Active irq-to-core mapping

bl_pal_linux_activate_irq_mapping.c

/**
 * Given a single populated irq_info, activate the mapping from irq to cpus
 *
 * @param teb 		Pointer to our teb
 * @param irq		IRQ line number to map
 * @param coremap	Pointer to coremap to map IRQ to
 *
 * @return 		BL_OK on success, BL_ERR otherwise.
 */
__BL_STATIC int
bl_pal_linux_activate_irq_mapping(bl_teb_t *teb,
                                  unsigned int irq,
                                  bl_pal_coremap_t *coremap)
{
	char affinity_proc_file[PATH_MAX];
	char coremap_buf[PATH_MAX];
	FILE *file;
	int errsave = 0;
	int res;

	bl_assert(teb != NULL);
	bl_assert(coremap != NULL);

	bl_error_clear(teb);

	res = bl_string_print_ex(affinity_proc_file,
	                         sizeof(affinity_proc_file),
	                         BL_STR_F_NOTRUNCATE,
	                         NULL,
	                         "/proc/irq/%u/smp_affinity",
	                         irq);
	if (res != BL_OK)
	{
		bl_error_set(teb, BL_ERR_STRING_TRUNCATED);
		return BL_ERR;
	}

	file = fopen(affinity_proc_file, "w");
	if (!file)
	{
		bl_error_set_aux(teb,
		                 BL_ERR_PAL_UNABLE_TO_OPEN_IRQ_AFFINITY,
		                 errno,
		                 "%s",
		                 affinity_proc_file);
		return BL_ERR;
	}

	/* Write the mask to apply to a buffer ready for dumping to correct file */

	res = bl_coremap_scnprintf(
	    coremap_buf, sizeof(coremap_buf), coremap, BL_PAL_MAX_CORES);
	bl_abort_ifx(
	    !(res > 0), coremap_buf, sizeof(coremap_buf), coremap, BL_PAL_MAX_CORES);

	/* log applied_mask .. */

	bl_debug_pal_t(teb,
	               "activate_irq_mapping: writing [%s] to: %s",
	               coremap_buf,
	               affinity_proc_file);

	res = fprintf(file, "%s", coremap_buf);

	/* Cache any errno that failed in the fprintf, as this will carry the procfs error
	 * code. */

	errsave = errno;

	if (fclose(file) || res == -1)
	{
		bl_error_set_aux(teb,
		                 BL_ERR_PAL_UPDATE_IRQ_AFFINITY_FAILED,
		                 errsave,
		                 "mask: %s",
		                 coremap_buf);
		return BL_ERR;
	}

	return BL_OK;
}