Hi Christopher, On Wed, Apr 03, 2013 at 07:01:01PM +0100, Christopher Covington wrote: > For accurate accounting call contextidr_thread_switch before a > task is scheduled, rather than after. > > Signed-off-by: Christopher Covington <c...@codeaurora.org> > --- > arch/arm64/kernel/process.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 0337cdb..c2cc249 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -311,11 +311,11 @@ struct task_struct *__switch_to(struct task_struct > *prev, > fpsimd_thread_switch(next); > tls_thread_switch(next); > hw_breakpoint_thread_switch(next); > + contextidr_thread_switch(next); > > /* the actual thread switch */ > last = cpu_switch_to(prev, next); > > - contextidr_thread_switch(next); > return last; > }
Catalin and I wondered about this and decided to go with the current approach in case a debugger, in response to the contextidr write, decided to go off and mine information about the *new* task using the sp. If we update the register before we've switched the registers, there's a sizeable window where the debugger will get confused. Do you have a real use-case that has triggered this patch? Cheers, Will -- 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/
