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https://github.com/cirosantilli/linux-kernel-module-cheat.git
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46 lines
1013 B
C
46 lines
1013 B
C
/* https://cirosantilli.com/linux-kernel-module-cheat#arm-baremetal-multicore
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*
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* Beware: things will blow up if the stack for CPU0 grow too much and
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* reaches that of CPU1. This is why it is so hard to do multithreading
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* without an OS that manages paging.
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*/
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#include <lkmc.h>
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uint64_t spinlock = 0;
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__asm__(
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".text\n"
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".global lkmc_cpu_not_0\n"
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"lkmc_cpu_not_0:\n"
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/* Put all CPUs except CPU1 to sleep. */
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" cmp x0, 1\n"
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" bne .Lsleep_forever\n"
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/* Prepare the stack for CPU1. This is what we need
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* this assembly function for. */
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" ldr x0, =(stack_top - 0x1000)\n"
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" mov sp, x0\n"
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" bl main_cpu1\n"
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".Lsleep_forever:\n"
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" wfe\n"
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" b .Lsleep_forever\n"
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);
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static void main_cpu1(void) {
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spinlock = 1;
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lkmc_arm_aarch64_dmb(sy);
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lkmc_arm_aarch64_sev();
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while (1) {
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lkmc_arm_aarch64_wfe();
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}
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}
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int main(void) {
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#if !LKMC_GEM5
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lkmc_aarch64_psci_cpu_on(1, (uint64_t)main_cpu1, 0);
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#endif
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while (!spinlock) {
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lkmc_arm_aarch64_wfe();
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}
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}
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