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Message-ID: <19223.1365570011@ale.ozlabs.ibm.com>
Date: Wed, 10 Apr 2013 15:00:11 +1000
From: Michael Neuling <mikey@...ling.org>
To: Alexey Kardashevskiy <aik@...abs.ru>
cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
linux-kernel@...r.kernel.org, Paul Mackerras <paulus@...ba.org>,
linuxppc-dev@...ts.ozlabs.org,
David Gibson <david@...son.dropbear.id.au>
Subject: Re: [PATCH] powerpc: fixing ptrace_get_reg to return an error
Alexey Kardashevskiy <aik@...abs.ru> wrote:
> Currently ptrace_get_reg returns error as a value
> what make impossible to tell whether it is a correct value or error code.
>
> The patch adds a parameter which points to the real return data and
> returns an error code.
>
> As get_user_msr() never fails and it is used in multiple places so it has not
> been changed by this patch.
>
> Signed-off-by: Alexey Kardashevskiy <aik@...abs.ru>
FWIW:
Acked-by: Michael Neuling <mikey@...ling.org>
> ---
> arch/powerpc/include/asm/ptrace.h | 3 ++-
> arch/powerpc/kernel/ptrace.c | 29 ++++++++++++++++++-----------
> arch/powerpc/kernel/ptrace32.c | 15 ++++++++++++---
> 3 files changed, 32 insertions(+), 15 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
> index 5f99568..becc08e 100644
> --- a/arch/powerpc/include/asm/ptrace.h
> +++ b/arch/powerpc/include/asm/ptrace.h
> @@ -92,7 +92,8 @@ static inline long regs_return_value(struct pt_regs *regs)
> } while(0)
>
> struct task_struct;
> -extern unsigned long ptrace_get_reg(struct task_struct *task, int regno);
> +extern int ptrace_get_reg(struct task_struct *task, int regno,
> + unsigned long *data);
> extern int ptrace_put_reg(struct task_struct *task, int regno,
> unsigned long data);
>
> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
> index 245c1b6..d5ff7ea 100644
> --- a/arch/powerpc/kernel/ptrace.c
> +++ b/arch/powerpc/kernel/ptrace.c
> @@ -180,9 +180,10 @@ static int set_user_msr(struct task_struct *task, unsigned long msr)
> }
>
> #ifdef CONFIG_PPC64
> -static unsigned long get_user_dscr(struct task_struct *task)
> +static int get_user_dscr(struct task_struct *task, unsigned long *data)
> {
> - return task->thread.dscr;
> + *data = task->thread.dscr;
> + return 0;
> }
>
> static int set_user_dscr(struct task_struct *task, unsigned long dscr)
> @@ -192,7 +193,7 @@ static int set_user_dscr(struct task_struct *task, unsigned long dscr)
> return 0;
> }
> #else
> -static unsigned long get_user_dscr(struct task_struct *task)
> +static int get_user_dscr(struct task_struct *task, unsigned long *data)
> {
> return -EIO;
> }
> @@ -216,19 +217,23 @@ static int set_user_trap(struct task_struct *task, unsigned long trap)
> /*
> * Get contents of register REGNO in task TASK.
> */
> -unsigned long ptrace_get_reg(struct task_struct *task, int regno)
> +int ptrace_get_reg(struct task_struct *task, int regno, unsigned long *data)
> {
> - if (task->thread.regs == NULL)
> + if ((task->thread.regs == NULL) || !data)
> return -EIO;
>
> - if (regno == PT_MSR)
> - return get_user_msr(task);
> + if (regno == PT_MSR) {
> + *data = get_user_msr(task);
> + return 0;
> + }
>
> if (regno == PT_DSCR)
> - return get_user_dscr(task);
> + return get_user_dscr(task, data);
>
> - if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long)))
> - return ((unsigned long *)task->thread.regs)[regno];
> + if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long))) {
> + *data = ((unsigned long *)task->thread.regs)[regno];
> + return 0;
> + }
>
> return -EIO;
> }
> @@ -1559,7 +1564,9 @@ long arch_ptrace(struct task_struct *child, long request,
>
> CHECK_FULL_REGS(child->thread.regs);
> if (index < PT_FPR0) {
> - tmp = ptrace_get_reg(child, (int) index);
> + ret = ptrace_get_reg(child, (int) index, &tmp);
> + if (ret)
> + break;
> } else {
> unsigned int fpidx = index - PT_FPR0;
>
> diff --git a/arch/powerpc/kernel/ptrace32.c b/arch/powerpc/kernel/ptrace32.c
> index c0244e7..f51599e 100644
> --- a/arch/powerpc/kernel/ptrace32.c
> +++ b/arch/powerpc/kernel/ptrace32.c
> @@ -95,7 +95,9 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
>
> CHECK_FULL_REGS(child->thread.regs);
> if (index < PT_FPR0) {
> - tmp = ptrace_get_reg(child, index);
> + ret = ptrace_get_reg(child, index, &tmp);
> + if (ret)
> + break;
> } else {
> flush_fp_to_thread(child);
> /*
> @@ -148,7 +150,11 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
> tmp = ((u64 *)child->thread.fpr)
> [FPRINDEX_3264(numReg)];
> } else { /* register within PT_REGS struct */
> - tmp = ptrace_get_reg(child, numReg);
> + unsigned long tmp2;
> + ret = ptrace_get_reg(child, numReg, &tmp2);
> + if (ret)
> + break;
> + tmp = tmp2;
> }
> reg32bits = ((u32*)&tmp)[part];
> ret = put_user(reg32bits, (u32 __user *)data);
> @@ -232,7 +238,10 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
> break;
> CHECK_FULL_REGS(child->thread.regs);
> if (numReg < PT_FPR0) {
> - unsigned long freg = ptrace_get_reg(child, numReg);
> + unsigned long freg;
> + ret = ptrace_get_reg(child, numReg, &freg);
> + if (ret)
> + break;
> if (index % 2)
> freg = (freg & ~0xfffffffful) | (data & 0xfffffffful);
> else
> --
> 1.7.10.4
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@...ts.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
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