From: Will Deacon <will@kernel.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Greg KH <greg@kroah.com>, Mark Rutland <mark.rutland@arm.com>,
Julien Thierry <julien.thierry@arm.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
stable@vger.kernel.org, mark.brown@arm.com,
julien.thierry.kdev@gmail.com,
Russell King <rmk+kernel@arm.linux.org.uk>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4.4 V2 25/43] arm64: Move BP hardening to check_and_switch_context
Date: Thu, 1 Aug 2019 08:34:45 +0100 [thread overview]
Message-ID: <20190801073444.4n45h6kcbmejvzte@willie-the-truck> (raw)
In-Reply-To: <20190801070541.hpmadulgp45txfem@vireshk-i7>
On Thu, Aug 01, 2019 at 12:35:41PM +0530, Viresh Kumar wrote:
> On 01-08-19, 08:57, Greg KH wrote:
> > On Thu, Aug 01, 2019 at 12:05:44PM +0530, Viresh Kumar wrote:
> > > On 01-08-19, 07:30, Julien Thierry wrote:
> > > > I must admit I am not familiar with backport/stable process enough. But
> > > > personally I think the your suggestion seems more sensible than
> > > > backporting 4 patches.
> > > >
> > > > Or you can maybe ignore patch 25 and say in patch 24 that among the
> > > > changes made for the 4.4 codebase, the call arm64_apply_bp_hardening()
> > > > was moved from post_ttbr_update_workaround as it doesn't exist and
> > > > placed in check_and_switch_context() as it is its final destination.
> > >
> > > Done that and dropped the other two patches.
> > >
> > > > However, I really don't know what's the best way to proceed according to
> > > > existing practices. So input from someone else would be welcome.
> > >
> > > Lets see if someone comes up and ask me to do something else :)
> >
> > Keeping the same patches that upstream has is almost always the better
> > thing to do in the long-run.
>
> That would require two additional patches to be backported, 22 and 23
> from this series. From your suggestion it seems that keeping them is
> better here ?
Yes. Backporting individual patches as they appear upstream is definitely
the preferred method for -stable. It makes the relationship to mainline
crystal clear, as well as any dependencies between patches that have been
backported. Everytime we tweak something unecessarily in a stable backport,
it just creates the potential for confusion and additional conflicts in
future backports, so it's best to follow the shape of upstream as closely as
possible, even if it results in additional patches.
So I wouldn't worry about total number of patches. I'd worry more about
things like conflicts, deviation from mainline and overall testing coverage.
Will
next prev parent reply other threads:[~2019-08-01 7:34 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 5:27 [PATCH v4.4 V2 00/43] V4.4 backport of arm64 Spectre patches Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 01/43] arm64: barrier: Add CSDB macros to control data-value prediction Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 02/43] arm64: Implement array_index_mask_nospec() Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 03/43] arm64: move TASK_* definitions to <asm/processor.h> Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 04/43] arm64: Make USER_DS an inclusive limit Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 05/43] arm64: Use pointer masking to limit uaccess speculation Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 06/43] arm64: entry: Ensure branch through syscall table is bounded under speculation Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 07/43] arm64: uaccess: Prevent speculative use of the current addr_limit Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 08/43] arm64: uaccess: Don't bother eliding access_ok checks in __{get, put}_user Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 09/43] mm/kasan: add API to check memory regions Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 10/43] arm64: kasan: instrument user memory access API Viresh Kumar
2019-07-12 5:27 ` [PATCH v4.4 V2 11/43] arm64: uaccess: Mask __user pointers for __arch_{clear, copy_*}_user Viresh Kumar
2019-07-31 12:37 ` Mark Rutland
2019-08-01 3:38 ` Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 12/43] arm64: cpufeature: Test 'matches' pointer to find the end of the list Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 13/43] arm64: cpufeature: Add scope for capability check Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 14/43] arm64: Introduce cpu_die_early Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 15/43] arm64: Move cpu_die_early to smp.c Viresh Kumar
2019-07-31 12:35 ` Mark Rutland
2019-08-01 3:35 ` Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 16/43] arm64: Verify CPU errata work arounds on hotplugged CPU Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 17/43] arm64: errata: Calling enable functions for CPU errata too Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 18/43] arm64: Rearrange CPU errata workaround checks Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 19/43] arm64: Run enable method for errata work arounds on late CPUs Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 20/43] arm64: cpufeature: Pass capability structure to ->enable callback Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 21/43] drivers/firmware: Expose psci_get_version through psci_ops structure Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 22/43] arm64: Factor out TTBR0_EL1 post-update workaround into a specific asm macro Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 23/43] arm64: Move post_ttbr_update_workaround to C code Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 24/43] arm64: Add skeleton to harden the branch predictor against aliasing attacks Viresh Kumar
2019-07-31 16:45 ` Mark Rutland
2019-08-01 5:20 ` Viresh Kumar
2019-08-06 12:18 ` Mark Rutland
2019-08-08 12:06 ` Viresh Kumar
2019-08-28 10:23 ` Viresh Kumar
2019-08-28 16:08 ` Mark Rutland
2019-07-12 5:28 ` [PATCH v4.4 V2 25/43] arm64: Move BP hardening to check_and_switch_context Viresh Kumar
2019-07-31 13:09 ` Julien Thierry
2019-08-01 5:09 ` Viresh Kumar
2019-08-01 6:30 ` Julien Thierry
2019-08-01 6:35 ` Viresh Kumar
2019-08-01 6:57 ` Greg KH
2019-08-01 7:05 ` Viresh Kumar
2019-08-01 7:34 ` Will Deacon [this message]
2019-08-01 7:41 ` Viresh Kumar
2019-08-01 8:43 ` Greg KH
2019-08-01 8:49 ` Julien Thierry
2019-07-12 5:28 ` [PATCH v4.4 V2 26/43] arm64: entry: Apply BP hardening for high-priority synchronous exceptions Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 27/43] arm64: entry: Apply BP hardening for suspicious interrupts from EL0 Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 28/43] arm64: cputype: Add missing MIDR values for Cortex-A72 and Cortex-A75 Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 29/43] arm64: cpu_errata: Allow an erratum to be match for all revisions of a core Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 30/43] arm64: Implement branch predictor hardening for affected Cortex-A CPUs Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 31/43] arm64: cputype info for Broadcom Vulcan Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 32/43] arm64: cputype: Add MIDR values for Cavium ThunderX2 CPUs Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 33/43] arm64: Branch predictor hardening for Cavium ThunderX2 Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 34/43] ARM: 8478/2: arm/arm64: add arm-smccc Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 35/43] arm/arm64: KVM: Advertise SMCCC v1.1 Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 36/43] arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 37/43] firmware/psci: Expose PSCI conduit Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 38/43] firmware/psci: Expose SMCCC version through psci_ops Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 39/43] arm/arm64: smccc: Make function identifiers an unsigned quantity Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 40/43] arm/arm64: smccc: Implement SMCCC v1.1 inline primitive Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 41/43] arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 42/43] arm64: Kill PSCI_GET_VERSION as a variant-2 workaround Viresh Kumar
2019-07-12 5:28 ` [PATCH v4.4 V2 43/43] arm64: futex: Mask __user pointers prior to dereference Viresh Kumar
2019-07-15 13:09 ` [PATCH v4.4 V2 00/43] V4.4 backport of arm64 Spectre patches Mark Rutland
2019-07-16 3:44 ` Viresh Kumar
2019-07-31 2:52 ` Viresh Kumar
2019-07-31 17:02 ` Mark Rutland
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