From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: mjw@us.ibm.com
Cc: linuxppc-dev@ozlabs.org, mikey@neuling.org, anton@samba.org
Subject: Re: [PATCH] powerpc/ptrace: remove BUG_ON when full register set not available
Date: Wed, 02 Mar 2011 14:08:36 +1100 [thread overview]
Message-ID: <1299035316.8833.806.camel@pasglop> (raw)
In-Reply-To: <1299011204.28753.8.camel@w500>
> --- ptracev2.orig/include/linux/regset.h 2011-02-20 12:15:57.000000000 -0600
> +++ ptracev2/include/linux/regset.h 2011-02-28 13:33:36.685302349 -0600
> @@ -240,6 +240,34 @@ static inline int user_regset_copyout(un
> }
> return 0;
> }
> +/* want the count to be the registers 14-31 inclusive */
> +#define POISON_REG_CNT (PT_R31-PT_R14+1)
> +static inline int user_regset_copyout_poison(unsigned int *pos,
> + unsigned int *count,
> + void **kbuf, void __user **ubuf,
> + const int start_pos,
> + const int end_pos)
> +{
I wouldn't put that in a generic location... especially something
like POISON_REG_CNT is very specific to powerpc and our ABI.
.../...
> static inline int user_regset_copyin(unsigned int *pos, unsigned int *count,
> const void **kbuf,
> --- ptracev2.orig/arch/powerpc/kernel/ptrace.c 2011-02-20 12:15:57.000000000 -0600
> +++ ptracev2/arch/powerpc/kernel/ptrace.c 2011-03-01 13:49:12.686354353 -0600
> @@ -234,11 +234,29 @@ static int gpr_get(struct task_struct *t
> if (target->thread.regs == NULL)
> return -EIO;
>
> - CHECK_FULL_REGS(target->thread.regs);
Wouldn't it be a simpler/cleaner approach to use a single function call
here that checks if the reg set is full and if not, put poison values
in the thread.regs structure itself ?
The resulting code would be more palatable...
Cheers,
Ben.
> - ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> - target->thread.regs,
> - 0, offsetof(struct pt_regs, msr));
> + if (!FULL_REGS(target->thread.regs)) {
> + /* Don't have the full register set. Copy out register r0-r13 */
> + ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> + target->thread.regs,
> + 0, sizeof(long)*PT_R14);
> +
> + /* Dont want to change the actual register values so rather than read the */
> + /* actual register copy a poison value into the buffer instead */
> + if (!ret)
> + ret = user_regset_copyout_poison(&pos, &count, &kbuf, &ubuf,
> + sizeof(long)*PT_R14, offsetof(struct pt_regs, nip));
> +
> + /* Copy out the rest of the registers as usual */
> + if (!ret)
> + ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> + target->thread.regs,
> + offsetof(struct pt_regs, nip), offsetof(struct pt_regs, msr));
> +
> + } else
> + ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> + target->thread.regs,
> + 0, offsetof(struct pt_regs, msr));
> if (!ret) {
> unsigned long msr = get_user_msr(target);
> ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &msr,
> @@ -645,11 +663,29 @@ static int gpr32_get(struct task_struct
> if (target->thread.regs == NULL)
> return -EIO;
>
> - CHECK_FULL_REGS(target->thread.regs);
> -
> pos /= sizeof(reg);
> count /= sizeof(reg);
>
> + if(!FULL_REGS(target->thread.regs)) {
> + if (kbuf) {
> + /* Don't have the full register set. Copy out register r0-r13 */
> + for (; count > 0 && pos < PT_R14; --count)
> + *k++ = regs[pos++];
> +
> + /* Dont want to change the actual register values so rather than read the */
> + /* actual register copy a poison value into the buffer instead */
> + for (; count > 0 && pos <= PT_R31; --count,pos++)
> + *k++ = 0xdeadbeef;
> +
> + } else {
> + for (; count > 0 && pos < PT_R14; --count)
> + if (__put_user((compat_ulong_t) regs[pos++], u++))
> + return -EFAULT;
> + for (; count > 0 && pos <= PT_R31; --count,pos++)
> + if (__put_user((compat_ulong_t) 0xdeadbeef, u++))
> + return -EFAULT;
> + }
> + }
> if (kbuf)
> for (; count > 0 && pos < PT_MSR; --count)
> *k++ = regs[pos++];
>
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
next prev parent reply other threads:[~2011-03-02 3:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-01 20:26 [PATCH] powerpc/ptrace: remove BUG_ON when full register set not available Michael Wolf
2011-03-02 3:08 ` Benjamin Herrenschmidt [this message]
2011-03-02 15:44 ` Michael Wolf
2011-03-21 0:18 [PATCH] powerpc/ptrace: Remove " Benjamin Herrenschmidt
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