in the original list.
+ * Assumes that sg_init_table() was already done.
+ */
+static inline void scatterwalk_get_sglist(struct scatter_walk *walk,
+ struct scatterlist sg_out[2])
+{
+ if (walk->offset >= walk->sg->offset + walk->sg->length)
+ scatterwalk_start(walk, sg_next(walk->sg));
+ sg_set_page(sg_out, sg_page(walk->sg),
+ walk->sg->offset + walk->sg->length - walk->offset,
+ walk->offset);
+ scatterwalk_crypto_chain(sg_out, sg_next(walk->sg), 2);
+}
+
+static inline void scatterwalk_map(struct scatter_walk *walk)
+{
+ struct page *base_page = sg_page(walk->sg);
+ unsigned int offset = walk->offset;
+ void *addr;
+
+ if (IS_ENABLED(CONFIG_HIGHMEM)) {
+ struct page *page;
+
+ page = base_page + (offset >> PAGE_SHIFT);
+ offset = offset_in_page(offset);
+ addr = kmap_local_page(page) + offset;
+ } else {
+ /*
+ * When !HIGHMEM we allow the walker to return segments that
+ * span a page boundary; see scatterwalk_clamp(). To make it
+ * clear that in this case we're working in the linear buffer of
+ * the whole sg entry in the kernel's direct map rather than
+ * within the mapped buffer of a single page, compute the
+ * address as an offset from the page_address() of the first
+ * page of the sg entry. Either way the result is the address
+ * in the direct map, but this makes it clearer what is really
+ * going on.
+ */
+ addr = page_address(base_page) + offset;
+ }
+
+ walk->__addr = addr;
+}
+
+/**
+ * scatterwalk_next() - Get the next data buffer in a scatterlist walk
+ * @walk: the scatter_walk
+ * @total: the total number of bytes remaining, > 0
+ *
+ * A virtual address for the next segment of data from the scatterlist will
+ * be placed into @walk->addr. The caller must call scatterwalk_done_src()
+ * or scatterwalk_done_dst() when it is done using this virtual address.
+ *
+ * Returns: the next number of bytes available, <= @total
+ */
+static inline unsigned int scatterwalk_next(struct scatter_walk *walk,
+ unsigned int total)
+{
+ unsigned int nbytes = scatterwalk_clamp(walk, total);
+
+ scatterwalk_map(walk);
+ return nbytes;
+}
+
+static inline void scatterwalk_unmap(struct scatter_walk *walk)
+{
+ if (IS_ENABLED(CONFIG_HIGHMEM))
+ kunmap_local(walk->__addr);
+}
+
+static inline void scatterwalk_advance(struct scatter_walk *walk,
+ unsigned int nbytes)
+{
+ walk->offset += nbytes;
+}
+
+/**
+ * scatterwalk_done_src() - Finish one step of a walk of source scatterlist
+ * @walk: the scatter_walk
+ * @nbytes: the number of bytes processed this step, less than or equal to the
+ * number of bytes that scatterwalk_next() returned.
+ *
+ * Use this if the mapped address was not written to, i.e. it is source data.
+ */
+static inline void scatterwalk_done_src(struct scatter_walk *walk,
+ unsigned int nbytes)
+{
+ scatterwalk_unmap(walk);
+ scatterwalk_advance(walk, nbytes);
+}
+
+/*
+ * Flush the dcache of any pages that overlap the region
+ * [offset, offset + nbytes) relative to base_page.
+ *
+ * This should be called only when ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE, to ensure
+ * that all relevant code (including the call to sg_page() in the caller, if
+ * applicable) gets fully optimized out when !ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE.
+ */
+static inline void __scatterwalk_flush_dcache_pages(struct page *base_page,
+ unsigned int offset,
+ unsigned int nbytes)
+{
+ unsigned int num_pages;
+
+ base_page += offset / PAGE_SIZE;
+ offset %= PAGE_SIZE;
+
+ /*
+ * This is an overflow-safe version of
+ * num_pages = DIV_ROUND_UP(offset + nbytes, PAGE_SIZE).
+ */
+ num_pages = nbytes / PAGE_SIZE;
+ num_pages += DIV_ROUND_UP(offset + (nbytes % PAGE_SIZE), PAGE_SIZE);
+
+ for (unsigned int i = 0; i < num_pages; i++)
+ flush_dcache_page(base_page + i);
+}
+
+/**
+ * scatterwalk_done_dst() - Finish one step of a walk of destination scatterlist
+ * @walk: the scatter_walk
+ * @nbytes: the number of bytes processed this step, less than or equal to the
+ * number of bytes that scatterwalk_next() returned.
+ *
+ * Use this if the mapped address may have been written to, i.e. it is
+ * destination data.
+ */
+static inline void scatterwalk_done_dst(struct scatter_walk *walk,
+ unsigned int nbytes)
+{
+ scatterwalk_unmap(walk);
+ if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE)
+ __scatterwalk_flush_dcache_pages(sg_page(walk->sg),
+ walk->offset, nbytes);
+ scatterwalk_advance(walk, nbytes);
+}
+
+void scatterwalk_skip(struct scatter_walk *walk, unsigned int nbytes);
+
+void memcpy_from_scatterwalk(void *buf, struct scatter_walk *walk,
+ unsigned int nbytes);
+
+void memcpy_to_scatterwalk(struct scatter_walk *walk, const void *buf,
+ unsigned int nbytes);
+
+void memcpy_from_sglist(void *buf, struct scatterlist *sg,
+ unsigned int start, unsigned int nbytes);
+
+void memcpy_to_sglist(struct scatterlist *sg, unsigned int start,
+ const void *buf, unsigned int nbytes);
+
+void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src,
+ unsigned int nbytes);
+
+/* In new code, please use memcpy_{from,to}_sglist() directly instead. */
+static inline void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
+ unsigned int start,
+ unsigned int nbytes, int out)
+{
+ if (out)
+ memcpy_to_sglist(sg, start, buf, nbytes);
+ else
+ memcpy_from_sglist(buf, sg, start, nbytes);
+}
+
+struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
+ struct scatterlist *src,
+ unsigned int len);
+
+#endif /* _CRYPTO_SCATTERWALK_H */