Re: [Xen-devel] [PATCH v5 13/28] xsplice, symbols: Implement symbol name resolution on address.

[Konrad Rzeszutek Wilk <konrad@xxxxxxxxxx>]

On Thu, Apr 07, 2016 at 09:46:49AM -0600, Jan Beulich wrote:
> >>> On 07.04.16 at 05:14, <konrad.wilk@xxxxxxxxxx> wrote:
> > On Fri, Apr 01, 2016 at 09:11:40AM -0600, Jan Beulich wrote:
> >> >>> On 24.03.16 at 21:00, <konrad.wilk@xxxxxxxxxx> wrote:
> >> > --- a/xen/arch/x86/Makefile
> >> > +++ b/xen/arch/x86/Makefile
> >> > @@ -113,12 +113,14 @@ $(TARGET)-syms: prelink.o xen.lds 
> >> > $(BASEDIR)/common/symbols-dummy.o
> >> >          $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
> >> >              $(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
> >> >          $(NM) -pa --format=sysv $(@D)/.$(@F).0 \
> >> > -                | $(BASEDIR)/tools/symbols --sysv --sort 
> >> > >$(@D)/.$(@F).0.S
> >> > +                | $(BASEDIR)/tools/symbols --all-symbols --sysv --sort \
> >> > +                >$(@D)/.$(@F).0.S
> >> >          $(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).0.o
> >> >          $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
> >> >              $(@D)/.$(@F).0.o -o $(@D)/.$(@F).1
> >> >          $(NM) -pa --format=sysv $(@D)/.$(@F).1 \
> >> > -                | $(BASEDIR)/tools/symbols --sysv --sort --warn-dup 
> >> > >$(@D)/.$(@F).1.S
> >> > +                | $(BASEDIR)/tools/symbols --all-symbols --sysv --sort 
> >> > --warn-dup \
> >> > +                >$(@D)/.$(@F).1.S
> >> 
> >> This addition should be dependent on CONFIG_XSPLICE, not the
> >> least because I expect it to bloat the symbol table quite a bit. And
> >> then - how come this is needed here, but not in the xen.efi rule?
> > 
> > I added it to xen.efi rule and got:
> > 
> > home/konrad/xen/xen/.xen.efi.0s.S: Assembler messages:
> > /home/konrad/xen/xen/.xen.efi.0s.S:21: Warning: value 0x7d2f80000543 
> > truncated to 0x80000543
> > /home/konrad/xen/xen/.xen.efi.0s.S:22: Warning: value 0x7d2f800008b2 
> > truncated to 0x800008b2
> > /home/konrad/xen/xen/.xen.efi.0s.S:23: Warning: value 0x7d2f800008b4 
> > truncated to 0x800008b4
> > /home/konrad/xen/xen/.xen.efi.0s.S:24: Warning: value 0x7d2f800008b9 
> > truncated to 0x800008b9
> > /home/konrad/xen/xen/.xen.efi.0s.S:25: Warning: value 0x7d2f8000103f 
> > truncated to 0x8000103f
> > /home/konrad/xen/xen/.xen.efi.0s.S:26: Warning: value 0x7d2f80001043 
> > truncated to 0x80001043
> > /home/konrad/xen/xen/.xen.efi.0s.S:27: Warning: value 0x7d2f80001047 
> > truncated to 0x80001047
> > /home/konrad/xen/xen/.xen.efi.0s.S:6746: Warning: value 0x100650000 
> > truncated to 0x650000
> > 
> > and so on.. Not sure why. The xen.efi file boots thought?
> 
> It's the kallsyms symbol table that suffers, so the image booting
> fine is not really surprising. But we'd need to understand what
> specific data objects these warnings originate from - perhaps
> linker generated symbols not sitting inside sections?

From the .xen.efi.0s.S:
.globl symbols_offsets
        ALGN
symbols_offsets:
#endif
        PTR     0x544 - SYMBOLS_ORIGIN
        PTR     0xa01 - SYMBOLS_ORIGIN
        PTR     0xa03 - SYMBOLS_ORIGIN
        PTR     0xa08 - SYMBOLS_ORIGIN
        PTR     0x118e - SYMBOLS_ORIGIN
        PTR     0x1192 - SYMBOLS_ORIGIN
        PTR     0x1196 - SYMBOLS_ORIGIN
        PTR     0xffff82d080100000 - SYMBOLS_ORIGIN
        PTR     0xffff82d080100000 - SYMBOLS_ORIGIN

which corresponds to:
multiboot1_header_start|0000000000000544|   ?  |                  | |     |
multiboot1_header_start|0000000000000a01|   ?  |                  | |     |
multiboot1_header_start|0000000000000a03|   ?  |                  | |     |
multiboot1_header_start|0000000000000a08|   ?  |                  | |     |
multiboot1_header_start|000000000000118e|   ?  |                  | |     |
multiboot1_header_start|0000000000001192|   ?  |                  | |     |
multiboot1_header_start|0000000000001196|   ?  |                  | |     |

which is also found:
multiboot1_header_start|ffff82d080100008|   t  |                  | |     | 

> 
> Jan
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel