Commit a5af8392 authored Mar 23, 2017 by Arnd Bergmann Committed by David S. Miller Mar 24, 2017

bna: avoid writing uninitialized data into hw registers



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: 8b230ed8 ("bna: Brocade 10Gb Ethernet device driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1f3466a0

drivers/net/ethernet/brocade/bna/bfa_ioc.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -1930,13 +1930,13 @@ static void
		bfa_ioc_send_enable(struct bfa_ioc *ioc)
		{
		struct bfi_ioc_ctrl_req enable_req;
		struct timeval tv;

		bfi_h2i_set(enable_req.mh, BFI_MC_IOC, BFI_IOC_H2I_ENABLE_REQ,
		bfa_ioc_portid(ioc));
		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)

		bfi_h2i_set(disable_req.mh, BFI_MC_IOC, BFI_IOC_H2I_DISABLE_REQ,
		bfa_ioc_portid(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));
		}