Commit c21ee04f authored by Cédric Le Goater's avatar Cédric Le Goater Committed by Michael Ellerman
Browse files

powerpc/xive: Add a kernel parameter for StoreEOI 



StoreEOI is activated by default on platforms supporting the feature
(POWER10) and will be used as soon as firmware advertises its
availability. The kernel parameter provides a way to deactivate its
use. It can be still be reactivated through debugfs.

Signed-off-by: default avatarCédric Le Goater <clg@kaod.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211105102636.1016378-10-clg@kaod.org
parent d7bc1e37

Documentation/admin-guide/kernel-parameters.txt

+6 −0
Original line number Diff line number Diff line
@@ -6446,6 +6446,12 @@ 
				  controller on both pseries and powernv

				  platforms. Only useful on POWER9 and above.



	xive.store-eoi=off	[PPC]

			By default on POWER10 and above, the kernel will use

			stores for EOI handling when the XIVE interrupt mode

			is active. This option allows the XIVE driver to use

			loads instead, as on POWER9.



	xhci-hcd.quirks		[USB,KNL]

			A hex value specifying bitmask with supplemental xhci

			host controller quirks. Meaning of each bit can be

arch/powerpc/sysdev/xive/common.c

+13 −0
Original line number Diff line number Diff line
@@ -1712,6 +1712,19 @@ static int __init xive_off(char *arg) 
}

__setup("xive=off", xive_off);



static int __init xive_store_eoi_cmdline(char *arg)

{

	if (!arg)

		return -EINVAL;



	if (strncmp(arg, "off", 3) == 0) {

		pr_info("StoreEOI disabled on kernel command line\n");

		xive_store_eoi = false;

	}

	return 0;

}

__setup("xive.store-eoi=", xive_store_eoi_cmdline);



#ifdef CONFIG_DEBUG_FS

static void xive_debug_show_ipi(struct seq_file *m, int cpu)

{