On Thu, Oct 15, 2015 at 09:24:17AM +0100, Russell King - ARM Linux wrote: > On Wed, Oct 14, 2015 at 10:51:17AM +0800, Shengjiu Wang wrote: > > __user_swpX_asm maybe failed in first STREX operation, emulate_swpX > > will try again, but the *data has been changed in first time. which > > cause the result is wrong. So need to recover the *data when failed. > > > > Signed-off-by: Shengjiu Wang <shengjiu.w...@freescale.com> > > --- > > arch/arm/kernel/swp_emulate.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c > > index 5b26e7e..c61fbf92 100644 > > --- a/arch/arm/kernel/swp_emulate.c > > +++ b/arch/arm/kernel/swp_emulate.c > > @@ -41,6 +41,7 @@ > > "1: strex"B" %0, %2, [%3]\n" \ > > " cmp %0, #0\n" \ > > " movne %0, %4\n" \ > > + " movne %1, %2\n" \ > > "2:\n" \ > > " .section .text.fixup,\"ax\"\n" \ > > " .align 2\n" \ > > I think I'd prefer this to be: > > __asm__ __volatile__( \ > "0: ldrex"B" %2, [%3]\n" \ > "1: strex"B" %0, %1, [%3]\n" \ > " cmp %0, #0\n" \ > " moveq %1, %2\n" \ > " movne %0, %4\n" \ > > so that we're not loading into %1 (an in-out non-temporary) but rather > loading it into a temporary - and only overwriting the saved register > value if the swap succeeds. > > Thanks.
I am ok with your change. Need I send another patch for this change? or will you send it by yourself? best regards wang shengjiu > > -- > FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up > according to speedtest.net. -- 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/
