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arm64: kernel: Prepare for a DISR user

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KVM would like to consume any pending SError (or RAS error) after guest
exit. Today it has to unmask SError and use dsb+isb to synchronise the
CPU. With the RAS extensions we can use ESB to synchronise any pending
SError.

Add the necessary macros to allow DISR to be read and converted to an
ESR.

We clear the DISR register when we enable the RAS cpufeature, and the
kernel has not executed any ESB instructions. Any value we find in DISR
must have belonged to firmware. Executing an ESB instruction is the
only way to update DISR, so we can expect firmware to have handled
any deferred SError. By the same logic we clear DISR in the idle path.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
James Morse
2018-01-15 19:38:59 +00:00
committed by Catalin Marinas
parent f751daa4f9
commit 68ddbf09ec
7 changed files with 44 additions and 0 deletions
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14
arch/arm64/include/asm/exception.h
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@@ -18,6 +18,8 @@
#ifndef __ASM_EXCEPTION_H
#define __ASM_EXCEPTION_H
#include <asm/esr.h>
#include <linux/interrupt.h>
#define __exception __attribute__((section(".exception.text")))
@@ -27,4 +29,16 @@
#define __exception_irq_entry __exception
#endif
static inline u32 disr_to_esr(u64 disr)
{
unsigned int esr = ESR_ELx_EC_SERROR << ESR_ELx_EC_SHIFT;
if ((disr & DISR_EL1_IDS) == 0)
esr |= (disr & DISR_EL1_ESR_MASK);
else
esr |= (disr & ESR_ELx_ISS_MASK);
return esr;
}
#endif /* __ASM_EXCEPTION_H */