On Thu, Mar 02, 2017 at 09:01:24PM +0000, Abel Vesa wrote:

On Tue, Feb 28, 2017 at 11:54:29AM +0000, Abel Vesa wrote:

quoted

On Tue, Feb 28, 2017 at 11:46:38AM +0000, Russell King - ARM Linux wrote:

quoted

On Tue, Feb 28, 2017 at 11:22:27AM +0000, Abel Vesa wrote:

quoted

On Tue, Feb 28, 2017 at 11:58:49AM +0100, Nicolai Stange wrote:

quoted

Hi Abel,

On Tue, Feb 28 2017, Abel Vesa wrote:

quoted

On Mon, Feb 27, 2017 at 04:52:06PM +0100, Nicolai Stange wrote:

quoted

On Fri, Feb 24 2017, Abel Vesa wrote:
Wouldn't it be better (and more consistent with other archs) to have

  pt_regs->ARM_lr = original lr
  pt_refs->ARM_pc = current lr

instead?

The stack would look like this then

@ ...           | ARM_ip | ARM_sp | ARM_lr      | ARM_pc      | ...          |
@ 0  4          48       52       56            60            64    68       72
@ R0 | R1 | ... | LR     | SP + 4 | original LR | original PC | PSR | OLD_R0 | original LR |

Just to make sure we're on the same page. If we are replacing the LR 
with the original_LR is it worth keeping around the one pushed before 
the ftrace_regs_caller is called?

Another thing, PC needs to be new_LR and then we can restore all 
regs r0 through r15 like this:

	ldmia   sp, {r0-r15}

That's the intention - the point is to save the state as it was at the
point that the function was entered, not at the point when the ftrace
code was entered.  What we don't want is the implementation details of
GCC's mcount or ftrace's adaption of mcount being exposed via ftrace.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.