Hi Larry, On Mon, May 26, 2014 at 07:56:12PM +0100, Larry Bassel wrote: > To implement the context tracker properly on arm64, > a function call needs to be made after debugging and > interrupts are turned on, but before the lr is changed > to point to ret_to_user(). If the function call > is made after the lr is changed the function will not > return to the correct place. > > For similar reasons, defer the setting of x0 so that > it doesn't need to be saved around the function call > (save far_el1 in x26 temporarily instead). > > Signed-off-by: Larry Bassel <[email protected]>
[...] > @@ -476,23 +481,27 @@ el0_undef: > // enable interrupts before calling the main handler > enable_dbg_and_irq > mov x0, sp > + adr lr, ret_to_user > b do_undefinstr > el0_dbg: > /* > * Debug exception handling > */ > tbnz x24, #0, el0_inv // EL0 only > - mrs x0, far_el1 > + mrs x26, far_el1 > + mov x0, x26 > mov x1, x25 > mov x2, sp > bl do_debug_exception > enable_dbg > + mov x0, x26 > b ret_to_user Why have you added this mov instruction? Will -- 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/
