Commit c67a0e41 authored by Nathan Lynch's avatar Nathan Lynch Committed by Michael Ellerman
Browse files

powerpc/rtas: clean up rtas_error_log_max initialization 



The code in rtas_get_error_log_max() doesn't cause problems in
practice, but there are no measures to ensure that the lazy
initialization of the static rtas_error_log_max variable is atomic,
and it's not worth adding them.

Initialize the static rtas_error_log_max variable at boot when we're
single-threaded instead of lazily on first use. Use the more
appropriate of_property_read_u32() API instead of rtas_token() to
consult the "rtas-error-log-max" property, which is not the name of an
RTAS function. Convert use of printk() to pr_warn() and distinguish
the possible error cases.

Signed-off-by: default avatarNathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: default avatarAndrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221118150751.469393-7-nathanl@linux.ibm.com
parent 9aafbfa5

arch/powerpc/kernel/rtas.c

+26 −11
Original line number Diff line number Diff line
@@ -353,6 +353,9 @@ int rtas_service_present(const char *service) 
EXPORT_SYMBOL(rtas_service_present);



#ifdef CONFIG_RTAS_ERROR_LOGGING



static u32 rtas_error_log_max __ro_after_init = RTAS_ERROR_LOG_MAX;



/*

 * Return the firmware-specified size of the error log buffer

 *  for all rtas calls that require an error buffer argument.
@@ -360,20 +363,29 @@ EXPORT_SYMBOL(rtas_service_present); 
 */

int rtas_get_error_log_max(void)

{

	static int rtas_error_log_max;

	if (rtas_error_log_max)

	return rtas_error_log_max;

}

EXPORT_SYMBOL(rtas_get_error_log_max);



static void __init init_error_log_max(void)

{

	static const char propname[] __initconst = "rtas-error-log-max";

	u32 max;



	rtas_error_log_max = rtas_token ("rtas-error-log-max");

	if ((rtas_error_log_max == RTAS_UNKNOWN_SERVICE) ||

	    (rtas_error_log_max > RTAS_ERROR_LOG_MAX)) {

		printk (KERN_WARNING "RTAS: bad log buffer size %d\n",

			rtas_error_log_max);

		rtas_error_log_max = RTAS_ERROR_LOG_MAX;

	if (of_property_read_u32(rtas.dev, propname, &max)) {

		pr_warn("%s not found, using default of %u\n",

			propname, RTAS_ERROR_LOG_MAX);

		max = RTAS_ERROR_LOG_MAX;

	}

	return rtas_error_log_max;



	if (max > RTAS_ERROR_LOG_MAX) {

		pr_warn("%s = %u, clamping max error log size to %u\n",

			propname, max, RTAS_ERROR_LOG_MAX);

		max = RTAS_ERROR_LOG_MAX;

	}



	rtas_error_log_max = max;

}

EXPORT_SYMBOL(rtas_get_error_log_max);





static char rtas_err_buf[RTAS_ERROR_LOG_MAX];
@@ -432,6 +444,7 @@ static char *__fetch_rtas_last_error(char *altbuf) 
#else /* CONFIG_RTAS_ERROR_LOGGING */

#define __fetch_rtas_last_error(x)	NULL

#define get_errorlog_buffer()		NULL

static void __init init_error_log_max(void) {}

#endif
@@ -1340,6 +1353,8 @@ void __init rtas_initialize(void) 
	no_entry = of_property_read_u32(rtas.dev, "linux,rtas-entry", &entry);

	rtas.entry = no_entry ? rtas.base : entry;



	init_error_log_max();



	/*

	 * Discover these now to avoid device tree lookups in the

	 * panic path.