From 25c8a78b1e00ac0cc640677eda78b462c2cd4c6e Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 27 Oct 2005 16:27:25 +1000 Subject: [PATCH] powerpc: Fix handling of fpscr on 64-bit The recent merge of fpu.S broken the handling of fpscr for ARCH=powerpc and CONFIG_PPC64=y. FP registers could be corrupted, leading to strange random application crashes. The confusion arises, because the thread_struct has (and requires) a 64-bit area to save the fpscr, because we use load/store double instructions to get it in to/out of the FPU. However, only the low 32-bits are actually used, so we want to treat it as a 32-bit quantity when manipulating its bits to avoid extra load/stores on 32-bit. This patch replaces the current definition with a structure of two 32-bit quantities (pad and val), to clarify things as much as is possible. The 'val' field is used when manipulating bits, the structure itself is used when obtaining the address for loading/unloading the value from the FPU. While we're at it, consolidate the 4 (!) almost identical versions of cvt_fd() and cvt_df() (arch/ppc/kernel/misc.S, arch/ppc64/kernel/misc.S, arch/powerpc/kernel/misc_32.S, arch/powerpc/kernel/misc_64.S) into a single version in fpu.S. The new version takes a pointer to thread_struct and applies the correct offset itself, rather than a pointer to the fpscr field itself, again to avoid confusion as to which is the correct field to use. Finally, this patch makes ARCH=ppc64 also use the consolidated fpu.S code, which it previously did not. Built for G5 (ARCH=ppc64 and ARCH=powerpc), 32-bit powermac (ARCH=ppc and ARCH=powerpc) and Walnut (ARCH=ppc, CONFIG_MATH_EMULATION=y). Booted on G5 (ARCH=powerpc) and things which previously fell over no longer do. Signed-off-by: David Gibson Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/Makefile | 5 ++--- arch/powerpc/kernel/fpu.S | 31 ++++++++++++++++++++++++++++--- arch/powerpc/kernel/misc_32.S | 27 --------------------------- arch/powerpc/kernel/misc_64.S | 19 ------------------- arch/powerpc/kernel/process.c | 2 +- arch/powerpc/kernel/signal_32.c | 2 +- arch/powerpc/kernel/traps.c | 2 +- 7 files changed, 33 insertions(+), 55 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index a733347964a0..94cf917b7854 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -29,7 +29,6 @@ extra-$(CONFIG_44x) := head_44x.o extra-$(CONFIG_FSL_BOOKE) := head_fsl_booke.o extra-$(CONFIG_8xx) := head_8xx.o extra-$(CONFIG_PPC64) += entry_64.o -extra-$(CONFIG_PPC_FPU) += fpu.o extra-y += vmlinux.lds obj-y += process.o init_task.o time.o \ @@ -49,7 +48,7 @@ else # stuff used from here for ARCH=ppc or ARCH=ppc64 obj-$(CONFIG_PPC64) += traps.o process.o init_task.o time.o -fpux-$(CONFIG_PPC32) += fpu.o -extra-$(CONFIG_PPC_FPU) += $(fpux-y) endif + +extra-$(CONFIG_PPC_FPU) += fpu.o diff --git a/arch/powerpc/kernel/fpu.S b/arch/powerpc/kernel/fpu.S index 563d445ff584..51fd78da25b7 100644 --- a/arch/powerpc/kernel/fpu.S +++ b/arch/powerpc/kernel/fpu.S @@ -48,7 +48,7 @@ _GLOBAL(load_up_fpu) addi r4,r4,THREAD /* want last_task_used_math->thread */ SAVE_32FPRS(0, r4) mffs fr0 - stfd fr0,THREAD_FPSCR-4(r4) + stfd fr0,THREAD_FPSCR(r4) LDL r5,PT_REGS(r4) tophys(r5,r5) LDL r4,_MSR-STACK_FRAME_OVERHEAD(r5) @@ -71,7 +71,7 @@ _GLOBAL(load_up_fpu) or r12,r12,r4 std r12,_MSR(r1) #endif - lfd fr0,THREAD_FPSCR-4(r5) + lfd fr0,THREAD_FPSCR(r5) mtfsf 0xff,fr0 REST_32FPRS(0, r5) #ifndef CONFIG_SMP @@ -104,7 +104,7 @@ _GLOBAL(giveup_fpu) CMPI 0,r5,0 SAVE_32FPRS(0, r3) mffs fr0 - stfd fr0,THREAD_FPSCR-4(r3) + stfd fr0,THREAD_FPSCR(r3) beq 1f LDL r4,_MSR-STACK_FRAME_OVERHEAD(r5) li r3,MSR_FP|MSR_FE0|MSR_FE1 @@ -117,3 +117,28 @@ _GLOBAL(giveup_fpu) STL r5,OFF(last_task_used_math)(r4) #endif /* CONFIG_SMP */ blr + +/* + * These are used in the alignment trap handler when emulating + * single-precision loads and stores. + * We restore and save the fpscr so the task gets the same result + * and exceptions as if the cpu had performed the load or store. + */ + +_GLOBAL(cvt_fd) + lfd 0,THREAD_FPSCR(r5) /* load up fpscr value */ + mtfsf 0xff,0 + lfs 0,0(r3) + stfd 0,0(r4) + mffs 0 + stfd 0,THREAD_FPSCR(r5) /* save new fpscr value */ + blr + +_GLOBAL(cvt_df) + lfd 0,THREAD_FPSCR(r5) /* load up fpscr value */ + mtfsf 0xff,0 + lfd 0,0(r3) + stfs 0,0(r4) + mffs 0 + stfd 0,THREAD_FPSCR(r5) /* save new fpscr value */ + blr diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S index 303229b090b8..3bedb532aed9 100644 --- a/arch/powerpc/kernel/misc_32.S +++ b/arch/powerpc/kernel/misc_32.S @@ -992,33 +992,6 @@ _GLOBAL(_get_SP) mr r3,r1 /* Close enough */ blr -/* - * These are used in the alignment trap handler when emulating - * single-precision loads and stores. - * We restore and save the fpscr so the task gets the same result - * and exceptions as if the cpu had performed the load or store. - */ - -#ifdef CONFIG_PPC_FPU -_GLOBAL(cvt_fd) - lfd 0,-4(r5) /* load up fpscr value */ - mtfsf 0xff,0 - lfs 0,0(r3) - stfd 0,0(r4) - mffs 0 /* save new fpscr value */ - stfd 0,-4(r5) - blr - -_GLOBAL(cvt_df) - lfd 0,-4(r5) /* load up fpscr value */ - mtfsf 0xff,0 - lfd 0,0(r3) - stfs 0,0(r4) - mffs 0 /* save new fpscr value */ - stfd 0,-4(r5) - blr -#endif - /* * Create a kernel thread * kernel_thread(fn, arg, flags) diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S index 4775bed42cac..b3e95ff0dba0 100644 --- a/arch/powerpc/kernel/misc_64.S +++ b/arch/powerpc/kernel/misc_64.S @@ -462,25 +462,6 @@ _GLOBAL(_outsl_ns) sync blr - -_GLOBAL(cvt_fd) - lfd 0,0(r5) /* load up fpscr value */ - mtfsf 0xff,0 - lfs 0,0(r3) - stfd 0,0(r4) - mffs 0 /* save new fpscr value */ - stfd 0,0(r5) - blr - -_GLOBAL(cvt_df) - lfd 0,0(r5) /* load up fpscr value */ - mtfsf 0xff,0 - lfd 0,0(r3) - stfs 0,0(r4) - mffs 0 /* save new fpscr value */ - stfd 0,0(r5) - blr - /* * identify_cpu and calls setup_cpu * In: r3 = base of the cpu_specs array diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 047da1ae21fe..8f85dabe4df3 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -665,7 +665,7 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp) #endif #endif /* CONFIG_SMP */ memset(current->thread.fpr, 0, sizeof(current->thread.fpr)); - current->thread.fpscr = 0; + current->thread.fpscr.val = 0; #ifdef CONFIG_ALTIVEC memset(current->thread.vr, 0, sizeof(current->thread.vr)); memset(¤t->thread.vscr, 0, sizeof(current->thread.vscr)); diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index 92452b2db26a..444c3e81884c 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -403,7 +403,7 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame, ELF_NFPREG * sizeof(double))) return 1; - current->thread.fpscr = 0; /* turn off all fp exceptions */ + current->thread.fpscr.val = 0; /* turn off all fp exceptions */ #ifdef CONFIG_ALTIVEC /* save altivec registers */ diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index f87580382da4..5d638ecddbd0 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -549,7 +549,7 @@ static void parse_fpe(struct pt_regs *regs) flush_fp_to_thread(current); - fpscr = current->thread.fpscr; + fpscr = current->thread.fpscr.val; /* Invalid operation */ if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX)) -- cgit v1.2.2