[PATCH 5.11 064/152] net: ipa: fix register write command validation

Greg Kroah-Hartman
2021-04-05T09:18:00Z

From: Alex Elder <elder@linaro.org>

[ Upstream commit 2d65ed76924bc772d3974b0894d870b1aa63b34a ]

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: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ipa/ipa_cmd.c | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ipa/ipa_cmd.c b/drivers/net/ipa/ipa_cmd.c
index 002e51448510..eb65a11e33ea 100644
--- a/drivers/net/ipa/ipa_cmd.c
+++ b/drivers/net/ipa/ipa_cmd.c
@@ -1,7 +1,7 @@
// 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;

- 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;
+ /* 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;
--
2.30.1