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ARM: 8783/1: NOMMU: Extend check for VBAR support 

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>
This commit is contained in:
Vladimir Murzin 2018-07-23 09:36:18 +01:00 committed by Russell King
parent 35f5a6acfb
commit c803ce3f18
1 changed files with 2 additions and 1 deletions
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3
arch/arm/mm/nommu.c
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@ -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;
}