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Wed, 19 Aug 2026 14:18:08 -0700 (PDT) Received: from 913411032810 named unknown by gmailapi.google.com with HTTPREST; Wed, 19 Aug 2026 14:18:07 -0700 Received: from 913411032810 named unknown by gmailapi.google.com with HTTPREST; Wed, 19 Aug 2026 14:18:07 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Rob Barnes Date: Wed, 19 Aug 2026 14:18:07 -0700 X-Gm-Features: AcwNN1VmKNEcux0JFgEK3kh9naLcr-GDtwD2UA9toUWhBvGm0Img9SdPjFMqptM Message-ID: Subject: [PATCH v3] platform/chrome: cros_ec_proto: Fix deferred response To: bleung@chromium.org, tzungbi@kernel.org Cc: tomhughes@chromium.org, chrome-platform@lists.linux.dev, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When cros_ec_wait_until_complete() succeeds after an EC_RES_IN_PROGRESS status, it previously returned the 4-byte transfer size of EC_CMD_GET_COMMS_STATUS. For 0-byte payload commands (such as EC_CMD_FLASH_ERASE), userspace received 4 bytes instead of 0, causing response size validation errors. For commands expecting non-zero response payloads, the kernel exited without issuing EC_CMD_RESEND_RESPONSE, leaving response buffers uninitialized. Refactor cros_ec_wait_until_complete() to pass orig_msg, issue EC_CMD_RESEND_RESPONSE into orig_msg->data when insize > 0, and return 0 for 0-byte response commands. Signed-off-by: Rob Barnes --- v3: - Rebase against upstream chrome-platform/for-firmware-next tree (Tzung-Bi). - Fix MIME/email transport line-wrapping and formatting issues (Tzung-Bi). v2: - Drop redundant commit description sentences (Tzung-Bi). - Align function signature parameters to open parenthesis (Tzung-Bi). - Check orig_msg->insize =3D=3D 0 and add comments explaining the logic (Tzung-Bi / Rob). - Use u32 instead of uint32_t (Tzung-Bi). - Rename 0bytes test to 0byte (Tzung-Bi). - Check header immutability for insize in test cases (Tzung-Bi). --- drivers/platform/chrome/cros_ec_proto.c | 32 +++- drivers/platform/chrome/cros_ec_proto_test.c | 158 ++++++++++++++++++- 2 files changed, 183 insertions(+), 7 deletions(-) diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c index 1d8d9168ec1a..6d7c57e381e5 100644 --- a/drivers/platform/chrome/cros_ec_proto.c +++ b/drivers/platform/chrome/cros_ec_proto.c @@ -138,7 +138,8 @@ static int cros_ec_xfer_command(struct cros_ec_device *ec_dev, struct cros_ec_co return ret; } -static int cros_ec_wait_until_complete(struct cros_ec_device *ec_dev, uint32_t *result) +static int cros_ec_wait_until_complete(struct cros_ec_device *ec_dev, + struct cros_ec_command *orig_msg) { DEFINE_RAW_FLEX(struct cros_ec_command, msg, data, sizeof(struct ec_response_get_comms_status)); @@ -161,7 +162,7 @@ static int cros_ec_wait_until_complete(struct cros_ec_device *ec_dev, uint32_t * if (ret < 0) return ret; - *result =3D msg->result; + orig_msg->result =3D msg->result; if (msg->result !=3D EC_RES_SUCCESS) return ret; @@ -170,8 +171,31 @@ static int cros_ec_wait_until_complete(struct cros_ec_device *ec_dev, uint32_t * break; } - if (!(status->flags & EC_COMMS_STATUS_PROCESSING)) + if (!(status->flags & EC_COMMS_STATUS_PROCESSING)) { + u32 orig_cmd, orig_outsize, orig_version; + + /* If no response payload is expected, return 0. */ + if (orig_msg->insize =3D=3D 0) + return 0; + + /* + * Request the response using EC_CMD_RESEND_RESPONSE. + * Restore the original message fields so it appears + * to be a direct response to the original command. + */ + orig_cmd =3D orig_msg->command; + orig_outsize =3D orig_msg->outsize; + orig_version =3D orig_msg->version; + + orig_msg->command =3D EC_CMD_RESEND_RESPONSE; + orig_msg->outsize =3D 0; + orig_msg->version =3D 0; + ret =3D cros_ec_xfer_command(ec_dev, orig_msg); + orig_msg->command =3D orig_cmd; + orig_msg->outsize =3D orig_outsize; + orig_msg->version =3D orig_version; return ret; + } } if (i >=3D EC_COMMAND_RETRIES) @@ -185,7 +209,7 @@ static int cros_ec_send_command(struct cros_ec_device *ec_dev, struct cros_ec_co int ret =3D cros_ec_xfer_command(ec_dev, msg); if (msg->result =3D=3D EC_RES_IN_PROGRESS) - ret =3D cros_ec_wait_until_complete(ec_dev, &msg->result); + ret =3D cros_ec_wait_until_complete(ec_dev, msg); return ret; } diff --git a/drivers/platform/chrome/cros_ec_proto_test.c b/drivers/platform/chrome/cros_ec_proto_test.c index 3f281996a686..a7b1d64f78ce 100644 --- a/drivers/platform/chrome/cros_ec_proto_test.c +++ b/drivers/platform/chrome/cros_ec_proto_test.c @@ -1744,7 +1744,7 @@ static void cros_ec_proto_test_cmd_xfer_protocol_v2_no_op(struct kunit *test) KUNIT_EXPECT_EQ(test, ret, -EIO); } -static void cros_ec_proto_test_cmd_xfer_in_progress_normal(struct kunit *t= est) +static void cros_ec_proto_test_cmd_xfer_in_progress_payload_0byte(struct kunit *test) { struct cros_ec_proto_test_priv *priv =3D test->priv; struct cros_ec_device *ec_dev =3D &priv->ec_dev; @@ -1774,7 +1774,7 @@ static void cros_ec_proto_test_cmd_xfer_in_progress_normal(struct kunit *test) } ret =3D cros_ec_cmd_xfer(ec_dev, &msg); - KUNIT_EXPECT_EQ(test, ret, sizeof(struct ec_response_get_comms_status)); + KUNIT_EXPECT_EQ(test, ret, 0); KUNIT_EXPECT_EQ(test, msg.result, EC_RES_SUCCESS); @@ -1799,6 +1799,156 @@ static void cros_ec_proto_test_cmd_xfer_in_progress_normal(struct kunit *test) KUNIT_EXPECT_EQ(test, cros_kunit_ec_pkt_xfer_mock_called, 2); } +static void cros_ec_proto_test_cmd_xfer_in_progress_payload_4bytes(struct kunit *test) +{ + struct cros_ec_proto_test_priv *priv =3D test->priv; + struct cros_ec_device *ec_dev =3D &priv->ec_dev; + struct ec_xfer_mock *mock; + u8 resp_data[4] =3D {0x11, 0x22, 0x33, 0x44}; + struct { + struct cros_ec_command msg; + u8 data[4]; + } buf; + struct cros_ec_command *msg =3D &buf.msg; + int ret; + + memset(&buf, 0, sizeof(buf)); + msg->version =3D 1; + msg->command =3D 0x1234; + msg->outsize =3D 2; + msg->insize =3D sizeof(buf.data); + + ec_dev->pkt_xfer =3D cros_kunit_ec_pkt_xfer_mock; + + /* For initial command returning EC_RES_IN_PROGRESS. */ + { + mock =3D cros_kunit_ec_xfer_mock_addx(test, 0, EC_RES_IN_PROGRESS, 0); + KUNIT_ASSERT_PTR_NE(test, mock, NULL); + } + + /* For EC_CMD_GET_COMMS_STATUS status polling. */ + { + struct ec_response_get_comms_status *data; + + mock =3D cros_kunit_ec_xfer_mock_add(test, sizeof(*data)); + KUNIT_ASSERT_PTR_NE(test, mock, NULL); + + data =3D (struct ec_response_get_comms_status *)mock->o_data; + data->flags =3D 0; + } + + /* For EC_CMD_RESEND_RESPONSE returning 4 bytes payload. */ + { + mock =3D cros_kunit_ec_xfer_mock_add(test, sizeof(resp_data)); + KUNIT_ASSERT_PTR_NE(test, mock, NULL); + memcpy(mock->o_data, resp_data, sizeof(resp_data)); + } + + ret =3D cros_ec_cmd_xfer(ec_dev, msg); + KUNIT_EXPECT_EQ(test, ret, 4); + KUNIT_EXPECT_EQ(test, msg->result, EC_RES_SUCCESS); + KUNIT_EXPECT_EQ(test, msg->command, 0x1234); + KUNIT_EXPECT_EQ(test, msg->outsize, 2); + KUNIT_EXPECT_EQ(test, msg->insize, sizeof(buf.data)); + KUNIT_EXPECT_EQ(test, msg->version, 1); + KUNIT_EXPECT_EQ(test, memcmp(msg->data, resp_data, sizeof(resp_data)), 0); + + /* Verify mock sequence */ + { + mock =3D cros_kunit_ec_xfer_mock_next(); + KUNIT_EXPECT_PTR_NE(test, mock, NULL); + + mock =3D cros_kunit_ec_xfer_mock_next(); + KUNIT_EXPECT_PTR_NE(test, mock, NULL); + KUNIT_EXPECT_EQ(test, mock->msg.command, EC_CMD_GET_COMMS_STATUS); + + mock =3D cros_kunit_ec_xfer_mock_next(); + KUNIT_EXPECT_PTR_NE(test, mock, NULL); + KUNIT_EXPECT_EQ(test, mock->msg.command, EC_CMD_RESEND_RESPONSE); + KUNIT_EXPECT_EQ(test, mock->msg.outsize, 0); + KUNIT_EXPECT_EQ(test, mock->msg.version, 0); + KUNIT_EXPECT_EQ(test, mock->msg.insize, 4); + } + + KUNIT_EXPECT_EQ(test, cros_kunit_ec_pkt_xfer_mock_called, 3); +} + +static void cros_ec_proto_test_cmd_xfer_in_progress_payload_gt4bytes(struct kunit *test) +{ + struct cros_ec_proto_test_priv *priv =3D test->priv; + struct cros_ec_device *ec_dev =3D &priv->ec_dev; + struct ec_xfer_mock *mock; + u8 resp_data[16]; + struct { + struct cros_ec_command msg; + u8 data[16]; + } buf; + struct cros_ec_command *msg =3D &buf.msg; + int ret, i; + + for (i =3D 0; i < sizeof(resp_data); ++i) + resp_data[i] =3D (u8)(i + 1); + + memset(&buf, 0, sizeof(buf)); + msg->version =3D 0; + msg->command =3D 0x5678; + msg->insize =3D sizeof(buf.data); + + ec_dev->pkt_xfer =3D cros_kunit_ec_pkt_xfer_mock; + + /* For initial command returning EC_RES_IN_PROGRESS. */ + { + mock =3D cros_kunit_ec_xfer_mock_addx(test, 0, EC_RES_IN_PROGRESS, 0); + KUNIT_ASSERT_PTR_NE(test, mock, NULL); + } + + /* For EC_CMD_GET_COMMS_STATUS status polling. */ + { + struct ec_response_get_comms_status *data; + + mock =3D cros_kunit_ec_xfer_mock_add(test, sizeof(*data)); + KUNIT_ASSERT_PTR_NE(test, mock, NULL); + + data =3D (struct ec_response_get_comms_status *)mock->o_data; + data->flags =3D 0; + } + + /* For EC_CMD_RESEND_RESPONSE returning 16 bytes payload. */ + { + mock =3D cros_kunit_ec_xfer_mock_add(test, sizeof(resp_data)); + KUNIT_ASSERT_PTR_NE(test, mock, NULL); + memcpy(mock->o_data, resp_data, sizeof(resp_data)); + } + + ret =3D cros_ec_cmd_xfer(ec_dev, msg); + KUNIT_EXPECT_EQ(test, ret, 16); + KUNIT_EXPECT_EQ(test, msg->result, EC_RES_SUCCESS); + KUNIT_EXPECT_EQ(test, msg->command, 0x5678); + KUNIT_EXPECT_EQ(test, msg->outsize, 0); + KUNIT_EXPECT_EQ(test, msg->insize, sizeof(buf.data)); + KUNIT_EXPECT_EQ(test, msg->version, 0); + KUNIT_EXPECT_EQ(test, memcmp(msg->data, resp_data, sizeof(resp_data)), 0); + + /* Verify mock sequence */ + { + mock =3D cros_kunit_ec_xfer_mock_next(); + KUNIT_EXPECT_PTR_NE(test, mock, NULL); + + mock =3D cros_kunit_ec_xfer_mock_next(); + KUNIT_EXPECT_PTR_NE(test, mock, NULL); + KUNIT_EXPECT_EQ(test, mock->msg.command, EC_CMD_GET_COMMS_STATUS); + + mock =3D cros_kunit_ec_xfer_mock_next(); + KUNIT_EXPECT_PTR_NE(test, mock, NULL); + KUNIT_EXPECT_EQ(test, mock->msg.command, EC_CMD_RESEND_RESPONSE); + KUNIT_EXPECT_EQ(test, mock->msg.outsize, 0); + KUNIT_EXPECT_EQ(test, mock->msg.version, 0); + KUNIT_EXPECT_EQ(test, mock->msg.insize, 16); + } + + KUNIT_EXPECT_EQ(test, cros_kunit_ec_pkt_xfer_mock_called, 3); +} + static void cros_ec_proto_test_cmd_xfer_in_progress_retries_eagain(struct kunit *test) { struct cros_ec_proto_test_priv *priv =3D test->priv; @@ -2703,7 +2853,9 @@ static struct kunit_case cros_ec_proto_test_cases[] = =3D { KUNIT_CASE(cros_ec_proto_test_cmd_xfer_protocol_v3_no_op), KUNIT_CASE(cros_ec_proto_test_cmd_xfer_protocol_v2_normal), KUNIT_CASE(cros_ec_proto_test_cmd_xfer_protocol_v2_no_op), - KUNIT_CASE(cros_ec_proto_test_cmd_xfer_in_progress_normal), + KUNIT_CASE(cros_ec_proto_test_cmd_xfer_in_progress_payload_0byte), + KUNIT_CASE(cros_ec_proto_test_cmd_xfer_in_progress_payload_4bytes), + KUNIT_CASE(cros_ec_proto_test_cmd_xfer_in_progress_payload_gt4bytes), KUNIT_CASE(cros_ec_proto_test_cmd_xfer_in_progress_retries_eagain), KUNIT_CASE(cros_ec_proto_test_cmd_xfer_in_progress_retries_status_process= ing), KUNIT_CASE(cros_ec_proto_test_cmd_xfer_in_progress_xfer_error),