Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 27 Apr 2022 11:46:56 -0700
In-Reply-To: <20220427184716.1949239-1-kaleshsingh@google.com>
Message-Id: <20220427184716.1949239-2-kaleshsingh@google.com>
Mime-Version: 1.0
References: <20220427184716.1949239-1-kaleshsingh@google.com>
Subject: [PATCH 1/4] KVM: arm64: Compile stacktrace.nvhe.o
From:   Kalesh Singh <kaleshsingh@google.com>
Cc:     mark.rutland@arm.com, will@kernel.org, maz@kernel.org,
        qperret@google.com, tabba@google.com, surenb@google.com,
        kernel-team@android.com, Kalesh Singh <kaleshsingh@google.com>,
        James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Mark Brown <broonie@kernel.org>,
        Peter Collingbourne <pcc@google.com>,
        Alexei Starovoitov <ast@kernel.org>,
        "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>,
        Andrew Jones <drjones@redhat.com>,
        Zenghui Yu <yuzenghui@huawei.com>,
        Keir Fraser <keirf@google.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
To:     unlisted-recipients:; (no To-header on input)
Precedence: bulk

Recompile stack unwinding code for use with the nVHE hypervisor. This is
a preparatory patch that will allow reusing most of the kernel unwinding
logic in the nVHE hypervisor.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
---
 arch/arm64/include/asm/stacktrace.h | 18 ++++---
 arch/arm64/kernel/stacktrace.c      | 73 ++++++++++++++++++-----------
 arch/arm64/kvm/hyp/nvhe/Makefile    |  3 +-
 3 files changed, 60 insertions(+), 34 deletions(-)

diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index aec9315bf156..f5af9a94c5a6 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -16,12 +16,14 @@
 #include <asm/sdei.h>
 
 enum stack_type {
-	STACK_TYPE_UNKNOWN,
+#ifndef __KVM_NVHE_HYPERVISOR__
 	STACK_TYPE_TASK,
 	STACK_TYPE_IRQ,
 	STACK_TYPE_OVERFLOW,
 	STACK_TYPE_SDEI_NORMAL,
 	STACK_TYPE_SDEI_CRITICAL,
+#endif /* !__KVM_NVHE_HYPERVISOR__ */
+	STACK_TYPE_UNKNOWN,
 	__NR_STACK_TYPES
 };
 
@@ -31,11 +33,6 @@ struct stack_info {
 	enum stack_type type;
 };
 
-extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
-			   const char *loglvl);
-
-DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
-
 static inline bool on_stack(unsigned long sp, unsigned long size,
 			    unsigned long low, unsigned long high,
 			    enum stack_type type, struct stack_info *info)
@@ -54,6 +51,12 @@ static inline bool on_stack(unsigned long sp, unsigned long size,
 	return true;
 }
 
+#ifndef __KVM_NVHE_HYPERVISOR__
+extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+			   const char *loglvl);
+
+DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
+
 static inline bool on_irq_stack(unsigned long sp, unsigned long size,
 				struct stack_info *info)
 {
@@ -88,6 +91,7 @@ static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
 static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
 			struct stack_info *info) { return false; }
 #endif
+#endif /* !__KVM_NVHE_HYPERVISOR__ */
 
 
 /*
@@ -101,6 +105,7 @@ static inline bool on_accessible_stack(const struct task_struct *tsk,
 	if (info)
 		info->type = STACK_TYPE_UNKNOWN;
 
+#ifndef __KVM_NVHE_HYPERVISOR__
 	if (on_task_stack(tsk, sp, size, info))
 		return true;
 	if (tsk != current || preemptible())
@@ -111,6 +116,7 @@ static inline bool on_accessible_stack(const struct task_struct *tsk,
 		return true;
 	if (on_sdei_stack(sp, size, info))
 		return true;
+#endif /* !__KVM_NVHE_HYPERVISOR__ */
 
 	return false;
 }
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 0467cb79f080..a84e38d41d38 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -81,23 +81,19 @@ NOKPROBE_SYMBOL(unwind_init);
  * records (e.g. a cycle), determined based on the location and fp value of A
  * and the location (but not the fp value) of B.
  */
-static int notrace unwind_next(struct task_struct *tsk,
-			       struct unwind_state *state)
+static int notrace __unwind_next(struct task_struct *tsk,
+				 struct unwind_state *state,
+				 struct stack_info *info)
 {
 	unsigned long fp = state->fp;
-	struct stack_info info;
-
-	/* Final frame; nothing to unwind */
-	if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
-		return -ENOENT;
 
 	if (fp & 0x7)
 		return -EINVAL;
 
-	if (!on_accessible_stack(tsk, fp, 16, &info))
+	if (!on_accessible_stack(tsk, fp, 16, info))
 		return -EINVAL;
 
-	if (test_bit(info.type, state->stacks_done))
+	if (test_bit(info->type, state->stacks_done))
 		return -EINVAL;
 
 	/*
@@ -113,7 +109,7 @@ static int notrace unwind_next(struct task_struct *tsk,
 	 * stack to another, it's never valid to unwind back to that first
 	 * stack.
 	 */
-	if (info.type == state->prev_type) {
+	if (info->type == state->prev_type) {
 		if (fp <= state->prev_fp)
 			return -EINVAL;
 	} else {
@@ -127,7 +123,45 @@ static int notrace unwind_next(struct task_struct *tsk,
 	state->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
 	state->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
 	state->prev_fp = fp;
-	state->prev_type = info.type;
+	state->prev_type = info->type;
+
+	return 0;
+}
+NOKPROBE_SYMBOL(__unwind_next);
+
+static int notrace unwind_next(struct task_struct *tsk,
+			       struct unwind_state *state);
+
+static void notrace unwind(struct task_struct *tsk,
+			   struct unwind_state *state,
+			   stack_trace_consume_fn consume_entry, void *cookie)
+{
+	while (1) {
+		int ret;
+
+		if (!consume_entry(cookie, state->pc))
+			break;
+		ret = unwind_next(tsk, state);
+		if (ret < 0)
+			break;
+	}
+}
+NOKPROBE_SYMBOL(unwind);
+
+#ifndef __KVM_NVHE_HYPERVISOR__
+static int notrace unwind_next(struct task_struct *tsk,
+			       struct unwind_state *state)
+{
+	struct stack_info info;
+	int err;
+
+	/* Final frame; nothing to unwind */
+	if (state->fp == (unsigned long)task_pt_regs(tsk)->stackframe)
+		return -ENOENT;
+
+	err = __unwind_next(tsk, state, &info);
+	if (err)
+		return err;
 
 	state->pc = ptrauth_strip_insn_pac(state->pc);
 
@@ -157,22 +191,6 @@ static int notrace unwind_next(struct task_struct *tsk,
 }
 NOKPROBE_SYMBOL(unwind_next);
 
-static void notrace unwind(struct task_struct *tsk,
-			   struct unwind_state *state,
-			   stack_trace_consume_fn consume_entry, void *cookie)
-{
-	while (1) {
-		int ret;
-
-		if (!consume_entry(cookie, state->pc))
-			break;
-		ret = unwind_next(tsk, state);
-		if (ret < 0)
-			break;
-	}
-}
-NOKPROBE_SYMBOL(unwind);
-
 static bool dump_backtrace_entry(void *arg, unsigned long where)
 {
 	char *loglvl = arg;
@@ -224,3 +242,4 @@ noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
 
 	unwind(task, &state, consume_entry, cookie);
 }
+#endif /* !__KVM_NVHE_HYPERVISOR__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index f9fe4dc21b1f..c0ff0d6fc403 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -14,7 +14,8 @@ lib-objs := $(addprefix ../../../lib/, $(lib-objs))
 
 obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \
 	 hyp-main.o hyp-smp.o psci-relay.o early_alloc.o page_alloc.o \
-	 cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o
+	 cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o \
+	 ../../../kernel/stacktrace.o
 obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
 	 ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o
 obj-$(CONFIG_DEBUG_LIST) += list_debug.o
-- 
2.36.0.rc2.479.g8af0fa9b8e-goog