| Message ID | 20201210210037.16660-1-klaus@linux.vnet.ibm.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | build: Fix linker script for builtin Kernel | expand |
On 12/10/2020 6:00 PM, Klaus Heinrich Kiwi wrote: > /* Optional kernel image */ > . = ALIGN(PAGE_SIZE); > .builtin_kernel : { > @@ -243,6 +241,8 @@ SECTIONS > __builtin_kernel_end = .; > } > > + DEBUG_SECTIONS > + FYI, an IBM colleague from the compiler team (Segher) mentioned we could add (NOLOAD) to the sections undere DEBUG_SECTIONS macro instead, and that could save us some memory as well.. I'll test this tomorrow and send a V2 if successful. But thoughts are welcome. -Klaus
On 12/10/2020 9:47 PM, Klaus Heinrich Kiwi wrote: > > > On 12/10/2020 6:00 PM, Klaus Heinrich Kiwi wrote: > >> /* Optional kernel image */ >> . = ALIGN(PAGE_SIZE); >> .builtin_kernel : { >> @@ -243,6 +241,8 @@ SECTIONS >> __builtin_kernel_end = .; >> } >> >> + DEBUG_SECTIONS >> + > > FYI, an IBM colleague from the compiler team (Segher) mentioned we could add (NOLOAD) > to the sections undere DEBUG_SECTIONS macro instead, and that could save us some > memory as well.. > > I'll test this tomorrow and send a V2 if successful. I did a few tests with the (NOLOAD) for the debug sections, but that alone wasn't sufficient to fix original issue.. additionally, I couldn't note any memory / size differences in the final binary. So unless Segher has other suggestions, I think we will need the patch above after all. Thanks, > -Klaus
On Fri, Dec 11, 2020 at 08:18:30AM -0300, Klaus Heinrich Kiwi wrote: > On 12/10/2020 9:47 PM, Klaus Heinrich Kiwi wrote: > >On 12/10/2020 6:00 PM, Klaus Heinrich Kiwi wrote: > > > >> /* Optional kernel image */ > >> . = ALIGN(PAGE_SIZE); > >> .builtin_kernel : { > >>@@ -243,6 +241,8 @@ SECTIONS > >> __builtin_kernel_end = .; > >> } > >> > >>+ DEBUG_SECTIONS > >>+ > > > >FYI, an IBM colleague from the compiler team (Segher) mentioned we could > >add (NOLOAD) > >to the sections undere DEBUG_SECTIONS macro instead, and that could save > >us some > >memory as well.. > > > >I'll test this tomorrow and send a V2 if successful. > > I did a few tests with the (NOLOAD) for the debug sections, but that alone > wasn't sufficient > to fix original issue.. additionally, I couldn't note any memory / size > differences in the final > binary. > > So unless Segher has other suggestions, I think we will need the patch > above after all. Flags are inherited from the previous section if you specify nothing, so I thought that was what caused the problem if you have the debug sections before everything else. Just putting the debug sections after other sections instead of before (just like every other project does) is probably a good idea no matter what... but figuring out what went wrong is at least fun for a Friday, isn't it? :-) Segher
On 12/11/20 2:30 AM, Klaus Heinrich Kiwi wrote: > Commit '6b08928d - build/lds: place debug sections according to > defaults' introduced a DEBUG_SECTIONS macro that is effectivelly > resetting the location pointer back to zero, making the next section > (builtin_kernel) collide with the earlier sections. > > Fix by moving these sections to the very end. Thanks! Merged to master as a98262ee. -Vasant
diff --git a/skiboot.lds.S b/skiboot.lds.S index 5da6f9d8..5a7f9e31 100644 --- a/skiboot.lds.S +++ b/skiboot.lds.S @@ -233,8 +233,6 @@ SECTIONS ASSERT((HEAP_BASE - SKIBOOT_BASE) >= _end, "Heap collision with image") - DEBUG_SECTIONS - /* Optional kernel image */ . = ALIGN(PAGE_SIZE); .builtin_kernel : { @@ -243,6 +241,8 @@ SECTIONS __builtin_kernel_end = .; } + DEBUG_SECTIONS + /* Discards */ /DISCARD/ : { *(.note.GNU-stack)
Commit '6b08928d - build/lds: place debug sections according to defaults' introduced a DEBUG_SECTIONS macro that is effectivelly resetting the location pointer back to zero, making the next section (builtin_kernel) collide with the earlier sections. Fix by moving these sections to the very end. Error message: $ make KERNEL=zImage.epapr [CC] asm/asm-offsets.s [GN] include/asm-offsets.h <...> [LD] skiboot.tmp.elf ld: section .builtin_kernel LMA [0000000000000000,0000000000285d87] overlaps section .head LMA [0000000000000000,0000000000003897] ld: section .naca LMA [0000000000004000,000000000000505f] overlaps section .builtin_kernel LMA [0000000000000000,0000000000285d87] make: *** [/skiboot/Makefile.main:333: skiboot.tmp.elf] Error 1 Fixes: 6b08928d - build/lds: place debug sections according to defaults Signed-off-by: Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com> --- skiboot.lds.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)