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new fpu code

PATCH New Jun Sun 1 participant 1 message Nov 1, 2002

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MIPS ptrace support
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Jun Sun

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PATCH 1/1 new fpu code

Whew! What an effort to create a patch for 4 arches instead of one!

Anyhow, attached are the complete patches for the new FPU context management code, for both 2.4 and 2.5, 32bit and 64bit.

. Get rid of lazy fpu switch. New algorithm is SMP safe. . Simplify signal/fpu handling
. Simplify FPU register access
. Unify FPU code between 2.4 and 2.5, and between 32bit and 64bit

Ralf, good enough?

Jun

arch/mips/kernel/process.c renamed from arch/mips/kernel/process.c.orig +16 -19
diff -Nru link/arch/mips/kernel/process.c.orig link/arch/mips/kernel/process.c
@@ -21,6 +21,7 @@
 
 #include <asm/bootinfo.h>
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
 #include <asm/mipsregs.h>

@@ -47,28 +48,25 @@
 	}
 }
 
-struct task_struct *last_task_used_math = NULL;
-
 asmlinkage void ret_from_fork(void);
 
+void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
+{
+	regs->cp0_status &= ~(ST0_CU0|ST0_KSU|ST0_CU1);
+       	regs->cp0_status |= KU_USER;
+	current->used_math = 0;
+	loose_fpu();
+	regs->cp0_epc = pc;
+	regs->regs[29] = sp;
+	current->thread.current_ds = USER_DS;
+}
+
 void exit_thread(void)
 {
-	/* Forget lazy fpu state */
-	if (last_task_used_math == current && mips_cpu.options & MIPS_CPU_FPU) {
-		__enable_fpu();
-		__asm__ __volatile__("cfc1\t$0,$31");
-		last_task_used_math = NULL;
-	}
 }
 
 void flush_thread(void)
 {
-	/* Forget lazy fpu state */
-	if (last_task_used_math == current && mips_cpu.options & MIPS_CPU_FPU) {
-		__enable_fpu();
-		__asm__ __volatile__("cfc1\t$0,$31");
-		last_task_used_math = NULL;
-	}
 }
 
 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,

@@ -80,11 +78,10 @@
 
 	childksp = (unsigned long)p + KERNEL_STACK_SIZE - 32;
 
-	if (last_task_used_math == current)
-		if (mips_cpu.options & MIPS_CPU_FPU) {
-			__enable_fpu();
-			save_fp(p);
-		}
+	if (is_fpu_owner()) {
+		save_fp(p);
+	}
+	
 	/* set up new TSS. */
 	childregs = (struct pt_regs *) childksp - 1;
 	*childregs = *regs;
arch/mips/kernel/ptrace.c renamed from arch/mips/kernel/ptrace.c.orig +4 -30
diff -Nru link/arch/mips/kernel/ptrace.c.orig link/arch/mips/kernel/ptrace.c
@@ -27,6 +27,7 @@
 #include <asm/uaccess.h>
 #include <asm/bootinfo.h>
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 
 /*
  * Called by kernel/ptrace.c when detaching..

@@ -42,7 +43,6 @@
 {
 	struct task_struct *child;
 	int ret;
-	extern void save_fp(struct task_struct *);
 
 	lock_kernel();
 #if 0

@@ -113,20 +113,7 @@
 			break;
 		case FPR_BASE ... FPR_BASE + 31:
 			if (child->used_math) {
-			        unsigned long long *fregs
-					= (unsigned long long *)
-					    &child->thread.fpu.hard.fp_regs[0];
-			 	if(!(mips_cpu.options & MIPS_CPU_FPU)) {
-					fregs = (unsigned long long *)
-						child->thread.fpu.soft.regs;
-				} else
-					if (last_task_used_math == child) {
-						__enable_fpu();
-						save_fp(child);
-						__disable_fpu();
-						last_task_used_math = NULL;
-						regs->cp0_status &= ~ST0_CU1;
-					}
+			        unsigned long long *fregs = get_fpu_regs(child);
 				/*
 				 * The odd registers are actually the high
 				 * order bits of the values stored in the even

@@ -204,21 +191,8 @@
 			break;
 		case FPR_BASE ... FPR_BASE + 31: {
 			unsigned long long *fregs;
-			fregs = (unsigned long long *)&child->thread.fpu.hard.fp_regs[0];
-			if (child->used_math) {
-				if (last_task_used_math == child) {
-					if(!(mips_cpu.options & MIPS_CPU_FPU)) {
-						fregs = (unsigned long long *)
-						child->thread.fpu.soft.regs;
-					} else {
-						__enable_fpu();
-						save_fp(child);
-						__disable_fpu();
-						last_task_used_math = NULL;
-						regs->cp0_status &= ~ST0_CU1;
-					}
-				}
-			} else {
+			fregs = (unsigned long long *)get_fpu_regs(child);
+			if (!child->used_math) {
 				/* FP not yet used  */
 				memset(&child->thread.fpu.hard, ~0,
 				       sizeof(child->thread.fpu.hard));
arch/mips/kernel/signal.c renamed from arch/mips/kernel/signal.c.orig +15 -82

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arch/mips/kernel/traps.c renamed from arch/mips/kernel/traps.c.orig +15 -29

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arch/mips/kernel/r2300_switch.S renamed from arch/mips/kernel/r2300_switch.S.orig +45 -33

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arch/mips/kernel/r4k_switch.S renamed from arch/mips/kernel/r4k_switch.S.orig +45 -36

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arch/mips/kernel/cpu-probe.c renamed from arch/mips/kernel/cpu-probe.c.orig +1 -0
diff -Nru link/arch/mips/kernel/cpu-probe.c.orig link/arch/mips/kernel/cpu-probe.c
@@ -3,6 +3,7 @@
 #include <linux/stddef.h>
 #include <asm/bugs.h>
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 #include <asm/mipsregs.h>
 
 /*
arch/mips/tools/offset.c renamed from arch/mips/tools/offset.c.orig +0 -1
diff -Nru link/arch/mips/tools/offset.c.orig link/arch/mips/tools/offset.c
@@ -151,7 +151,6 @@
 	offset("#define SC_MDLO       ", struct sigcontext, sc_mdlo);
 	offset("#define SC_PC         ", struct sigcontext, sc_pc);
 	offset("#define SC_STATUS     ", struct sigcontext, sc_status);
-	offset("#define SC_OWNEDFP    ", struct sigcontext, sc_ownedfp);
 	offset("#define SC_FPC_CSR    ", struct sigcontext, sc_fpc_csr);
 	offset("#define SC_FPC_EIR    ", struct sigcontext, sc_fpc_eir);
 	offset("#define SC_CAUSE      ", struct sigcontext, sc_cause);
arch/mips64/kernel/process.c renamed from arch/mips64/kernel/process.c.orig +20 -21

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arch/mips64/kernel/ptrace.c renamed from arch/mips64/kernel/ptrace.c.orig +4 -34
diff -Nru link/arch/mips64/kernel/ptrace.c.orig link/arch/mips64/kernel/ptrace.c
@@ -23,6 +23,7 @@
 #include <linux/user.h>
 
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 #include <asm/mipsregs.h>
 #include <asm/pgtable.h>
 #include <asm/page.h>

@@ -112,23 +113,7 @@
 			break;
 		case FPR_BASE ... FPR_BASE + 31:
 			if (child->used_math) {
-				unsigned long *fregs
-					= (unsigned long *)
-					    &child->thread.fpu.hard.fp_regs[0];
-				if (mips_cpu.options & MIPS_CPU_FPU) {
-#ifndef CONFIG_SMP
-					if (last_task_used_math == child) {
-						__enable_fpu();
-						save_fp(child);
-						__disable_fpu();
-						last_task_used_math = NULL;
-					}
-#endif
-				} else {
-					fregs = (unsigned long *)
-						child->thread.fpu.soft.regs;
-				}
-
+				unsigned long *fregs = get_fpu_regs(child);
 				tmp = (unsigned long) fregs[addr - FPR_BASE];
 			} else {
 				tmp = -EIO;

@@ -191,23 +176,8 @@
 			regs->regs[addr] = data;
 			break;
 		case FPR_BASE ... FPR_BASE + 31: {
-			unsigned long *fregs;
-			fregs = (unsigned long *)&child->thread.fpu.hard.fp_regs[0];
-			if (child->used_math) {
-#ifndef CONFIG_SMP
-				if (last_task_used_math == child)
-					if (mips_cpu.options & MIPS_CPU_FPU) {
-						__enable_fpu();
-						save_fp(child);
-						__disable_fpu();
-						last_task_used_math = NULL;
-						regs->cp0_status &= ~ST0_CU1;
-					} else {
-						fregs = (unsigned long *)
-						child->thread.fpu.soft.regs;
-					}
-#endif
-			} else {
+			unsigned long *fregs = get_fpu_regs(child);
+			if (!child->used_math) {
 				/* FP not yet used  */
 				memset(&child->thread.fpu.hard, ~0,
 				       sizeof(child->thread.fpu.hard));
arch/mips64/kernel/signal.c renamed from arch/mips64/kernel/signal.c.orig +15 -79

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arch/mips64/kernel/traps.c renamed from arch/mips64/kernel/traps.c.orig +16 -39

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arch/mips64/kernel/r4k_switch.S renamed from arch/mips64/kernel/r4k_switch.S.orig +51 -47

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arch/mips64/kernel/cpu-probe.c renamed from arch/mips64/kernel/cpu-probe.c.orig +1 -0
diff -Nru link/arch/mips64/kernel/cpu-probe.c.orig link/arch/mips64/kernel/cpu-probe.c
@@ -3,6 +3,7 @@
 #include <linux/stddef.h>
 #include <asm/bugs.h>
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 #include <asm/mipsregs.h>
 
 /*
arch/mips64/kernel/signal32.c renamed from arch/mips64/kernel/signal32.c.orig +15 -79

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include/asm-mips/processor.h renamed from include/asm-mips/processor.h.orig +3 -10
diff -Nru link/include/asm-mips/processor.h.orig link/include/asm-mips/processor.h
@@ -72,9 +72,6 @@
 #define wp_works_ok 1
 #define wp_works_ok__is_a_macro /* for versions in ksyms.c */
 
-/* Lazy FPU handling on uni-processor */
-extern struct task_struct *last_task_used_math;
-
 /*
  * User space process size: 2GB. This is hardcoded into a few places,
  * so don't change it unless you know what you are doing.  TASK_SIZE

@@ -211,20 +208,16 @@
 /*
  * Do necessary setup to start up a newly executed thread.
  */
-#define start_thread(regs, new_pc, new_sp) do {				\
-	/* New thread loses kernel and FPU privileges. */	       	\
-	regs->cp0_status = (regs->cp0_status & ~(ST0_CU0|ST0_KSU|ST0_CU1)) | KU_USER;\
-	regs->cp0_epc = new_pc;						\
-	regs->regs[29] = new_sp;					\
-	current->thread.current_ds = USER_DS;				\
-} while (0)
+extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp);
 
+struct task_struct;
 unsigned long get_wchan(struct task_struct *p);
 
 #define __PT_REG(reg) ((long)&((struct pt_regs *)0)->reg - sizeof(struct pt_regs))
 #define __KSTK_TOS(tsk) ((unsigned long)(tsk) + KERNEL_STACK_SIZE - 32)
 #define KSTK_EIP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_epc)))
 #define KSTK_ESP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(regs[29])))
+#define KSTK_STATUS(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_status)))
 
 /* Allocation and freeing of basic task resources. */
 /*
include/asm-mips/mipsregs.h renamed from include/asm-mips/mipsregs.h.orig +0 -42

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include/asm-mips/sigcontext.h renamed from include/asm-mips/sigcontext.h.orig +0 -1
diff -Nru link/include/asm-mips/sigcontext.h.orig link/include/asm-mips/sigcontext.h
@@ -18,7 +18,6 @@
 	unsigned long long sc_pc;
 	unsigned long long sc_regs[32];
 	unsigned long long sc_fpregs[32];
-	unsigned int       sc_ownedfp;
 	unsigned int       sc_fpc_csr;
 	unsigned int       sc_fpc_eir;		/* Unused */
 	unsigned int       sc_used_math;
include/asm-mips/system.h renamed from include/asm-mips/system.h.orig +0 -5
diff -Nru link/include/asm-mips/system.h.orig link/include/asm-mips/system.h
@@ -250,11 +250,6 @@
 
 struct task_struct;
 
-extern asmlinkage void lazy_fpu_switch(void *);
-extern asmlinkage void init_fpu(void);
-extern asmlinkage void save_fp(struct task_struct *);
-extern asmlinkage void restore_fp(struct task_struct *);
-
 #define switch_to(prev,next,last) \
 do { \
 	(last) = resume(prev, next); \
include/asm-mips64/processor.h renamed from include/asm-mips64/processor.h.orig +3 -24
diff -Nru link/include/asm-mips64/processor.h.orig link/include/asm-mips64/processor.h
@@ -103,17 +103,6 @@
 #define wp_works_ok 1
 #define wp_works_ok__is_a_macro /* for versions in ksyms.c */
 
-/* Lazy FPU handling on uni-processor */
-extern struct task_struct *last_task_used_math;
-
-#ifndef CONFIG_SMP
-#define IS_FPU_OWNER()		(last_task_used_math == current)
-#define CLEAR_FPU_OWNER()	last_task_used_math = NULL;
-#else
-#define IS_FPU_OWNER()		(current->flags & PF_USEDFPU)
-#define CLEAR_FPU_OWNER()	current->flags &= ~PF_USEDFPU;
-#endif
-
 /*
  * User space process size: 1TB. This is hardcoded into a few places,
  * so don't change it unless you know what you are doing.  TASK_SIZE

@@ -256,26 +245,16 @@
 /*
  * Do necessary setup to start up a newly executed thread.
  */
-#define start_thread(regs, pc, sp) 					\
-do {									\
-	unsigned long __status;						\
-									\
-	/* New thread looses kernel privileges. */			\
-	__status = regs->cp0_status & ~(ST0_CU0|ST0_FR|ST0_KSU);	\
-	__status |= KSU_USER;						\
-	__status |= (current->thread.mflags & MF_32BIT) ? 0 : ST0_FR;	\
-	regs->cp0_status = __status;					\
-	regs->cp0_epc = pc;						\
-	regs->regs[29] = sp;						\
-	current->thread.current_ds = USER_DS;				\
-} while(0)
+extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp);
 
+struct task_struct;
 unsigned long get_wchan(struct task_struct *p);
 
 #define __PT_REG(reg) ((long)&((struct pt_regs *)0)->reg - sizeof(struct pt_regs))
 #define __KSTK_TOS(tsk) ((unsigned long)(tsk) + KERNEL_STACK_SIZE - 32)
 #define KSTK_EIP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_epc)))
 #define KSTK_ESP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(regs[29])))
+#define KSTK_STATUS(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_status)))
 
 /* Allocation and freeing of basic task resources. */
 /*
include/asm-mips64/mipsregs.h renamed from include/asm-mips64/mipsregs.h.orig +0 -41

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include/asm-mips64/sigcontext.h renamed from include/asm-mips64/sigcontext.h.orig +0 -1
diff -Nru link/include/asm-mips64/sigcontext.h.orig link/include/asm-mips64/sigcontext.h
@@ -20,7 +20,6 @@
 	unsigned long long sc_mdlo;
 	unsigned long long sc_pc;
 	unsigned int       sc_status;
-	unsigned int       sc_ownedfp;
 	unsigned int       sc_fpc_csr;
 	unsigned int       sc_fpc_eir;
 	unsigned int       sc_used_math;
include/asm-mips64/system.h renamed from include/asm-mips64/system.h.orig +0 -17
diff -Nru link/include/asm-mips64/system.h.orig link/include/asm-mips64/system.h
@@ -222,25 +222,8 @@
 
 struct task_struct;
 
-extern asmlinkage void lazy_fpu_switch(void *, void *);
-extern asmlinkage void init_fpu(void);
-extern asmlinkage void save_fp(struct task_struct *);
-extern asmlinkage void restore_fp(struct task_struct *);
-
-#ifdef CONFIG_SMP
-#define SWITCH_DO_LAZY_FPU \
-	if (prev->flags & PF_USEDFPU) { \
-		lazy_fpu_switch(prev, 0); \
-		clear_cp0_status(ST0_CU1); \
-		prev->flags &= ~PF_USEDFPU; \
-	}
-#else /* CONFIG_SMP */
-#define SWITCH_DO_LAZY_FPU	do { } while(0)
-#endif /* CONFIG_SMP */
-
 #define switch_to(prev,next,last) \
 do { \
-	SWITCH_DO_LAZY_FPU; \
 	(last) = resume(prev, next); \
 } while(0)
arch/mips/kernel/process.c renamed from arch/mips/kernel/process.c.orig +15 -19
diff -Nru link/arch/mips/kernel/process.c.orig link/arch/mips/kernel/process.c
@@ -21,6 +21,7 @@
 
 #include <asm/bootinfo.h>
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
 #include <asm/mipsregs.h>

@@ -56,28 +57,25 @@
 	}
 }
 
-struct task_struct *last_task_used_math = NULL;
-
 asmlinkage void ret_from_fork(void);
 
+void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
+{
+	regs->cp0_status &= ~(ST0_CU0|ST0_KSU|ST0_CU1);
+       	regs->cp0_status |= KU_USER;
+	current->used_math = 0;
+	loose_fpu();
+	regs->cp0_epc = pc;
+	regs->regs[29] = sp;
+	current->thread.current_ds = USER_DS;
+}
+
 void exit_thread(void)
 {
-	/* Forget lazy fpu state */
-	if (last_task_used_math == current && mips_cpu.options & MIPS_CPU_FPU) {
-		__enable_fpu();
-		__asm__ __volatile__("cfc1\t$0,$31");
-		last_task_used_math = NULL;
-	}
 }
 
 void flush_thread(void)
 {
-	/* Forget lazy fpu state */
-	if (last_task_used_math == current && mips_cpu.options & MIPS_CPU_FPU) {
-		__enable_fpu();
-		__asm__ __volatile__("cfc1\t$0,$31");
-		last_task_used_math = NULL;
-	}
 }
 
 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,

@@ -90,11 +88,9 @@
 
 	childksp = (unsigned long)ti + KERNEL_STACK_SIZE - 32;
 
-	if (last_task_used_math == current)
-		if (mips_cpu.options & MIPS_CPU_FPU) {
-			__enable_fpu();
-			save_fp(p);
-		}
+	if (is_fpu_owner()) {
+		save_fp(p);
+	}
 
 	/* set up new TSS. */
 	childregs = (struct pt_regs *) childksp - 1;
arch/mips/kernel/ptrace.c renamed from arch/mips/kernel/ptrace.c.orig +4 -30
diff -Nru link/arch/mips/kernel/ptrace.c.orig link/arch/mips/kernel/ptrace.c
@@ -28,6 +28,7 @@
 #include <asm/uaccess.h>
 #include <asm/bootinfo.h>
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 
 /*
  * Called by kernel/ptrace.c when detaching..

@@ -43,7 +44,6 @@
 {
 	struct task_struct *child;
 	int ret;
-	extern void save_fp(struct task_struct *);
 
 	lock_kernel();
 #if 0

@@ -114,20 +114,7 @@
 			break;
 		case FPR_BASE ... FPR_BASE + 31:
 			if (child->used_math) {
-			        unsigned long long *fregs
-					= (unsigned long long *)
-					    &child->thread.fpu.hard.fp_regs[0];
-			 	if(!(mips_cpu.options & MIPS_CPU_FPU)) {
-					fregs = (unsigned long long *)
-						child->thread.fpu.soft.regs;
-				} else
-					if (last_task_used_math == child) {
-						__enable_fpu();
-						save_fp(child);
-						__disable_fpu();
-						last_task_used_math = NULL;
-						regs->cp0_status &= ~ST0_CU1;
-					}
+			        unsigned long long *fregs = get_fpu_regs(child);
 				/*
 				 * The odd registers are actually the high
 				 * order bits of the values stored in the even

@@ -205,21 +192,8 @@
 			break;
 		case FPR_BASE ... FPR_BASE + 31: {
 			unsigned long long *fregs;
-			fregs = (unsigned long long *)&child->thread.fpu.hard.fp_regs[0];
-			if (child->used_math) {
-				if (last_task_used_math == child) {
-					if(!(mips_cpu.options & MIPS_CPU_FPU)) {
-						fregs = (unsigned long long *)
-						child->thread.fpu.soft.regs;
-					} else {
-						__enable_fpu();
-						save_fp(child);
-						__disable_fpu();
-						last_task_used_math = NULL;
-						regs->cp0_status &= ~ST0_CU1;
-					}
-				}
-			} else {
+			fregs = (unsigned long long *)get_fpu_regs(child);
+			if (!child->used_math) {
 				/* FP not yet used  */
 				memset(&child->thread.fpu.hard, ~0,
 				       sizeof(child->thread.fpu.hard));
arch/mips/kernel/signal.c renamed from arch/mips/kernel/signal.c.orig +15 -82

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arch/mips/kernel/traps.c renamed from arch/mips/kernel/traps.c.orig +15 -30

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arch/mips/kernel/r2300_switch.S renamed from arch/mips/kernel/r2300_switch.S.orig +45 -31

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arch/mips/kernel/r4k_switch.S renamed from arch/mips/kernel/r4k_switch.S.orig +44 -32

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arch/mips/kernel/cpu-probe.c renamed from arch/mips/kernel/cpu-probe.c.orig +1 -0
diff -Nru link/arch/mips/kernel/cpu-probe.c.orig link/arch/mips/kernel/cpu-probe.c
@@ -3,6 +3,7 @@
 #include <linux/stddef.h>
 #include <asm/bugs.h>
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 #include <asm/mipsregs.h>
 
 /*
arch/mips/tools/offset.c renamed from arch/mips/tools/offset.c.orig +0 -1
diff -Nru link/arch/mips/tools/offset.c.orig link/arch/mips/tools/offset.c
@@ -155,7 +155,6 @@
 	offset("#define SC_MDLO       ", struct sigcontext, sc_mdlo);
 	offset("#define SC_PC         ", struct sigcontext, sc_pc);
 	offset("#define SC_STATUS     ", struct sigcontext, sc_status);
-	offset("#define SC_OWNEDFP    ", struct sigcontext, sc_ownedfp);
 	offset("#define SC_FPC_CSR    ", struct sigcontext, sc_fpc_csr);
 	offset("#define SC_FPC_EIR    ", struct sigcontext, sc_fpc_eir);
 	offset("#define SC_CAUSE      ", struct sigcontext, sc_cause);
arch/mips64/kernel/process.c renamed from arch/mips64/kernel/process.c.orig +19 -18
diff -Nru link/arch/mips64/kernel/process.c.orig link/arch/mips64/kernel/process.c
@@ -30,6 +30,7 @@
 #include <asm/io.h>
 #include <asm/elf.h>
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 
 /*
  * We use this if we don't have any better idle routine..

@@ -55,28 +56,30 @@
 	}
 }
 
-struct task_struct *last_task_used_math = NULL;
-
 asmlinkage void ret_from_fork(void);
 
+void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
+{
+	unsigned long status;
+
+	/* New thread looses kernel privileges. */
+	status = regs->cp0_status & ~(ST0_CU0|ST0_FR|ST0_KSU);
+	status |= KSU_USER;
+	status |= (current->thread.mflags & MF_32BIT) ? 0 : ST0_FR;
+	regs->cp0_status = status;
+	current->used_math = 0;
+	loose_fpu();
+	regs->cp0_epc = pc;
+	regs->regs[29] = sp;
+	current_thread_info()->addr_limit = USER_DS;
+}
+
 void exit_thread(void)
 {
-	/* Forget lazy fpu state */
-	if (last_task_used_math == current && mips_cpu.options & MIPS_CPU_FPU) {
-		__enable_fpu();
-		__asm__ __volatile__("cfc1\t$0,$31");
-		last_task_used_math = NULL;
-	}
 }
 
 void flush_thread(void)
 {
-	/* Forget lazy fpu state */
-	if (last_task_used_math == current && mips_cpu.options & MIPS_CPU_FPU) {
-		__enable_fpu();
-		__asm__ __volatile__("cfc1\t$0,$31");
-		last_task_used_math = NULL;
-	}
 }
 
 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,

@@ -89,10 +92,8 @@
 
 	childksp = (unsigned long)ti + KERNEL_STACK_SIZE - 32;
 
-	if (last_task_used_math == current)
-		if (mips_cpu.options & MIPS_CPU_FPU) {
-			__enable_fpu();
-			save_fp(p);
+	if (is_fpu_owner()) {
+		save_fp(p);
 	}
 
 	/* set up new TSS. */
arch/mips64/kernel/ptrace.c renamed from arch/mips64/kernel/ptrace.c.orig +4 -35
diff -Nru link/arch/mips64/kernel/ptrace.c.orig link/arch/mips64/kernel/ptrace.c
@@ -23,6 +23,7 @@
 #include <linux/user.h>
 
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 #include <asm/mipsregs.h>
 #include <asm/pgtable.h>
 #include <asm/page.h>

@@ -112,23 +113,7 @@
 			break;
 		case FPR_BASE ... FPR_BASE + 31:
 			if (child->used_math) {
-				unsigned long *fregs
-					= (unsigned long *)
-					    &child->thread.fpu.hard.fp_regs[0];
-				if (mips_cpu.options & MIPS_CPU_FPU) {
-#ifndef CONFIG_SMP
-					if (last_task_used_math == child) {
-						__enable_fpu();
-						save_fp(child);
-						__disable_fpu();
-						last_task_used_math = NULL;
-					}
-#endif
-				} else {
-					fregs = (unsigned long *)
-						child->thread.fpu.soft.regs;
-				}
-
+				unsigned long *fregs = get_fpu_regs(child);
 				tmp = (unsigned long) fregs[addr - FPR_BASE];
 			} else {
 				tmp = -EIO;

@@ -191,24 +176,8 @@
 			regs->regs[addr] = data;
 			break;
 		case FPR_BASE ... FPR_BASE + 31: {
-			unsigned long *fregs;
-			fregs = (unsigned long *)&child->thread.fpu.hard.fp_regs[0];
-			if (child->used_math) {
-#ifndef CONFIG_SMP
-				if (last_task_used_math == child) {
-					if (mips_cpu.options & MIPS_CPU_FPU) {
-						__enable_fpu();
-						save_fp(child);
-						__disable_fpu();
-						last_task_used_math = NULL;
-						regs->cp0_status &= ~ST0_CU1;
-					} else {
-						fregs = (unsigned long *)
-						child->thread.fpu.soft.regs;
-					}
-				}
-#endif
-			} else {
+			unsigned long *fregs = get_fpu_regs(child);
+			if (!child->used_math) {
 				/* FP not yet used  */
 				memset(&child->thread.fpu.hard, ~0,
 				       sizeof(child->thread.fpu.hard));
arch/mips64/kernel/signal.c renamed from arch/mips64/kernel/signal.c.orig +14 -79

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arch/mips64/kernel/traps.c renamed from arch/mips64/kernel/traps.c.orig +17 -31

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arch/mips64/kernel/r4k_switch.S renamed from arch/mips64/kernel/r4k_switch.S.orig +51 -46

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arch/mips64/kernel/cpu-probe.c renamed from arch/mips64/kernel/cpu-probe.c.orig +1 -0
diff -Nru link/arch/mips64/kernel/cpu-probe.c.orig link/arch/mips64/kernel/cpu-probe.c
@@ -3,6 +3,7 @@
 #include <linux/stddef.h>
 #include <asm/bugs.h>
 #include <asm/cpu.h>
+#include <asm/fpu.h>
 #include <asm/mipsregs.h>
 
 /*
arch/mips64/kernel/signal32.c renamed from arch/mips64/kernel/signal32.c.orig +15 -80

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include/asm-mips/processor.h renamed from include/asm-mips/processor.h.orig +3 -10
diff -Nru link/include/asm-mips/processor.h.orig link/include/asm-mips/processor.h
@@ -71,9 +71,6 @@
 #define wp_works_ok 1
 #define wp_works_ok__is_a_macro /* for versions in ksyms.c */
 
-/* Lazy FPU handling on uni-processor */
-extern struct task_struct *last_task_used_math;
-
 /*
  * User space process size: 2GB. This is hardcoded into a few places,
  * so don't change it unless you know what you are doing.  TASK_SIZE

@@ -196,20 +193,16 @@
 /*
  * Do necessary setup to start up a newly executed thread.
  */
-#define start_thread(regs, new_pc, new_sp) do {				\
-	/* New thread loses kernel and FPU privileges. */	       	\
-	regs->cp0_status = (regs->cp0_status & ~(ST0_CU0|ST0_KSU|ST0_CU1)) | KU_USER;\
-	regs->cp0_epc = new_pc;						\
-	regs->regs[29] = new_sp;					\
-	current_thread_info()->addr_limit = USER_DS;			\
-} while (0)
+extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp);
 
+struct task_struct;
 unsigned long get_wchan(struct task_struct *p);
 
 #define __PT_REG(reg) ((long)&((struct pt_regs *)0)->reg - sizeof(struct pt_regs))
 #define __KSTK_TOS(tsk) ((unsigned long)(tsk->thread_info) + KERNEL_STACK_SIZE - 32)
 #define KSTK_EIP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_epc)))
 #define KSTK_ESP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(regs[29])))
+#define KSTK_STATUS(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_status)))
 
 #define cpu_relax()	barrier()
include/asm-mips/mipsregs.h renamed from include/asm-mips/mipsregs.h.orig +0 -42

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include/asm-mips/sigcontext.h renamed from include/asm-mips/sigcontext.h.orig +0 -1
diff -Nru link/include/asm-mips/sigcontext.h.orig link/include/asm-mips/sigcontext.h
@@ -18,7 +18,6 @@
 	unsigned long long sc_pc;
 	unsigned long long sc_regs[32];
 	unsigned long long sc_fpregs[32];
-	unsigned int       sc_ownedfp;
 	unsigned int       sc_fpc_csr;
 	unsigned int       sc_fpc_eir;		/* Unused */
 	unsigned int       sc_used_math;
include/asm-mips/system.h renamed from include/asm-mips/system.h.orig +0 -5
diff -Nru link/include/asm-mips/system.h.orig link/include/asm-mips/system.h
@@ -225,11 +225,6 @@
 
 struct task_struct;
 
-extern asmlinkage void lazy_fpu_switch(void *prev, void *next);
-extern asmlinkage void init_fpu(void);
-extern asmlinkage void save_fp(struct task_struct *);
-extern asmlinkage void restore_fp(struct task_struct *);
-
 #define switch_to(prev,next,last) \
 do { \
 	(last) =resume(prev, next, next->thread_info); \
include/asm-mips64/mipsregs.h renamed from include/asm-mips64/mipsregs.h.orig +0 -41

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include/asm-mips64/sigcontext.h renamed from include/asm-mips64/sigcontext.h.orig +0 -1
diff -Nru link/include/asm-mips64/sigcontext.h.orig link/include/asm-mips64/sigcontext.h
@@ -20,7 +20,6 @@
 	unsigned long long sc_mdlo;
 	unsigned long long sc_pc;
 	unsigned int       sc_status;
-	unsigned int       sc_ownedfp;
 	unsigned int       sc_fpc_csr;
 	unsigned int       sc_fpc_eir;
 	unsigned int       sc_used_math;
include/asm-mips64/system.h renamed from include/asm-mips64/system.h.orig +0 -5
diff -Nru link/include/asm-mips64/system.h.orig link/include/asm-mips64/system.h
@@ -211,11 +211,6 @@
 
 struct task_struct;
 
-extern asmlinkage void lazy_fpu_switch(void *prev, void *next);
-extern asmlinkage void init_fpu(void);
-extern asmlinkage void save_fp(struct task_struct *);
-extern asmlinkage void restore_fp(struct task_struct *);
-
 #define switch_to(prev,next,last) \
 do { \
 	(last) = resume(prev, next, next->thread_info); \
include/asm-mips64/processor.h renamed from include/asm-mips64/processor.h.orig +3 -16
diff -Nru link/include/asm-mips64/processor.h.orig link/include/asm-mips64/processor.h
@@ -100,9 +100,6 @@
 #define wp_works_ok 1
 #define wp_works_ok__is_a_macro /* for versions in ksyms.c */
 
-/* Lazy FPU handling on uni-processor */
-extern struct task_struct *last_task_used_math;
-
 /*
  * User space process size: 1TB. This is hardcoded into a few places,
  * so don't change it unless you know what you are doing.  TASK_SIZE

@@ -231,26 +228,16 @@
 /*
  * Do necessary setup to start up a newly executed thread.
  */
-#define start_thread(regs, pc, sp) 					\
-do {									\
-	unsigned long __status;						\
-									\
-	/* New thread looses kernel privileges. */			\
-	__status = regs->cp0_status & ~(ST0_CU0|ST0_FR|ST0_KSU);	\
-	__status |= KSU_USER;						\
-	__status |= (current->thread.mflags & MF_32BIT) ? 0 : ST0_FR;	\
-	regs->cp0_status = __status;					\
-	regs->cp0_epc = pc;						\
-	regs->regs[29] = sp;						\
-	current_thread_info()->addr_limit = USER_DS;			\
-} while(0)
+extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp);
 
+struct task_struct;
 unsigned long get_wchan(struct task_struct *p);
 
 #define __PT_REG(reg) ((long)&((struct pt_regs *)0)->reg - sizeof(struct pt_regs))
 #define __KSTK_TOS(tsk) ((unsigned long)(tsk->thread_info) + KERNEL_STACK_SIZE - 32)
 #define KSTK_EIP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_epc)))
 #define KSTK_ESP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(regs[29])))
+#define KSTK_STATUS(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_status)))
 
 #define cpu_relax()	barrier()