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Commit b275bfb2 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman
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powerpc/mm/radix: Add a kernel command line to disable radix 



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: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 912cc87a

Documentation/kernel-parameters.txt

+3 −0
Original line number Original line Diff line number Diff line
@@ -929,6 +929,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
	disable=	[IPV6]

	disable=	[IPV6]

			See Documentation/networking/ipv6.txt.

			See Documentation/networking/ipv6.txt.





	disable_radix	[PPC]

			Disable RADIX MMU mode on POWER9



	disable_cpu_apicid= [X86,APIC,SMP]

	disable_cpu_apicid= [X86,APIC,SMP]

			Format: <int>

			Format: <int>

			The number of initial APIC ID for the

			The number of initial APIC ID for the

arch/powerpc/kernel/prom.c

+13 −0
Original line number Original line Diff line number Diff line
@@ -646,6 +646,14 @@ static void __init early_reserve_mem(void) 
#endif

#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)

void __init early_init_devtree(void *params)

{

{

	phys_addr_t limit;

	phys_addr_t limit;
@@ -735,6 +743,11 @@ void __init early_init_devtree(void *params) 
	 */

	 */

	spinning_secondaries = boot_cpu_count - 1;

	spinning_secondaries = boot_cpu_count - 1;

#endif

#endif

	/*

	 * now fixup radix MMU mode based on kernel command line

	 */

	if (disable_radix)

		cur_cpu_spec->mmu_features &= ~MMU_FTR_RADIX;





#ifdef CONFIG_PPC_POWERNV

#ifdef CONFIG_PPC_POWERNV

	/* Scan and build the list of machine check recoverable ranges */

	/* Scan and build the list of machine check recoverable ranges */