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[PATCH] loads-stores.rst: add footnote that clarifies GETPC usage
From: |
Emanuele Giuseppe Esposito |
Subject: |
[PATCH] loads-stores.rst: add footnote that clarifies GETPC usage |
Date: |
Thu, 15 Oct 2020 11:51:47 +0200 |
Current documentation is not too clear on the GETPC usage.
In particular, when used outside the top level helper function
it causes unexpected behavior.
Signed-off-by: Emanuele Giuseppe Esposito <e.emanuelegiuseppe@gmail.com>
---
docs/devel/loads-stores.rst | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/docs/devel/loads-stores.rst b/docs/devel/loads-stores.rst
index 9a944ef1af..59c1225391 100644
--- a/docs/devel/loads-stores.rst
+++ b/docs/devel/loads-stores.rst
@@ -93,7 +93,13 @@ guest CPU state in case of a guest CPU exception. This is
passed
to ``cpu_restore_state()``. Therefore the value should either be 0,
to indicate that the guest CPU state is already synchronized, or
the result of ``GETPC()`` from the top level ``HELPER(foo)``
-function, which is a return address into the generated code.
+function, which is a return address into the generated code [#gpc]_.
+
+.. [#gpc] Note that ``GETPC()`` should be used with great care: calling
+ it in other functions that are *not* the top level
+ ``HELPER(foo)`` will cause unexpected behavior. Instead, the
+ value of ``GETPC()`` should be read from the helper and passed
+ if needed to the functions that the helper calls.
Function names follow the pattern:
--
2.17.1
- [PATCH] loads-stores.rst: add footnote that clarifies GETPC usage,
Emanuele Giuseppe Esposito <=