Commit 9c1d9de5 authored by Théo Lebrun's avatar Théo Lebrun Committed by Greg Kroah-Hartman
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nvmem: rmem: make ->reg_read() straight forward code 



memory_read_from_buffer() is a weird choice; it:
 - is made for iteration with ppos a pointer.
 - does futile error checking in our case.
 - does NOT ensure we read exactly N bytes.

Replace it by:
1. A check that (offset + bytes) lands inside the region and,
2. a plain memcpy().

Signed-off-by: default avatarThéo Lebrun <theo.lebrun@bootlin.com>
Signed-off-by: default avatarSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20241230143035.265518-5-srinivas.kandagatla@linaro.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6fdbc7b9

drivers/nvmem/rmem.c

+6 −9
Original line number Diff line number Diff line
@@ -21,10 +21,10 @@ static int rmem_read(void *context, unsigned int offset, 
		     void *val, size_t bytes)

{

	struct rmem *priv = context;

	size_t available = priv->mem->size;

	loff_t off = offset;

	void *addr;

	int count;



	if ((phys_addr_t)offset + bytes > priv->mem->size)

		return -EIO;



	/*

	 * Only map the reserved memory at this point to avoid potential rogue
@@ -36,20 +36,17 @@ static int rmem_read(void *context, unsigned int offset, 
	 * An alternative would be setting the memory as RO, set_memory_ro(),

	 * but as of Dec 2020 this isn't possible on arm64.

	 */

	addr = memremap(priv->mem->base, available, MEMREMAP_WB);

	addr = memremap(priv->mem->base, priv->mem->size, MEMREMAP_WB);

	if (!addr) {

		dev_err(priv->dev, "Failed to remap memory region\n");

		return -ENOMEM;

	}



	count = memory_read_from_buffer(val, bytes, &off, addr, available);

	memcpy(val, addr + offset, bytes);



	memunmap(addr);



	if (count < 0)

		return count;



	return count == bytes ? 0 : -EIO;

	return 0;

}



static int rmem_probe(struct platform_device *pdev)