I am confused. I saw the rest of your response. Let me go through it. Regards, Hon Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx> Sent: Wednesday, September 8, 2021 9:20:25 AM To: HON LUU <hon@xxxxxxxxxxxxxxxx> Cc: gcc-help@xxxxxxxxxxx <gcc-help@xxxxxxxxxxx> Subject: Re: gcc question Hi! On Wed, Sep 08, 2021 at 03:06:54PM +0000, HON LUU wrote: > + The modified gcc command did not compile. The error message would look like this. > In file included from ././include/linux/compiler_types.h:58, > from <command-line>: > ./arch/x86/include/asm/jump_label.h: In function ‘unmap_user_buf.part.3’: > ./include/linux/compiler-gcc.h:305:38: error: asm operand 0 probably doesn’t match constraints [-Werror] > #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) > ^~~ > ./arch/x86/include/asm/jump_label.h:38:2: note: in expansion of macro ‘asm_volatile_goto’ > asm_volatile_goto("1:" > ^~~~~~~~~~~~~~~~~ > ./include/linux/compiler-gcc.h:305:38: error: impossible constraint in ‘asm’ > #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) > ^~~ > ./arch/x86/include/asm/jump_label.h:38:2: note: in expansion of macro ‘asm_volatile_goto’ > asm_volatile_goto("1:" > ^~~~~~~~~~~~~~~~~ > cc1: all warnings being treated as errors (Use LANG=C or LC_ALL=C to not get those weird quotes, just like you would use this to get error messages that aren't translated, that the compiler developers can actually read :-) ) You need to show the full code of the asm_volatile_goto, and the declarations of everything used in its operands, for us to get a handle on what is going on here. Bonus points if you manage to make a stand- alone compilable testcase that shows the problem. GL;HF, Segher
