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    Subject[PATCH AUTOSEL 4.18 074/131] ARM: 8783/1: NOMMU: Extend check for VBAR support
    Date
    From: Vladimir Murzin <vladimir.murzin@arm.com>

    [ Upstream commit c803ce3f18bd93b3b4a15d1da0c5b5ebc60e0b85 ]

    ARMv8R adds support for VBAR and updates ID_PFR1 with the new filed
    Sec_frac (bits [23:20]):

    Security fractional field. When the Security field is 0000, determines
    the support for features from the ARMv7 Security Extensions. Permitted
    values are:

    0000 No features from the ARMv7 Security Extensions are implemented.
    This value is not supported in ARMv8 if ID_PFR1 bits [7:4] are zero.

    0001 The implementation includes the VBAR, and the TCR.PD0 and TCR.PD1
    bits.

    0010 As for 0001, plus the ability to access Secure or Non-secure
    physical memory is supported.

    All other values are reserved.

    This field is only valid when ID_PFR1[7:4] == 0, otherwise it holds
    the value 0000.

    Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
    Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
    Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
    ---
    arch/arm/mm/nommu.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
    index 5dd6c58d653b..7d67c70bbded 100644
    --- a/arch/arm/mm/nommu.c
    +++ b/arch/arm/mm/nommu.c
    @@ -53,7 +53,8 @@ static inline bool security_extensions_enabled(void)
    {
    /* Check CPUID Identification Scheme before ID_PFR1 read */
    if ((read_cpuid_id() & 0x000f0000) == 0x000f0000)
    - return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4);
    + return cpuid_feature_extract(CPUID_EXT_PFR1, 4) ||
    + cpuid_feature_extract(CPUID_EXT_PFR1, 20);
    return 0;
    }

    --
    2.17.1
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