Re: [kvm-unit-tests PATCH v2 2/6] lib/stack: print base addresses on efi

[Andrew Jones <andrew.jones@linux.dev>]

On Sun, Jun 25, 2023 at 11:07:12PM +0000, Nadav Amit wrote:
> From: Nadav Amit <namit@vmware.com>
> 
> Making sense from dumped stacks when running EFI tests is very hard due
> to the relocation. Fix it by adjusting the address back to the original
> address.
> 
> Introduce CONFIG_RELOC, which would be set on arm64 and on EFI configs.
> 
> Signed-off-by: Nadav Amit <namit@vmware.com>
> 
> ---
> 
> v1->v2: Introduce CONFIG_RELOC to support ARM64 [Andrew]
> ---
>  configure   |  3 +++
>  lib/stack.c | 31 +++++++++++++++++++++++++++++--
>  2 files changed, 32 insertions(+), 2 deletions(-)
> 
> diff --git a/configure b/configure
> index b665f7d..8a3c8fe 100755
> --- a/configure
> +++ b/configure
> @@ -416,6 +416,9 @@ EOF
>  if [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then
>      echo "TARGET=$target" >> config.mak
>  fi
> +if [ "$efi" = "y" ] || [ "$arch" = "arm64" ]; then
> +    echo "CONFIG_RELOC=y" >> config.mak

This won't work, because, unlike CONFIG_EFI, nothing is defining
CONFIG_RELOC in the build. We need CONFIG_RELOC in lib/config.h
or to append -DCONFIG_RELOC to CFLAGS in a makefile when some
config.mak variable is set. I think my preference would be
something like

diff --git a/Makefile b/Makefile
index 307bc291844a..ae79059e7e6f 100644
--- a/Makefile
+++ b/Makefile
@@ -40,7 +40,7 @@ OBJDIRS += $(LIBFDT_objdir)

 # EFI App
 ifeq ($(CONFIG_EFI),y)
-EFI_CFLAGS := -DCONFIG_EFI
+EFI_CFLAGS := -DCONFIG_EFI -DCONFIG_RELOC
 # The following CFLAGS and LDFLAGS come from:
 #   - GNU-EFI/Makefile.defaults
 #   - GNU-EFI/apps/Makefile
diff --git a/arm/Makefile.arm64 b/arm/Makefile.arm64
index 60385e2d2b2b..960880f1c09f 100644
--- a/arm/Makefile.arm64
+++ b/arm/Makefile.arm64
@@ -12,6 +12,7 @@ CFLAGS += -mstrict-align

 mno_outline_atomics := $(call cc-option, -mno-outline-atomics, "")
 CFLAGS += $(mno_outline_atomics)
+CFLAGS += -DCONFIG_RELOC

 define arch_elf_check =
        $(if $(shell ! $(READELF) -rW $(1) >&/dev/null && echo "nok"),
diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common
index 8ce00340b6be..c2e976e41f20 100644
--- a/powerpc/Makefile.common
+++ b/powerpc/Makefile.common
@@ -24,6 +24,7 @@ CFLAGS += -ffreestanding
 CFLAGS += -O2 -msoft-float -mno-altivec $(mabi_no_altivec)
 CFLAGS += -I $(SRCDIR)/lib -I $(SRCDIR)/lib/libfdt -I lib
 CFLAGS += -Wa,-mregnames
+CFLAGS += -DCONFIG_RELOC

 # We want to keep intermediate files
 .PRECIOUS: %.o


(I also threw in ppc64 since it also relocates.)

Thanks,
drew