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From: Alexandru Elisei <alexandru.elisei@arm.com>
To: kvm@vger.kernel.org
Cc: pbonzini@redhat.com, rkrcmar@redhat.com, drjones@redhat.com,
	maz@kernel.org, andre.przywara@arm.com, vladimir.murzin@arm.com,
	mark.rutland@arm.com
Subject: [kvm-unit-tests PATCH 14/18] lib: arm/arm64: Refuse to disable the MMU with non-identity stack pointer
Date: Wed, 27 Nov 2019 14:24:06 +0000	[thread overview]
Message-ID: <20191127142410.1994-15-alexandru.elisei@arm.com> (raw)
In-Reply-To: <20191127142410.1994-1-alexandru.elisei@arm.com>

When the MMU is off, all addresses are physical addresses. If the stack
pointer is not an identity mapped address (the virtual address is not the
same as the physical address), then we end up trying to access an invalid
memory region. This can happen if we call mmu_disable from a secondary CPU,
which has its stack allocated from the vmalloc region.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
 lib/arm/mmu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c
index ed5411c157bb..773c764c4836 100644
--- a/lib/arm/mmu.c
+++ b/lib/arm/mmu.c
@@ -68,8 +68,12 @@ void mmu_enable(pgd_t *pgtable)
 extern void asm_mmu_disable(void);
 void mmu_disable(void)
 {
+	unsigned long sp = current_stack_pointer;
 	int cpu = current_thread_info()->cpu;
 
+	assert_msg(__virt_to_phys(sp) == sp,
+			"Attempting to disable MMU with non-identity mapped stack");
+
 	mmu_mark_disabled(cpu);
 
 	asm_mmu_disable();
-- 
2.20.1


  parent reply	other threads:[~2019-11-27 14:25 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-27 14:23 [kvm-unit-tests PATCH 00/18] Various fixes Alexandru Elisei
2019-11-27 14:23 ` [kvm-unit-tests PATCH 01/18] lib: arm/arm64: Remove unnecessary dcache maintenance operations Alexandru Elisei
2019-11-27 14:23 ` [kvm-unit-tests PATCH 02/18] lib: arm64: Remove barriers before TLB operations Alexandru Elisei
2019-11-27 14:23 ` [kvm-unit-tests PATCH 03/18] lib: Add WRITE_ONCE and READ_ONCE implementations in compiler.h Alexandru Elisei
2019-11-27 14:23 ` [kvm-unit-tests PATCH 04/18] lib: arm/arm64: Use WRITE_ONCE to update the translation tables Alexandru Elisei
2019-11-27 14:23 ` [kvm-unit-tests PATCH 05/18] lib: arm/arm64: Remove unused CPU_OFF parameter Alexandru Elisei
2019-11-27 14:23 ` [kvm-unit-tests PATCH 06/18] arm/arm64: psci: Don't run C code without stack or vectors Alexandru Elisei
2019-11-27 14:23 ` [kvm-unit-tests PATCH 07/18] lib: arm/arm64: Add missing include for alloc_page.h in pgtable.h Alexandru Elisei
2019-11-27 14:24 ` [kvm-unit-tests PATCH 08/18] lib: arm: Implement flush_tlb_all Alexandru Elisei
2019-11-27 14:24 ` [kvm-unit-tests PATCH 09/18] lib: arm/arm64: Teach mmu_clear_user about block mappings Alexandru Elisei
2019-11-27 14:24 ` [kvm-unit-tests PATCH 10/18] arm/arm64: selftest: Add prefetch abort test Alexandru Elisei
2019-11-27 18:47   ` Andrew Jones
2019-11-28  9:59     ` Alexandru Elisei
2019-11-28 16:56       ` Alexandru Elisei
2019-11-27 14:24 ` [kvm-unit-tests PATCH 11/18] arm64: timer: Write to ICENABLER to disable timer IRQ Alexandru Elisei
2019-11-27 14:24 ` [kvm-unit-tests PATCH 12/18] arm64: timer: EOIR the interrupt after masking the timer Alexandru Elisei
2019-11-27 14:24 ` [kvm-unit-tests PATCH 13/18] arm64: timer: Test behavior when timer disabled or masked Alexandru Elisei
2019-11-27 14:24 ` Alexandru Elisei [this message]
2019-11-27 14:24 ` [kvm-unit-tests PATCH 15/18] arm/arm64: Perform dcache clean + invalidate after turning MMU off Alexandru Elisei
2019-11-27 14:24 ` [kvm-unit-tests PATCH 16/18] arm: cstart64.S: Downgrade TLBI to non-shareable in asm_mmu_enable Alexandru Elisei
2019-11-27 14:24 ` [kvm-unit-tests PATCH 17/18] arm/arm64: Invalidate TLB before enabling MMU Alexandru Elisei
2019-11-27 14:24 ` [kvm-unit-tests PATCH 18/18] arm: cstart64.S: Remove icache invalidation from asm_mmu_enable Alexandru Elisei
2019-11-27 14:41   ` Alexandru Elisei

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