[PATCH v2 3/7] powerpc/eeh_cache: Add a way to dump the EEH address cache

[Sam Bobroff]

On Fri, Feb 15, 2019 at 11:48:13AM +1100, Oliver O'Halloran wrote:
> Adds a debugfs file that can be read to view the contents of the EEH
> address cache. This is pretty similar to the existing
> eeh_addr_cache_print() function, but that function is intended to debug
> issues inside of the kernel since it's #ifdef`ed out by default, and writes
> into the kernel log.
> 
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>

Reviewed-by: Sam Bobroff <sbobroff at linux.ibm.com>

> ---
> v2: Added missing #endif
>     Replaced while loop with a for
> ---
>  arch/powerpc/include/asm/eeh.h  |  3 +++
>  arch/powerpc/kernel/eeh.c       |  1 +
>  arch/powerpc/kernel/eeh_cache.c | 30 ++++++++++++++++++++++++++----
>  3 files changed, 30 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
> index 2daecd677855..478f199d5663 100644
> --- a/arch/powerpc/include/asm/eeh.h
> +++ b/arch/powerpc/include/asm/eeh.h
> @@ -460,6 +460,9 @@ static inline void eeh_readsl(const volatile void __iomem *addr, void * buf,
>  		eeh_check_failure(addr);
>  }
>  
> +
> +void eeh_cache_debugfs_init(void);
> +
>  #endif /* CONFIG_PPC64 */
>  #endif /* __KERNEL__ */
>  #endif /* _POWERPC_EEH_H */
> diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
> index d021f5abeec5..82d22c671c0e 100644
> --- a/arch/powerpc/kernel/eeh.c
> +++ b/arch/powerpc/kernel/eeh.c
> @@ -1810,6 +1810,7 @@ static int __init eeh_init_proc(void)
>  					   &eeh_enable_dbgfs_ops);
>  		debugfs_create_u32("eeh_max_freezes", 0600,
>  				powerpc_debugfs_root, &eeh_max_freezes);
> +		eeh_cache_debugfs_init();
>  #endif
>  	}
>  
> diff --git a/arch/powerpc/kernel/eeh_cache.c b/arch/powerpc/kernel/eeh_cache.c
> index b2c320e0fcef..5c5697cced41 100644
> --- a/arch/powerpc/kernel/eeh_cache.c
> +++ b/arch/powerpc/kernel/eeh_cache.c
> @@ -26,6 +26,7 @@
>  #include <linux/spinlock.h>
>  #include <linux/atomic.h>
>  #include <asm/pci-bridge.h>
> +#include <asm/debugfs.h>
>  #include <asm/ppc-pci.h>
>  
>  
> @@ -298,9 +299,30 @@ void eeh_addr_cache_build(void)
>  		eeh_addr_cache_insert_dev(dev);
>  		eeh_sysfs_add_device(dev);
>  	}
> +}
>  
> -#ifdef DEBUG
> -	/* Verify tree built up above, echo back the list of addrs. */
> -	eeh_addr_cache_print(&pci_io_addr_cache_root);
> -#endif
> +static int eeh_addr_cache_show(struct seq_file *s, void *v)
> +{
> +	struct pci_io_addr_range *piar;
> +	struct rb_node *n;
> +
> +	spin_lock(&pci_io_addr_cache_root.piar_lock);
> +	for (n = rb_first(&pci_io_addr_cache_root.rb_root); n; n = rb_next(n)) {
> +		piar = rb_entry(n, struct pci_io_addr_range, rb_node);
> +
> +		seq_printf(s, "%s addr range [%pap-%pap]: %s\n",
> +		       (piar->flags & IORESOURCE_IO) ? "i/o" : "mem",
> +		       &piar->addr_lo, &piar->addr_hi, pci_name(piar->pcidev));
> +	}
> +	spin_unlock(&pci_io_addr_cache_root.piar_lock);
> +
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(eeh_addr_cache);
> +
> +void eeh_cache_debugfs_init(void)
> +{
> +	debugfs_create_file_unsafe("eeh_address_cache", 0400,
> +			powerpc_debugfs_root, NULL,
> +			&eeh_addr_cache_fops);
>  }
> -- 
> 2.20.1
> 
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