| // Copyright 2023 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| .globl restricted_enter_wrapper |
| restricted_enter_wrapper: |
| // A0 contains the options vector, and A1 contains the reason code pointer. |
| |
| // Make space for all of the normal mode context on the stack. |
| addi sp, sp, -128 |
| |
| // Save the reason code pointer. |
| sd a1, (sp) |
| |
| // Save the shadow call stack pointer. |
| sd gp, 8(sp) |
| |
| // Save all of the callee saved registers. |
| sd s0, 16(sp) |
| sd s1, 24(sp) |
| sd s2, 32(sp) |
| sd s3, 40(sp) |
| sd s4, 48(sp) |
| sd s5, 56(sp) |
| sd s6, 64(sp) |
| sd s7, 72(sp) |
| sd s8, 80(sp) |
| sd s9, 88(sp) |
| sd s10, 96(sp) |
| sd s11, 104(sp) |
| |
| // Save the return address. |
| sd ra, 112(sp) |
| |
| // Save the thread pointer. |
| sd tp, 120(sp) |
| |
| // Pass restricted exit as the return vector to the syscall. |
| la a1, restricted_exit |
| |
| // Pass the stack pointer as the context argument to the syscall. |
| mv a2, sp |
| |
| call zx_restricted_enter |
| |
| // If we got here it must have failed. |
| // Restore the return address from prior to the syscall. We have to do this |
| // because RA is caller-saved. |
| ld ra, 112(sp) |
| // Reset the stack. |
| addi sp, sp, 128 |
| ret |
| |
| .globl restricted_exit |
| restricted_exit: |
| // Back from restricted mode |
| // a0 holds the context, which is the stack pointer |
| // a1 holds the reason code |
| |
| // Restore the stack pointer at the point of the restricted enter wrapper. |
| mv sp, a0 |
| |
| // Restore the shadow call stack pointer. |
| ld gp, 8(sp) |
| |
| // Restore the callee saved registers. |
| ld s0, 16(sp) |
| ld s1, 24(sp) |
| ld s2, 32(sp) |
| ld s3, 40(sp) |
| ld s4, 48(sp) |
| ld s5, 56(sp) |
| ld s6, 64(sp) |
| ld s7, 72(sp) |
| ld s8, 80(sp) |
| ld s9, 88(sp) |
| ld s10, 96(sp) |
| ld s11, 104(sp) |
| |
| // Restore the return address. |
| ld ra, 112(sp) |
| |
| // Restore the thread pointer. |
| ld tp, 120(sp) |
| |
| // Move the reason code into the stored pointer. |
| ld t3, (sp) |
| sd a1, (t3) |
| |
| // Pop all the normal mode context off the stack. |
| addi sp, sp, 128 |
| |
| // Return to whatever address was in RA. |
| // Make it appear as if the wrapper had returned ZX_OK. |
| mv a0, zero |
| ret |
