Ralf Baechle wrote:
> On Fri, May 03, 2002 at 04:41:56PM -0700, Jun Sun wrote:
>
> > It appears earlier version of kernel does not have this problem. I have not
> > fully figured out why.
>
> We didn't handle exceptions in branch delay slots. Try this patch and
> tell me if it helps.
It fix a problem I have had for quite a while in the r4k_fpu.S. The code in
question is:
jr ra
.set nomacro
EX(sw t0,SC_FPC_EIR(a0))
.set macro
I have fixed it locally by removing the SW from the delay-slot, but obviously
your fix is the right one.
But I guess we need the same fix in arch/mips/kernel/unaligned.c.
>
> Ralf
>
> Index: arch/mips/mm/fault.c
> ===================================================================
> RCS file: /home/pub/cvs/linux/arch/mips/mm/fault.c,v
> retrieving revision 1.25.2.2
> diff -u -r1.25.2.2 fault.c
> --- arch/mips/mm/fault.c 16 Jan 2002 03:49:24 -0000 1.25.2.2
> +++ arch/mips/mm/fault.c 4 May 2002 01:28:34 -0000
> @@ -19,6 +19,7 @@
> #include <linux/smp_lock.h>
> #include <linux/version.h>
>
> +#include <asm/branch.h>
> #include <asm/hardirq.h>
> #include <asm/pgalloc.h>
> #include <asm/mmu_context.h>
> @@ -77,7 +78,7 @@
> struct vm_area_struct * vma;
> struct task_struct *tsk = current;
> struct mm_struct *mm = tsk->mm;
> - unsigned long fixup;
> + unsigned long epc, fixup;
> siginfo_t info;
>
> /*
> @@ -181,7 +182,8 @@
>
> no_context:
> /* Are we prepared to handle this kernel fault? */
> - fixup = search_exception_table(regs->cp0_epc);
> + epc = regs->cp0_epc + delay_slot(regs) ? 4 : 0;
> + fixup = search_exception_table(epc);
> if (fixup) {
> long new_epc;
>
> Index: arch/mips64/mm/fault.c
> ===================================================================
> RCS file: /home/pub/cvs/linux/arch/mips64/mm/fault.c,v
> retrieving revision 1.26.2.6
> diff -u -r1.26.2.6 fault.c
> --- arch/mips64/mm/fault.c 23 Feb 2002 02:16:42 -0000 1.26.2.6
> +++ arch/mips64/mm/fault.c 4 May 2002 01:28:34 -0000
> @@ -21,6 +21,7 @@
> #include <linux/smp_lock.h>
> #include <linux/version.h>
>
> +#include <asm/branch.h>
> #include <asm/hardirq.h>
> #include <asm/pgalloc.h>
> #include <asm/mmu_context.h>
> @@ -103,7 +104,7 @@
> struct vm_area_struct * vma;
> struct task_struct *tsk = current;
> struct mm_struct *mm = tsk->mm;
> - unsigned long fixup;
> + unsigned long epc, fixup;
> siginfo_t info;
>
> #if 0
> @@ -208,7 +209,8 @@
>
> no_context:
> /* Are we prepared to handle this kernel fault? */
> - fixup = search_exception_table(regs->cp0_epc);
> + epc = regs->cp0_epc + delay_slot(regs) ? 4 : 0;
> + fixup = search_exception_table(epc);
> if (fixup) {
> long new_epc;
>
--
_ _ ____ ___ Carsten Langgaard Mailto:carstenl@mips.com
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