diff options
| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-03-28 13:36:29 +1100 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-04-07 10:33:15 +1000 |
| commit | a944a9c40b81a71609692c4909bb57e1d01f4bb7 (patch) | |
| tree | 88bf4fbfa126ba8c66cf315d34f04913b6e05260 /arch/powerpc | |
| parent | 7222f779acf94a123557c7bbbfbcc19424589f52 (diff) | |
| download | linux-a944a9c40b81a71609692c4909bb57e1d01f4bb7.tar.bz2 | |
powerpc/ppc64: Gracefully handle early interrupts
If we take an interrupt such as a trap caused by a BUG_ON before the
MMU has been setup, the interrupt handlers try to enable virutal mode
and cause a recursive crash, making the original problem very hard
to debug.
This fixes it by adjusting the "kernel_msr" value in the PACA so that
it only has MSR_IR and MSR_DR (translation for instruction and data)
set after the MMU has been initialized for the processor.
We may still not have a console yet but at least we don't get into
a recursive fault (and early debug console or memory dump via JTAG
of the kernel buffer *will* give us the proper error).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/paca.c | 3 | ||||
| -rw-r--r-- | arch/powerpc/kernel/setup_64.c | 15 |
2 files changed, 17 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c index bf0aada02fe4..ad302f845e5d 100644 --- a/arch/powerpc/kernel/paca.c +++ b/arch/powerpc/kernel/paca.c @@ -152,7 +152,8 @@ void __init initialise_paca(struct paca_struct *new_paca, int cpu) new_paca->paca_index = cpu; new_paca->kernel_toc = kernel_toc; new_paca->kernelbase = (unsigned long) _stext; - new_paca->kernel_msr = MSR_KERNEL; + /* Only set MSR:IR/DR when MMU is initialized */ + new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR); new_paca->hw_cpu_id = 0xffff; new_paca->kexec_state = KEXEC_STATE_NONE; new_paca->__current = &init_task; diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index d8aabbdc6483..1d33e817ab2d 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -261,6 +261,14 @@ void __init early_setup(unsigned long dt_ptr) /* Initialize the hash table or TLB handling */ early_init_mmu(); + /* + * At this point, we can let interrupts switch to virtual mode + * (the MMU has been setup), so adjust the MSR in the PACA to + * have IR and DR set. + */ + get_paca()->kernel_msr = MSR_KERNEL; + + /* Reserve large chunks of memory for use by CMA for KVM */ kvm_cma_reserve(); /* @@ -293,6 +301,13 @@ void early_setup_secondary(void) /* Initialize the hash table or TLB handling */ early_init_mmu_secondary(); + + /* + * At this point, we can let interrupts switch to virtual mode + * (the MMU has been setup), so adjust the MSR in the PACA to + * have IR and DR set. + */ + get_paca()->kernel_msr = MSR_KERNEL; } #endif /* CONFIG_SMP */ |