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| author | Cédric Le Goater <clg@kaod.org> | 2021-11-05 11:26:34 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-11-25 11:25:30 +1100 |
| commit | c21ee04f11ae068aa132cce56d09f618d4a66259 (patch) | |
| tree | 7076bdeccb6468b807ad56702e0dccf07c45bd5e | |
| parent | d7bc1e376cb786e9e8483455584d89cad4b5808f (diff) | |
| download | lwn-c21ee04f11ae068aa132cce56d09f618d4a66259.tar.gz lwn-c21ee04f11ae068aa132cce56d09f618d4a66259.zip | |
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: 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
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 6 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/xive/common.c | 13 |
2 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 2711ddb4835a..6248a061788a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -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 diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c index b3b1dbf29d4d..3b453973a5d2 100644 --- a/arch/powerpc/sysdev/xive/common.c +++ b/arch/powerpc/sysdev/xive/common.c @@ -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) { |