To make it easier to test 32 bit Arm softmmu issues implement a basic
boot.S so we can build the multiarch tests. Currently CHECK_UNALIGNED
is disabled as I haven't got the right magic set for it to work.

Message-Id: <20231115205542.3092038-10-alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---
v2
  - use endf macro for global function symbols in boot.S
---
 tests/tcg/arm/Makefile.softmmu-target |  64 +++++-
 tests/tcg/arm/system/boot.S           | 301 ++++++++++++++++++++++++++
 tests/tcg/arm/system/kernel.ld        |  24 ++
 3 files changed, 379 insertions(+), 10 deletions(-)
 create mode 100644 tests/tcg/arm/system/boot.S
 create mode 100644 tests/tcg/arm/system/kernel.ld

diff --git a/tests/tcg/arm/Makefile.softmmu-target b/tests/tcg/arm/Makefile.softmmu-target
index 7857ab9324..aadc12767e 100644
--- a/tests/tcg/arm/Makefile.softmmu-target
+++ b/tests/tcg/arm/Makefile.softmmu-target
@@ -8,20 +8,64 @@ ARM_SRC=$(SRC_PATH)/tests/tcg/arm/system
 # Set search path for all sources
 VPATH 		+= $(ARM_SRC)
 
-ARM_TESTS=test-armv6m-undef
+# Specific Test Rules
 
-TESTS += $(ARM_TESTS)
+test-armv6m-undef: test-armv6m-undef.S
+	$(CC) -mcpu=cortex-m0 -mfloat-abi=soft \
+		-Wl,--build-id=none -x assembler-with-cpp \
+		$< -o $@ -nostdlib -N -static \
+		-T $(ARM_SRC)/$@.ld
 
-LDFLAGS+=-nostdlib -N -static
+run-test-armv6m-undef: QEMU_OPTS+=-semihosting -M microbit -kernel
 
-%: %.S %.ld
-	$(CC) $(CFLAGS) $(ASFLAGS) $(EXTRA_CFLAGS) $< -o $@ $(LDFLAGS) -T $(ARM_SRC)/$@.ld
+ARM_TESTS+=test-armv6m-undef
 
-# Specific Test Rules
+# These objects provide the basic boot code and helper functions for all tests
+CRT_OBJS=boot.o
 
-test-armv6m-undef: EXTRA_CFLAGS+=-mcpu=cortex-m0 -mfloat-abi=soft -Wl,--build-id=none -x assembler-with-cpp
+ARM_TEST_SRCS=$(wildcard $(ARM_SRC)/*.c)
+ARM_TESTS+=$(patsubst $(ARM_SRC)/%.c, %, $(ARM_TEST_SRCS))
 
-run-test-armv6m-undef: QEMU_OPTS+=-semihosting -M microbit -kernel
+CRT_PATH=$(ARM_SRC)
+LINK_SCRIPT=$(ARM_SRC)/kernel.ld
+LDFLAGS=-Wl,-T$(LINK_SCRIPT)
+CFLAGS+=-nostdlib -ggdb -O0 $(MINILIB_INC)
+LDFLAGS+=-static -nostdlib -N $(CRT_OBJS) $(MINILIB_OBJS) -lgcc
+
+# building head blobs
+.PRECIOUS: $(CRT_OBJS)
+
+%.o: $(ARM_SRC)/%.S
+	$(CC) $(CFLAGS) $(EXTRA_CFLAGS) -x assembler-with-cpp -c $< -o $@
+
+# Build and link the tests
+%: %.c $(LINK_SCRIPT) $(CRT_OBJS) $(MINILIB_OBJS)
+	$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $< -o $@ $(LDFLAGS)
+
+memory: CFLAGS+=-DCHECK_UNALIGNED=0
+
+# Running
+QEMU_BASE_MACHINE=-M virt -cpu max -display none
+QEMU_OPTS+=$(QEMU_BASE_MACHINE) -semihosting-config enable=on,target=native,chardev=output -kernel
+
+# Simple Record/Replay Test
+.PHONY: memory-record
+run-memory-record: memory-record memory
+	$(call run-test, $<, \
+	  $(QEMU) -monitor none -display none \
+		  -chardev file$(COMMA)path=$<.out$(COMMA)id=output \
+		  -icount shift=5$(COMMA)rr=record$(COMMA)rrfile=record.bin \
+		  $(QEMU_OPTS) memory)
+
+.PHONY: memory-replay
+run-memory-replay: memory-replay run-memory-record
+	$(call run-test, $<, \
+	  $(QEMU) -monitor none -display none \
+		  -chardev file$(COMMA)path=$<.out$(COMMA)id=output \
+		  -icount shift=5$(COMMA)rr=replay$(COMMA)rrfile=record.bin \
+		  $(QEMU_OPTS) memory)
+
+EXTRA_RUNS+=run-memory-replay
 
-# We don't currently support the multiarch system tests
-undefine MULTIARCH_TESTS
+TESTS += $(ARM_TESTS) $(MULTIARCH_TESTS)
+EXTRA_RUNS+=$(MULTIARCH_RUNS)
diff --git a/tests/tcg/arm/system/boot.S b/tests/tcg/arm/system/boot.S
new file mode 100644
index 0000000000..7915502ae4
--- /dev/null
+++ b/tests/tcg/arm/system/boot.S
@@ -0,0 +1,301 @@
+/*
+ * Minimal ArmV7 system boot code.
+ *
+ * Using semihosting for serial output and exit functions.
+ */
+
+/*
+ * Semihosting interface on ARM AArch32
+ * R0 - semihosting call number
+ * R1 - semihosting parameter
+ */
+#define semihosting_call svc 0x123456
+#define SYS_WRITEC	0x03	/* character to debug channel */
+#define SYS_WRITE0	0x04	/* string to debug channel */
+#define SYS_EXIT	0x18
+
+#define ADP_Stopped_ApplicationExit	0x20026
+#define ADP_Stopped_InternalError	0x20024
+
+/*
+ * Helper macro for the linker calling subroutines from the C code.
+ */
+.macro 	endf 	name
+	.global	\name
+	.type	\name, %function
+	.size	\name, . - \name
+.endm
+
+	.section	.interrupt_vector, "ax"
+	.align	5
+
+vector_table:
+	b   reset		/* reset vector */
+	b   undef_instr        /* undefined instruction vector */
+	b   software_intr    	/* software interrupt vector */
+	b   prefetch_abort		/* prefetch abort vector */
+	b   data_abort	        /* data abort vector */
+	nop			            /* reserved */
+	b   IRQ_handler        	/* IRQ vector */
+	b   FIQ_handler        	/* FIQ vector */
+
+	.text
+__start:
+	ldr  	r0, =vector_table
+	mcr  	p15, 0, r0, c12, c0, 0  /* Set up VBAR */
+
+	ldr	sp, =stack_end		/* Set up the stack */
+	bl	mmu_setup		/* Set up the MMU */
+	bl	main			/* Jump to main */
+
+endf	__start
+
+_exit:
+	cmp r0, #0
+	ite EQ  // if-then-else. "EQ" is for if equal, else otherwise
+	ldreq r1, =ADP_Stopped_ApplicationExit // if r0 == 0
+	ldrne r1, =ADP_Stopped_InternalError   // else
+	mov r0, #SYS_EXIT
+	semihosting_call
+
+endf	_exit
+
+	/*
+ * Helper Functions
+ */
+
+mmu_setup:
+	/*
+  	 * The MMU setup for this is very simple using two stage one
+	 * translations. The first 1Mb section points to the text
+	 * section and the second points to the data and rss.
+         * Currently the fattest test only needs ~50k for that so we
+ 	 * have plenty of space.
+	 *
+	 * The short descriptor Section format is as follows:
+	 *
+	 *  PA[31:20] - Section Base Address
+	 *  NS[19] - Non-secure bit
+	 *  0[18] - Section (1 for Super Section)
+	 *  nG[17] - Not global bit
+	 *  S[16] - Shareable
+	 *  TEX[14:12] - Memory Region Attributes
+	 *  AP[15, 11:10] - Access Permission Bits
+	 *  IMPDEF[9]
+	 *  Domain[8:5]
+	 *  XN[4] - Execute never bit
+	 *  C[3] - Memory Region Attributes
+	 *  B[2] - Memory Region Attributes
+	 *  1[1]
+	 *  PXN[0] - Privileged Execute Never
+	 *
+	 * r0 - point at the table
+	 * r1 - address
+	 * r2 - entry
+	 * r3 - common section bits
+	 * r4 - scratch
+	 */
+
+	/*
+	 * Memory Region Bits
+	 *
+	 *   TEX[14:12] = 000
+	 *     C[3]     = 1
+	 *     B[2]     = 1
+	 *
+	 * Outer and Inner WB, no write allocate
+	 */
+	mov r3, #0
+	ldr r4, =(3 << 2)
+	orr r3, r4, r4
+
+	/* Section bit */
+	orr r3, r3, #2
+
+	/* Page table setup (identity mapping). */
+	ldr r0, =ttb
+
+	/* First block: .text/RO/execute enabled */
+	ldr r1, =.text
+	ldr r2, =0xFFF00000  			/* 1MB block alignment */
+	and r2, r1, r2
+	orr r2, r2, r3				/* common bits */
+	orr r2, r2, #(1 << 15)			/* AP[2] = 1 */
+	orr r2, r2, #(1 << 10)			/* AP[0] = 1 => RO @ PL1 */
+
+	lsr r4, r2, #(20 - 2)
+	str r2, [r0, r4, lsl #0]		/* write entry */
+
+	/* Second block: .data/RW/no execute */
+	ldr r1, =.data
+	ldr r2, =0xFFF00000  			/* 1MB block alignment */
+	and r2, r1, r2
+	orr r2, r2, r3				/* common bits */
+	orr r2, r2, #(1 << 10)			/* AP[0] = 1 => RW @ PL1 */
+	orr r2, r2, #(1 << 4)			/* XN[4] => no execute */
+
+	lsr r4, r2, #(20 - 2)
+	str r2, [r0, r4, lsl #0]		/* write entry */
+
+	/*
+	 * DACR - Domain Control
+	 *
+	 * Enable client mode for domain 0 (we don't use any others)
+	 */
+	ldr r0, =0x1
+	mcr p15, 0, r0, c3, c0, 0
+
+	/*
+	 * TTCBR - Translation Table Base Control Register
+	 *
+	 * EAE[31] = 0, 32-bit translation, short descriptor format
+	 * N[2:0] = 5 ( TTBRO uses 31:14-5 => 9 bit lookup stage )
+	 */
+	ldr r0, =0x5
+	mcr p15, 0, r0, c1, c0, 2
+
+	/*
+	 * TTBR0 -Translation Table Base Register 0
+	 *
+	 * [31:9] = Base address of table
+	 *
+	 * QEMU doesn't really care about the cache sharing
+	 * attributes so we don't need to either.
+	 */
+	ldr r0, =ttb
+	mcr p15, 0, r0, c2, c0, 0
+
+	/*
+	 * SCTLR- System Control Register
+	 *
+   	 * TE[30] = 0, exceptions to A32 state
+	 * AFE[29] = 0, AP[0] is the access permissions bit
+	 * EE[25] = 0, Little-endian
+	 * WXN[19] = 0 = no effect, Write does not imply XN (execute never)
+	 * I[12] = Instruction cachability control
+	 * C[2] = Data cachability control
+	 * M[0] = 1, enable stage 1 address translation for EL0/1
+         *
+	 * At this point virtual memory is enabled.
+	 */
+	ldr r0, =0x1005
+	mcr p15, 0, r0, c1, c0, 0
+
+	isb
+
+	mov  pc, lr  /* done, return to caller */
+
+/* Output a single character to serial port */
+__sys_outc:
+	STMFD sp!, {r0-r1}  // push r0, r1 onto stack
+	mov r1, sp
+	mov r0, #SYS_WRITEC
+	semihosting_call
+	LDMFD sp!, {r0-r1}  // pop r0, r1 from stack
+	bx lr
+
+endf __sys_outc
+
+reset:
+	ldr	r1, =reset_error
+	b exception_handler
+
+undef_instr:
+	ldr	r1, =undef_intr_error
+	b exception_handler
+
+software_intr:
+	ldr	r1, =software_intr_error
+	b exception_handler
+
+prefetch_abort:
+	ldr	r1, =prefetch_abort_error
+	b exception_handler
+
+data_abort:
+	ldr	r1, =data_abort_error
+	b exception_handler
+
+IRQ_handler:
+	ldr	r1, =irq_error
+	b exception_handler
+
+FIQ_handler:
+	ldr	r1, =fiq_error
+	b exception_handler
+
+/*
+ * Initiate a exit semihosting call whenever there is any exception
+ * r1 already holds the string.
+ */
+exception_handler:
+	mov	r0, #SYS_WRITE0
+	semihosting_call
+	mov	r0, #SYS_EXIT
+	mov	r1, #1
+	semihosting_call
+
+endf	exception_handler
+
+/*
+ * We implement a stub raise() function which errors out as tests
+ * shouldn't trigger maths errors.
+ */
+	.global raise
+raise:
+	mov	r0, #SYS_WRITE0
+	ldr	r1, =maths_error
+	semihosting_call
+	mov	r0, #SYS_EXIT
+	ldr	r1, =ADP_Stopped_InternalError
+	semihosting_call
+
+endf raise
+
+	.data
+
+.data
+
+reset_error:
+	.ascii "Reset exception occurred.\n\0"
+
+undef_intr_error:
+	.ascii "Undefined Instruction Exception Occurred.\n\0"
+
+software_intr_error:
+	.ascii "Software Interrupt Occurred.\n\0"
+
+prefetch_abort_error:
+	.ascii "Prefetch Abort Occurred.\n\0"
+
+data_abort_error:
+	.ascii "Data Abort Occurred.\n\0"
+
+irq_error:
+	.ascii "IRQ exception occurred.\n\0"
+
+fiq_error:
+	.ascii "FIQ exception occurred.\n\0"
+
+maths_error:
+	.ascii "Software maths exception.\n\0"
+
+
+	/*
+	 * 1st Stage Translation table
+	 * 4096 entries, indexed by [31:20]
+	 * each entry covers 1Mb of address space
+	 * aligned on 16kb
+	 */
+	.align	15
+ttb:
+	.space	(4096 * 4), 0
+
+	.align	12
+
+	/* Space for stack */
+	.align	5
+	.section .bss
+stack:
+	.space 65536, 0
+stack_end:
diff --git a/tests/tcg/arm/system/kernel.ld b/tests/tcg/arm/system/kernel.ld
new file mode 100644
index 0000000000..7b3a76dcbf
--- /dev/null
+++ b/tests/tcg/arm/system/kernel.ld
@@ -0,0 +1,24 @@
+ENTRY(__start)
+
+SECTIONS
+{
+    /* virt machine, RAM starts at 1gb */
+    . = (1 << 30);
+    .text : {
+        *(.text)
+    }
+    .rodata : {
+        *(.rodata)
+    }
+    /* align r/w section to next 2mb */
+    . = ALIGN(1 << 21);
+    .data : {
+        *(.data)
+    }
+    .bss : {
+        *(.bss)
+    }
+    /DISCARD/ : {
+        *(.ARM.attributes)
+    }
+}
-- 
2.39.2
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On Mon, 20 Nov 2023 at 15:08, Alex Bennée <alex.bennee@linaro.org> wrote:
>
> To make it easier to test 32 bit Arm softmmu issues implement a basic
> boot.S so we can build the multiarch tests. Currently CHECK_UNALIGNED
> is disabled as I haven't got the right magic set for it to work.
>
> Message-Id: <20231115205542.3092038-10-alex.bennee@linaro.org>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>


> +# Running
> +QEMU_BASE_MACHINE=-M virt -cpu max -display none
> +QEMU_OPTS+=$(QEMU_BASE_MACHINE) -semihosting-config enable=on,target=native,chardev=output -kernel
> +

A minor thing, but I just ran into an awkwardness in the
equivalent set of variables in the aarch64 subdirectory:
if you ever want to define a different machine type then
there's no convenient way to say "give me the standard
options but a different machine", because the QEMU_OPTS
has the base machine in it and there's no variable with
just the semihosting etc options in it. For aarch64 I opted for:

+QEMU_BASE_ARGS=-semihosting-config enable=on,target=native,chardev=output
+QEMU_OPTS+=$(QEMU_BASE_MACHINE) $(QEMU_BASE_ARGS) -kernel

because then you can have a particular test do something like
+QEMU_EL2_MACHINE=-machine virt,virtualization=on,gic-version=2 -cpu
cortex-a57 -smp 4
+run-vtimer: QEMU_OPTS=$(QEMU_EL2_MACHINE) $(QEMU_BASE_ARGS) -kernel

You could argue about whether '-display none' should be in
QEMU_BASE_ARGS. I figure -kernel should not be because it
has the weird "must go last" property.

(These tweaks to the aarch64 makefile coming soon in a different
patch...)

thanks
-- PMM
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On 11/20/23 07:08, Alex Bennée wrote:
> +/*
> + * Helper macro for the linker calling subroutines from the C code.
> + */

That's not all it's for.  Better "annotating functions with elf type and size".

> +vector_table:
> +	b   reset		/* reset vector */
> +	b   undef_instr        /* undefined instruction vector */
> +	b   software_intr    	/* software interrupt vector */
> +	b   prefetch_abort		/* prefetch abort vector */
> +	b   data_abort	        /* data abort vector */
> +	nop			            /* reserved */
> +	b   IRQ_handler        	/* IRQ vector */
> +	b   FIQ_handler        	/* FIQ vector */

Missing endf, for the purpose of qemu load_symbols().

> +mmu_setup:
> +reset:
> +undef_instr:
> +software_intr:
> +prefetch_abort:
> +data_abort:
> +IRQ_handler:
> +FIQ_handler:

Also missing.

With those fixed,

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~