/* https://cirosantilli.com/linux-kernel-module-cheat#x86-shift-and-rotate-instructions */ #include LKMC_PROLOGUE mov $0x81, %r12 clc rcl $1, %r12b /* We'll have to save and restore flags across our asserts! * 2x PUSHF to maintain 16-bit stack alignment. * https://cirosantilli.com/linux-kernel-module-cheat#x86_64-calling-convention */ pushf pushf LKMC_ASSERT(jc) LKMC_ASSERT_EQ(%r12, $2) popf rcl $1, %r12b pushf LKMC_ASSERT(jnc) LKMC_ASSERT_EQ(%r12, $5) popf rcr $2, %r12b pushf LKMC_ASSERT(jnc) LKMC_ASSERT_EQ(%r12, $0x81) popf rcr $1, %r12b pushf LKMC_ASSERT(jc) LKMC_ASSERT_EQ(%r12, $0x40) add $16, %rsp LKMC_EPILOGUE