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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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