* [PATCH v5 2/3] misc: amd-sbi: Address copy_to/from_user() warning reported in smatch
2025-07-16 11:07 [PATCH v5 1/3] misc: amd-sbi: Address potential integer overflow issue reported in smatch Akshay Gupta
@ 2025-07-16 11:07 ` Akshay Gupta
2025-07-16 11:07 ` [PATCH v5 3/3] misc: amd-sbi: Explicitly clear in/out arg "mb_in_out" Akshay Gupta
1 sibling, 0 replies; 3+ messages in thread
From: Akshay Gupta @ 2025-07-16 11:07 UTC (permalink / raw)
To: linux-kernel
Cc: gregkh, arnd, Anand.Umarji, Akshay Gupta, Dan Carpenter,
Naveen Krishna Chatradhi
Smatch warnings are reported for below commit,
Commit bb13a84ed6b7 ("misc: amd-sbi: Add support for CPUID protocol")
from Apr 28, 2025 (linux-next), leads to the following Smatch static
checker warning:
drivers/misc/amd-sbi/rmi-core.c:376 apml_rmi_reg_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
drivers/misc/amd-sbi/rmi-core.c:394 apml_mailbox_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
drivers/misc/amd-sbi/rmi-core.c:411 apml_cpuid_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
drivers/misc/amd-sbi/rmi-core.c:428 apml_mcamsr_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
copy_to/from_user() returns number of bytes, not copied.
In case data not copied, return "-EFAULT".
Additionally, fixes the "-EPROTOTYPE" error return as intended.
Fixes: 35ac2034db72 ("misc: amd-sbi: Add support for AMD_SBI IOCTL")
Fixes: bb13a84ed6b7 ("misc: amd-sbi: Add support for CPUID protocol")
Fixes: 69b1ba83d21c ("misc: amd-sbi: Add support for read MCA register protocol")
Fixes: cf141287b774 ("misc: amd-sbi: Add support for register xfer")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/aDVyO8ByVsceybk9@stanley.mountain/
Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
Signed-off-by: Akshay Gupta <akshay.gupta@amd.com>
---
Changes from v3:
- Update commit message to include "Fixes: Commit ID" as Greg's suggestion
Changes from v2:
- Update commit message to add, "fix the -EPROTOTYPE error return".
Changes from v1:
- Split patch as per Greg's suggestion
drivers/misc/amd-sbi/rmi-core.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/amd-sbi/rmi-core.c b/drivers/misc/amd-sbi/rmi-core.c
index 3570f3b269a9..9048517c088c 100644
--- a/drivers/misc/amd-sbi/rmi-core.c
+++ b/drivers/misc/amd-sbi/rmi-core.c
@@ -372,7 +372,8 @@ static int apml_rmi_reg_xfer(struct sbrmi_data *data,
mutex_unlock(&data->lock);
if (msg.rflag && !ret)
- return copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg));
+ if (copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg)))
+ return -EFAULT;
return ret;
}
@@ -390,7 +391,9 @@ static int apml_mailbox_xfer(struct sbrmi_data *data, struct apml_mbox_msg __use
if (ret && ret != -EPROTOTYPE)
return ret;
- return copy_to_user(arg, &msg, sizeof(struct apml_mbox_msg));
+ if (copy_to_user(arg, &msg, sizeof(struct apml_mbox_msg)))
+ return -EFAULT;
+ return ret;
}
static int apml_cpuid_xfer(struct sbrmi_data *data, struct apml_cpuid_msg __user *arg)
@@ -407,7 +410,9 @@ static int apml_cpuid_xfer(struct sbrmi_data *data, struct apml_cpuid_msg __user
if (ret && ret != -EPROTOTYPE)
return ret;
- return copy_to_user(arg, &msg, sizeof(struct apml_cpuid_msg));
+ if (copy_to_user(arg, &msg, sizeof(struct apml_cpuid_msg)))
+ return -EFAULT;
+ return ret;
}
static int apml_mcamsr_xfer(struct sbrmi_data *data, struct apml_mcamsr_msg __user *arg)
@@ -424,7 +429,9 @@ static int apml_mcamsr_xfer(struct sbrmi_data *data, struct apml_mcamsr_msg __us
if (ret && ret != -EPROTOTYPE)
return ret;
- return copy_to_user(arg, &msg, sizeof(struct apml_mcamsr_msg));
+ if (copy_to_user(arg, &msg, sizeof(struct apml_mcamsr_msg)))
+ return -EFAULT;
+ return ret;
}
static long sbrmi_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
--
2.25.1
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH v5 3/3] misc: amd-sbi: Explicitly clear in/out arg "mb_in_out"
2025-07-16 11:07 [PATCH v5 1/3] misc: amd-sbi: Address potential integer overflow issue reported in smatch Akshay Gupta
2025-07-16 11:07 ` [PATCH v5 2/3] misc: amd-sbi: Address copy_to/from_user() warning " Akshay Gupta
@ 2025-07-16 11:07 ` Akshay Gupta
1 sibling, 0 replies; 3+ messages in thread
From: Akshay Gupta @ 2025-07-16 11:07 UTC (permalink / raw)
To: linux-kernel
Cc: gregkh, arnd, Anand.Umarji, Akshay Gupta, Naveen Krishna Chatradhi
- New AMD processor will support different input/output for same command.
- In some scenarios the input value is not cleared, which will be added to
output before reporting the data.
- Clearing input explicitly will be a cleaner and safer approach.
Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
Signed-off-by: Akshay Gupta <akshay.gupta@amd.com>
---
New patch
drivers/misc/amd-sbi/rmi-core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/misc/amd-sbi/rmi-core.c b/drivers/misc/amd-sbi/rmi-core.c
index 9048517c088c..3dec2fc00124 100644
--- a/drivers/misc/amd-sbi/rmi-core.c
+++ b/drivers/misc/amd-sbi/rmi-core.c
@@ -320,6 +320,10 @@ int rmi_mailbox_xfer(struct sbrmi_data *data,
ret = regmap_read(data->regmap, SBRMI_OUTBNDMSG7, &ec);
if (ret || ec)
goto exit_clear_alert;
+
+ /* Clear the input value before updating the output data */
+ msg->mb_in_out = 0;
+
/*
* For a read operation, the initiator (BMC) reads the firmware
* response Command Data Out[31:0] from SBRMI::OutBndMsg_inst[4:1]
--
2.25.1
^ permalink raw reply [flat|nested] 3+ messages in thread