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Subject[PATCH 4.4 41/78] bna: avoid writing uninitialized data into hw registers
4.4-stable review patch.  If anyone has any objections, please let me know.


From: Arnd Bergmann <>

[ Upstream commit a5af83925363eb85d467933e3d6ec5a87001eb7c ]

The latest gcc-7 snapshot warns about bfa_ioc_send_enable/bfa_ioc_send_disable
writing undefined values into the hardware registers:

drivers/net/ethernet/brocade/bna/bfa_ioc.c: In function 'bfa_iocpf_sm_disabling_entry':
arch/arm/include/asm/io.h:109:22: error: '*((void *)&disable_req+4)' is used uninitialized in this function [-Werror=uninitialized]
arch/arm/include/asm/io.h:109:22: error: '*((void *)&disable_req+8)' is used uninitialized in this function [-Werror=uninitialized]

The two functions look like they should do the same thing, but only one
of them initializes the time stamp and clscode field. The fact that we
only get a warning for one of the two functions seems to be arbitrary,
based on the inlining decisions in the compiler.

To address this, I'm making both functions do the same thing:

- set the clscode from the ioc structure in both
- set the time stamp from ktime_get_real_seconds (which also
avoids the signed-integer overflow in 2038 and extends the
well-defined behavior until 2106).
- zero-fill the reserved field

Fixes: 8b230ed8ec96 ("bna: Brocade 10Gb Ethernet device driver")
Signed-off-by: Arnd Bergmann <>
Signed-off-by: David S. Miller <>
Signed-off-by: Sasha Levin <>
Signed-off-by: Greg Kroah-Hartman <>
drivers/net/ethernet/brocade/bna/bfa_ioc.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

--- a/drivers/net/ethernet/brocade/bna/bfa_ioc.c
+++ b/drivers/net/ethernet/brocade/bna/bfa_ioc.c
@@ -1930,13 +1930,13 @@ static void
bfa_ioc_send_enable(struct bfa_ioc *ioc)
struct bfi_ioc_ctrl_req enable_req;
- struct timeval tv;

enable_req.clscode = htons(ioc->clscode);
- do_gettimeofday(&tv);
- enable_req.tv_sec = ntohl(tv.tv_sec);
+ enable_req.rsvd = htons(0);
+ /* overflow in 2106 */
+ enable_req.tv_sec = ntohl(ktime_get_real_seconds());
bfa_ioc_mbox_send(ioc, &enable_req, sizeof(struct bfi_ioc_ctrl_req));

@@ -1947,6 +1947,10 @@ bfa_ioc_send_disable(struct bfa_ioc *ioc

+ disable_req.clscode = htons(ioc->clscode);
+ disable_req.rsvd = htons(0);
+ /* overflow in 2106 */
+ disable_req.tv_sec = ntohl(ktime_get_real_seconds());
bfa_ioc_mbox_send(ioc, &disable_req, sizeof(struct bfi_ioc_ctrl_req));

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