Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-androidlsk-v4.4-16.11-android

10 files changed, 151 insertions, 22 deletions

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 054ac25e7c2e..36a30c80032d 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -22,6 +22,8 @@
 
 #define ARM_EXCEPTION_IRQ	  0
 #define ARM_EXCEPTION_TRAP	  1
+/* The hyp-stub will return this for any kvm_call_hyp() call */
+#define ARM_EXCEPTION_HYP_GONE	  2
 
 #define KVM_ARM64_DEBUG_DIRTY_SHIFT	0
 #define KVM_ARM64_DEBUG_DIRTY		(1 << KVM_ARM64_DEBUG_DIRTY_SHIFT)
@@ -29,11 +31,27 @@
 #define kvm_ksym_ref(sym)		phys_to_virt((u64)&sym - kimage_voffset)
 
 #ifndef __ASSEMBLY__
+#if __GNUC__ > 4
+#define kvm_ksym_shift			(PAGE_OFFSET - KIMAGE_VADDR)
+#else
+/*
+ * GCC versions 4.9 and older will fold the constant below into the addend of
+ * the reference to 'sym' above if kvm_ksym_shift is declared static or if the
+ * constant is used directly. However, since we use the small code model for
+ * the core kernel, the reference to 'sym' will be emitted as a adrp/add pair,
+ * with a +/- 4 GB range, resulting in linker relocation errors if the shift
+ * is sufficiently large. So prevent the compiler from folding the shift into
+ * the addend, by making the shift a variable with external linkage.
+ */
+__weak u64 kvm_ksym_shift = PAGE_OFFSET - KIMAGE_VADDR;
+#endif
+
 struct kvm;
 struct kvm_vcpu;
 
 extern char __kvm_hyp_init[];
 extern char __kvm_hyp_init_end[];
+extern char __kvm_hyp_reset[];
 
 extern char __kvm_hyp_vector[];
 
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index bbdaa56c2224..3be7a7b52d80 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -44,6 +44,7 @@
 int __attribute_const__ kvm_target_cpu(void);
 int kvm_reset_vcpu(struct kvm_vcpu *vcpu);
 int kvm_arch_dev_ioctl_check_extension(long ext);
+phys_addr_t kvm_hyp_reset_entry(void);
 
 struct kvm_arch {
 	/* The VMID generation used for the virt. memory system */
@@ -330,7 +331,17 @@ static inline void __cpu_init_stage2(void)
 {
 }
 
-static inline void kvm_arch_hardware_disable(void) {}
+static inline void __cpu_reset_hyp_mode(phys_addr_t boot_pgd_ptr,
+					phys_addr_t phys_idmap_start)
+{
+	/*
+	 * Call reset code, and switch back to stub hyp vectors.
+	 * Uses __kvm_call_hyp() to avoid kaslr's kvm_ksym_ref() translation.
+	 */
+	__kvm_call_hyp((void *)kvm_hyp_reset_entry(),
+		       boot_pgd_ptr, phys_idmap_start);
+}
+
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 0bf8b4320a91..342a5ac2f3da 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -99,6 +99,7 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_mmu_get_boot_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
+phys_addr_t kvm_get_idmap_start(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 9f22dd607958..06e6a5238c4c 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -18,6 +18,22 @@
 #ifndef __ASM__VIRT_H
 #define __ASM__VIRT_H
 
+/*
+ * The arm64 hcall implementation uses x0 to specify the hcall type. A value
+ * less than 0xfff indicates a special hcall, such as get/set vector.
+ * Any other value is used as a pointer to the function to call.
+ */
+
+/* HVC_GET_VECTORS - Return the value of the vbar_el2 register. */
+#define HVC_GET_VECTORS 0
+
+/*
+ * HVC_SET_VECTORS - Set the value of the vbar_el2 register.
+ *
+ * @x1: Physical address of the new vector table.
+ */
+#define HVC_SET_VECTORS 1
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index a272f335c289..8727f4490772 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -22,6 +22,8 @@
 #include <linux/irqchip/arm-gic-v3.h>
 
 #include <asm/assembler.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_asm.h>
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
@@ -53,15 +55,26 @@ ENDPROC(__hyp_stub_vectors)
 	.align 11
 
 el1_sync:
-	mrs	x1, esr_el2
-	lsr	x1, x1, #26
-	cmp	x1, #0x16
-	b.ne	2f				// Not an HVC trap
-	cbz	x0, 1f
-	msr	vbar_el2, x0			// Set vbar_el2
-	b	2f
-1:	mrs	x0, vbar_el2			// Return vbar_el2
-2:	eret
+	mrs	x30, esr_el2
+	lsr	x30, x30, #ESR_ELx_EC_SHIFT
+
+	cmp	x30, #ESR_ELx_EC_HVC64
+	b.ne	9f				// Not an HVC trap
+
+	cmp	x0, #HVC_GET_VECTORS
+	b.ne	1f
+	mrs	x0, vbar_el2
+	b	9f
+
+1:	cmp	x0, #HVC_SET_VECTORS
+	b.ne	2f
+	msr	vbar_el2, x1
+	b	9f
+
+	/* Someone called kvm_call_hyp() against the hyp-stub... */
+2:	mov     x0, #ARM_EXCEPTION_HYP_GONE
+
+9:	eret
 ENDPROC(el1_sync)
 
 .macro invalid_vector	label
@@ -101,10 +114,18 @@ ENDPROC(\label)
  */
 
 ENTRY(__hyp_get_vectors)
-	mov	x0, xzr
-	// fall through
-ENTRY(__hyp_set_vectors)
+	str	lr, [sp, #-16]!
+	mov	x0, #HVC_GET_VECTORS
 	hvc	#0
+	ldr	lr, [sp], #16
 	ret
 ENDPROC(__hyp_get_vectors)
+
+ENTRY(__hyp_set_vectors)
+	str	lr, [sp, #-16]!
+	mov	x1, x0
+	mov	x0, #HVC_SET_VECTORS
+	hvc	#0
+	ldr	lr, [sp], #16
+	ret
 ENDPROC(__hyp_set_vectors)
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 198cf10b262d..25006a7a5316 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -183,6 +183,13 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		exit_handler = kvm_get_exit_handler(vcpu);
 
 		return exit_handler(vcpu, run);
+	case ARM_EXCEPTION_HYP_GONE:
+		/*
+		 * EL2 has been reset to the hyp-stub. This happens when a guest
+		 * is pre-empted by kvm_reboot()'s shutdown call.
+		 */
+		run->exit_reason = KVM_EXIT_FAIL_ENTRY;
+		return 0;
 	default:
 		kvm_pr_unimpl("Unsupported exception type: %d",
 			      exception_index);
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 034d152c3fbe..d87635e678b7 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -152,6 +152,44 @@ merged:
 	eret
 ENDPROC(__kvm_hyp_init)
 
+	/*
+	 * x0: HYP boot pgd
+	 * x1: HYP phys_idmap_start
+	 */
+ENTRY(__kvm_hyp_reset)
+	/* We're in trampoline code in VA, switch back to boot page tables */
+	msr	ttbr0_el2, x0
+	isb
+
+	/* Ensure the PA branch doesn't find a stale tlb entry or stale code. */
+	ic	iallu
+	tlbi	alle2
+	dsb	sy
+	isb
+
+	/* Branch into PA space */
+	adr	x0, 1f
+	bfi	x1, x0, #0, #PAGE_SHIFT
+	br	x1
+
+	/* We're now in idmap, disable MMU */
+1:	mrs	x0, sctlr_el2
+	ldr	x1, =SCTLR_ELx_FLAGS
+	bic	x0, x0, x1		// Clear SCTL_M and etc
+	msr	sctlr_el2, x0
+	isb
+
+	/* Invalidate the old TLBs */
+	tlbi	alle2
+	dsb	sy
+
+	/* Install stub vectors */
+	adr_l	x0, __hyp_stub_vectors
+	msr	vbar_el2, x0
+
+	eret
+ENDPROC(__kvm_hyp_reset)
+
 	.ltorg
 
 	.popsection
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 48f19a37b3df..7ce931565151 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -35,16 +35,21 @@
  * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c).  Return values are
  * passed in x0.
  *
- * A function pointer with a value of 0 has a special meaning, and is
- * used to implement __hyp_get_vectors in the same way as in
+ * A function pointer with a value less than 0xfff has a special meaning,
+ * and is used to implement __hyp_get_vectors in the same way as in
  * arch/arm64/kernel/hyp_stub.S.
+ * HVC behaves as a 'bl' call and will clobber lr.
  */
 ENTRY(__kvm_call_hyp)
-alternative_if_not ARM64_HAS_VIRT_HOST_EXTN	
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
+	str     lr, [sp, #-16]!
 	hvc	#0
+	ldr     lr, [sp], #16
 	ret
 alternative_else
 	b	__vhe_hyp_call
 	nop
+	nop
+	nop
 alternative_endif
 ENDPROC(__kvm_call_hyp)
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 1bdeee70833e..44c79fd81ad1 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -43,19 +43,17 @@
 	 * Shuffle the parameters before calling the function
 	 * pointed to in x0. Assumes parameters in x[1,2,3].
 	 */
-	sub	sp, sp, #16
-	str	lr, [sp]
 	mov	lr, x0
 	mov	x0, x1
 	mov	x1, x2
 	mov	x2, x3
 	blr	lr
-	ldr	lr, [sp]
-	add	sp, sp, #16
 .endm
 
 ENTRY(__vhe_hyp_call)
+	str	lr, [sp, #-16]!
 	do_el2_call
+	ldr	lr, [sp], #16
 	/*
 	 * We used to rely on having an exception return to get
 	 * an implicit isb. In the E2H case, we don't have it anymore.
@@ -81,8 +79,8 @@ el1_sync:				// Guest trapped into EL2
 	/* Here, we're pretty sure the host called HVC. */
 	restore_x0_to_x3
 
-	/* Check for __hyp_get_vectors */
-	cbnz	x0, 1f
+	cmp	x0, #HVC_GET_VECTORS
+	b.ne	1f
 	mrs	x0, vbar_el2
 	b	2f
 
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index f34745cb3d23..d6e155a212dc 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -29,7 +29,9 @@
 #include <asm/cputype.h>
 #include <asm/ptrace.h>
 #include <asm/kvm_arm.h>
+#include <asm/kvm_asm.h>
 #include <asm/kvm_coproc.h>
+#include <asm/kvm_mmu.h>
 
 /*
  * ARMv8 Reset Values
@@ -123,3 +125,15 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 	/* Reset timer */
 	return kvm_timer_vcpu_reset(vcpu, cpu_vtimer_irq);
 }
+
+extern char __hyp_idmap_text_start[];
+
+phys_addr_t kvm_hyp_reset_entry(void)
+{
+	unsigned long offset;
+
+	offset = (unsigned long)__kvm_hyp_reset
+		 - ((unsigned long)__hyp_idmap_text_start & PAGE_MASK);
+
+	return TRAMPOLINE_VA + offset;
+}