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arm64: mdscr_el1: avoid exposing DCC to userspace

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We don't want to expose the DCC to userspace, particularly as there is
a kernel console driver for it.

This patch resets mdscr_el1 to disable userspace access to the DCC
registers on the cold boot path.

Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2015-08-20 11:47:13 +01:00
parent bf0c4e0473
commit d8d23fa0f2
1 changed files with 2 additions and 1 deletions
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arch/arm64/mm/proc.S
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@ -151,7 +151,8 @@ ENTRY(__cpu_setup)
mov x0, #3 << 20 mov x0, #3 << 20
msr cpacr_el1, x0 // Enable FP/ASIMD msr cpacr_el1, x0 // Enable FP/ASIMD
msr mdscr_el1, xzr // Reset mdscr_el1 mov x0, #1 << 12 // Reset mdscr_el1 and disable
msr mdscr_el1, x0 // access to the DCC from EL0
/* /*
* Memory region attributes for LPAE: * Memory region attributes for LPAE:
* *