diff options
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/start.S | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/arm64/kernel/start.S b/arch/arm64/kernel/start.S index 6ee9941..3cf58d2 100644 --- a/arch/arm64/kernel/start.S +++ b/arch/arm64/kernel/start.S @@ -222,6 +222,24 @@ park: wfe b 1b 2: + /* interrupts masked at release, the manual's boot state */ + msr daifset, #0xf + /* + * every PE must read the same virtual counter. whatever + * ran before this loader could have left a per cpu offset + * in the virtual counter view, the kernel has no way to + * repair that itself. CNTVOFF_EL2 is writable at EL2 and + * the write holds for the EL1 virtual timer the kernel + * runs on. below EL2 it is out of reach, the reset value + * is the best a lower EL can do. + */ + mrs x4, CurrentEL + lsr x4, x4, #2 + cmp x4, #2 + b.lt 3f + msr cntvoff_el2, xzr + isb +3: mov x0, xzr /* secondaries enter with x0-x3 zero */ mov x1, xzr mov x2, xzr @@ -396,6 +414,15 @@ exc_serr: mov x1, #0 mov x2, lr bl exc_report + /* + * an SError while this loader runs means the machine is + * broken. handing the kernel a cpu that already lost is + * worse than stopping: report, then drive the reset domain + * the same way PSCI SYSTEM_RESET does. the reset call does + * not return, the park below is the fallback if a reset + * domain ignores the request. + */ + bl tb_system_reset ldp x29, x30, [sp], #16 b park |