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atl2: prevent compiler memory access misordering

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While no problems have been observed in practice yet, modern compilers
may reorder memory access operations, and that could lead to problems
with memory-mapped I/O typically done by drivers. This patch prevents
any potentially problematic reordering by the compiler in the ATL2
driver.

In addition, this patch removes a number of gcc/clang warnings.
This commit is contained in:
David van Moolenbroek 2011-11-04 14:14:59 +01:00
parent c83a90e2f1
commit ff542f0b27
1 changed files with 27 additions and 19 deletions
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46
drivers/atl2/atl2.c
View file

@ -37,7 +37,7 @@ PRIVATE struct {
int irq; /* IRQ number */
int hook_id; /* IRQ hook ID */
int mode; /* datalink mode */
char *base; /* base address of memory-mapped registers */
volatile u8_t *base; /* base address of memory-mapped registers */
u32_t size; /* size of memory-mapped area */
u32_t hwaddr[2]; /* MAC address, in register representation */
@ -628,25 +628,27 @@ PRIVATE int atl2_tx_advance(void)
*/
size = stat & ATL2_TXS_SIZE_MASK;
assert(state.txd_tail <= ATL2_TXD_BUFSIZE - sizeof(u32_t));
assert((u32_t) state.txd_tail <=
ATL2_TXD_BUFSIZE - sizeof(u32_t));
dsize = * (u32_t *) (state.txd_base + state.txd_tail);
if (size != dsize)
printf("ATL2: TxD/TxS size mismatch (%lx vs %lx)\n",
printf("ATL2: TxD/TxS size mismatch (%x vs %x)\n",
size, dsize);
/* Advance tails accordingly. */
size = sizeof(u32_t) + ATL2_ALIGN_32(dsize);
assert(state.txd_num >= size);
assert((u32_t) state.txd_num >= size);
state.txd_tail = (state.txd_tail + size) % ATL2_TXD_BUFSIZE;
state.txd_num -= size;
state.txs_tail = (state.txs_tail + 1) % ATL2_TXS_COUNT;
state.txs_num--;
if (stat & ATL2_TXS_SUCCESS)
if (stat & ATL2_TXS_SUCCESS) {
ATL2_DEBUG(("ATL2: successfully sent packet\n"));
else
} else {
ATL2_DEBUG(("ATL2: failed to send packet\n"));
}
/* Update statistics. */
atl2_tx_stat(stat);
@ -718,8 +720,11 @@ PRIVATE void atl2_rx_advance(int next)
}
/* If new RxD descriptors are now up for reuse, tell the device. */
if (update_tail)
if (update_tail) {
__insn_barrier();
ATL2_WRITE_U32(ATL2_RXD_IDX_REG, state.rxd_tail);
}
}
/*===========================================================================*
@ -935,13 +940,16 @@ PRIVATE void atl2_writev(const message *m, int from_int)
/* Update the TxD head. */
state.txd_num += sizeof(u32_t) + ATL2_ALIGN_32(count);
pos = ATL2_ALIGN_32(pos) % ATL2_TXD_BUFSIZE;
assert(pos == (state.txd_tail + state.txd_num) % ATL2_TXD_BUFSIZE);
assert((int) pos ==
(state.txd_tail + state.txd_num) % ATL2_TXD_BUFSIZE);
/* Initialize and update the TxS head. */
state.txs_base[(state.txs_tail + state.txs_num) % ATL2_TXS_COUNT] = 0;
state.txs_num++;
/* Tell the device about our new position. */
__insn_barrier();
ATL2_WRITE_U32(ATL2_TXD_IDX_REG, pos / sizeof(u32_t));
/* We have now successfully set up the transmission of a packet. */
@ -971,7 +979,7 @@ suspend:
/*===========================================================================*
* atl2_intr *
*===========================================================================*/
PRIVATE void atl2_intr(const message *m)
PRIVATE void atl2_intr(const message *UNUSED(m))
{
/* Interrupt received.
*/
@ -1030,21 +1038,21 @@ PRIVATE void atl2_conf(message *m)
{
/* Configure the mode of the card.
*/
ether_addr_t *addr;
ether_addr_t addr;
int r;
state.mode = m->DL_MODE;
atl2_set_mode();
addr = (ether_addr_t *) m->DL_HWADDR;
addr.ea_addr[0] = state.hwaddr[1] >> 8;
addr.ea_addr[1] = state.hwaddr[1] & 0xff;
addr.ea_addr[2] = state.hwaddr[0] >> 24;
addr.ea_addr[3] = (state.hwaddr[0] >> 16) & 0xff;
addr.ea_addr[4] = (state.hwaddr[0] >> 8) & 0xff;
addr.ea_addr[5] = state.hwaddr[0] & 0xff;
addr->ea_addr[0] = state.hwaddr[1] >> 8;
addr->ea_addr[1] = state.hwaddr[1] & 0xff;
addr->ea_addr[2] = state.hwaddr[0] >> 24;
addr->ea_addr[3] = (state.hwaddr[0] >> 16) & 0xff;
addr->ea_addr[4] = (state.hwaddr[0] >> 8) & 0xff;
addr->ea_addr[5] = state.hwaddr[0] & 0xff;
memcpy(m->DL_HWADDR, &addr, sizeof(addr));
m->m_type = DL_CONF_REPLY;
m->DL_STAT = OK;
@ -1155,7 +1163,7 @@ PRIVATE void atl2_dump(void)
/*===========================================================================*
* sef_cb_init_fresh *
*===========================================================================*/
PRIVATE int sef_cb_init_fresh(int type, sef_init_info_t *UNUSED(info))
PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
{
/* Initialize the atl2 driver.
*/
@ -1216,7 +1224,7 @@ PRIVATE void sef_cb_signal_handler(int signo)
free_contig(state.rxd_base_u,
state.rxd_align + ATL2_RXD_COUNT * ATL2_RXD_SIZE);
vm_unmap_phys(SELF, state.base, state.size);
vm_unmap_phys(SELF, (void *) state.base, state.size);
/* We cannot free the PCI device at this time. */