efirtc causing panic (was Re: Panic booting 12-RC2 on amd64)
Konstantin Belousov
kib at freebsd.org
Fri May 31 18:35:34 UTC 2019
On Fri, May 31, 2019 at 04:19:57PM +0200, Jan Martin Mikkelsen wrote:
> Hi,
>
> Christian has pointed me at this https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=233534 which he raised after his email. The workaround was to boot with “efi.rt.disabled=1”.
>
> I took a closer look at what is going on. The problem is that the EFI rt_gettime call is faulting, and the fault is handled in efirt_support.S and a failure is reported. These messages is in the kernel output:
>
> kernel trap 12 with interrupts disabled
> kernel trap 12 with interrupts disabled
> EFI rt_gettime call faulted, error 14
> efirtc0: cannot read EFI realtime clock, error 14
>
> So far, so good. The problem is that that later in startup the "smp_targeted_tlb_shootdown: interrupts disabled” panic occurs, if the SMP is enabled. With SMP disabled this does not occur and the system runs.
>
> I’m not sure whether this is a BIOS problem (seems likely) or something that could handled after dealing with the fault in efirt_support.S.
>
> While looking I found the code below that looks wrong in efi_enter(), but that is not the problem in this case.
>
> Just adding this to the archive in case someone else looks more closely later.
Try this. Only compile-time tested.
diff --git a/sys/amd64/amd64/efirt_support.S b/sys/amd64/amd64/efirt_support.S
index cd578eddcfb..b54b13b01fe 100644
--- a/sys/amd64/amd64/efirt_support.S
+++ b/sys/amd64/amd64/efirt_support.S
@@ -47,6 +47,9 @@ ENTRY(efi_rt_arch_call)
movq %r13, EC_R13(%rdi)
movq %r14, EC_R14(%rdi)
movq %r15, EC_R15(%rdi)
+ pushfq
+ popq %rax
+ movq %rax, EC_RFLAGS(%rdi)
movq PCPU(CURTHREAD), %rax
movq %rdi, TD_MD+MD_EFIRT_TMP(%rax)
movq PCPU(CURPCB), %rsi
@@ -98,6 +101,8 @@ efi_rt_arch_call_tail:
movq EC_RBP(%rdi), %rbp
movq EC_RSP(%rdi), %rsp
movq EC_RBX(%rdi), %rbx
+ pushq EC_RFLAGS(%rdi)
+ popfq
popq %rbp
ret
diff --git a/sys/amd64/amd64/genassym.c b/sys/amd64/amd64/genassym.c
index de3969734a1..2e81b823262 100644
--- a/sys/amd64/amd64/genassym.c
+++ b/sys/amd64/amd64/genassym.c
@@ -272,3 +272,4 @@ ASSYM(EC_R12, offsetof(struct efirt_callinfo, ec_r12));
ASSYM(EC_R13, offsetof(struct efirt_callinfo, ec_r13));
ASSYM(EC_R14, offsetof(struct efirt_callinfo, ec_r14));
ASSYM(EC_R15, offsetof(struct efirt_callinfo, ec_r15));
+ASSYM(EC_RFLAGS, offsetof(struct efirt_callinfo, ec_rflags));
diff --git a/sys/amd64/include/efi.h b/sys/amd64/include/efi.h
index 082223792ac..e630a338c17 100644
--- a/sys/amd64/include/efi.h
+++ b/sys/amd64/include/efi.h
@@ -72,6 +72,7 @@ struct efirt_callinfo {
register_t ec_r13;
register_t ec_r14;
register_t ec_r15;
+ register_t ec_rflags;
};
#endif /* __AMD64_INCLUDE_EFI_H_ */
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