From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suzuki.Poulose@arm.com (Suzuki K Poulose) Date: Fri, 15 Apr 2016 11:36:57 +0100 Subject: [PATCH] arm64: fix invalidation of wrong __early_cpu_boot_status cacheline In-Reply-To: <20160415102017.GA8021@leverpostej> References: <1460715081-16542-1-git-send-email-ard.biesheuvel@linaro.org> <20160415102017.GA8021@leverpostej> Message-ID: <5710C449.3050900@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 15/04/16 11:20, Mark Rutland wrote: > On Fri, Apr 15, 2016 at 12:11:21PM +0200, Ard Biesheuvel wrote: >> In head.S, the str_l macro, which takes a source register, a symbol name >> and a temp register, is used to store a status value to the variable >> __early_cpu_boot_status. Subsequently, the value of the temp register is >> reused to invalidate any cachelines covering this variable. >> >> However, since str_l resolves to >> >> adrp \tmp, \sym >> str \src, [\tmp, :lo12:\sym] >> >> the temp register never actually holds the address of the variable but >> only of the 4 KB window that covers it, and reusing it leads to the >> wrong cacheline being invalidated. So instead, take the address >> explicitly before doing the store, and reuse that value to perform >> the cache invalidation. >> >> Signed-off-by: Ard Biesheuvel >> --- >> >> This deserves a cc stable, since the macro is always invoked for each CPU >> at boot. > > Sounds good, also: > > Fixes: bb9052744f4b7ae1 ("arm64: Handle early CPU boot failures") This first appeared in 4.6-rc1, so I don't think we need to Cc stable. The initial patch was using adr_l as in this fix. Catalin, was there a specific reason for that change ? I remember you mentioning something about it. Nevertheless, Acked-by: Suzuki K Poulose