On Tue, Sep 17, 2013 at 11:21:13PM +0200, Ralf Baechle wrote: > On Sun, Aug 11, 2013 at 05:10:17PM +0530, Jayachandran C wrote: > > > Allow usage of scratch register for current pgd even when > > MIPS_PGD_C0_CONTEXT is not configured. MIPS_PGD_C0_CONTEXT is set > > for 64r2 platforms to indicate availability of Xcontext for saving > > cpuid, thus freeing Context to be used for saving PGD. This option > > was also tied to using a scratch register for storing PGD. > > > > This commit will allow usage of scratch register to store the current > > pgd if one can be allocated for the platform, even when > > MIPS_PGD_C0_CONTEXT is not set. The cpuid will be kept in the CP0 > > Context register in this case. > > > > The code to store the current pgd for the TLB miss handler is now > > generated in all cases. When scratch register is available, the PGD > > is also stored in the scratch register. > > This patch breaks the build for almost all platforms. Amusingly it > doesn't break Cavium however which is why I didn't notice it right away. > > The build error is the same for all platforms: > > [...] > LD init/built-in.o > arch/mips/built-in.o: In function `per_cpu_trap_init': > (.text+0x80e4): undefined reference to `tlbmiss_handler_setup_pgd' > arch/mips/built-in.o: In function `build_setup_pgd': > tlbex.c:(.text+0xe31c): undefined reference to `tlbmiss_handler_setup_pgd' > tlbex.c:(.text+0xe328): undefined reference to `tlbmiss_handler_setup_pgd' > tlbex.c:(.text+0xe324): undefined reference to `tlbmiss_handler_setup_pgd_end' > tlbex.c:(.text+0xe32c): undefined reference to `tlbmiss_handler_setup_pgd_end' > kernel/built-in.o: In function `__schedule': > core.c:(.sched.text+0x1b74): undefined reference to `tlbmiss_handler_setup_pgd' > mm/built-in.o: In function `use_mm': > (.text+0x1a530): undefined reference to `tlbmiss_handler_setup_pgd' > fs/built-in.o: In function `flush_old_exec': > (.text+0x8da8): undefined reference to `tlbmiss_handler_setup_pgd' > make[2]: *** [vmlinux] Error 1 > make[1]: *** [sub-make] Error 2 > make: *** [all] Error 2 > make: Leaving directory `/home/ralf/src/linux/obj/cobalt-build' > > I'm reverting the patch now. The commit 774b6175 "MIPS: tlbex: Guard tlbmiss_handler_setup_pgd" that went into 3.12-rc1 takes out tlbmiss_handler_setup_pgd definition when CONFIG_MIPS_PGD_C0_CONTEXT is not defined. That clashes with this change and caused the failure. You can revert 774b6175 before applying this and things should work, I had tested it with qemu on malta as well as on XLP. JC.
