From d261b4e0b35b448dbbf4a1a9038dc414d0e9a743 Mon Sep 17 00:00:00 2001
From: Harry Chen <i@harrychen.xyz>
Date: Mon, 13 May 2019 21:18:25 +0800
Subject: [PATCH] Save/restore FP registers when context switching (broken
 mipsel arch)

Signed-off-by: Harry Chen <i@harrychen.xyz>
---
 kernel/Makefile                      |  2 +-
 kernel/src/arch/mipsel/boot/trap.S   | 85 +++++++++++++++++++++++++++-
 kernel/src/arch/mipsel/context.rs    | 33 +++++++++++
 kernel/src/arch/mipsel/driver/mod.rs |  2 +-
 kernel/targets/mipsel.json           |  2 +-
 5 files changed, 118 insertions(+), 6 deletions(-)

diff --git a/kernel/Makefile b/kernel/Makefile
index b0ccb2a..275d0b7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -346,7 +346,7 @@ else ifeq ($(arch), aarch64)
 	@cargo xbuild $(build_args)
 else ifeq ($(arch), mipsel)
 	@for file in context entry trap ; do \
-	    $(hostcc) -E src/arch/$(arch)/boot/$${file}.S -o src/arch/$(arch)/boot/$${file}.gen.s ; \
+	    $(hostcc) -Dboard_$(board) -E src/arch/$(arch)/boot/$${file}.S -o src/arch/$(arch)/boot/$${file}.gen.s ; \
 	done
 	@cargo xbuild $(build_args)
 endif
diff --git a/kernel/src/arch/mipsel/boot/trap.S b/kernel/src/arch/mipsel/boot/trap.S
index 07b7ffa..4ec8650 100644
--- a/kernel/src/arch/mipsel/boot/trap.S
+++ b/kernel/src/arch/mipsel/boot/trap.S
@@ -43,8 +43,15 @@ trap_from_kernel:
 	move sp, k0
 	
 sp_aligned:
-	# allocate 38 words for trapframe + 6 extra words
-	addiu sp, sp, -176
+	# allocate 38 / 70 words for trapframe + 6 extra words
+
+#ifdef board_thinpad
+#define TRAPFRAME_SIZE 304
+#else
+#define TRAPFRAME_SIZE 176
+#endif
+
+	addiu sp, sp, -TRAPFRAME_SIZE
 
 	# save general registers
 	sw ra, 160(sp)
@@ -80,6 +87,42 @@ sp_aligned:
 	sw AT, 40(sp)
 	nop	
 
+#ifdef board_thinpad
+	# save floating point registers
+	swc1 $f0, 164(sp)
+	swc1 $f1, 168(sp)
+	swc1 $f2, 172(sp)
+	swc1 $f3, 176(sp)
+	swc1 $f4, 180(sp)
+	swc1 $f5, 184(sp)
+	swc1 $f6, 188(sp)
+	swc1 $f7, 192(sp)
+	swc1 $f8, 196(sp)
+	swc1 $f9, 200(sp)
+	swc1 $f10, 204(sp)
+	swc1 $f11, 208(sp)
+	swc1 $f12, 212(sp)
+	swc1 $f13, 216(sp)
+	swc1 $f14, 220(sp)
+	swc1 $f15, 224(sp)
+	swc1 $f16, 228(sp)
+	swc1 $f17, 232(sp)
+	swc1 $f18, 236(sp)
+	swc1 $f19, 240(sp)
+	swc1 $f20, 244(sp)
+	swc1 $f21, 248(sp)
+	swc1 $f22, 252(sp)
+	swc1 $f23, 256(sp)
+	swc1 $f24, 260(sp)
+	swc1 $f25, 264(sp)
+	swc1 $f26, 268(sp)
+	swc1 $f27, 272(sp)
+	swc1 $f28, 276(sp)
+	swc1 $f29, 280(sp)
+	swc1 $f30, 284(sp)
+	swc1 $f31, 288(sp)
+#endif
+
 	# save hi/lo
 	mflo t1
 	sw t1, 36(sp)
@@ -158,9 +201,45 @@ trap_return:
 	lw fp, 156(sp)
 	lw ra, 160(sp)
 
+#ifdef board_thinpad
+	# restore floating point registers
+	lwc1 $f0, 164(sp)
+	lwc1 $f1, 168(sp)
+	lwc1 $f2, 172(sp)
+	lwc1 $f3, 176(sp)
+	lwc1 $f4, 180(sp)
+	lwc1 $f5, 184(sp)
+	lwc1 $f6, 188(sp)
+	lwc1 $f7, 192(sp)
+	lwc1 $f8, 196(sp)
+	lwc1 $f9, 200(sp)
+	lwc1 $f10, 204(sp)
+	lwc1 $f11, 208(sp)
+	lwc1 $f12, 212(sp)
+	lwc1 $f13, 216(sp)
+	lwc1 $f14, 220(sp)
+	lwc1 $f15, 224(sp)
+	lwc1 $f16, 228(sp)
+	lwc1 $f17, 232(sp)
+	lwc1 $f18, 236(sp)
+	lwc1 $f19, 240(sp)
+	lwc1 $f20, 244(sp)
+	lwc1 $f21, 248(sp)
+	lwc1 $f22, 252(sp)
+	lwc1 $f23, 256(sp)
+	lwc1 $f24, 260(sp)
+	lwc1 $f25, 264(sp)
+	lwc1 $f26, 268(sp)
+	lwc1 $f27, 272(sp)
+	lwc1 $f28, 276(sp)
+	lwc1 $f29, 280(sp)
+	lwc1 $f30, 284(sp)
+	lwc1 $f31, 288(sp)
+#endif
+
 	# save kernel stack
 	lw k0, 0(sp)
-	addiu k1, sp, 176
+	addiu k1, sp, TRAPFRAME_SIZE
 	movn k1, k0, k0
 
 	la k0, _cur_kstack_ptr
diff --git a/kernel/src/arch/mipsel/context.rs b/kernel/src/arch/mipsel/context.rs
index 116e9f0..9441313 100644
--- a/kernel/src/arch/mipsel/context.rs
+++ b/kernel/src/arch/mipsel/context.rs
@@ -52,6 +52,39 @@ pub struct TrapFrame {
     pub sp: usize,
     pub fp: usize,
     pub ra: usize,
+    /// Floating-point registers (contains garbage if no FP support present)
+    pub f0: usize,
+    pub f1: usize,
+    pub f2: usize,
+    pub f3: usize,
+    pub f4: usize,
+    pub f5: usize,
+    pub f6: usize,
+    pub f7: usize,
+    pub f8: usize,
+    pub f9: usize,
+    pub f10: usize,
+    pub f11: usize,
+    pub f12: usize,
+    pub f13: usize,
+    pub f14: usize,
+    pub f15: usize,
+    pub f16: usize,
+    pub f17: usize,
+    pub f18: usize,
+    pub f19: usize,
+    pub f20: usize,
+    pub f21: usize,
+    pub f22: usize,
+    pub f23: usize,
+    pub f24: usize,
+    pub f25: usize,
+    pub f26: usize,
+    pub f27: usize,
+    pub f28: usize,
+    pub f29: usize,
+    pub f30: usize,
+    pub f31: usize,
     /// Reserved
     pub reserved: usize,
     pub __padding: [usize; 2],
diff --git a/kernel/src/arch/mipsel/driver/mod.rs b/kernel/src/arch/mipsel/driver/mod.rs
index 071142b..206d601 100644
--- a/kernel/src/arch/mipsel/driver/mod.rs
+++ b/kernel/src/arch/mipsel/driver/mod.rs
@@ -10,7 +10,7 @@ pub mod console;
 /// Initialize common drivers
 pub fn init() {
     board::init_driver();
-    console::init();
+    // console::init();
     if let Some(con) = console::CONSOLE.lock().as_mut() {
         con.clear();
     }
diff --git a/kernel/targets/mipsel.json b/kernel/targets/mipsel.json
index 346e3e8..7cc6d7d 100644
--- a/kernel/targets/mipsel.json
+++ b/kernel/targets/mipsel.json
@@ -7,7 +7,7 @@
   "target-pointer-width": "32",
   "target-c-int-width": "32",
   "os": "none",
-  "features": "+mips32r2,+soft-float",
+  "features": "+mips32r2,+single-float",
   "max-atomic-width": "32",
   "linker": "rust-lld",
   "linker-flavor": "ld.lld",