From mboxrd@z Thu Jan 1 00:00:00 1970 From: vladimir.murzin@arm.com (Vladimir Murzin) Date: Tue, 08 Dec 2015 12:41:50 +0000 Subject: [PATCH V2] ARM: SWP emulation: Restore original *data when failed In-Reply-To: <20151208104418.GB8644@n2100.arm.linux.org.uk> References: <726a7ce88982fba5df84e4d22b083e39b57a6bc6.1444900732.git.shengjiu.wang@freescale.com> <5666AF7D.5000703@arm.com> <20151208104418.GB8644@n2100.arm.linux.org.uk> Message-ID: <5666D00E.1000301@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 08/12/15 10:44, Russell King - ARM Linux wrote: > On Tue, Dec 08, 2015 at 10:22:53AM +0000, Vladimir Murzin wrote: >> On 15/10/15 10:30, 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 >>> causes the result is wrong. >>> This patch is to fix this issue. When STREX succeed, change the *data. >>> if it fail, *data is not changed. >>> >>> Signed-off-by: Shengjiu Wang >>> --- >>> arch/arm/kernel/swp_emulate.c | 6 +++--- >>> 1 file changed, 3 insertions(+), 3 deletions(-) >>> >>> diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c >>> index 5b26e7e..c3fe769d 100644 >>> --- a/arch/arm/kernel/swp_emulate.c >>> +++ b/arch/arm/kernel/swp_emulate.c >>> @@ -36,10 +36,10 @@ >>> */ >>> #define __user_swpX_asm(data, addr, res, temp, B) \ >>> __asm__ __volatile__( \ >>> - " mov %2, %1\n" \ >>> - "0: ldrex"B" %1, [%3]\n" \ >>> - "1: strex"B" %0, %2, [%3]\n" \ >>> + "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" \ >>> "2:\n" \ >>> " .section .text.fixup,\"ax\"\n" \ >>> >> >> I wonder what is status of this patch? I see that arm64 counterpart has >> landed in mainline, but I didn't manage to track down this one - is it >> because it never been submitted to patch system? > > Most probably. > I've just submitted (on behalf of Shengjiu) it as 8475/1 with assumption you have no concerns about the patch. Thanks Vladimir