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| -rw-r--r-- | docs/porting-guide.md | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/docs/porting-guide.md b/docs/porting-guide.md index 004f70d6..741ee207 100644 --- a/docs/porting-guide.md +++ b/docs/porting-guide.md @@ -654,7 +654,8 @@ CPU-specific linear index into blocks of memory (for example while allocating per-CPU stacks). This function will be invoked very early in the initialization sequence which mandates that this function should be implemented in assembly and should not rely on the avalability of a C -runtime environment. +runtime environment. This function can clobber x0 - x8 and must preserve +x9 - x29. This function plays a crucial role in the power domain topology framework in PSCI and details of this can be found in [Power Domain Topology Design]. |