On 11/23/22 13:45, Claudio Imbrenda wrote:
On Wed, 23 Nov 2022 08:46:52 +0000
Janosch Frank <frankja@xxxxxxxxxxxxx> wrote:
A linker script has a few benefits:
- Random data doesn't end up in the binary breaking tests
- We can easily define a lowcore and load the snippet from 0x0 instead
of 0x4000 which makes asm snippets behave like c snippets
- We can easily define an invalid PGM new PSW to ensure an exit on a
guest PGM
Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
looks good in general, but I have a few questions
---
lib/s390x/snippet.h | 3 +--
s390x/Makefile | 5 +++--
s390x/mvpg-sie.c | 2 +-
s390x/pv-diags.c | 6 +++---
s390x/snippets/asm/flat.lds | 43 +++++++++++++++++++++++++++++++++++++
5 files changed, 51 insertions(+), 8 deletions(-)
create mode 100644 s390x/snippets/asm/flat.lds
diff --git a/lib/s390x/snippet.h b/lib/s390x/snippet.h
index b17b2a4c..57045994 100644
--- a/lib/s390x/snippet.h
+++ b/lib/s390x/snippet.h
@@ -32,8 +32,7 @@
#define SNIPPET_PV_TWEAK0 0x42UL
#define SNIPPET_PV_TWEAK1 0UL
-#define SNIPPET_OFF_C 0
-#define SNIPPET_OFF_ASM 0x4000
+#define SNIPPET_UNPACK_OFF 0
/*
diff --git a/s390x/Makefile b/s390x/Makefile
index bf1504f9..bb0f9eb8 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -135,7 +135,8 @@ $(SNIPPET_DIR)/c/%.o: $(SNIPPET_DIR)/c/%.c $(asm-offsets)
$(CC) $(CFLAGS) -c -nostdlib -o $@ $<
$(SNIPPET_DIR)/asm/%.gbin: $(SNIPPET_DIR)/asm/%.o
- $(OBJCOPY) -O binary -j ".rodata" -j ".text" -j ".data" -j ".bss" --set-section-flags .bss=alloc,load,contents $(patsubst %.gbin,%.o,$@) $@
+ $(CC) $(LDFLAGS) -o $@ -T $(SRCDIR)/s390x/snippets/asm/flat.lds $(patsubst %.gbin,%.o,$@)
I think you can simply use $< instead of the patsubst expression
Right, I'll fix that momentarily.
[...]
+ .text : {
+ *(.text)
+ *(.text.*)
+ }
+ . = ALIGN(64K);
any reason to align to 64k? (instead of e.g. 4k)
Well, I've copied that from s390x/flat.lds...
I'll have a look at the required alignments when I find time.
+ etext = .;
+ . = ALIGN(16);
do you need the ALIGN? I would think we are already aligned here
+ .data : {
+ *(.data)
+ *(.data.rel*)
+ }
+ . = ALIGN(16);
+ .rodata : { *(.rodata) *(.rodata.*) }
+ . = ALIGN(16);
+ __bss_start = .;
+ .bss : { *(.bss) }
+ __bss_end = .;
+ . = ALIGN(64K);
same question as above regarding 64k
+}
