102 lines
2.2 KiB
ArmAsm
102 lines
2.2 KiB
ArmAsm
/* MARKUS MAIWALD (ARCHITECT) | VOXIS FORGE (AI)
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RUMPK HAL // RISC-V 64 CONTEXT SWITCH (Boundaries Protected)
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*/
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.global cpu_switch_to
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.type cpu_switch_to, @function
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cpu_switch_to:
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addi sp, sp, -128
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sd ra, 0(sp)
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sd gp, 8(sp)
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sd tp, 16(sp)
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sd s0, 24(sp)
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sd s1, 32(sp)
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sd s2, 40(sp)
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sd s3, 48(sp)
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sd s4, 56(sp)
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sd s5, 64(sp)
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sd s6, 72(sp)
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sd s7, 80(sp)
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sd s8, 88(sp)
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sd s9, 96(sp)
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sd s10, 104(sp)
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sd s11, 112(sp)
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csrr t0, sscratch
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sd t0, 120(sp)
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sd sp, 0(a0)
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mv sp, a1
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ld t0, 120(sp)
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csrw sscratch, t0
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ld ra, 0(sp)
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ld gp, 8(sp)
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ld tp, 16(sp)
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ld s0, 24(sp)
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ld s1, 32(sp)
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ld s2, 40(sp)
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ld s3, 48(sp)
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ld s4, 56(sp)
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ld s5, 64(sp)
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ld s6, 72(sp)
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ld s7, 80(sp)
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ld s8, 88(sp)
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ld s9, 96(sp)
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ld s10, 104(sp)
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ld s11, 112(sp)
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addi sp, sp, 128
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ret
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.global rumpk_yield_guard
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.type rumpk_yield_guard, @function
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rumpk_yield_guard:
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addi sp, sp, -16
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sd gp, 0(sp)
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sd ra, 8(sp)
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.option push
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.option norelax
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la gp, __global_pointer$
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.option pop
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call rumpk_yield_internal
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ld gp, 0(sp)
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ld ra, 8(sp)
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addi sp, sp, 16
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ret
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.global rumpk_enter_userland
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.type rumpk_enter_userland, @function
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# void rumpk_enter_userland(uint64_t entry, uint64_t argc, uint64_t argv, uint64_t sp);
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# a0 = entry, a1 = argc, a2 = argv, a3 = sp
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rumpk_enter_userland:
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# 🏛️ PIVOT TO USER MODE (C-ABI Handover)
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# 1. Prepare Program Counter
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csrw sepc, a0
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# 2. Prepare Stack and sscratch
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# sscratch MUST contain the Kernel Stack for the trap handler
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csrw sscratch, sp
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mv sp, a3
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# 3. Prepare Arguments (argc, argv)
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mv t0, a1 # Temporarily store argc
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mv a1, a2 # a1 = argv
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mv a0, t0 # a0 = argc
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# 4. Configure sstatus for U-mode transition
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li t0, (1 << 8)
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csrc sstatus, t0 # Clear SPP (User)
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li t0, (1 << 5)
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csrs sstatus, t0 # Enable SPIE
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li t0, (1 << 18)
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csrs sstatus, t0 # Enable SUM (Supervisor User Memory)
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# 5. Flush Caches
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fence.i
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# 6. The Leap of Faith
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sret
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