On Mon, Jun 8, 2015 at 1:34 AM, Ingo Molnar <[email protected]> wrote: > So the SYSENTER instruction is pretty quirky and it has different behavior > depending on bitness and CPU maker. > > Yet we create a false sense of coherency by naming it 'ia32_sysenter_target' > in both of the cases. > > Split the name into its two uses: > > ia32_sysenter_target (32) -> entry_SYSENTER_32 > ia32_sysenter_target (64) -> entry_SYSENTER_compat >
Now that I'm rebasing my pile on top of this, I have a minor gripe about this one. There are (in my mind, anyway), two SYSENTER instructions: the 32-bit one and the 64-bit one. (That is, there's SYSENTER32, which happens when you do SYSENTER in 32-bit or compat mode, and SYSENTER64, which happens when you do SYSENTER in long mode.) SYSENTER32, from user code's perspective, does the same thing in either case [1]. That means that it really does make sense that we'd have two implementations of the same entry point, one written in 32-bit asm and one written in 64-bit asm. The patch I'm rebasing merges the two wrmsrs to MSR_IA32_SYSENTER, and this change makes it uglier. [1] Sort of. We probably have differently nonsensical calling conventions, but that's our fault and has nothing to do with the hardware. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
