Messages in this thread | | | Date | Mon, 16 Nov 2020 17:33:34 +0800 | From | Wen Gong <> | Subject | Re: drivers/net/wireless/ath/ath10k/sdio.c:2234:2: warning: Non-boolean value returned from function returning bool |
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On 2020-11-16 15:53, Kalle Valo wrote: > + ath10k list > > kernel test robot <rong.a.chen@intel.com> writes: > >> tree: >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >> master >> head: f01c30de86f1047e9bae1b1b1417b0ce8dcd15b1 >> commit: 3c45f21af84eb05a355919abc80cf70a3a681cee ath10k: sdio: add >> firmware coredump support >> compiler: nios2-linux-gcc (GCC) 9.3.0 >> >> If you fix the issue, kindly add following tag as appropriate >> Reported-by: kernel test robot <rong.a.chen@intel.com> >> >> >> cppcheck possible warnings: (new ones prefixed by >>, may not real >> problems) >> >>>> drivers/net/wireless/ath/ath10k/sdio.c:2234:2: warning: Non-boolean >> value returned from function returning bool >> [returnNonBoolInBooleanFunction] >> return param & HI_OPTION_SDIO_CRASH_DUMP_ENHANCEMENT_FW; >> ^ > > Is this really a problem? I guess we could change that to "!!(param & > HI_OPTION_SDIO_CRASH_DUMP_ENHANCEMENT_FW)" but how is that better and > does it make any practical difference when > ath10k_sdio_is_fast_dump_supported() returns a boolean anyway? It should not be a real problem by test before. ath10k_sdio_is_fast_dump_supported return true in test before. and fast_dump get true from ath10k_sdio_is_fast_dump_supported in ath10k_sdio_fw_crashed_dump.
the risk maybe like this: u32 param in ath10k_sdio_is_fast_dump_supported is 4 bytes, and bool is 1 byte. if Gcc does not do any convertion from u32 to bool, then the bool value will only get the lower byte(byte 0) of the 4 bytes, then maybe get an mistake result.
I did a disassemble of sdio.o with/without below change, and dump sdio.o, it have no difference in this place: I change send a patch with below change if needed. @@ -2231,7 +2231,7 @@ static bool ath10k_sdio_is_fast_dump_supported(struct ath10k *ar)
ath10k_dbg(ar, ATH10K_DBG_SDIO, "sdio hi_option_flag2 %x\n", param);
- return param & HI_OPTION_SDIO_CRASH_DUMP_ENHANCEMENT_FW; + return !!(param & HI_OPTION_SDIO_CRASH_DUMP_ENHANCEMENT_FW); }
objdump -Sl sdio.o > sdio.o-Sl.txt
0000000000002b00 <ath10k_sdio_fw_crashed_dump>: void ath10k_sdio_fw_crashed_dump(struct ath10k *ar) { ... /home/wgong/ath11k/ath-master/ath/drivers/net/wireless/ath/ath10k/sdio.c:2234
return param & HI_OPTION_SDIO_CRASH_DUMP_ENHANCEMENT_FW; 2b75: 8b 44 24 44 mov 0x44(%rsp),%eax 2b79: 25 00 08 00 00 and $0x800,%eax //"the SF, ZF, and PF flags are set according to the result".ZF will be 0 if true. 2b7e: 89 44 24 2c mov %eax,0x2c(%rsp) 2b82: 40 0f 95 c5 setne %bpl //"Set byte if not equal (ZF=0)".stored the ZF flag to bpl as value of fast_dump. ath10k_sdio_fw_crashed_dump(): /home/wgong/ath11k/ath-master/ath/drivers/net/wireless/ath/ath10k/sdio.c:2483 char guid[UUID_STRING_LEN + 1]; bool fast_dump;
fast_dump = ath10k_sdio_is_fast_dump_supported(ar);
if (fast_dump) 2b86: 0f 85 c3 03 00 00 jne 2f4f <ath10k_sdio_fw_crashed_dump+0x44f> //"Jump near if not equal (ZF=0)" ... /home/wgong/ath11k/ath-master/ath/drivers/net/wireless/ath/ath10k/sdio.c:2499 ath10k_sdio_dump_registers(ar, crash_data, fast_dump); 2be5: 40 0f b6 d5 movzbl %bpl,%edx //use the bpl stored as value of fast_dump 2be9: 48 89 de mov %rbx,%rsi 2bec: 4c 89 ff mov %r15,%rdi 2bef: e8 8c fb ff ff callq 2780 <ath10k_sdio_dump_registers>
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