Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/arch/mips/kernel/r2300_switch.S b/arch/mips/kernel/r2300_switch.S
new file mode 100644
index 0000000..243e7b6
--- /dev/null
+++ b/arch/mips/kernel/r2300_switch.S
@@ -0,0 +1,174 @@
+/*
+ * r2300_switch.S: R2300 specific task switching code.
+ *
+ * Copyright (C) 1994, 1995, 1996, 1999 by Ralf Baechle
+ * Copyright (C) 1994, 1995, 1996 by Andreas Busse
+ *
+ * Multi-cpu abstraction and macros for easier reading:
+ * Copyright (C) 1996 David S. Miller (dm@engr.sgi.com)
+ *
+ * Further modifications to make this work:
+ * Copyright (c) 1998-2000 Harald Koerfgen
+ */
+#include <linux/config.h>
+#include <asm/asm.h>
+#include <asm/cachectl.h>
+#include <asm/fpregdef.h>
+#include <asm/mipsregs.h>
+#include <asm/offset.h>
+#include <asm/page.h>
+#include <asm/regdef.h>
+#include <asm/stackframe.h>
+#include <asm/thread_info.h>
+
+#include <asm/asmmacro.h>
+
+ .set mips1
+ .align 5
+
+/*
+ * Offset to the current process status flags, the first 32 bytes of the
+ * stack are not used.
+ */
+#define ST_OFF (_THREAD_SIZE - 32 - PT_SIZE + PT_STATUS)
+
+/*
+ * FPU context is saved iff the process has used it's FPU in the current
+ * time slice as indicated by TIF_USEDFPU. In any case, the CU1 bit for user
+ * space STATUS register should be 0, so that a process *always* starts its
+ * userland with FPU disabled after each context switch.
+ *
+ * FPU will be enabled as soon as the process accesses FPU again, through
+ * do_cpu() trap.
+ */
+
+/*
+ * task_struct *resume(task_struct *prev, task_struct *next,
+ * struct thread_info *next_ti) )
+ */
+LEAF(resume)
+#ifndef CONFIG_CPU_HAS_LLSC
+ sw zero, ll_bit
+#endif
+ mfc0 t1, CP0_STATUS
+ sw t1, THREAD_STATUS(a0)
+ cpu_save_nonscratch a0
+ sw ra, THREAD_REG31(a0)
+
+ /*
+ * check if we need to save FPU registers
+ */
+ lw t3, TASK_THREAD_INFO(a0)
+ lw t0, TI_FLAGS(t3)
+ li t1, _TIF_USEDFPU
+ and t2, t0, t1
+ beqz t2, 1f
+ nor t1, zero, t1
+
+ and t0, t0, t1
+ sw t0, TI_FLAGS(t3)
+
+ /*
+ * clear saved user stack CU1 bit
+ */
+ lw t0, ST_OFF(t3)
+ li t1, ~ST0_CU1
+ and t0, t0, t1
+ sw t0, ST_OFF(t3)
+
+ fpu_save_single a0, t0 # clobbers t0
+
+1:
+ /*
+ * The order of restoring the registers takes care of the race
+ * updating $28, $29 and kernelsp without disabling ints.
+ */
+ move $28, a2
+ cpu_restore_nonscratch a1
+
+ addiu t1, $28, _THREAD_SIZE - 32
+ sw t1, kernelsp
+
+ mfc0 t1, CP0_STATUS /* Do we really need this? */
+ li a3, 0xff01
+ and t1, a3
+ lw a2, THREAD_STATUS(a1)
+ nor a3, $0, a3
+ and a2, a3
+ or a2, t1
+ mtc0 a2, CP0_STATUS
+ move v0, a0
+ jr ra
+ END(resume)
+
+/*
+ * Save a thread's fp context.
+ */
+LEAF(_save_fp)
+ fpu_save_single a0, t1 # clobbers t1
+ jr ra
+ END(_save_fp)
+
+/*
+ * Restore a thread's fp context.
+ */
+LEAF(_restore_fp)
+ fpu_restore_single a0, t1 # clobbers t1
+ jr ra
+ END(_restore_fp)
+
+/*
+ * Load the FPU with signalling NANS. This bit pattern we're using has
+ * the property that no matter whether considered as single or as double
+ * precision represents signaling NANS.
+ *
+ * We initialize fcr31 to rounding to nearest, no exceptions.
+ */
+
+#define FPU_DEFAULT 0x00000000
+
+LEAF(_init_fpu)
+ mfc0 t0, CP0_STATUS
+ li t1, ST0_CU1
+ or t0, t1
+ mtc0 t0, CP0_STATUS
+
+ li t1, FPU_DEFAULT
+ ctc1 t1, fcr31
+
+ li t0, -1
+
+ mtc1 t0, $f0
+ mtc1 t0, $f1
+ mtc1 t0, $f2
+ mtc1 t0, $f3
+ mtc1 t0, $f4
+ mtc1 t0, $f5
+ mtc1 t0, $f6
+ mtc1 t0, $f7
+ mtc1 t0, $f8
+ mtc1 t0, $f9
+ mtc1 t0, $f10
+ mtc1 t0, $f11
+ mtc1 t0, $f12
+ mtc1 t0, $f13
+ mtc1 t0, $f14
+ mtc1 t0, $f15
+ mtc1 t0, $f16
+ mtc1 t0, $f17
+ mtc1 t0, $f18
+ mtc1 t0, $f19
+ mtc1 t0, $f20
+ mtc1 t0, $f21
+ mtc1 t0, $f22
+ mtc1 t0, $f23
+ mtc1 t0, $f24
+ mtc1 t0, $f25
+ mtc1 t0, $f26
+ mtc1 t0, $f27
+ mtc1 t0, $f28
+ mtc1 t0, $f29
+ mtc1 t0, $f30
+ mtc1 t0, $f31
+ jr ra
+ END(_init_fpu)