On 2017/01/31 07:43AM, Michael Ellerman wrote:
> Anju T Sudhakar <a...@linux.vnet.ibm.com> writes:
>
> > Detour buffer contains instructions to create an in memory pt_regs.
> > After the execution of the pre-handler, a call is made for instruction
> > emulation.
> > The NIP is determined in advanced through dummy instruction emulation and a
> > branch
> > instruction is created to the NIP at the end of the trampoline.
> >
> > Instruction slot for detour buffer is allocated from the reserved area.
> > For the time being, 64KB is reserved in memory for this purpose.
> >
> > Instructions which can be emulated using analyse_instr() are suppliants
> > for optimization. Before optimization ensure that the address range
> > between the detour buffer allocated and the instruction being probed
> > is within ± 32MB.
> >
> > Signed-off-by: Anju T Sudhakar <a...@linux.vnet.ibm.com>
> > Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
> > ---
> > .../features/debug/optprobes/arch-support.txt | 2 +-
> > arch/powerpc/Kconfig | 1 +
> > arch/powerpc/include/asm/kprobes.h | 24 +-
> > arch/powerpc/include/asm/sstep.h | 1 +
> > arch/powerpc/kernel/Makefile | 1 +
> > arch/powerpc/kernel/optprobes.c | 331
> > +++++++++++++++++++++
> > arch/powerpc/kernel/optprobes_head.S | 135 +++++++++
> > arch/powerpc/lib/sstep.c | 21 ++
> > 8 files changed, 514 insertions(+), 2 deletions(-)
> > create mode 100644 arch/powerpc/kernel/optprobes.c
> > create mode 100644 arch/powerpc/kernel/optprobes_head.S
>
> This breaks the pseries_defconfig (at least) build:
>
> In file included from ../include/linux/kprobes.h:45:0,
> from ../arch/powerpc/kernel/optprobes.c:12:
> ../arch/powerpc/kernel/optprobes.c: In function
> ‘arch_prepare_optimized_kprobe’:
> ../arch/powerpc/include/asm/kprobes.h:79:16: error: ‘MODULE_NAME_LEN’
> undeclared (first use in this function)
> char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN]; \
> ^
> ../arch/powerpc/kernel/optprobes.c:230:2: note: in expansion of macro
> ‘kprobe_lookup_name’
> kprobe_lookup_name("optimized_callback", op_callback_addr);
> ^~~~~~~~~~~~~~~~~~
> ../arch/powerpc/include/asm/kprobes.h:79:16: note: each undeclared
> identifier is reported only once for each function it appears in
> char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN]; \
> ^
> ../arch/powerpc/kernel/optprobes.c:230:2: note: in expansion of macro
> ‘kprobe_lookup_name’
> kprobe_lookup_name("optimized_callback", op_callback_addr);
> ^~~~~~~~~~~~~~~~~~
> ../arch/powerpc/include/asm/kprobes.h:82:14: error: assignment discards
> ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
> if ((modsym = strchr(name, ':')) != NULL) { \
> ^
> ../arch/powerpc/kernel/optprobes.c:230:2: note: in expansion of macro
> ‘kprobe_lookup_name’
> kprobe_lookup_name("optimized_callback", op_callback_addr);
> ^~~~~~~~~~~~~~~~~~
> ../arch/powerpc/include/asm/kprobes.h:79:7: error: unused variable
> ‘dot_name’ [-Werror=unused-variable]
> char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN]; \
> ^
> ../arch/powerpc/kernel/optprobes.c:230:2: note: in expansion of macro
> ‘kprobe_lookup_name’
> kprobe_lookup_name("optimized_callback", op_callback_addr);
> ^~~~~~~~~~~~~~~~~~
> ../arch/powerpc/include/asm/kprobes.h:82:14: error: assignment discards
> ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
> if ((modsym = strchr(name, ':')) != NULL) { \
> ^
> ../arch/powerpc/kernel/optprobes.c:231:2: note: in expansion of macro
> ‘kprobe_lookup_name’
> kprobe_lookup_name("emulate_step", emulate_step_addr);
> ^~~~~~~~~~~~~~~~~~
> ../arch/powerpc/include/asm/kprobes.h:79:7: error: unused variable
> ‘dot_name’ [-Werror=unused-variable]
> char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN]; \
> ^
> ../arch/powerpc/kernel/optprobes.c:231:2: note: in expansion of macro
> ‘kprobe_lookup_name’
> kprobe_lookup_name("emulate_step", emulate_step_addr);
> ^~~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
> make[2]: *** [arch/powerpc/kernel/optprobes.o] Error 1
> make[2]: *** Waiting for unfinished jobs....
> make[1]: *** [arch/powerpc/kernel] Error 2
> make[1]: *** Waiting for unfinished jobs....
> make: *** [sub-make] Error 2
>
>
> This may not be your bug, but your patch exposes it unfortunately.
Sorry for the trouble, we should have caught this.
- Naveen
