Merge branch 'kvm-arm64/nvhe-panic-info' into kvmarm-master/next

Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/include/asm/kvm_hyp.h

@@ -102,7 +102,6 @@ u64 __guest_enter(struct kvm_vcpu *vcpu);
 
 bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt);
 
-void __noreturn hyp_panic(void);
 #ifdef __KVM_NVHE_HYPERVISOR__
 void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
 			       u64 elr, u64 par);

arch/arm64/include/asm/kvm_mmu.h

@@ -121,6 +121,8 @@ void kvm_update_va_mask(struct alt_instr *alt,
 void kvm_compute_layout(void);
 void kvm_apply_hyp_relocations(void);
 
+#define __hyp_pa(x) (((phys_addr_t)(x)) + hyp_physvirt_offset)
+
 static __always_inline unsigned long __kern_hyp_va(unsigned long v)
 {
 	asm volatile(ALTERNATIVE_CB("and %0, %0, #1\n"

arch/arm64/kernel/image-vars.h

@@ -71,8 +71,7 @@ KVM_NVHE_ALIAS(kvm_compute_final_ctr_el0);
 KVM_NVHE_ALIAS(kvm_vgic_global_state);
 
 /* Kernel symbols used to call panic() from nVHE hyp code (via ERET). */
-KVM_NVHE_ALIAS(__hyp_panic_string);
-KVM_NVHE_ALIAS(panic);
+KVM_NVHE_ALIAS(nvhe_hyp_panic_handler);
 
 /* Vectors installed by hyp-init on reset HVC. */
 KVM_NVHE_ALIAS(__hyp_stub_vectors);

arch/arm64/kvm/handle_exit.c

@@ -291,3 +291,48 @@ void handle_exit_early(struct kvm_vcpu *vcpu, int exception_index)
 	if (exception_index == ARM_EXCEPTION_EL1_SERROR)
 		kvm_handle_guest_serror(vcpu, kvm_vcpu_get_esr(vcpu));
 }
+
+void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr, u64 elr,
+					      u64 par, uintptr_t vcpu,
+					      u64 far, u64 hpfar) {
+	u64 elr_in_kimg = __phys_to_kimg(__hyp_pa(elr));
+	u64 hyp_offset = elr_in_kimg - kaslr_offset() - elr;
+	u64 mode = spsr & PSR_MODE_MASK;
+
+	/*
+	 * The nVHE hyp symbols are not included by kallsyms to avoid issues
+	 * with aliasing. That means that the symbols cannot be printed with the
+	 * "%pS" format specifier, so fall back to the vmlinux address if
+	 * there's no better option.
+	 */
+	if (mode != PSR_MODE_EL2t && mode != PSR_MODE_EL2h) {
+		kvm_err("Invalid host exception to nVHE hyp!\n");
+	} else if (ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 &&
+		   (esr & ESR_ELx_BRK64_ISS_COMMENT_MASK) == BUG_BRK_IMM) {
+		struct bug_entry *bug = find_bug(elr_in_kimg);
+		const char *file = NULL;
+		unsigned int line = 0;
+
+		/* All hyp bugs, including warnings, are treated as fatal. */
+		if (bug)
+			bug_get_file_line(bug, &file, &line);
+
+		if (file)
+			kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line);
+		else
+			kvm_err("nVHE hyp BUG at: %016llx!\n", elr + hyp_offset);
+	} else {
+		kvm_err("nVHE hyp panic at: %016llx!\n", elr + hyp_offset);
+	}
+
+	/*
+	 * Hyp has panicked and we're going to handle that by panicking the
+	 * kernel. The kernel offset will be revealed in the panic so we're
+	 * also safe to reveal the hyp offset as a debugging aid for translating
+	 * hyp VAs to vmlinux addresses.
+	 */
+	kvm_err("Hyp Offset: 0x%llx\n", hyp_offset);
+
+	panic("HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%016lx\n",
+	      spsr, elr, esr, far, hpfar, par, vcpu);
+}

arch/arm64/kvm/hyp/include/hyp/switch.h

@@ -30,8 +30,6 @@
 #include <asm/processor.h>
 #include <asm/thread_info.h>
 
-extern const char __hyp_panic_string[];
-
 extern struct exception_table_entry __start___kvm_ex_table;
 extern struct exception_table_entry __stop___kvm_ex_table;
 

arch/arm64/kvm/hyp/include/nvhe/gfp.h

@@ -51,7 +51,7 @@ static inline void hyp_set_page_refcounted(struct hyp_page *p)
 	hyp_spin_lock(&pool->lock);
 	if (p->refcount) {
 		hyp_spin_unlock(&pool->lock);
-		hyp_panic();
+		BUG();
 	}
 	p->refcount = 1;
 	hyp_spin_unlock(&pool->lock);

arch/arm64/kvm/hyp/include/nvhe/memory.h

@@ -2,6 +2,7 @@
 #ifndef __KVM_HYP_MEMORY_H
 #define __KVM_HYP_MEMORY_H
 
+#include <asm/kvm_mmu.h>
 #include <asm/page.h>
 
 #include <linux/types.h>
@@ -14,11 +15,9 @@ struct hyp_page {
 	struct list_head node;
 };
 
-extern s64 hyp_physvirt_offset;
 extern u64 __hyp_vmemmap;
 #define hyp_vmemmap ((struct hyp_page *)__hyp_vmemmap)
 
-#define __hyp_pa(virt)	((phys_addr_t)(virt) + hyp_physvirt_offset)
 #define __hyp_va(phys)	((void *)((phys_addr_t)(phys) - hyp_physvirt_offset))
 
 static inline void *hyp_phys_to_virt(phys_addr_t phys)

arch/arm64/kvm/hyp/nvhe/host.S

@@ -79,22 +79,18 @@ SYM_FUNC_START(__hyp_do_panic)
 	mov	lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
 		      PSR_MODE_EL1h)
 	msr	spsr_el2, lr
-	ldr	lr, =panic
+	ldr	lr, =nvhe_hyp_panic_handler
 	hyp_kimg_va lr, x6
 	msr	elr_el2, lr
 
 	mov	x29, x0
 
-	/* Load the format string into x0 and arguments into x1-7 */
-	ldr	x0, =__hyp_panic_string
-	hyp_kimg_va x0, x6
-
-	/* Load the format arguments into x1-7. */
-	mov	x6, x3
-	get_vcpu_ptr x7, x3
-	mrs	x3, esr_el2
-	mrs	x4, far_el2
-	mrs	x5, hpfar_el2
+	/* Load the panic arguments into x0-7 */
+	mrs	x0, esr_el2
+	get_vcpu_ptr x4, x5
+	mrs	x5, far_el2
+	mrs	x6, hpfar_el2
+	mov	x7, xzr			// Unused argument
 
 	/* Enter the host, conditionally restoring the host context. */
 	cbz	x29, __host_enter_without_restoring

arch/arm64/kvm/hyp/nvhe/hyp-main.c

@@ -251,6 +251,6 @@ void handle_trap(struct kvm_cpu_context *host_ctxt)
 		handle_host_mem_abort(host_ctxt);
 		break;
 	default:
-		hyp_panic();
+		BUG();
 	}
 }

arch/arm64/kvm/hyp/nvhe/hyp-smp.c

@@ -18,8 +18,7 @@ u64 __ro_after_init hyp_cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID
 
 u64 cpu_logical_map(unsigned int cpu)
 {
-	if (cpu >= ARRAY_SIZE(hyp_cpu_logical_map))
-		hyp_panic();
+	BUG_ON(cpu >= ARRAY_SIZE(hyp_cpu_logical_map));
 
 	return hyp_cpu_logical_map[cpu];
 }
@@ -30,8 +29,7 @@ unsigned long __hyp_per_cpu_offset(unsigned int cpu)
 	unsigned long this_cpu_base;
 	unsigned long elf_base;
 
-	if (cpu >= ARRAY_SIZE(kvm_arm_hyp_percpu_base))
-		hyp_panic();
+	BUG_ON(cpu >= ARRAY_SIZE(kvm_arm_hyp_percpu_base));
 
 	cpu_base_array = (unsigned long *)&kvm_arm_hyp_percpu_base;
 	this_cpu_base = kern_hyp_va(cpu_base_array[cpu]);

arch/arm64/kvm/hyp/nvhe/mem_protect.c

@@ -271,11 +271,9 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
 	int ret = 0;
 
 	esr = read_sysreg_el2(SYS_ESR);
-	if (!__get_fault_info(esr, &fault))
-		hyp_panic();
+	BUG_ON(!__get_fault_info(esr, &fault));
 
 	addr = (fault.hpfar_el2 & HPFAR_MASK) << 8;
 	ret = host_stage2_idmap(addr);
-	if (ret && ret != -EAGAIN)
-		hyp_panic();
+	BUG_ON(ret && ret != -EAGAIN);
 }

arch/arm64/kvm/hyp/vhe/switch.c

@@ -27,8 +27,6 @@
 #include <asm/processor.h>
 #include <asm/thread_info.h>
 
-const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";
-
 /* VHE specific context */
 DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
 DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
@@ -207,7 +205,7 @@ static void __hyp_call_panic(u64 spsr, u64 elr, u64 par)
 	__deactivate_traps(vcpu);
 	sysreg_restore_host_state_vhe(host_ctxt);
 
-	panic(__hyp_panic_string,
+	panic("HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n",
 	      spsr, elr,
 	      read_sysreg_el2(SYS_ESR), read_sysreg_el2(SYS_FAR),
 	      read_sysreg(hpfar_el2), par, vcpu);

include/linux/bug.h

@@ -36,6 +36,9 @@ static inline int is_warning_bug(const struct bug_entry *bug)
 	return bug->flags & BUGFLAG_WARNING;
 }
 
+void bug_get_file_line(struct bug_entry *bug, const char **file,
+		       unsigned int *line);
+
 struct bug_entry *find_bug(unsigned long bugaddr);
 
 enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);

lib/bug.c

@@ -127,6 +127,22 @@ static inline struct bug_entry *module_find_bug(unsigned long bugaddr)
 }
 #endif
 
+void bug_get_file_line(struct bug_entry *bug, const char **file,
+		       unsigned int *line)
+{
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
+	*file = bug->file;
+#else
+	*file = (const char *)bug + bug->file_disp;
+#endif
+	*line = bug->line;
+#else
+	*file = NULL;
+	*line = 0;
+#endif
+}
+
 struct bug_entry *find_bug(unsigned long bugaddr)
 {
 	struct bug_entry *bug;
@@ -153,32 +169,20 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 
 	disable_trace_on_warning();
 
-	file = NULL;
-	line = 0;
-	warning = 0;
+	bug_get_file_line(bug, &file, &line);
 
-	if (bug) {
-#ifdef CONFIG_DEBUG_BUGVERBOSE
-#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
-		file = bug->file;
-#else
-		file = (const char *)bug + bug->file_disp;
-#endif
-		line = bug->line;
-#endif
-		warning = (bug->flags & BUGFLAG_WARNING) != 0;
-		once = (bug->flags & BUGFLAG_ONCE) != 0;
-		done = (bug->flags & BUGFLAG_DONE) != 0;
+	warning = (bug->flags & BUGFLAG_WARNING) != 0;
+	once = (bug->flags & BUGFLAG_ONCE) != 0;
+	done = (bug->flags & BUGFLAG_DONE) != 0;
 
-		if (warning && once) {
-			if (done)
-				return BUG_TRAP_TYPE_WARN;
+	if (warning && once) {
+		if (done)
+			return BUG_TRAP_TYPE_WARN;
 
-			/*
-			 * Since this is the only store, concurrency is not an issue.
-			 */
-			bug->flags |= BUGFLAG_DONE;
-		}
+		/*
+		 * Since this is the only store, concurrency is not an issue.
+		 */
+		bug->flags |= BUGFLAG_DONE;
 	}
 
 	/*