Linux Kernel Module Cheat

userland/arch/x86_64/freestanding/linux/hello.S

userland/arch/x86_64/freestanding/linux/int_system_call.S

userland/arch/x86_64/inline_asm/freestanding/linux/hello.c: this shows how to do system calls from inline assembly without any C standard library helpers like syscall

userland/arch/x86_64/inline_asm/freestanding/linux/hello_regvar.c: same as userland/arch/x86_64/inline_asm/freestanding/linux/hello.c but using register variables instead of register constraints

userland/arch/arm/freestanding/linux/hello.S

userland/arch/arm/inline_asm/freestanding/linux/hello.c: there are no register constraints in ARM, so register variables are the most efficient way of storing variables in specific general purpose registers: https://stackoverflow.com/questions/3929442/how-to-specify-an-individual-register-as-constraint-in-arm-gcc-inline-assembly/54845046#54845046

userland/arch/aarch64/freestanding/linux/hello.S

userland/arch/aarch64/inline_asm/freestanding/linux/hello.c

userland/arch/aarch64/inline_asm/freestanding/linux/hello_clobbers.c