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Re: [patch] simulate_ll and simulate_sc(resend)

To: Yoichi Yuasa <yoichi_yuasa@montavista.co.jp>
Subject: Re: [patch] simulate_ll and simulate_sc(resend)
From: Ralf Baechle <ralf@linux-mips.org>
Date: Tue, 4 Mar 2003 21:36:05 +0100
Cc: linux-mips@linux-mips.org, jsun@mvista.com
In-reply-to: <20030303192137.34d21352.yoichi_yuasa@montavista.co.jp>; from yoichi_yuasa@montavista.co.jp on Mon, Mar 03, 2003 at 07:21:37PM +0900
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20030303192137.34d21352.yoichi_yuasa@montavista.co.jp>
Sender: linux-mips-bounce@linux-mips.org
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On Mon, Mar 03, 2003 at 07:21:37PM +0900, Yoichi Yuasa wrote:

> I found a bug in simulate_ll and simulate_sc.
> The board that uses ll/sc emulation is not started.
> 
> When send_sig in these, in order not to operate the value of EPC correctly,
> simulate_* happens continuously.
> 
> The previous patches were not perfect, I changed more.
> Please apply these patches to CVS tree.

As previously mentioned there were some problems with your fix, so I
wrote an alternative fix which is attached below.  It's untested because
I don't have any ll/sc-less test platform.

  Ralf

Index: arch/mips/kernel/traps.c
===================================================================
RCS file: /home/cvs/linux/arch/mips/kernel/traps.c,v
retrieving revision 1.99.2.41
diff -u -r1.99.2.41 traps.c
--- arch/mips/kernel/traps.c    10 Feb 2003 22:50:48 -0000      1.99.2.41
+++ arch/mips/kernel/traps.c    4 Mar 2003 20:32:10 -0000
@@ -134,13 +134,14 @@
                ll_bit = 0;
        }
        ll_task = current;
+
        regs->regs[(opcode & RT) >> 16] = value;
 
        compute_return_epc(regs);
        return;
 
 sig:
-       send_sig(signal, current, 1);
+       force_sig(signal, current);
 }
 
 static inline void simulate_sc(struct pt_regs *regs, unsigned int opcode)
@@ -172,19 +173,21 @@
        }
        if (ll_bit == 0 || ll_task != current) {
                regs->regs[reg] = 0;
-               goto sig;
+               return;
        }
 
-       if (put_user(regs->regs[reg], vaddr))
+       if (put_user(regs->regs[reg], vaddr)) {
                signal = SIGSEGV;
-       else
-               regs->regs[reg] = 1;
+               goto sig;
+       }
+
+       regs->regs[reg] = 1;
 
        compute_return_epc(regs);
        return;
 
 sig:
-       send_sig(signal, current, 1);
+       force_sig(signal, current);
 }
 
 /*

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