xiaoxiang781216 commented on a change in pull request #5782:
URL: https://github.com/apache/incubator-nuttx/pull/5782#discussion_r834611239
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File path: arch/risc-v/src/common/riscv_assert.c
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@@ -338,6 +338,10 @@ static void riscv_dumpstate(void)
else
{
riscv_saveusercontext(rtcb->xcp.regs);
+
+ /* riscv_saveusercontext modifies the local context (a0), restore it */
+
+ rtcb = running_task();
Review comment:
> The prototype of riscv_saveusercontext indicates that it modifies the
return value in context (a0,which is rtcb). I just did what the prototype
indicated. So yes, indeed, rtcb will not be preserved as it is destroyed by
riscv_saveusercontext .
>
a0 is used to pass argument and return value, it's expect that
riscv_saveusercontext will destroy a0. But, if rtcb is still used after
riscv_saveusercontext, compiler will save rtcb to other callee saved register
or even stack before invoking riscv_saveusercontext. So, I don't understand why
we need specially handle it here.
Since the similar code exist in other arch too, it's better to fix all place
if this is a real problem, but I don't think so.
> I can of course change what riscv_saveusercontext does, and modify the
prototype?
what prototype?
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