powerpc/8xx: add exception frame marker

[Michael Ellerman]

On Tue, 2018-11-27 at 17:38:16 UTC, Christophe Leroy wrote:
> This patch adds STACK_FRAME_REGS_MARKER in the stack at exception entry
> in order to see interrupts in call traces as below:
> 
> [    0.013964] Call Trace:
> [    0.014014] [c0745db0] [c007a9d4] tick_periodic.constprop.5+0xd8/0x104 (unreliable)
> [    0.014086] [c0745dc0] [c007aa20] tick_handle_periodic+0x20/0x9c
> [    0.014181] [c0745de0] [c0009cd0] timer_interrupt+0xa0/0x264
> [    0.014258] [c0745e10] [c000e484] ret_from_except+0x0/0x14
> [    0.014390] --- interrupt: 901 at console_unlock.part.7+0x3f4/0x528
> [    0.014390]     LR = console_unlock.part.7+0x3f0/0x528
> [    0.014455] [c0745ee0] [c0050334] console_unlock.part.7+0x114/0x528 (unreliable)
> [    0.014542] [c0745f30] [c00524e0] register_console+0x3d8/0x44c
> [    0.014625] [c0745f60] [c0675aac] cpm_uart_console_init+0x18/0x2c
> [    0.014709] [c0745f70] [c06614f4] console_init+0x114/0x1cc
> [    0.014795] [c0745fb0] [c0658b68] start_kernel+0x300/0x3d8
> [    0.014864] [c0745ff0] [c00022cc] start_here+0x44/0x98
> 
> Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/0ed5b55884f8b1fa368454d47cc6ec

cheers