[Skiboot] [PATCH] Fix infinite loop in wait_for_resource if CAPP ucode load fails

[Alistair Popple]

Stewart,

Looks ok and fixed the problem for me, feel free to add:

Acked-by: Alistair Popple <alistair at popple.id.au>

On Tue, 12 May 2015 14:05:59 Stewart Smith wrote:
> On failing to load CAPP microcode, we would call wait_for_resource_loaded
> for the next PHB but without issuing a new request, thus making
> wait_for_resource spin forever waiting for something that will
> never complete.
> 
> Fix is to just track result of load.
> 
> Reported-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Signed-off-by: Stewart Smith <stewart at linux.vnet.ibm.com>
> ---
>  hw/phb3.c |   19 ++++++++-----------
>  1 file changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/hw/phb3.c b/hw/phb3.c
> index d9cb57d..eb2ed46 100644
> --- a/hw/phb3.c
> +++ b/hw/phb3.c
> @@ -2182,7 +2182,7 @@ static struct {
>  	uint32_t			ec_level;
>  	struct capp_lid_hdr		*lid;
>  	size_t size;
> -	bool loaded;
> +	int load_result;
>  } capp_ucode_info = { 0, NULL, 0, false };
> 
>  #define CAPP_UCODE_MAX_SIZE 0x20000
> @@ -2190,26 +2190,23 @@ static struct {
>  static int64_t capp_lid_download(void)
>  {
>  	int64_t ret;
> -	int loaded;
> 
> -	if (capp_ucode_info.loaded == true)
> -		return OPAL_SUCCESS;
> +	if (capp_ucode_info.load_result != OPAL_EMPTY)
> +		return capp_ucode_info.load_result;
> 
> -	loaded = wait_for_resource_loaded(RESOURCE_ID_CAPP,
> -					  capp_ucode_info.ec_level);
> +	capp_ucode_info.load_result = wait_for_resource_loaded(
> +		RESOURCE_ID_CAPP,
> +		capp_ucode_info.ec_level);
> 
> -	if (loaded != OPAL_SUCCESS) {
> +	if (capp_ucode_info.load_result != OPAL_SUCCESS) {
>  		prerror("CAPP: Error loading ucode lid. index=%x\n",
>  			capp_ucode_info.ec_level);
>  		ret = OPAL_RESOURCE;
>  		free(capp_ucode_info.lid);
>  		capp_ucode_info.lid = NULL;
> -		capp_ucode_info.loaded = false;
>  		goto end;
>  	}
> 
> -	capp_ucode_info.loaded = true;
> -
>  	ret = OPAL_SUCCESS;
>  end:
>  	return ret;
> @@ -4506,7 +4503,7 @@ int phb3_preload_capp_ucode(void)
> 
>  	/* Assert that we're preloading */
>  	assert(capp_ucode_info.lid == NULL);
> -	capp_ucode_info.loaded = false;
> +	capp_ucode_info.load_result = OPAL_EMPTY;
> 
>  	capp_ucode_info.ec_level = index;