Hi Larry, On 05/22/2014 03:27 PM, Larry Bassel wrote: > Make calls to ct_user_enter when the kernel is exited > and ct_user_exit when the kernel is entered (in el0_da, > el0_ia, el0_svc, el0_irq and all of the "error" paths). > > These macros expand to function calls which will only work > properly if el0_sync and related code has been rearranged > (in a previous patch of this series). > > The calls to ct_user_exit are made after hw debugging has been > enabled (enable_dbg_and_irq). > > The call to ct_user_enter is made at the beginning of the > kernel_exit macro. > > This patch is based on earlier work by Kevin Hilman. > Save/restore optimizations were also done by Kevin.
> --- a/arch/arm64/kernel/entry.S > +++ b/arch/arm64/kernel/entry.S > @@ -30,6 +30,44 @@ > #include <asm/unistd32.h> > > /* > + * Context tracking subsystem. Used to instrument transitions > + * between user and kernel mode. > + */ > + .macro ct_user_exit, restore = 0 > +#ifdef CONFIG_CONTEXT_TRACKING > + bl context_tracking_user_exit > + .if \restore == 1 > + /* > + * Save/restore needed during syscalls. Restore syscall arguments from > + * the values already saved on stack during kernel_entry. > + */ > + ldp x0, x1, [sp] > + ldp x2, x3, [sp, #S_X2] > + ldp x4, x5, [sp, #S_X4] > + ldp x6, x7, [sp, #S_X6] > + .endif > +#endif > + .endm > + > + .macro ct_user_enter, save = 0 > +#ifdef CONFIG_CONTEXT_TRACKING > + .if \save == 1 > + /* > + * Save/restore only needed on syscall fastpath, which uses > + * x0-x2. > + */ > + push x2, x3 Why is x3 saved? > + push x0, x1 > + .endif > + bl context_tracking_user_enter > + .if \save == 1 > + pop x0, x1 > + pop x2, x3 > + .endif > +#endif > + .endm Thanks, Christopher -- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by the Linux Foundation. -- 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/
