Hi Will,
On 6 January 2014 19:30, Will Deacon <will.dea...@arm.com> wrote:
> Hi Jean,
>
> Thanks for the updated patches. One minor comment on this one.
Thanks for reviewing!
> On Mon, Dec 30, 2013 at 04:25:30PM +0000, Jean Pihet wrote:
>> From: Jean Pihet <jean.pi...@newoldbits.com>
>>
>> This patch implements the functions required for the perf registers API,
>> allowing the perf tool to interface kernel register dumps with libunwind
>> in order to provide userspace backtracing.
>> Compat mode is also supported.
>
> [...]
>
>> +u64 perf_reg_value(struct pt_regs *regs, int idx)
>> +{
>> + if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX))
>> + return 0;
>
> While this is probably fine, I'd feel more comfortable if you had separate
> limit checks for native and compat...
>
>> + /*
>> + * Compat (i.e. 32 bit) mode:
>> + * - PC has been set in the pt_regs struct in kernel_entry,
>> + * - Handle SP and LR here.
>> + */
>> + if (compat_user_mode(regs)) {
>
> i.e. have a WARN_ON_ONCE here for the compat structure size.
>
>> + if ((u32)idx == PERF_REG_ARM64_SP)
>> + return regs->compat_sp;
>> + if ((u32)idx == PERF_REG_ARM64_LR)
>> + return regs->compat_lr;
>> + }
>
> then stick an else here with the original check.
>
> Make sense?
Yes
I will resend an updated version asap.
>
> Will
Jean
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