@@ -108,6 +108,13 @@
.endm
/*
+ * RAS Error Synchronization barrier
+ */
+ .macro esb
+ hint #16
+ .endm
+
+/*
* NOP sequence
*/
.macro nops, num
@@ -136,6 +136,13 @@
#define ESR_ELx_WFx_ISS_WFE (UL(1) << 0)
#define ESR_ELx_xVC_IMM_MASK ((1UL << 16) - 1)
+#define DISR_EL1_IDS (UL(1) << 24)
+/*
+ * DISR_EL1 and ESR_ELx share the bottom 13 bits, but the RES0 bits may mean
+ * different things in the future...
+ */
+#define DISR_EL1_ESR_MASK (ESR_ELx_AET | ESR_ELx_EA | ESR_ELx_FSC)
+
/* ESR value templates for specific events */
/* BRK instruction trap from AArch64 state */
@@ -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 */
@@ -194,5 +194,6 @@ static inline void spin_lock_prefetch(const void *ptr)
int cpu_enable_pan(void *__unused);
int cpu_enable_cache_maint_trap(void *__unused);
int cpu_enable_iesb(void *__unused);
+int cpu_clear_disr(void *__unused);
#endif /* __ASM_PROCESSOR_H */
@@ -179,6 +179,7 @@
#define SYS_AMAIR_EL1 sys_reg(3, 0, 10, 3, 0)
#define SYS_VBAR_EL1 sys_reg(3, 0, 12, 0, 0)
+#define SYS_DISR_EL1 sys_reg(3, 0, 12, 1, 1)
#define SYS_ICC_IAR0_EL1 sys_reg(3, 0, 12, 8, 0)
#define SYS_ICC_EOIR0_EL1 sys_reg(3, 0, 12, 8, 1)
@@ -911,6 +911,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.sign = FTR_UNSIGNED,
.field_pos = ID_AA64PFR0_RAS_SHIFT,
.min_field_value = ID_AA64PFR0_RAS_V1,
+ .enable = cpu_clear_disr,
},
#ifdef CONFIG_ARM64_IESB
{
@@ -1342,3 +1343,11 @@ int cpu_enable_iesb(void *__unused)
return 0;
}
+
+int cpu_clear_disr(void *__unused)
+{
+ /* Firmware may have left a deferred SError in this register. */
+ write_sysreg_s(0, SYS_DISR_EL1);
+
+ return 0;
+}
@@ -124,6 +124,11 @@ ENTRY(cpu_do_resume)
ubfx x11, x11, #1, #1
msr oslar_el1, x11
reset_pmuserenr_el0 x0 // Disable PMU access from EL0
+
+alternative_if ARM64_HAS_RAS_EXTN
+ msr_s SYS_DISR_EL1, xzr
+alternative_else_nop_endif
+
isb
ret
ENDPROC(cpu_do_resume)
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. While the kernel has issued ESB instructions before this point it has only done so with SError unmasked, 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. Signed-off-by: James Morse <james.morse@arm.com> --- arch/arm64/include/asm/assembler.h | 7 +++++++ arch/arm64/include/asm/esr.h | 7 +++++++ arch/arm64/include/asm/exception.h | 14 ++++++++++++++ arch/arm64/include/asm/processor.h | 1 + arch/arm64/include/asm/sysreg.h | 1 + arch/arm64/kernel/cpufeature.c | 9 +++++++++ arch/arm64/mm/proc.S | 5 +++++ 7 files changed, 44 insertions(+)