* Torsten Duwe [off-list ref] [2016-02-23 18:00:17]:

On Wed, Feb 17, 2016 at 02:08:41PM +1100, Michael Ellerman wrote:

quoted

That stub uses r2 to find the location of itself, but it only works if r2 holds
the TOC for scsi_mod.ko. In this case r2 still contains ibmvscsi.ko's TOC.

Here's my solution, a bit rough still. This replaces the module_64.c change
from patch 2/8:

I shuffle the trampoline instructions so the R2-save-to-stack comes first.
This allows me to construct a profiling trampoline code that
looks very similar. The first instruction, harmful to -mprofile-kernel
can now be replaced with a load of the *kernel* TOC value via paca.
Arithmetic is done in r11, to keep it bitwise identical where possible.
Likewise the result is "moved" to r12 via an addi.

What do you think?

Hi Torsten,

 I hit build failure, after replacing this patch with patch 2/8 module_64.c
hunk.

  CC      arch/powerpc/kernel/module.o
  CC      arch/powerpc/kernel/module_64.o
In file included from ./arch/powerpc/include/asm/asm-offsets.h:1:0,
                 from arch/powerpc/kernel/module_64.c:30:
include/generated/asm-offsets.h:14:0: error: "NMI_MASK" redefined [-Werror]
 #define NMI_MASK 1048576 /* NMI_MASK  # */
 ^
In file included from include/linux/spinlock.h:50:0,
                 from include/linux/seqlock.h:35,
                 from include/linux/time.h:5,
                 from include/linux/stat.h:18,
                 from include/linux/module.h:10,
                 from arch/powerpc/kernel/module_64.c:21:
include/linux/preempt.h:46:0: note: this is the location of the previous definition
 #define NMI_MASK (__IRQ_MASK(NMI_BITS)     << NMI_SHIFT)
 ^
In file included from ./arch/powerpc/include/asm/asm-offsets.h:1:0,
                 from arch/powerpc/kernel/module_64.c:30:
include/generated/asm-offsets.h:148:0: error: "CLONE_VM" redefined [-Werror]
 #define CLONE_VM 256 /* CLONE_VM  # */
 ^
In file included from include/linux/sched.h:4:0,
                 from ./arch/powerpc/include/asm/elf.h:12,
                 from include/linux/elf.h:4,
                 from include/linux/module.h:15,
                 from arch/powerpc/kernel/module_64.c:21:
include/uapi/linux/sched.h:8:0: note: this is the location of the previous definition
 #define CLONE_VM 0x00000100 /* set if VM shared between processes */
 ^
In file included from ./arch/powerpc/include/asm/asm-offsets.h:1:0,
                 from arch/powerpc/kernel/module_64.c:30:
include/generated/asm-offsets.h:149:0: error: "CLONE_UNTRACED" redefined [-Werror]
 #define CLONE_UNTRACED 8388608 /* CLONE_UNTRACED  # */
 ^
In file included from include/linux/sched.h:4:0,
                 from ./arch/powerpc/include/asm/elf.h:12,
                 from include/linux/elf.h:4,
                 from include/linux/module.h:15,
                 from arch/powerpc/kernel/module_64.c:21:
include/uapi/linux/sched.h:22:0: note: this is the location of the previous definition
 #define CLONE_UNTRACED  0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */
 ^
In file included from ./arch/powerpc/include/asm/asm-offsets.h:1:0,
                 from arch/powerpc/kernel/module_64.c:30:
include/generated/asm-offsets.h:185:0: error: "NSEC_PER_SEC" redefined [-Werror]
 #define NSEC_PER_SEC 1000000000 /* NSEC_PER_SEC  # */
 ^
In file included from include/linux/time.h:7:0,
                 from include/linux/stat.h:18,
                 from include/linux/module.h:10,
                 from arch/powerpc/kernel/module_64.c:21:
include/linux/time64.h:35:0: note: this is the location of the previous definition
 #define NSEC_PER_SEC 1000000000L
 ^
In file included from ./arch/powerpc/include/asm/asm-offsets.h:1:0,
                 from arch/powerpc/kernel/module_64.c:30:
include/generated/asm-offsets.h:188:0: error: "PGD_TABLE_SIZE" redefined [-Werror]
 #define PGD_TABLE_SIZE 32768 /* PGD_TABLE_SIZE  # */
 ^
In file included from ./arch/powerpc/include/asm/book3s/64/hash.h:58:0,
                 from ./arch/powerpc/include/asm/book3s/64/pgtable.h:8,
                 from ./arch/powerpc/include/asm/mmu-hash64.h:24,
                 from ./arch/powerpc/include/asm/mmu.h:185,
                 from ./arch/powerpc/include/asm/lppaca.h:36,
                 from ./arch/powerpc/include/asm/paca.h:21,
                 from ./arch/powerpc/include/asm/hw_irq.h:42,
                 from ./arch/powerpc/include/asm/irqflags.h:11,
                 from include/linux/irqflags.h:15,
                 from include/linux/spinlock.h:53,
                 from include/linux/seqlock.h:35,
                 from include/linux/time.h:5,
                 from include/linux/stat.h:18,
                 from include/linux/module.h:10,
                 from arch/powerpc/kernel/module_64.c:21:
./arch/powerpc/include/asm/book3s/64/hash-64k.h:133:0: note: this is the location of the previous definition
 #define PGD_TABLE_SIZE (sizeof(pgd_t) << PGD_INDEX_SIZE)
 ^
cc1: all warnings being treated as errors
scripts/Makefile.build:258: recipe for target 'arch/powerpc/kernel/module_64.o' failed
make[1]: *** [arch/powerpc/kernel/module_64.o] Error 1
Makefile:950: recipe for target 'arch/powerpc/kernel' failed
make: *** [arch/powerpc/kernel] Error 2

Thanks,
Kamalesh.