Messages in this thread | | | Date | Fri, 17 Jan 2014 10:07:23 +0000 | From | Will Deacon <> | Subject | Re: [PATCH] ARM64: perf: support dwarf unwinding in compat mode |
| |
On Fri, Jan 17, 2014 at 09:00:09AM +0000, Jean Pihet wrote: > On 16 January 2014 14:47, Jean Pihet <jean.pihet@linaro.org> wrote: > >> So the simplest thing would be to make compat_user_stack_pointer expand to > >> user_stack_pointer(current_pt_regs()) on arm64 and merge that in with your > >> original patch fixing user_stack_pointer. > > I see 2 issues in your proposal: > > 1) user_stack_pointer(regs) calls compat_user_stack_pointer if > compat_user_mode(regs)) and compat_user_stack_pointer expands to > user_stack_pointer. I see a circular dependency in the macros.
Not today it doesn't, so you just need to avoid writing the circular dependency and instead make user_stack_pointer access (regs)->compat_sp instead.
> 2) current_pt_regs() returns the current task regs although perf > passes a regs struct that had been recorded previously.
Yes, but compat_user_stack_pointer doesn't take a regs paramater anyway, so there's no change in behaviour here.
Will
| |