Hi Jean,
Thanks for the updated patches. One minor comment on this one.
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?
Will
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