diff options
Diffstat (limited to 'arch/arm64/kernel/sdei.c')
| -rw-r--r-- | arch/arm64/kernel/sdei.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c index 7689f2031c0c..e04b3e90c003 100644 --- a/arch/arm64/kernel/sdei.c +++ b/arch/arm64/kernel/sdei.c @@ -178,12 +178,6 @@ static __kprobes unsigned long _sdei_handler(struct pt_regs *regs, sdei_api_event_context(i, ®s->regs[i]); } - /* - * We didn't take an exception to get here, set PAN. UAO will be cleared - * by sdei_event_handler()s force_uaccess_begin() call. - */ - __uaccess_enable_hw_pan(); - err = sdei_event_handler(regs, arg); if (err) return SDEI_EV_FAILED; @@ -222,12 +216,39 @@ static __kprobes unsigned long _sdei_handler(struct pt_regs *regs, return vbar + 0x480; } +static void __kprobes notrace __sdei_pstate_entry(void) +{ + /* + * The original SDEI spec (ARM DEN 0054A) can be read ambiguously as to + * whether PSTATE bits are inherited unchanged or generated from + * scratch, and the TF-A implementation always clears PAN and always + * clears UAO. There are no other known implementations. + * + * Subsequent revisions (ARM DEN 0054B) follow the usual rules for how + * PSTATE is modified upon architectural exceptions, and so PAN is + * either inherited or set per SCTLR_ELx.SPAN, and UAO is always + * cleared. + * + * We must explicitly reset PAN to the expected state, including + * clearing it when the host isn't using it, in case a VM had it set. + */ + if (system_uses_hw_pan()) + set_pstate_pan(1); + else if (cpu_has_pan()) + set_pstate_pan(0); +} asmlinkage __kprobes notrace unsigned long __sdei_handler(struct pt_regs *regs, struct sdei_registered_event *arg) { unsigned long ret; + /* + * We didn't take an exception to get here, so the HW hasn't + * set/cleared bits in PSTATE that we may rely on. Initialize PAN. + */ + __sdei_pstate_entry(); + nmi_enter(); ret = _sdei_handler(regs, arg); |