Commit 000a42b3 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman
Browse files

powerpc/book3s64/keys/kuap: Reset AMR/IAMR values on kexec 



As we kexec across kernels that use AMR/IAMR for different purposes
we need to ensure that new kernels get kexec'd with a reset value
of AMR/IAMR. For ex: the new kernel can use key 0 for kernel mapping and the old
AMR value prevents access to key 0.

This patch also removes reset if IAMR and AMOR in kexec_sequence. Reset of AMOR
is not needed and the IAMR reset is partial (it doesn't do the reset
on secondary cpus) and is redundant with this patch.

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200709032946.881753-19-aneesh.kumar@linux.ibm.com
parent 7cdd3745

arch/powerpc/include/asm/book3s/64/kexec.h

0 → 100644
+23 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



#ifndef _ASM_POWERPC_BOOK3S_64_KEXEC_H_

#define _ASM_POWERPC_BOOK3S_64_KEXEC_H_





#define reset_sprs reset_sprs

static inline void reset_sprs(void)

{

	if (cpu_has_feature(CPU_FTR_ARCH_206)) {

		mtspr(SPRN_AMR, 0);

		mtspr(SPRN_UAMOR, 0);

	}



	if (cpu_has_feature(CPU_FTR_ARCH_207S)) {

		mtspr(SPRN_IAMR, 0);

	}



	/*  Do we need isync()? We are going via a kexec reset */

	isync();

}



#endif

arch/powerpc/include/asm/kexec.h

+12 −0
Original line number Diff line number Diff line
@@ -150,6 +150,18 @@ static inline void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) 
}



#endif /* CONFIG_KEXEC_CORE */



#ifdef CONFIG_PPC_BOOK3S_64

#include <asm/book3s/64/kexec.h>

#endif



#ifndef reset_sprs

#define reset_sprs reset_sprs

static inline void reset_sprs(void)

{

}

#endif



#endif /* ! __ASSEMBLY__ */

#endif /* __KERNEL__ */

#endif /* _ASM_POWERPC_KEXEC_H */

arch/powerpc/kernel/misc_64.S

+0 −14
Original line number Diff line number Diff line
@@ -413,20 +413,6 @@ _GLOBAL(kexec_sequence) 
	li	r0,0

	std	r0,16(r1)



BEGIN_FTR_SECTION

	/*

	 * This is the best time to turn AMR/IAMR off.

	 * key 0 is used in radix for supervisor<->user

	 * protection, but on hash key 0 is reserved

	 * ideally we want to enter with a clean state.

	 * NOTE, we rely on r0 being 0 from above.

	 */

	mtspr	SPRN_IAMR,r0

BEGIN_FTR_SECTION_NESTED(42)

	mtspr	SPRN_AMOR,r0

END_FTR_SECTION_NESTED_IFSET(CPU_FTR_HVMODE, 42)

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)



	/* save regs for local vars on new stack.

	 * yes, we won't go back, but ...

	 */

arch/powerpc/kexec/core_64.c

+2 −0
Original line number Diff line number Diff line
@@ -152,6 +152,8 @@ static void kexec_smp_down(void *arg) 
	if (ppc_md.kexec_cpu_down)

		ppc_md.kexec_cpu_down(0, 1);



	reset_sprs();



	kexec_smp_wait();

	/* NOTREACHED */

}

arch/powerpc/mm/book3s64/pgtable.c

+3 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <asm/powernv.h>

#include <asm/firmware.h>

#include <asm/ultravisor.h>

#include <asm/kexec.h>



#include <mm/mmu_decl.h>

#include <trace/events/thp.h>
@@ -165,6 +166,8 @@ void mmu_cleanup_all(void) 
		radix__mmu_cleanup_all();

	else if (mmu_hash_ops.hpte_clear_all)

		mmu_hash_ops.hpte_clear_all();



	reset_sprs();

}



#ifdef CONFIG_MEMORY_HOTPLUG

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