From e0784d8375962da584fa92be8457845f433e2ae2 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 10 Nov 2020 22:52:48 +0100 Subject: hw/net/can/ctucan: Avoid unused value in ctucan_send_ready_buffers() Coverity points out that in ctucan_send_ready_buffers() we set buff_st_mask = 0xf << (i * 4) inside the loop, but then we never use it before overwriting it later. The only thing we use the mask for is as part of the code that is inserting the new buff_st field into tx_status. That is more comprehensibly written using deposit32(), so do that and drop the mask variable entirely. We also update the buff_st local variable at multiple points during this function, but nothing can ever see these intermediate values, so just drop those, write the final TXT_TOK as a fixed constant value, and collapse the only remaining set/use of buff_st down into an extract32(). Fixes: Coverity CID 1432869 Signed-off-by: Peter Maydell Acked-by: Pavel Pisa Tested-by: Pavel Pisa Signed-off-by: Jason Wang --- hw/net/can/ctucan_core.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) (limited to 'hw/net') diff --git a/hw/net/can/ctucan_core.c b/hw/net/can/ctucan_core.c index 8486f429d7..f49c76261c 100644 --- a/hw/net/can/ctucan_core.c +++ b/hw/net/can/ctucan_core.c @@ -240,8 +240,6 @@ static void ctucan_send_ready_buffers(CtuCanCoreState *s) uint8_t *pf; int buff2tx_idx; uint32_t tx_prio_max; - unsigned int buff_st; - uint32_t buff_st_mask; if (!s->mode_settings.s.ena) { return; @@ -256,10 +254,7 @@ static void ctucan_send_ready_buffers(CtuCanCoreState *s) for (i = 0; i < CTUCAN_CORE_TXBUF_NUM; i++) { uint32_t prio; - buff_st_mask = 0xf << (i * 4); - buff_st = (s->tx_status.u32 >> (i * 4)) & 0xf; - - if (buff_st != TXT_RDY) { + if (extract32(s->tx_status.u32, i * 4, 4) != TXT_RDY) { continue; } prio = (s->tx_priority.u32 >> (i * 4)) & 0x7; @@ -271,10 +266,7 @@ static void ctucan_send_ready_buffers(CtuCanCoreState *s) if (buff2tx_idx == -1) { break; } - buff_st_mask = 0xf << (buff2tx_idx * 4); - buff_st = (s->tx_status.u32 >> (buff2tx_idx * 4)) & 0xf; int_stat.u32 = 0; - buff_st = TXT_RDY; pf = s->tx_buffer[buff2tx_idx].data; ctucan_buff2frame(pf, &frame); s->status.s.idle = 0; @@ -283,12 +275,11 @@ static void ctucan_send_ready_buffers(CtuCanCoreState *s) s->status.s.idle = 1; s->status.s.txs = 0; s->tx_fr_ctr.s.tx_fr_ctr_val++; - buff_st = TXT_TOK; int_stat.s.txi = 1; int_stat.s.txbhci = 1; s->int_stat.u32 |= int_stat.u32 & ~s->int_mask.u32; - s->tx_status.u32 = (s->tx_status.u32 & ~buff_st_mask) | - (buff_st << (buff2tx_idx * 4)); + s->tx_status.u32 = deposit32(s->tx_status.u32, + buff2tx_idx * 4, 4, TXT_TOK); } while (1); } -- cgit v1.2.3