Messages in this thread | | | Date | Tue, 7 Jan 2014 09:49:46 +0100 | Subject | Re: [PATCH 1/3] ARM64: perf: add support for perf registers API | From | Jean Pihet <> |
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Hi Will,
On 6 January 2014 19:30, Will Deacon <will.deacon@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.pihet@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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