Commits
Mark Rutland committed df35a8f51fc
ARM: 8634/1: hw_breakpoint: blacklist Scorpion CPUs commit ddc37832a1349f474c4532de381498020ed71d31 upstream. On APQ8060, the kernel crashes in arch_hw_breakpoint_init, taking an undefined instruction trap within write_wb_reg. This is because Scorpion CPUs erroneously appear to set DBGPRSR.SPD when WFI is issued, even if the core is not powered down. When DBGPRSR.SPD is set, breakpoint and watchpoint registers are treated as undefined. It's possible to trigger similar crashes later on from userspace, by requesting the kernel to install a breakpoint or watchpoint, as we can go idle at any point between the reset of the debug registers and their later use. This has always been the case. Given that this has always been broken, no-one has complained until now, and there is no clear workaround, disable hardware breakpoints and watchpoints on Scorpion to avoid these issues. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reported-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Russell King <linux@armlinux.org.uk> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>