[PATCH 2.5] FPU
STALE8649d
From: Vivien Chappelier <hidden>
Date: 2003-01-26 01:57:34
Hi, At various places in the 2.5 kernel, the fpu is accessed in kernel mode with CU1 not set, causing an unexpected exception. This patch makes sure FPU can be accessed by the kernel, though it may only be a workaround. Any comment from someone with a better understanding of the FPU access/context switching code? Vivien.
--- include/asm-mips64/fpu.h 2002-12-11 20:44:20.000000000 +0100
+++ include/asm-mips64/fpu.h 2002-12-11 21:51:44.000000000 +0100@@ -109,6 +109,7 @@ static inline void save_fp(struct task_struct *tsk) { + enable_fpu(); if (mips_cpu.options & MIPS_CPU_FPU) _save_fp(tsk); } --- include/asm-mips/fpu.h 2002-12-11 20:44:20.000000000 +0100 +++ include/asm-mips/fpu.h 2002-12-11 21:51:44.000000000 +0100
@@ -109,6 +109,7 @@ static inline void save_fp(struct task_struct *tsk) { + enable_fpu(); if (mips_cpu.options & MIPS_CPU_FPU) _save_fp(tsk); } --- arch/mips64/kernel/signal.c 2002-11-09 16:10:14.000000000 +0100 +++ arch/mips64/kernel/signal.c 2003-01-14 01:35:42.000000000 +0100
@@ -162,20 +162,19 @@ err |= __put_user(current->used_math, &sc->sc_used_math); - if (!current->used_math) - goto out; + if (current->used_math) { + + /* + * Save FPU state to signal context. + * Signal handler will "inherit" current FPU state. + */ - /* - * Save FPU state to signal context. Signal handler will "inherit" - * current FPU state. - */ - if (!is_fpu_owner()) { own_fpu(); restore_fp(current); + + err |= save_fp_context(sc); } - err |= save_fp_context(sc); -out: return err; } --- arch/mips/kernel/signal.c 2002-11-09 16:10:08.000000000 +0100 +++ arch/mips/kernel/signal.c 2003-01-14 01:36:41.000000000 +0100
@@ -313,20 +313,19 @@ err |= __put_user(current->used_math, &sc->sc_used_math); - if (!current->used_math) - goto out; + if (current->used_math) { + + /* + * Save FPU state to signal context. + * Signal handler will "inherit" current FPU state. + */ - /* - * Save FPU state to signal context. Signal handler will "inherit" - * current FPU state. - */ - if (!is_fpu_owner()) { own_fpu(); restore_fp(current); + + err |= save_fp_context(sc); } - err |= save_fp_context(sc); -out: return err; } --- arch/mips64/kernel/signal32.c 2002-11-09 16:10:14.000000000 +0100 +++ arch/mips64/kernel/signal32.c 2003-01-14 01:34:52.000000000 +0100
@@ -457,20 +430,19 @@ err |= __put_user(current->used_math, &sc->sc_used_math); - if (!current->used_math) - goto out; + if (current->used_math) { + + /* + * Save FPU state to signal context. + * Signal handler will "inherit" current FPU state. + */ - /* - * Save FPU state to signal context. Signal handler will "inherit" - * current FPU state. - */ - if (!is_fpu_owner()) { own_fpu(); restore_fp(current); + + err |= save_fp_context(sc); } - err |= save_fp_context(sc); -out: return err; }