From 6a50b8a68d5a0595dc78c90f5d0969021beb7ea1 Mon Sep 17 00:00:00 2001
From: Justin Weiss
Date: Sat, 29 Feb 2020 10:50:30 -0800
Subject: [3DS] Fix dynarec prefetch aborts

Similar fix to https://github.com/libretro/pcsx_rearmed/pull/390. The
Nintendo svcBackdoor can cause stack corruption if an interrupt
happens during it, this uses Luma3DS/Rosalina's svcCustomBackdoor instead.
---
 3ds/3ds_cache_utils.S | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 3ds/3ds_cache_utils.S

(limited to '3ds/3ds_cache_utils.S')

diff --git a/3ds/3ds_cache_utils.S b/3ds/3ds_cache_utils.S
new file mode 100644
index 0000000..c8df651
--- /dev/null
+++ b/3ds/3ds_cache_utils.S
@@ -0,0 +1,25 @@
+  .text
+  .arm
+  .balign 4
+
+  .func ctr_clear_cache_kernel
+ctr_clear_cache_kernel:
+  cpsid aif
+  mov r0, #0
+  mcr p15, 0, r0, c7, c10, 0    @ Clean entire data cache
+  mcr p15, 0, r0, c7, c10, 5    @ Data Memory Barrier
+  mcr p15, 0, r0, c7, c5, 0     @ Invalidate entire instruction cache / Flush BTB
+  mcr p15, 0, r0, c7, c10, 4    @ Data Sync Barrier
+  bx lr
+  .endfunc
+
+  @@ Clear the entire data cache / invalidate the instruction cache. Uses
+  @@ Rosalina svcCustomBackdoor to avoid svcBackdoor stack corruption
+  @@ during interrupts.
+  .global ctr_clear_cache
+  .func ctr_clear_cache
+ctr_clear_cache:
+  ldr r0, =ctr_clear_cache_kernel
+  svc 0x80                      @ svcCustomBackdoor
+  bx lr
+  .endfunc
-- 
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