Commit 2d65ed76 authored by Alex Elder's avatar Alex Elder Committed by David S. Miller
Browse files

net: ipa: fix register write command validation 



In ipa_cmd_register_write_valid() we verify that values we will
supply to a REGISTER_WRITE IPA immediate command will fit in
the fields that need to hold them.  This patch fixes some issues
in that function and ipa_cmd_register_write_offset_valid().

The dev_err() call in ipa_cmd_register_write_offset_valid() has
some printf format errors:
  - The name of the register (corresponding to the string format
    specifier) was not supplied.
  - The IPA base offset and offset need to be supplied separately to
    match the other format specifiers.
Also make the ~0 constant used there to compute the maximum
supported offset value explicitly unsigned.

There are two other issues in ipa_cmd_register_write_valid():
  - There's no need to check the hash flush register for platforms
    (like IPA v4.2) that do not support hashed tables
  - The highest possible endpoint number, whose status register
    offset is computed, is COUNT - 1, not COUNT.

Fix these problems, and add some additional commentary.

Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4c7ccfcd

drivers/net/ipa/ipa_cmd.c

+24 −8
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.

 * Copyright (C) 2019-2020 Linaro Ltd.

 * Copyright (C) 2019-2021 Linaro Ltd.

 */



#include <linux/types.h>
@@ -244,11 +244,15 @@ static bool ipa_cmd_register_write_offset_valid(struct ipa *ipa, 
	if (ipa->version != IPA_VERSION_3_5_1)

		bit_count += hweight32(REGISTER_WRITE_FLAGS_OFFSET_HIGH_FMASK);

	BUILD_BUG_ON(bit_count > 32);

	offset_max = ~0 >> (32 - bit_count);

	offset_max = ~0U >> (32 - bit_count);



	/* Make sure the offset can be represented by the field(s)

	 * that holds it.  Also make sure the offset is not outside

	 * the overall IPA memory range.

	 */

	if (offset > offset_max || ipa->mem_offset > offset_max - offset) {

		dev_err(dev, "%s offset too large 0x%04x + 0x%04x > 0x%04x)\n",

				ipa->mem_offset + offset, offset_max);

			name, ipa->mem_offset, offset, offset_max);

		return false;

	}
@@ -261,12 +265,24 @@ static bool ipa_cmd_register_write_valid(struct ipa *ipa) 
	const char *name;

	u32 offset;



	/* If hashed tables are supported, ensure the hash flush register

	 * offset will fit in a register write IPA immediate command.

	 */

	if (ipa->version != IPA_VERSION_4_2) {

		offset = ipa_reg_filt_rout_hash_flush_offset(ipa->version);

		name = "filter/route hash flush";

		if (!ipa_cmd_register_write_offset_valid(ipa, name, offset))

			return false;

	}



	offset = IPA_REG_ENDP_STATUS_N_OFFSET(IPA_ENDPOINT_COUNT);

	/* Each endpoint can have a status endpoint associated with it,

	 * and this is recorded in an endpoint register.  If the modem

	 * crashes, we reset the status endpoint for all modem endpoints

	 * using a register write IPA immediate command.  Make sure the

	 * worst case (highest endpoint number) offset of that endpoint

	 * fits in the register write command field(s) that must hold it.

	 */

	offset = IPA_REG_ENDP_STATUS_N_OFFSET(IPA_ENDPOINT_COUNT - 1);

	name = "maximal endpoint status";

	if (!ipa_cmd_register_write_offset_valid(ipa, name, offset))

		return false;