From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 9F1EFB6F14 for ; Mon, 21 Mar 2011 11:16:09 +1100 (EST) Subject: Re: [PATCH v2] powerpc/ptrace: remove BUG_ON when full register set not available From: Benjamin Herrenschmidt To: mjw@us.ibm.com In-Reply-To: <1300282642.15145.2.camel@w500> References: <1300282642.15145.2.camel@w500> Content-Type: text/plain; charset="UTF-8" Date: Mon, 21 Mar 2011 11:15:54 +1100 Message-ID: <1300666554.2402.88.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, mikey@neuling.org, anton@samba.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2011-03-16 at 08:37 -0500, Michael Wolf wrote: > In some cases during a threaded core dump not all > the threads will have a full register set. This > will cause problems when the sigkill is sent to > the thread. To solve this problem a poison value > (0xdeadbeef) will be placed in the buffer in place > of the actual register values. This will affect > gpr14 to gpr31. > > Signed-off-by: Mike Wolf Patch is busted on ppc32 (you add #define's in the middle of a multi-line macro) and of doubtful stylistic value :-) I'll merge a slightly reworked variant that includes a new cset comment with Paulus explanation in it. Cheers, Ben. > ---------- > --- linux-2.6.32-71.el6.ppc64.orig/arch/powerpc/include/asm/ptrace.h 2010-08-31 23:56:50.000000000 -0500 > +++ linux-2.6.32-71.el6.ppc64/arch/powerpc/include/asm/ptrace.h 2011-03-14 11:43:33.176667099 -0500 > @@ -123,8 +123,14 @@ extern int ptrace_put_reg(struct task_st > #define TRAP(regs) ((regs)->trap & ~0xF) > #ifdef __powerpc64__ > #define CHECK_FULL_REGS(regs) BUG_ON(regs->trap & 1) > +#define PARTIAL_REG_FILL 0xdeadbeefdeadbeefUL > +#define PARTIAL_REG_START 14 > +#define PARTIAL_REG_END 31 > #else > #define CHECK_FULL_REGS(regs) \ > +#define PARTIAL_REG_FILL 0xdeadbeef > +#define PARTIAL_REG_START 14 > +#define PARTIAL_REG_END 31 > do { \ > if ((regs)->trap & 1) \ > printk(KERN_CRIT "%s: partial register set\n", __func__); \ > --- linux-2.6.32-71.el6.ppc64.orig/arch/powerpc/kernel/ptrace.c 2009-12-02 21:51:21.000000000 -0600 > +++ linux-2.6.32-71.el6.ppc64/arch/powerpc/kernel/ptrace.c 2011-03-14 13:01:51.955586126 -0500 > @@ -125,11 +125,16 @@ static int gpr_get(struct task_struct *t > void *kbuf, void __user *ubuf) > { > int ret; > + int partial_reg; > > if (target->thread.regs == NULL) > return -EIO; > > - CHECK_FULL_REGS(target->thread.regs); > + if (!FULL_REGS(target->thread.regs)) > + /* We have a partial register set. Fill 14-31 with bogus values */ > + for(partial_reg=PARTIAL_REG_START;partial_reg <= PARTIAL_REG_END; > + partial_reg++) > + target->thread.regs->gpr[partial_reg] = PARTIAL_REG_FILL; > > ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, > target->thread.regs, > @@ -536,11 +541,16 @@ static int gpr32_get(struct task_struct > compat_ulong_t *k = kbuf; > compat_ulong_t __user *u = ubuf; > compat_ulong_t reg; > + int partial_reg; > > if (target->thread.regs == NULL) > return -EIO; > > - CHECK_FULL_REGS(target->thread.regs); > + if (!FULL_REGS(target->thread.regs)) > + /* We have a partial register set. Fill 14-31 with bogus values */ > + for(partial_reg=PARTIAL_REG_START;partial_reg <= PARTIAL_REG_END; > + partial_reg++) > + target->thread.regs->gpr[partial_reg] = PARTIAL_REG_FILL; > > pos /= sizeof(reg); > count /= sizeof(reg); > > > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev