powerpc/pseries: Add kernel parameter to disable batched hcalls
This introduces a pair of kernel parameters that can be used to disable
the MULTITCE and BULK_REMOVE h-calls.
By default, those hcalls are enabled, active, and good for throughput
and performance. The ability to disable them will be useful for some of
the PREEMPT_RT related investigation and work occurring on Power.
Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
cc: Olof Johansson <olof@lixom.net>
cc: Anton Blanchard <anton@samba.org>
cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index cdd2a6e..69bb6a9 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -403,6 +403,10 @@
bttv.pll= See Documentation/video4linux/bttv/Insmod-options
bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
+ bulk_remove=off [PPC] This parameter disables the use of the pSeries
+ firmware feature for flushing multiple hpte entries
+ at a time.
+
c101= [NET] Moxa C101 synchronous serial card
cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
@@ -1490,6 +1494,10 @@
mtdparts= [MTD]
See drivers/mtd/cmdlinepart.c.
+ multitce=off [PPC] This parameter disables the use of the pSeries
+ firmware feature for updating multiple TCE entries
+ at a time.
+
onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index a77bcae..fa2906a 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -622,3 +622,17 @@
set_pci_dma_ops(&dma_iommu_ops);
}
+static int __init disable_multitce(char *str)
+{
+ if (strcmp(str, "off") == 0 &&
+ firmware_has_feature(FW_FEATURE_LPAR) &&
+ firmware_has_feature(FW_FEATURE_MULTITCE)) {
+ printk(KERN_INFO "Disabling MULTITCE firmware feature\n");
+ ppc_md.tce_build = tce_build_pSeriesLP;
+ ppc_md.tce_free = tce_free_pSeriesLP;
+ powerpc_firmware_features &= ~FW_FEATURE_MULTITCE;
+ }
+ return 1;
+}
+
+__setup("multitce=", disable_multitce);
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index f129040..5d3ea9f 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -627,6 +627,18 @@
spin_unlock_irqrestore(&pSeries_lpar_tlbie_lock, flags);
}
+static int __init disable_bulk_remove(char *str)
+{
+ if (strcmp(str, "off") == 0 &&
+ firmware_has_feature(FW_FEATURE_BULK_REMOVE)) {
+ printk(KERN_INFO "Disabling BULK_REMOVE firmware feature");
+ powerpc_firmware_features &= ~FW_FEATURE_BULK_REMOVE;
+ }
+ return 1;
+}
+
+__setup("bulk_remove=", disable_bulk_remove);
+
void __init hpte_init_lpar(void)
{
ppc_md.hpte_invalidate = pSeries_lpar_hpte_invalidate;