Re: [boot-wrapper PATCH v2 8/9] configure: Autodetect GICv3

[Mark Rutland <mark.rutland@arm.com>]

On Wed, Dec 22, 2021 at 06:16:06PM +0000, Andre Przywara wrote:
> Currently the user has to specify the GIC architecture version (v2 or
> v3) on the ./configure command line, even though this is actually
> redundant information, since the DTB can carry only one GIC type.
> 
> Unconditionally query for the two GIC compatible strings in the provided
> DTB, then choose the GIC type automatically depending on which string is
> found.
> 
> This saves the user from specifying the GIC type on the configure
> command line, and avoids errors when the wrong type was accidentally
> named.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  Makefile.am  | 23 +++++++++--------------
>  configure.ac |  8 --------
>  2 files changed, 9 insertions(+), 22 deletions(-)
> 
> diff --git a/Makefile.am b/Makefile.am
> index d9ad6d1..3d8128f 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -63,19 +63,14 @@ PSCI_NODE	:=
>  CPU_NODES	:=
>  endif
>  
> -if GICV3
> -GIC_DIST_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 0 'arm,gic-v3')
> -GIC_RDIST_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 1 'arm,gic-v3')
> -DEFINES		+= -DGIC_DIST_BASE=$(GIC_DIST_BASE)
> -DEFINES		+= -DGIC_RDIST_BASE=$(GIC_RDIST_BASE)
> -COMMON_OBJ	+= gic-v3.o
> -else
> -GIC_DIST_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 0 'arm,cortex-a15-gic')
> -GIC_CPU_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 1 'arm,cortex-a15-gic')
> -DEFINES		+= -DGIC_CPU_BASE=$(GIC_CPU_BASE)
> -DEFINES		+= -DGIC_DIST_BASE=$(GIC_DIST_BASE)
> -COMMON_OBJ	+= gic.o
> -endif
> +GICV3_DIST_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 0 'arm,gic-v3' 2> /dev/null)
> +GIC_RDIST_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 1 'arm,gic-v3' 2> /dev/null)
> +GICV2_DIST_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 0 'arm,cortex-a15-gic' 2> /dev/null)
> +GIC_CPU_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 1 'arm,cortex-a15-gic' 2> /dev/null)
> +DEFINES		+= $(if $(GICV3_DIST_BASE), -DGIC_DIST_BASE=$(GICV3_DIST_BASE), -DGIC_DIST_BASE=$(GICV2_DIST_BASE))
> +DEFINES		+= $(if $(GIC_RDIST_BASE), -DGIC_RDIST_BASE=$(GIC_RDIST_BASE), )
> +DEFINES		+= $(if $(GIC_CPU_BASE), -DGIC_CPU_BASE=$(GIC_CPU_BASE), )
> +GIC_OBJ		:= $(if $(GICV3_DIST_BASE), gic-v3.o, gic.o)

Hmm... can we organise this such that if we don't find either GICv2 or GICv3 we
produce a build-time error? Currently this'll silently go with GICv2.

Other than that nit, this is a nice quality-of-life improvement!

Thanks,
Mark.

>  
>  if KERNEL_32
>  MBOX_OFFSET	:= 0x7ff8
> @@ -134,7 +129,7 @@ CFLAGS		+= -fno-pic -fno-pie
>  CFLAGS		+= -Os
>  LDFLAGS		+= --gc-sections
>  
> -OBJ		:= $(addprefix $(ARCH_SRC),$(ARCH_OBJ)) $(addprefix $(COMMON_SRC),$(COMMON_OBJ))
> +OBJ		:= $(addprefix $(ARCH_SRC),$(ARCH_OBJ)) $(addprefix $(COMMON_SRC),$(COMMON_OBJ)) $(addprefix $(COMMON_SRC),$(GIC_OBJ))
>  
>  # Don't lookup all prerequisites in $(top_srcdir), only the source files. When
>  # building outside the source tree $(ARCH_SRC) needs to be created.
> diff --git a/configure.ac b/configure.ac
> index 9e3b722..ed3e094 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -111,13 +111,6 @@ AC_ARG_WITH([xen-cmdline],
>  	[X_CMDLINE=$withval])
>  AC_SUBST([XEN_CMDLINE], [$X_CMDLINE])
>  
> -# Allow a user to pass --enable-gicv3
> -AC_ARG_ENABLE([gicv3],
> -	AS_HELP_STRING([--enable-gicv3], [enable GICv3 instead of GICv2]),
> -	[USE_GICV3=$enableval])
> -AM_CONDITIONAL([GICV3], [test "x$USE_GICV3" = "xyes"])
> -AS_IF([test "x$USE_GICV3" = "xyes"], [], [USE_GICV3=no])
> -
>  # Ensure that we have all the needed programs
>  AC_PROG_CC
>  AC_PROG_CPP
> @@ -144,7 +137,6 @@ echo "  Device tree blob:                  ${KERN_DTB}"
>  echo "  Linux kernel command line:         ${CMDLINE}"
>  echo "  Embedded initrd:                   ${FILESYSTEM:-NONE}"
>  echo "  Use PSCI?                          ${USE_PSCI}"
> -echo "  Use GICv3?                         ${USE_GICV3}"
>  echo "  Boot-wrapper execution state:      AArch${BOOTWRAPPER_ES}"
>  echo "  Kernel execution state:            AArch${KERNEL_ES}"
>  echo "  Xen image                          ${XEN_IMAGE:-NONE}"
> -- 
> 2.25.1
> 

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