[Minios-devel] [UNIKRAFT early RFC PATCH 09/11] plat/kvm/arm: Add simple percpu variable support

[Jia He <justin.he@xxxxxxx>]

Signed-off-by: Jia He <justin.he@xxxxxxx>
---
 plat/common/include/smp.h |  7 +++++++
 plat/kvm/arm/setup.c      | 22 ++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/plat/common/include/smp.h b/plat/common/include/smp.h
index 38f801d..15bb92d 100644
--- a/plat/common/include/smp.h
+++ b/plat/common/include/smp.h
@@ -34,8 +34,15 @@
 #ifndef __PLAT_CMN_SMP_H__
 #define __PLAT_CMN_SMP_H__
 
+#include <inttypes.h>
+struct pcpu {
+       uint32_t        pc_cpuid;       /* This cpu number */
+};
+
 #define        MAXCPU          8 /* hard limitation for CPU number */
 extern int cpu_possible_map[MAXCPU];
+struct pcpu __pcpu[MAXCPU];
+struct pcpu *pcpup = &__pcpu[0];
 
 void release_aps(void);
 int start_cpu(uint64_t target_cpu);
diff --git a/plat/kvm/arm/setup.c b/plat/kvm/arm/setup.c
index 4035202..b262d94 100644
--- a/plat/kvm/arm/setup.c
+++ b/plat/kvm/arm/setup.c
@@ -330,6 +330,17 @@ void init_secondary(uint64_t cpu)
 
        uk_pr_info("init secondary cpu=%lu\n", cpu);
 
+       /*
+        * Set the pcpu pointer with a backup in tpidr_el1 to be
+        * loaded when entering the kernel from userland.
+        */
+       __asm __volatile(
+               "mov x18, %0\n"
+               "msr tpidr_el1, %0" :: "r"(pcpup));
+
+       pcpup[cpu].pc_cpuid = cpu;
+       uk_pr_info("pcpup[%lu]=%u\n", cpu, pcpup[cpu].pc_cpuid);
+
        /* Spin until the BSP releases the APs */
        while (!aps_ready)
                __asm __volatile("wfe");
@@ -408,6 +419,17 @@ void _libkvmplat_start(void *dtb_pointer)
        uk_pr_info("Switch from bootstrap stack to stack @%p\n",
                   _libkvmplat_stack_top);
 
+       /* Set the pcpu data, this is needed by pmap_bootstrap */
+       pcpup = &__pcpu[0];
+
+       /*
+        * Set the pcpu pointer with a backup in tpidr_el1 to be
+        * loaded when entering the kernel from userland.
+        */
+       __asm __volatile(
+               "mov x18, %0\n"
+               "msr tpidr_el1, %0" :: "r"(pcpup));
+
        _libkvmplat_newstack((uint64_t) _libkvmplat_stack_top,
                                _libkvmplat_entry2, NULL);
 }
-- 
2.17.1


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