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powerpc/xive: Add a kernel parameter for StoreEOI

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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 <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211105102636.1016378-10-clg@kaod.org
This commit is contained in:
Cédric Le Goater 2021-11-05 11:26:34 +01:00 committed by Michael Ellerman
parent d7bc1e376c
commit c21ee04f11
2 changed files with 19 additions and 0 deletions
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6
Documentation/admin-guide/kernel-parameters.txt
View File

@ -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

13
arch/powerpc/sysdev/xive/common.c
View File

@ -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)
{