[GitHub] [incubator-nuttx] masayuki2009 commented on a diff in pull request #7247: arch: qemu-rv: Modify qemu_rv_mm_init() for SMP

[GitBox <gi...@apache.org>]

masayuki2009 commented on code in PR #7247:
URL: https://github.com/apache/incubator-nuttx/pull/7247#discussion_r988424776


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arch/risc-v/src/qemu-rv/qemu_rv_mm_init.c:
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@@ -252,9 +261,23 @@ void qemu_rv_kernel_mappings(void)
 
 void qemu_rv_mm_init(void)
 {
-  /* Setup the kernel mappings */
+#ifdef CONFIG_SMP
+  irqstate_t flags;
+  flags = spin_lock_irqsave(&g_mm_init_spin);

Review Comment:
   @xiaoxiang781216 
   Yes, we need the code to run BUILD_KERNEL in SMP, because all cores start at the same time.
   In ARMv-7A, @GUIDINGLI recently modified the startup code which uses ARM_SEV to send a signal to all cores.
   However, RISC-V does not have such instruction and technically we can send signals by IPI but I think this should be implemented in another PR later.
   



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