Re: [PATCH v1 9/9] livepatch: tests: Make them compile under ARM64

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Aug 17, 2016 at 07:29:12PM +0100, Julien Grall wrote:
> Hi Konrad,
> 
> On 15/08/16 00:07, Konrad Rzeszutek Wilk wrote:
> > We need to two things:
> > 1) Wrap the platform-specific objcopy paramters in defines
> 
> s/paramters/parameters/
> 
> >    The input and output parmeters for $(OBJCOPY) are different
> 
> Ditto.
> 
> >    based on the platforms. As such provide them in the
> >    OBJCOPY_MAGIC define and use that.
> > 
> > 2) The alternative is a bit different and there are no
> >    exceptions under ARM.
> > 
> > We are not yet attempting to build them under ARM32 so
> > that is still ifdefed out.
> > 
> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > 
> > ---
> > Cc: Andrew Cooper <andrew.cooper3@citrix.com>
> > Cc: George Dunlap <George.Dunlap@eu.citrix.com>
> > Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> > Cc: Jan Beulich <jbeulich@suse.com>
> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > Cc: Stefano Stabellini <sstabellini@kernel.org>
> > Cc: Tim Deegan <tim@xen.org>
> > Cc: Wei Liu <wei.liu2@citrix.com>
> > 
> > v1: First submission
> > ---
> >  xen/common/Makefile                    |  2 +-
> >  xen/common/test/Makefile               | 10 ++++++++--
> >  xen/common/test/xen_hello_world_func.c |  7 ++++++-
> >  3 files changed, 15 insertions(+), 4 deletions(-)
> > 
> > diff --git a/xen/common/Makefile b/xen/common/Makefile
> > index 22806b6..fe83653 100644
> > --- a/xen/common/Makefile
> > +++ b/xen/common/Makefile
> > @@ -82,6 +82,6 @@ subdir-$(CONFIG_HAS_DEVICE_TREE) += libfdt
> > 
> >  .PHONY: tests
> >  tests:
> > -ifeq ($(XEN_TARGET_ARCH),x86_64)
> > +ifneq ($(XEN_TARGET_ARCH),arm32)
> >  	$(MAKE) -f $(BASEDIR)/Rules.mk -C test livepatch
> >  endif
> > diff --git a/xen/common/test/Makefile b/xen/common/test/Makefile
> > index 23dff1d..3eed6dd 100644
> > --- a/xen/common/test/Makefile
> > +++ b/xen/common/test/Makefile
> > @@ -1,5 +1,11 @@
> >  include $(XEN_ROOT)/Config.mk
> > 
> > +ifeq ($(XEN_TARGET_ARCH),x86_64)
> > +OBJCOPY_MAGIC := -I binary -O elf64-x86-64 -B i386:x86-64
> > +else
> 
> Is there any reason to fallback on arm64 flags by default? Would not it be
> better to have an else if here?
> 
> > +OBJCOPY_MAGIC := -I binary -O elf64-littleaarch64 -B aarch64

I presume you are referring to this comment. I am not sure how you would
identify whether the elf64-littleaarch64 is not part of the OBJCOPY?

Oh I guess you can: objcopy --info

Or are you saying just use 'arm64' instead of 'aarch64' ?

> > +endif
> > +
> >  CODE_ADDR=$(shell nm --defined $(1) | grep $(2) | awk '{print "0x"$$1}')
> >  CODE_SZ=$(shell nm --defined -S $(1) | grep $(2) | awk '{ print "0x"$$2}')
> > 
> > @@ -54,7 +60,7 @@ $(LIVEPATCH): xen_hello_world_func.o xen_hello_world.o note.o
> >  .PHONY: note.o
> >  note.o:
> >  	$(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(BASEDIR)/xen-syms $@.bin
> > -	$(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
> > +	$(OBJCOPY) $(OBJCOPY_MAGIC) \
> >  		   --rename-section=.data=.livepatch.depends -S $@.bin $@
> >  	rm -f $@.bin
> > 
> > @@ -65,7 +71,7 @@ note.o:
> >  .PHONY: hello_world_note.o
> >  hello_world_note.o: $(LIVEPATCH)
> >  	$(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(LIVEPATCH) $@.bin
> > -	$(OBJCOPY)  -I binary -O elf64-x86-64 -B i386:x86-64 \
> > +	$(OBJCOPY) $(OBJCOPY_MAGIC) \
> >  		   --rename-section=.data=.livepatch.depends -S $@.bin $@
> >  	rm -f $@.bin
> > 
> > diff --git a/xen/common/test/xen_hello_world_func.c b/xen/common/test/xen_hello_world_func.c
> > index 03d6b84..0e1a722 100644
> > --- a/xen/common/test/xen_hello_world_func.c
> > +++ b/xen/common/test/xen_hello_world_func.c
> > @@ -6,14 +6,17 @@
> >  #include <xen/types.h>
> > 
> >  #include <asm/alternative.h>
> > +#ifdef CONFIG_X86
> >  #include <asm/nops.h>
> >  #include <asm/uaccess.h>
> > 
> >  static unsigned long *non_canonical_addr = (unsigned long *)0xdead000000000000ULL;
> > +#endif
> > 
> >  /* Our replacement function for xen_extra_version. */
> >  const char *xen_hello_world(void)
> >  {
> > +#ifdef CONFIG_X86
> >      unsigned long tmp;
> >      int rc;
> > 
> > @@ -24,7 +27,9 @@ const char *xen_hello_world(void)
> >       */
> >      rc = __get_user(tmp, non_canonical_addr);
> >      BUG_ON(rc != -EFAULT);
> > -
> > +#else
> > +     asm(ALTERNATIVE("nop", "nop", 1));
> 
> Why the hardcoded 1 here? I am wondering if we should introduce a new
> capability "LIVEPATCH_TEST" which is enabled by default. So we can test that
> the the alternative is working on all the platform. What do you think?

Sure, but I am not sure what number you would like? Perhaps 42 :-) ?

> 
> > +#endif
> >      return "Hello World";
> >  }
> -- 
> Julien Grall

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