This patch adds the kernel command line disable_radix which disable
the radix MMU mode even if firmware indicates radix support via
ibm,pa-features device tree node.
This helps in testing different MMU mode easily.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
Documentation/kernel-parameters.txt | 3 +++
arch/powerpc/kernel/prom.c | 13 +++++++++++++
2 files changed, 16 insertions(+)
diff --git a/Documentation/kernel-parameters.txt
b/Documentation/kernel-parameters.txt
index 738bae4a5958..bba7ef30d74e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -929,6 +929,9 @@ bytes respectively. Such letter suffixes can also be
entirely omitted.
disable= [IPV6]
See Documentation/networking/ipv6.txt.
+ disable_radix [PPC]
+ Disable RADIX MMU mode on POWER9
+
disable_cpu_apicid= [X86,APIC,SMP]
Format: <int>
The number of initial APIC ID for the
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 946e34ffeae9..022540b9366d 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -645,6 +645,14 @@ static void __init early_reserve_mem(void)
#endif
}
+static bool disable_radix;
+static int __init parse_disable_radix(char *p)
+{
+ disable_radix = true;
+ return 0;
+}
+early_param("disable_radix", parse_disable_radix);
+
void __init early_init_devtree(void *params)
{
phys_addr_t limit;
@@ -739,6 +747,11 @@ void __init early_init_devtree(void *params)
/* Scan and build the list of machine check recoverable ranges */
of_scan_flat_dt(early_init_dt_scan_recoverable_ranges, NULL);
#endif
+ /*
+ * now fixup radix MMU mode based on kernel command line
+ */
+ if (disable_radix)
+ cur_cpu_spec->mmu_features &= ~MMU_FTR_RADIX;
DBG(" <- early_init_devtree()\n");
}
--
2.7.4
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
