Re: [PATCH RFC 8/8] tile: implement syscall restart generically

From: Chris Metcalf
Date: Mon Oct 31 2011 - 11:48:23 EST

On 10/23/2011 6:20 AM, Jonas Bonn wrote:
> Manipulating task state to effect re-execution of an interrupted syscall
> used to be purely architecture specific code. However, as most arch's
> were essentially just making minor adjustments to almost identical logic,
> this code could be moved to a common implementation.
> The generic variant introduces the function handle_syscall_restart() to be
> called after get_signal_to_deliver(). The architecture specific register
> manipulations required to effect the actual restart are now implemented
> in the generic syscall interface found in asm/syscall.h
> This patch transitions this architecture's signal handling code over to
> using the generic syscall restart code by:
> i) Implementing the register manipulations in asm/syscall.h
> ii) Replacing the restart logic with a call to handle_syscall_restart
> Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
> Signed-off-by: Jonas Bonn <jonas@xxxxxxxxxxxx>

I like the idea, though the patch isn't quite right:

- You need to move the definition of INT_SWINT_1_SIGRETURN from
<asm/sigframe.h> to <asm/syscall.h>. You then have to add #includes of
<asm/syscall.h> to signal.c and stack.c in arch/tile/kernel. (And probably
use syscall_clear() in signal.c.)

- In syscall_do_restartblock() you need to use regs->regs[], not regs->gprs[].

Chris Metcalf, Tilera Corp.

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