| Date | Mon, 17 Jun 2019 14:56:37 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI |
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On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote: > From: Catalin Marinas <catalin.marinas@arm.com> > > It is not desirable to relax the ABI to allow tagged user addresses into > the kernel indiscriminately. This patch introduces a prctl() interface > for enabling or disabling the tagged ABI with a global sysctl control > for preventing applications from enabling the relaxed ABI (meant for > testing user-space prctl() return error checking without reconfiguring > the kernel). The ABI properties are inherited by threads of the same > application and fork()'ed children but cleared on execve(). > > The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle > MTE-specific settings like imprecise vs precise exceptions. > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
A question for the user-space folk: if an application opts in to this ABI, would you want the sigcontext.fault_address and/or siginfo.si_addr to contain the tag? We currently clear it early in the arm64 entry.S but we could find a way to pass it down if needed.
-- Catalin
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