On Wed, Jun 17, 2015 at 3:02 AM, Ingo Molnar <mi...@kernel.org> wrote: > > * Ingo Molnar <mi...@kernel.org> wrote: > >> >> * Andy Lutomirski <l...@kernel.org> wrote: >> >> > This is separate for ease of bisection. >> > >> > Signed-off-by: Andy Lutomirski <l...@kernel.org> >> > --- >> > arch/x86/entry/entry_64.S | 68 >> > +++++------------------------------------------ >> > 1 file changed, 7 insertions(+), 61 deletions(-) >> > >> > diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S >> > index 33acc3dcc281..a5044d7a9d43 100644 >> > --- a/arch/x86/entry/entry_64.S >> > +++ b/arch/x86/entry/entry_64.S >> > @@ -229,6 +229,11 @@ entry_SYSCALL_64_fastpath: >> > */ >> > USERGS_SYSRET64 >> > >> > +GLOBAL(int_ret_from_sys_call_irqs_off) >> > + TRACE_IRQS_ON >> > + ENABLE_INTERRUPTS(CLBR_NONE) >> > + jmp int_ret_from_sys_call >> >> Any reason why irq state tracking cannot be done in C as well, like the rest >> of >> the irq state tracking code? > > Never mind, I see you've done exactly that in patch #12. >
There are still some TRACE_IRQS_ON, LOCKDEP_SYS_EXIT, and such scattered throughout the asm. it's plausible that even more of that could be moved to C. We could also benchmark and find out how bad it would be if we just always filled pt_regs in completely in syscalls. If the performance hit isn't enough to matter, then we could potentially move the entire syscall path except pt_regs setup and sysret/iret into three C functions. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
