The command is 32-bit, but we are loading the 16 upper bits with
the 'get_uint16(s->scb + 2)' call.
Once shifted by 16, the command bits match the status bits:
- Command
Bit 31 ACK-CX Acknowledges that the CU completed an Action Command.
Bit 30 ACK-FR Acknowledges that the RU received a frame.
Bit 29 ACK-CNA Acknowledges that the Command Unit became not active.
Bit 28 ACK-RNR Acknowledges that the Receive Unit became not ready.
- Status
Bit 15 CX The CU finished executing a command with its I(interrupt) bit set.
Bit 14 FR The RU finished receiving a frame.
Bit 13 CNA The Command Unit left the Active state.
Bit 12 RNR The Receive Unit left the Ready state.
Add the SCB_COMMAND_ACK_MASK definition to simplify the code.
This fixes Coverity 1419392 (CONSTANT_EXPRESSION_RESULT):
/hw/net/i82596.c: 352 in examine_scb()
346 cuc = (command >> 8) & 0x7;
347 ruc = (command >> 4) & 0x7;
348 DBG(printf("MAIN COMMAND %04x cuc %02x ruc %02x\n", command, cuc, ruc));
349 /* and clear the scb command word */
350 set_uint16(s->scb + 2, 0);
351
>>> CID 1419392: (CONSTANT_EXPRESSION_RESULT)
>>> "command & (2147483648UL /* 1UL << 31 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if".
352 if (command & BIT(31)) /* ACK-CX */
353 s->scb_status &= ~SCB_STATUS_CX;
>>> CID 1419392: (CONSTANT_EXPRESSION_RESULT)
>>> "command & (1073741824UL /* 1UL << 30 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if".
354 if (command & BIT(30)) /*ACK-FR */
355 s->scb_status &= ~SCB_STATUS_FR;
>>> CID 1419392: (CONSTANT_EXPRESSION_RESULT)
>>> "command & (536870912UL /* 1UL << 29 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if".
356 if (command & BIT(29)) /*ACK-CNA */
357 s->scb_status &= ~SCB_STATUS_CNA;
>>> CID 1419392: (CONSTANT_EXPRESSION_RESULT)
>>> "command & (268435456UL /* 1UL << 28 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if".
358 if (command & BIT(28)) /*ACK-RNR */
359 s->scb_status &= ~SCB_STATUS_RNR;
Fixes: Covertiy CID 1419392 (commit 376b851909)
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
hw/net/i82596.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/hw/net/i82596.c b/hw/net/i82596.c
index 3a0e1ec4c0..b7c2458a96 100644
--- a/hw/net/i82596.c
+++ b/hw/net/i82596.c
@@ -43,6 +43,9 @@
#define SCB_STATUS_CNA 0x2000 /* CU left active state */
#define SCB_STATUS_RNR 0x1000 /* RU left active state */
+#define SCB_COMMAND_ACK_MASK \
+ (SCB_STATUS_CX | SCB_STATUS_FR | SCB_STATUS_CNA | SCB_STATUS_RNR)
+
#define CU_IDLE 0
#define CU_SUSPENDED 1
#define CU_ACTIVE 2
@@ -349,14 +352,7 @@ static void examine_scb(I82596State *s)
/* and clear the scb command word */
set_uint16(s->scb + 2, 0);
- if (command & BIT(31)) /* ACK-CX */
- s->scb_status &= ~SCB_STATUS_CX;
- if (command & BIT(30)) /*ACK-FR */
- s->scb_status &= ~SCB_STATUS_FR;
- if (command & BIT(29)) /*ACK-CNA */
- s->scb_status &= ~SCB_STATUS_CNA;
- if (command & BIT(28)) /*ACK-RNR */
- s->scb_status &= ~SCB_STATUS_RNR;
+ s->scb_status &= ~(command & SCB_COMMAND_ACK_MASK);
switch (cuc) {
case 0: /* no change */
--
2.21.1
On Fri, 14 Feb 2020 at 00:48, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote: > > The command is 32-bit, but we are loading the 16 upper bits with > the 'get_uint16(s->scb + 2)' call. > > Once shifted by 16, the command bits match the status bits: > > - Command > Bit 31 ACK-CX Acknowledges that the CU completed an Action Command. > Bit 30 ACK-FR Acknowledges that the RU received a frame. > Bit 29 ACK-CNA Acknowledges that the Command Unit became not active. > Bit 28 ACK-RNR Acknowledges that the Receive Unit became not ready. > > - Status > Bit 15 CX The CU finished executing a command with its I(interrupt) bit set. > Bit 14 FR The RU finished receiving a frame. > Bit 13 CNA The Command Unit left the Active state. > Bit 12 RNR The Receive Unit left the Ready state. > > Add the SCB_COMMAND_ACK_MASK definition to simplify the code. > > This fixes Coverity 1419392 (CONSTANT_EXPRESSION_RESULT): > > /hw/net/i82596.c: 352 in examine_scb() > 346 cuc = (command >> 8) & 0x7; > 347 ruc = (command >> 4) & 0x7; > 348 DBG(printf("MAIN COMMAND %04x cuc %02x ruc %02x\n", command, cuc, ruc)); > 349 /* and clear the scb command word */ > 350 set_uint16(s->scb + 2, 0); > 351 > >>> CID 1419392: (CONSTANT_EXPRESSION_RESULT) > >>> "command & (2147483648UL /* 1UL << 31 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if". > 352 if (command & BIT(31)) /* ACK-CX */ > 353 s->scb_status &= ~SCB_STATUS_CX; > >>> CID 1419392: (CONSTANT_EXPRESSION_RESULT) > >>> "command & (1073741824UL /* 1UL << 30 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if". > 354 if (command & BIT(30)) /*ACK-FR */ > 355 s->scb_status &= ~SCB_STATUS_FR; > >>> CID 1419392: (CONSTANT_EXPRESSION_RESULT) > >>> "command & (536870912UL /* 1UL << 29 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if". > 356 if (command & BIT(29)) /*ACK-CNA */ > 357 s->scb_status &= ~SCB_STATUS_CNA; > >>> CID 1419392: (CONSTANT_EXPRESSION_RESULT) > >>> "command & (268435456UL /* 1UL << 28 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if". > 358 if (command & BIT(28)) /*ACK-RNR */ > 359 s->scb_status &= ~SCB_STATUS_RNR; > > Fixes: Covertiy CID 1419392 (commit 376b851909) ("Coverity") > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Jason, are you planning to pick this one up? thanks -- PMM
On 2020/3/13 下午7:01, Peter Maydell wrote: > On Fri, 14 Feb 2020 at 00:48, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote: >> The command is 32-bit, but we are loading the 16 upper bits with >> the 'get_uint16(s->scb + 2)' call. >> >> Once shifted by 16, the command bits match the status bits: >> >> - Command >> Bit 31 ACK-CX Acknowledges that the CU completed an Action Command. >> Bit 30 ACK-FR Acknowledges that the RU received a frame. >> Bit 29 ACK-CNA Acknowledges that the Command Unit became not active. >> Bit 28 ACK-RNR Acknowledges that the Receive Unit became not ready. >> >> - Status >> Bit 15 CX The CU finished executing a command with its I(interrupt) bit set. >> Bit 14 FR The RU finished receiving a frame. >> Bit 13 CNA The Command Unit left the Active state. >> Bit 12 RNR The Receive Unit left the Ready state. >> >> Add the SCB_COMMAND_ACK_MASK definition to simplify the code. >> >> This fixes Coverity 1419392 (CONSTANT_EXPRESSION_RESULT): >> >> /hw/net/i82596.c: 352 in examine_scb() >> 346 cuc = (command >> 8) & 0x7; >> 347 ruc = (command >> 4) & 0x7; >> 348 DBG(printf("MAIN COMMAND %04x cuc %02x ruc %02x\n", command, cuc, ruc)); >> 349 /* and clear the scb command word */ >> 350 set_uint16(s->scb + 2, 0); >> 351 >> >>> CID 1419392: (CONSTANT_EXPRESSION_RESULT) >> >>> "command & (2147483648UL /* 1UL << 31 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if". >> 352 if (command & BIT(31)) /* ACK-CX */ >> 353 s->scb_status &= ~SCB_STATUS_CX; >> >>> CID 1419392: (CONSTANT_EXPRESSION_RESULT) >> >>> "command & (1073741824UL /* 1UL << 30 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if". >> 354 if (command & BIT(30)) /*ACK-FR */ >> 355 s->scb_status &= ~SCB_STATUS_FR; >> >>> CID 1419392: (CONSTANT_EXPRESSION_RESULT) >> >>> "command & (536870912UL /* 1UL << 29 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if". >> 356 if (command & BIT(29)) /*ACK-CNA */ >> 357 s->scb_status &= ~SCB_STATUS_CNA; >> >>> CID 1419392: (CONSTANT_EXPRESSION_RESULT) >> >>> "command & (268435456UL /* 1UL << 28 */)" is always 0 regardless of the values of its operands. This occurs as the logical operand of "if". >> 358 if (command & BIT(28)) /*ACK-RNR */ >> 359 s->scb_status &= ~SCB_STATUS_RNR; >> >> Fixes: Covertiy CID 1419392 (commit 376b851909) > ("Coverity") > >> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > Reviewed-by: Peter Maydell <peter.maydell@linaro.org> > > Jason, are you planning to pick this one up? Yes. queued. Thanks > thanks > -- PMM >
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