| Message ID | 20151015130247.GB29301@arm.com |
|---|---|
| State | New |
| Headers | show |
On 15/10/15 14:02, Will Deacon wrote: > On Thu, Oct 15, 2015 at 10:17:47AM +0100, Vladimir Murzin wrote: >> We might need the same change for arm64 counterpart (see >> arch/arm64/kernel/armv8_deprecated.c). > > Something like below? Looks good. Should these two go to stable? Vladimir > > Will > >>From 63c3e83073cfac2e011adf0ed6f335275cc977a7 Mon Sep 17 00:00:00 2001 > From: Will Deacon <will.deacon@arm.com> > Date: Thu, 15 Oct 2015 13:55:53 +0100 > Subject: [PATCH] arm64: compat: fix stxr failure case in SWP emulation > > If the STXR instruction fails in the SWP emulation code, we leave *data > overwritten with the loaded value, therefore corrupting the data written > by a subsequent, successful attempt. > > This patch re-jigs the code so that we only write back to *data once we > know that the update has happened. > > Reported-by: Shengjiu Wang <shengjiu.wang@freescale.com> > Reported-by: Vladimir Murzin <vladimir.murzin@arm.com> > Signed-off-by: Will Deacon <will.deacon@arm.com> > --- > arch/arm64/kernel/armv8_deprecated.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c > index bcee7abac68e..6039d1eb5912 100644 > --- a/arch/arm64/kernel/armv8_deprecated.c > +++ b/arch/arm64/kernel/armv8_deprecated.c > @@ -284,12 +284,12 @@ static void register_insn_emulation_sysctl(struct ctl_table *table) > __asm__ __volatile__( \ > ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ > CONFIG_ARM64_PAN) \ > - " mov %w2, %w1\n" \ > - "0: ldxr"B" %w1, [%3]\n" \ > - "1: stxr"B" %w0, %w2, [%3]\n" \ > + "0: ldxr"B" %w2, [%3]\n" \ > + "1: stxr"B" %w0, %w1, [%3]\n" \ > " cbz %w0, 2f\n" \ > " mov %w0, %w4\n" \ > "2:\n" \ > + " mov %w1, %w2\n" \ > " .pushsection .fixup,\"ax\"\n" \ > " .align 2\n" \ > "3: mov %w0, %w5\n" \ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On 15/10/15 14:25, Vladimir Murzin wrote: > On 15/10/15 14:02, Will Deacon wrote: >> On Thu, Oct 15, 2015 at 10:17:47AM +0100, Vladimir Murzin wrote: >>> We might need the same change for arm64 counterpart (see >>> arch/arm64/kernel/armv8_deprecated.c). >> >> Something like below? > > Looks good. Should these two go to stable? On the second thought looks like we still update *data in case stxr fails (or I need more coffee). Vladimir > > Vladimir > >> >> Will >> >> >From 63c3e83073cfac2e011adf0ed6f335275cc977a7 Mon Sep 17 00:00:00 2001 >> From: Will Deacon <will.deacon@arm.com> >> Date: Thu, 15 Oct 2015 13:55:53 +0100 >> Subject: [PATCH] arm64: compat: fix stxr failure case in SWP emulation >> >> If the STXR instruction fails in the SWP emulation code, we leave *data >> overwritten with the loaded value, therefore corrupting the data written >> by a subsequent, successful attempt. >> >> This patch re-jigs the code so that we only write back to *data once we >> know that the update has happened. >> >> Reported-by: Shengjiu Wang <shengjiu.wang@freescale.com> >> Reported-by: Vladimir Murzin <vladimir.murzin@arm.com> >> Signed-off-by: Will Deacon <will.deacon@arm.com> >> --- >> arch/arm64/kernel/armv8_deprecated.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c >> index bcee7abac68e..6039d1eb5912 100644 >> --- a/arch/arm64/kernel/armv8_deprecated.c >> +++ b/arch/arm64/kernel/armv8_deprecated.c >> @@ -284,12 +284,12 @@ static void register_insn_emulation_sysctl(struct ctl_table *table) >> __asm__ __volatile__( \ >> ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ >> CONFIG_ARM64_PAN) \ >> - " mov %w2, %w1\n" \ >> - "0: ldxr"B" %w1, [%3]\n" \ >> - "1: stxr"B" %w0, %w2, [%3]\n" \ >> + "0: ldxr"B" %w2, [%3]\n" \ >> + "1: stxr"B" %w0, %w1, [%3]\n" \ >> " cbz %w0, 2f\n" \ >> " mov %w0, %w4\n" \ >> "2:\n" \ >> + " mov %w1, %w2\n" \ >> " .pushsection .fixup,\"ax\"\n" \ >> " .align 2\n" \ >> "3: mov %w0, %w5\n" \ >> > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index bcee7abac68e..6039d1eb5912 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -284,12 +284,12 @@ static void register_insn_emulation_sysctl(struct ctl_table *table) __asm__ __volatile__( \ ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ CONFIG_ARM64_PAN) \ - " mov %w2, %w1\n" \ - "0: ldxr"B" %w1, [%3]\n" \ - "1: stxr"B" %w0, %w2, [%3]\n" \ + "0: ldxr"B" %w2, [%3]\n" \ + "1: stxr"B" %w0, %w1, [%3]\n" \ " cbz %w0, 2f\n" \ " mov %w0, %w4\n" \ "2:\n" \ + " mov %w1, %w2\n" \ " .pushsection .fixup,\"ax\"\n" \ " .align 2\n" \ "3: mov %w0, %w5\n" \