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Amit Kachhap authored
This patch add changes for Pointer Authentication enhanced features mandatory for Armv8.6. These features are, * Uses an enhanced PAC generation logic which hardens finding the correct PAC value of the authenticated pointer. However, no code change is required for this. * Fault is generated now when the ptrauth authentication instruction fails in authenticating the PAC present in the address. This is different from earlier case when such failures just adds an error code in the top byte and waits for subsequent load/store to abort. The ptrauth instructions which may cause this fault are autiasp, retaa etc. The above features are now represented by additional configurations for the Address Authentication cpufeature. These different configurations are now updated to FTR_EXACT instead of FTR_LOWER_SAFE as they all have different behaviour. The fault received in the kernel due to FPAC is treated as Illegal instruction and hence signal SIGILL is injected with ILL_ILLOPN as the signal code. Note that this is different from earlier ARMv8.3 ptrauth where signal SIGSEGV is issued due to Pointer authentication failures. Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
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