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Message-Id: <20220721055728.718573-12-kaleshsingh@google.com>
Date: Wed, 20 Jul 2022 22:57:22 -0700
From: Kalesh Singh <kaleshsingh@...gle.com>
To: maz@...nel.org, mark.rutland@....com, broonie@...nel.org,
madvenka@...ux.microsoft.com, tabba@...gle.com
Cc: will@...nel.org, qperret@...gle.com, kaleshsingh@...gle.com,
james.morse@....com, alexandru.elisei@....com,
suzuki.poulose@....com, catalin.marinas@....com,
andreyknvl@...il.com, vincenzo.frascino@....com,
mhiramat@...nel.org, ast@...nel.org, drjones@...hat.com,
wangkefeng.wang@...wei.com, elver@...gle.com, keirf@...gle.com,
yuzenghui@...wei.com, ardb@...nel.org, oupton@...gle.com,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
linux-kernel@...r.kernel.org, android-mm@...gle.com,
kernel-team@...roid.com
Subject: [PATCH v5 11/17] KVM: arm64: Stub implementation of non-protected
nVHE HYP stack unwinder
Add stub implementations of non-protected nVHE stack unwinder, for
building. These are implemented later in this series.
Signed-off-by: Kalesh Singh <kaleshsingh@...gle.com>
---
Changes in v5:
- Mark unwind_next() as inline, per Marc
- Comment !__KVM_NVHE_HYPERVISOR__ unwinder path, per Marc
arch/arm64/include/asm/stacktrace/nvhe.h | 26 ++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/arch/arm64/include/asm/stacktrace/nvhe.h b/arch/arm64/include/asm/stacktrace/nvhe.h
index 80d71932afff..3078501f8e22 100644
--- a/arch/arm64/include/asm/stacktrace/nvhe.h
+++ b/arch/arm64/include/asm/stacktrace/nvhe.h
@@ -8,6 +8,12 @@
* the HYP memory. The stack is unwinded in EL2 and dumped to a shared
* buffer where the host can read and print the stacktrace.
*
+ * 2) Non-protected nVHE mode - the host can directly access the
+ * HYP stack pages and unwind the HYP stack in EL1. This saves having
+ * to allocate shared buffers for the host to read the unwinded
+ * stacktrace.
+ *
+ *
* Copyright (C) 2022 Google LLC
*/
#ifndef __ASM_STACKTRACE_NVHE_H
@@ -55,5 +61,25 @@ static inline int notrace unwind_next(struct unwind_state *state)
NOKPROBE_SYMBOL(unwind_next);
#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */
+#else /* !__KVM_NVHE_HYPERVISOR__ */
+/*
+ * Conventional (non-protected) nVHE HYP stack unwinder
+ *
+ * In non-protected mode, the unwinding is done from kernel proper context
+ * (by the host in EL1).
+ */
+
+static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
+ struct stack_info *info)
+{
+ return false;
+}
+
+static inline int notrace unwind_next(struct unwind_state *state)
+{
+ return 0;
+}
+NOKPROBE_SYMBOL(unwind_next);
+
#endif /* __KVM_NVHE_HYPERVISOR__ */
#endif /* __ASM_STACKTRACE_NVHE_H */
--
2.37.0.170.g444d1eabd0-goog
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