diff mbox series

[kvm-unit-tests,v2,3/7] s390x: Add a linker script to assembly snippets

Message ID 20221020090009.2189-4-frankja@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series s390x: PV fixups | expand

Commit Message

Janosch Frank Oct. 20, 2022, 9 a.m. UTC 
A linker script has a few benefits:
- 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
- We can remove a lot of the offset variables from lib/s390x/snippet.h

As we gain another step and file extension by linking, a comment
explains which file extensions are generated and why.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
 lib/s390x/snippet.h         | 14 +++++---------
 s390x/Makefile              | 18 ++++++++++++++----
 s390x/mvpg-sie.c            |  2 +-
 s390x/pv-diags.c            |  6 +++---
 s390x/snippets/asm/flat.lds | 35 +++++++++++++++++++++++++++++++++++
 5 files changed, 58 insertions(+), 17 deletions(-)
 create mode 100644 s390x/snippets/asm/flat.lds

Comments

Claudio Imbrenda Oct. 20, 2022, 10:02 a.m. UTC | #1 
On Thu, 20 Oct 2022 09:00:05 +0000
Janosch Frank <frankja@linux.ibm.com> wrote:

> A linker script has a few benefits:
> - 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
> - We can remove a lot of the offset variables from lib/s390x/snippet.h
> 
> As we gain another step and file extension by linking, a comment
> explains which file extensions are generated and why.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
>  lib/s390x/snippet.h         | 14 +++++---------
>  s390x/Makefile              | 18 ++++++++++++++----
>  s390x/mvpg-sie.c            |  2 +-
>  s390x/pv-diags.c            |  6 +++---
>  s390x/snippets/asm/flat.lds | 35 +++++++++++++++++++++++++++++++++++
>  5 files changed, 58 insertions(+), 17 deletions(-)
>  create mode 100644 s390x/snippets/asm/flat.lds
> 
> diff --git a/lib/s390x/snippet.h b/lib/s390x/snippet.h
> index b17b2a4c..fcd04081 100644
> --- a/lib/s390x/snippet.h
> +++ b/lib/s390x/snippet.h
> @@ -32,8 +32,6 @@
>  
>  #define SNIPPET_PV_TWEAK0	0x42UL
>  #define SNIPPET_PV_TWEAK1	0UL
> -#define SNIPPET_OFF_C		0
> -#define SNIPPET_OFF_ASM		0x4000
>  
>  
>  /*
> @@ -57,15 +55,14 @@ static const struct psw snippet_psw = {
>   * @vm: VM that this function will populated, has to be initialized already
>   * @gbin: Snippet gbin data pointer
>   * @gbin_len: Length of the gbin data
> - * @off: Offset from guest absolute 0x0 where snippet is copied to
>   */
>  static inline void snippet_init(struct vm *vm, const char *gbin,
> -				uint64_t gbin_len, uint64_t off)
> +				uint64_t gbin_len)
>  {
>  	uint64_t mso = vm->sblk->mso;
>  
>  	/* Copy test image to guest memory */
> -	memcpy((void *)mso + off, gbin, gbin_len);
> +	memcpy((void *)mso, gbin, gbin_len);
>  
>  	/* Setup guest PSW */
>  	vm->sblk->gpsw = snippet_psw;
> @@ -87,23 +84,22 @@ static inline void snippet_init(struct vm *vm, const char *gbin,
>   * @hdr: Snippet SE header data pointer
>   * @gbin_len: Length of the gbin data
>   * @hdr_len: Length of the hdr data
> - * @off: Offset from guest absolute 0x0 where snippet is copied to
>   */
>  static inline void snippet_pv_init(struct vm *vm, const char *gbin,
>  				   const char *hdr, uint64_t gbin_len,
> -				   uint64_t hdr_len, uint64_t off)
> +				   uint64_t hdr_len)
>  {
>  	uint64_t tweak[2] = {SNIPPET_PV_TWEAK0, SNIPPET_PV_TWEAK1};
>  	uint64_t mso = vm->sblk->mso;
>  	int i;
>  
> -	snippet_init(vm, gbin, gbin_len, off);
> +	snippet_init(vm, gbin, gbin_len);
>  
>  	uv_create_guest(vm);
>  	uv_set_se_hdr(vm->uv.vm_handle, (void *)hdr, hdr_len);
>  
>  	/* Unpack works on guest addresses so we only need off */
> -	uv_unpack(vm, off, gbin_len, tweak[0]);
> +	uv_unpack(vm, 0, gbin_len, tweak[0]);
>  	uv_verify_load(vm);
>  
>  	/*
> diff --git a/s390x/Makefile b/s390x/Makefile
> index 3b175015..0eaa72f4 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -124,6 +124,13 @@ else
>  snippet-hdr-obj =
>  endif
>  
> +# Each snippet will generate the following files (in order): \
> +  *.o is a snippet that has been compiled \
> +  *.ol is a snippet that has been linked \
> +  *.gbin is a snippet that has been converted to binary \
> +  *.gobj is the final format after converting the binary into a elf file again, \
> +  it will be linked into the tests
> +
>  # the asm/c snippets %.o have additional generated files as dependencies
>  $(SNIPPET_DIR)/asm/%.o: $(SNIPPET_DIR)/asm/%.S $(asm-offsets)
>  	$(CC) $(CFLAGS) -c -nostdlib -o $@ $<
> @@ -131,17 +138,20 @@ $(SNIPPET_DIR)/asm/%.o: $(SNIPPET_DIR)/asm/%.S $(asm-offsets)
>  $(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 $(patsubst %.gbin,%.o,$@) $@
> +$(SNIPPET_DIR)/asm/%.ol: $(SNIPPET_DIR)/asm/%.o
> +	$(CC) $(LDFLAGS) -o $@ -T $(SNIPPET_DIR)/asm/flat.lds $<
> +
> +$(SNIPPET_DIR)/asm/%.gbin: $(SNIPPET_DIR)/asm/%.ol
> +	$(OBJCOPY) -O binary -j ".rodata" -j ".lowcore" -j ".text" -j ".data" -j ".bss" --set-section-flags .bss=alloc,load,contents $< $@
>  	truncate -s '%4096' $@

can't you do $(CC) and $(OBJCOPY) in one step like you do for C
snippets? then you don't need the .ol intermediate

>  
>  $(SNIPPET_DIR)/c/%.gbin: $(SNIPPET_DIR)/c/%.o $(snippet_lib) $(FLATLIBS)
> -	$(CC) $(LDFLAGS) -o $@ -T $(SRCDIR)/s390x/snippets/c/flat.lds $< $(snippet_lib) $(FLATLIBS)
> +	$(CC) $(LDFLAGS) -o $@ -T $(SNIPPET_DIR)/c/flat.lds $< $(snippet_lib) $(FLATLIBS)
>  	$(OBJCOPY) -O binary -j ".rodata" -j ".lowcore" -j ".text" -j ".data" -j ".bss" --set-section-flags .bss=alloc,load,contents $@ $@
>  	truncate -s '%4096' $@
>  
>  $(SNIPPET_DIR)/asm/%.hdr: $(SNIPPET_DIR)/asm/%.gbin $(HOST_KEY_DOCUMENT)
> -	$(GEN_SE_HEADER) -k $(HOST_KEY_DOCUMENT) -c $<,0x4000,0x00000000000000420000000000000000 --psw-addr 0x4000 -o $@
> +	$(GEN_SE_HEADER) -k $(HOST_KEY_DOCUMENT) -c $<,0x0,0x00000000000000420000000000000000 --psw-addr 0x4000 -o $@
>  
>  $(SNIPPET_DIR)/c/%.hdr: $(SNIPPET_DIR)/c/%.gbin $(HOST_KEY_DOCUMENT)
>  	$(GEN_SE_HEADER) -k $(HOST_KEY_DOCUMENT) -c $<,0x0,0x00000000000000420000000000000000 --psw-addr 0x4000 -o $@
> diff --git a/s390x/mvpg-sie.c b/s390x/mvpg-sie.c
> index 46a2edb6..17e209ad 100644
> --- a/s390x/mvpg-sie.c
> +++ b/s390x/mvpg-sie.c
> @@ -87,7 +87,7 @@ static void setup_guest(void)
>  
>  	snippet_setup_guest(&vm, false);
>  	snippet_init(&vm, SNIPPET_NAME_START(c, mvpg_snippet),
> -		     SNIPPET_LEN(c, mvpg_snippet), SNIPPET_OFF_C);
> +		     SNIPPET_LEN(c, mvpg_snippet));
>  
>  	/* Enable MVPG interpretation as we want to test KVM and not ourselves */
>  	vm.sblk->eca = ECA_MVPGI;
> diff --git a/s390x/pv-diags.c b/s390x/pv-diags.c
> index 9ced68c7..d472c994 100644
> --- a/s390x/pv-diags.c
> +++ b/s390x/pv-diags.c
> @@ -28,7 +28,7 @@ static void test_diag_500(void)
>  
>  	snippet_pv_init(&vm, SNIPPET_NAME_START(asm, snippet_pv_diag_500),
>  			SNIPPET_HDR_START(asm, snippet_pv_diag_500),
> -			size_gbin, size_hdr, SNIPPET_OFF_ASM);
> +			size_gbin, size_hdr);
>  
>  	sie(&vm);
>  	report(vm.sblk->icptcode == ICPT_PV_INSTR && vm.sblk->ipa == 0x8302 &&
> @@ -83,7 +83,7 @@ static void test_diag_288(void)
>  
>  	snippet_pv_init(&vm, SNIPPET_NAME_START(asm, snippet_pv_diag_288),
>  			SNIPPET_HDR_START(asm, snippet_pv_diag_288),
> -			size_gbin, size_hdr, SNIPPET_OFF_ASM);
> +			size_gbin, size_hdr);
>  
>  	sie(&vm);
>  	report(vm.sblk->icptcode == ICPT_PV_INSTR && vm.sblk->ipa == 0x8302 &&
> @@ -124,7 +124,7 @@ static void test_diag_yield(void)
>  
>  	snippet_pv_init(&vm, SNIPPET_NAME_START(asm, snippet_pv_diag_yield),
>  			SNIPPET_HDR_START(asm, snippet_pv_diag_yield),
> -			size_gbin, size_hdr, SNIPPET_OFF_ASM);
> +			size_gbin, size_hdr);
>  
>  	/* 0x44 */
>  	report_prefix_push("0x44");
> diff --git a/s390x/snippets/asm/flat.lds b/s390x/snippets/asm/flat.lds
> new file mode 100644
> index 00000000..388d7d5d
> --- /dev/null
> +++ b/s390x/snippets/asm/flat.lds
> @@ -0,0 +1,35 @@
> +SECTIONS
> +{
> +	.lowcore : {
> +		 /* Restart new PSW for booting via PSW restart. */
> +		 . = 0x1a0;
> +		 QUAD(0x0000000180000000)
> +		 QUAD(0x0000000000004000)
> +		 /*
> +		  * Invalid PGM new PSW so we hopefully get a code 8
> +		  * intercept on a PGM for PV snippets.
> +		  */
> +		 . = 0x1d0;
> +		 QUAD(0x0008000000000000)
> +		 QUAD(0x0000000000000001)
> +	}
> +	. = 0x4000;
> +	.text : {
> +		*(.text)
> +		*(.text.*)
> +	}
> +	. = ALIGN(64K);
> +	etext = .;
> +	. = ALIGN(16);
> +	.data : {
> +		*(.data)
> +		*(.data.rel*)
> +	}
> +	. = ALIGN(16);
> +	.rodata : { *(.rodata) *(.rodata.*) }
> +	. = ALIGN(16);

do you really need to ALIGN(16) right after ALIGN(64K) ?

> +	__bss_start = .;
> +	.bss : { *(.bss) }
> +	__bss_end = .;
> +	. = ALIGN(64K);

why align the end? and why 64K instead of e.g. 4K?

> +}
diff mbox series

Patch

diff --git a/lib/s390x/snippet.h b/lib/s390x/snippet.h
index b17b2a4c..fcd04081 100644
--- a/lib/s390x/snippet.h
+++ b/lib/s390x/snippet.h
@@ -32,8 +32,6 @@ 
 
 #define SNIPPET_PV_TWEAK0	0x42UL
 #define SNIPPET_PV_TWEAK1	0UL
-#define SNIPPET_OFF_C		0
-#define SNIPPET_OFF_ASM		0x4000
 
 
 /*
@@ -57,15 +55,14 @@  static const struct psw snippet_psw = {
  * @vm: VM that this function will populated, has to be initialized already
  * @gbin: Snippet gbin data pointer
  * @gbin_len: Length of the gbin data
- * @off: Offset from guest absolute 0x0 where snippet is copied to
  */
 static inline void snippet_init(struct vm *vm, const char *gbin,
-				uint64_t gbin_len, uint64_t off)
+				uint64_t gbin_len)
 {
 	uint64_t mso = vm->sblk->mso;
 
 	/* Copy test image to guest memory */
-	memcpy((void *)mso + off, gbin, gbin_len);
+	memcpy((void *)mso, gbin, gbin_len);
 
 	/* Setup guest PSW */
 	vm->sblk->gpsw = snippet_psw;
@@ -87,23 +84,22 @@  static inline void snippet_init(struct vm *vm, const char *gbin,
  * @hdr: Snippet SE header data pointer
  * @gbin_len: Length of the gbin data
  * @hdr_len: Length of the hdr data
- * @off: Offset from guest absolute 0x0 where snippet is copied to
  */
 static inline void snippet_pv_init(struct vm *vm, const char *gbin,
 				   const char *hdr, uint64_t gbin_len,
-				   uint64_t hdr_len, uint64_t off)
+				   uint64_t hdr_len)
 {
 	uint64_t tweak[2] = {SNIPPET_PV_TWEAK0, SNIPPET_PV_TWEAK1};
 	uint64_t mso = vm->sblk->mso;
 	int i;
 
-	snippet_init(vm, gbin, gbin_len, off);
+	snippet_init(vm, gbin, gbin_len);
 
 	uv_create_guest(vm);
 	uv_set_se_hdr(vm->uv.vm_handle, (void *)hdr, hdr_len);
 
 	/* Unpack works on guest addresses so we only need off */
-	uv_unpack(vm, off, gbin_len, tweak[0]);
+	uv_unpack(vm, 0, gbin_len, tweak[0]);
 	uv_verify_load(vm);
 
 	/*
diff --git a/s390x/Makefile b/s390x/Makefile
index 3b175015..0eaa72f4 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -124,6 +124,13 @@  else
 snippet-hdr-obj =
 endif
 
+# Each snippet will generate the following files (in order): \
+  *.o is a snippet that has been compiled \
+  *.ol is a snippet that has been linked \
+  *.gbin is a snippet that has been converted to binary \
+  *.gobj is the final format after converting the binary into a elf file again, \
+  it will be linked into the tests
+
 # the asm/c snippets %.o have additional generated files as dependencies
 $(SNIPPET_DIR)/asm/%.o: $(SNIPPET_DIR)/asm/%.S $(asm-offsets)
 	$(CC) $(CFLAGS) -c -nostdlib -o $@ $<
@@ -131,17 +138,20 @@  $(SNIPPET_DIR)/asm/%.o: $(SNIPPET_DIR)/asm/%.S $(asm-offsets)
 $(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 $(patsubst %.gbin,%.o,$@) $@
+$(SNIPPET_DIR)/asm/%.ol: $(SNIPPET_DIR)/asm/%.o
+	$(CC) $(LDFLAGS) -o $@ -T $(SNIPPET_DIR)/asm/flat.lds $<
+
+$(SNIPPET_DIR)/asm/%.gbin: $(SNIPPET_DIR)/asm/%.ol
+	$(OBJCOPY) -O binary -j ".rodata" -j ".lowcore" -j ".text" -j ".data" -j ".bss" --set-section-flags .bss=alloc,load,contents $< $@
 	truncate -s '%4096' $@
 
 $(SNIPPET_DIR)/c/%.gbin: $(SNIPPET_DIR)/c/%.o $(snippet_lib) $(FLATLIBS)
-	$(CC) $(LDFLAGS) -o $@ -T $(SRCDIR)/s390x/snippets/c/flat.lds $< $(snippet_lib) $(FLATLIBS)
+	$(CC) $(LDFLAGS) -o $@ -T $(SNIPPET_DIR)/c/flat.lds $< $(snippet_lib) $(FLATLIBS)
 	$(OBJCOPY) -O binary -j ".rodata" -j ".lowcore" -j ".text" -j ".data" -j ".bss" --set-section-flags .bss=alloc,load,contents $@ $@
 	truncate -s '%4096' $@
 
 $(SNIPPET_DIR)/asm/%.hdr: $(SNIPPET_DIR)/asm/%.gbin $(HOST_KEY_DOCUMENT)
-	$(GEN_SE_HEADER) -k $(HOST_KEY_DOCUMENT) -c $<,0x4000,0x00000000000000420000000000000000 --psw-addr 0x4000 -o $@
+	$(GEN_SE_HEADER) -k $(HOST_KEY_DOCUMENT) -c $<,0x0,0x00000000000000420000000000000000 --psw-addr 0x4000 -o $@
 
 $(SNIPPET_DIR)/c/%.hdr: $(SNIPPET_DIR)/c/%.gbin $(HOST_KEY_DOCUMENT)
 	$(GEN_SE_HEADER) -k $(HOST_KEY_DOCUMENT) -c $<,0x0,0x00000000000000420000000000000000 --psw-addr 0x4000 -o $@
diff --git a/s390x/mvpg-sie.c b/s390x/mvpg-sie.c
index 46a2edb6..17e209ad 100644
--- a/s390x/mvpg-sie.c
+++ b/s390x/mvpg-sie.c
@@ -87,7 +87,7 @@  static void setup_guest(void)
 
 	snippet_setup_guest(&vm, false);
 	snippet_init(&vm, SNIPPET_NAME_START(c, mvpg_snippet),
-		     SNIPPET_LEN(c, mvpg_snippet), SNIPPET_OFF_C);
+		     SNIPPET_LEN(c, mvpg_snippet));
 
 	/* Enable MVPG interpretation as we want to test KVM and not ourselves */
 	vm.sblk->eca = ECA_MVPGI;
diff --git a/s390x/pv-diags.c b/s390x/pv-diags.c
index 9ced68c7..d472c994 100644
--- a/s390x/pv-diags.c
+++ b/s390x/pv-diags.c
@@ -28,7 +28,7 @@  static void test_diag_500(void)
 
 	snippet_pv_init(&vm, SNIPPET_NAME_START(asm, snippet_pv_diag_500),
 			SNIPPET_HDR_START(asm, snippet_pv_diag_500),
-			size_gbin, size_hdr, SNIPPET_OFF_ASM);
+			size_gbin, size_hdr);
 
 	sie(&vm);
 	report(vm.sblk->icptcode == ICPT_PV_INSTR && vm.sblk->ipa == 0x8302 &&
@@ -83,7 +83,7 @@  static void test_diag_288(void)
 
 	snippet_pv_init(&vm, SNIPPET_NAME_START(asm, snippet_pv_diag_288),
 			SNIPPET_HDR_START(asm, snippet_pv_diag_288),
-			size_gbin, size_hdr, SNIPPET_OFF_ASM);
+			size_gbin, size_hdr);
 
 	sie(&vm);
 	report(vm.sblk->icptcode == ICPT_PV_INSTR && vm.sblk->ipa == 0x8302 &&
@@ -124,7 +124,7 @@  static void test_diag_yield(void)
 
 	snippet_pv_init(&vm, SNIPPET_NAME_START(asm, snippet_pv_diag_yield),
 			SNIPPET_HDR_START(asm, snippet_pv_diag_yield),
-			size_gbin, size_hdr, SNIPPET_OFF_ASM);
+			size_gbin, size_hdr);
 
 	/* 0x44 */
 	report_prefix_push("0x44");
diff --git a/s390x/snippets/asm/flat.lds b/s390x/snippets/asm/flat.lds
new file mode 100644
index 00000000..388d7d5d
--- /dev/null
+++ b/s390x/snippets/asm/flat.lds
@@ -0,0 +1,35 @@ 
+SECTIONS
+{
+	.lowcore : {
+		 /* Restart new PSW for booting via PSW restart. */
+		 . = 0x1a0;
+		 QUAD(0x0000000180000000)
+		 QUAD(0x0000000000004000)
+		 /*
+		  * Invalid PGM new PSW so we hopefully get a code 8
+		  * intercept on a PGM for PV snippets.
+		  */
+		 . = 0x1d0;
+		 QUAD(0x0008000000000000)
+		 QUAD(0x0000000000000001)
+	}
+	. = 0x4000;
+	.text : {
+		*(.text)
+		*(.text.*)
+	}
+	. = ALIGN(64K);
+	etext = .;
+	. = ALIGN(16);
+	.data : {
+		*(.data)
+		*(.data.rel*)
+	}
+	. = ALIGN(16);
+	.rodata : { *(.rodata) *(.rodata.*) }
+	. = ALIGN(16);
+	__bss_start = .;
+	.bss : { *(.bss) }
+	__bss_end = .;
+	. = ALIGN(64K);
+}