[PATCH 09/11] powerpc/xive: Add a kernel parameter for StoreEOI
From: Cédric Le Goater <clg@kaod.org>
Date: 2021-11-05 10:32:39
Subsystem:
documentation, linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Jonathan Corbet, Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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> --- 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