linux_dsm_epyc7002/arch/powerpc/platforms/powernv/powernv.h
Nicholas Piggin b746e3e01e powerpc/powernv: Flush console before platform error reboot
Unrecovered MCE and HMI errors are sent through a special restart OPAL
call to log the platform error. The downside is that they don't go
through normal Linux crash paths, so they don't give much information
to the Linux console.

Change this by providing a special crash function which does some of
the console flushing from the panic() path before calling firmware to
reboot.

The downside of this is a little more code to execute before reaching
the firmware reboot. However in practice, it's critical to get the
Linux console messages output in order to debug a problem. So this is
a desirable tradeoff.

Note on the implementation: It is difficult to plumb a custom reboot
handler into the panic path, because panic does a little bit too much
work. For example, it will try to delay with the timebase, but that
may be corrupted in some cases resulting in a hang without reaching
the platform reboot. Another problem is that panic can invoke the
crash dump code which is not what we want in the case of a hardware
platform error. Long-term the best solution will be to rework the
panic path so it can be suitable for this kind of panic, but for now
we just duplicate a bit of the code.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:03 +10:00

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C

#ifndef _POWERNV_H
#define _POWERNV_H
#ifdef CONFIG_SMP
extern void pnv_smp_init(void);
#else
static inline void pnv_smp_init(void) { }
#endif
extern void pnv_platform_error_reboot(struct pt_regs *regs, const char *msg) __noreturn;
struct pci_dev;
#ifdef CONFIG_PCI
extern void pnv_pci_init(void);
extern void pnv_pci_shutdown(void);
#else
static inline void pnv_pci_init(void) { }
static inline void pnv_pci_shutdown(void) { }
#endif
extern u32 pnv_get_supported_cpuidle_states(void);
extern void pnv_lpc_init(void);
extern void opal_handle_events(uint64_t events);
extern void opal_event_shutdown(void);
bool cpu_core_split_required(void);
#endif /* _POWERNV_H */