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: Cédric Le Goater <c...@kaod.org>
---
arch/powerpc/sysdev/xive/common.c | 13 +++++++++++++
Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
2 files changed, 19 insertions(+)
diff --git a/arch/powerpc/sysdev/xive/common.c
b/arch/powerpc/sysdev/xive/common.c
index 11e2aaa13965..67fd3a306369 100644
--- a/arch/powerpc/sysdev/xive/common.c
+++ b/arch/powerpc/sysdev/xive/common.c
@@ -1713,6 +1713,19 @@ 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)
{
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 43dc35fe5bc0..10fa093251e8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6387,6 +6387,12 @@
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
--
2.31.1
