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_schm...@vnet.ibm.com>
cc: Olof Johansson <o...@lixom.net>
cc: Anton Blanchard <an...@samba.org>
cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
---
v2 - Per feedback from Olof, the code is reworked to utilize kernel
parameter runtime checks, rather than CONFIG options.
- Added relevant change to kernel-parameters.txt
v3 - ran through checkpatch and fixed whitespace issues.
- consolidated the if() staircases to save indentation.
diff --git a/Documentation/kernel-parameters.txt
b/Documentation/kernel-parameters.txt
index e2c7487..5c40801 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -426,6 +426,10 @@ and is between 256 and 4096 characters. It is defined in
the file
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.
+
BusLogic= [HW,SCSI]
See drivers/scsi/BusLogic.c, comment before function
BusLogic_ParseDriverOptions().
@@ -1499,6 +1503,10 @@ and is between 256 and 4096 characters. It is defined in
the file
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 902987d..e174a2f 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -625,3 +625,17 @@ void iommu_init_early_pSeries(void)
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 0707653..82d15e7 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -599,6 +599,18 @@ static void pSeries_lpar_flush_hash_range(unsigned long
number, int local)
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;
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