Почему Linux5.15 Arm64 `cpu_context_switch` устанавливает `sp_el0` в следующую базу Task_struct ⇐ Linux

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I read the code below at

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arch/arm64/kernel/entry.S

in Linux5.15

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/*  * Register switch for AArch64. The callee-saved registers need to be saved  * and restored. On entry:  *   x0 = previous task_struct (must be preserved across the switch)  *   x1 = next task_struct  * Previous and next are guaranteed not to be the same.  *  */ SYM_FUNC_START(cpu_switch_to)     mov x10, #THREAD_CPU_CONTEXT // x10 = offsetof(struct task_struct, thread.cpu_context)     add x8, x0, x10 // x8 = previous cpu_context address     mov x9, sp      stp x19, x20, [x8], #16     // store callee-saved registers     stp x21, x22, [x8], #16          stp x23, x24, [x8], #16     stp x25, x26, [x8], #16     stp x27, x28, [x8], #16     stp x29, x9, [x8], #16       str lr, [x8]     add x8, x1, x10      ldp x19, x20, [x8], #16     // restore callee-saved registers     ldp x21, x22, [x8], #16     ldp x23, x24, [x8], #16     ldp x25, x26, [x8], #16     ldp x27, x28, [x8], #16     ldp x29, x9, [x8], #16      ldr lr, [x8]      mov sp, x9                     // 

Источник: [url]https://stackoverflow.com/questions/78131788/why-linux5-15-arm64-cpu-context-switch-set-sp-el0-to-next-task-struct-base[/url]