| Message ID | 20190430165234.32272-4-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | demacro softmmu (plus tests/coverage) | expand |
On 4/30/19 9:52 AM, Alex Bennée wrote: > +.error: > + .string "Terminated by exception.\n" Put it in .rodata just because we can? > + /* Page table setup (identity mapping). */ > + adrp x0, ttb > + add x0, x0, :lo12:ttb You are in control of the layout of the executable, and adr has a 1MB range. Why use adrp+add? > + /* Create some (big) pages */ > + adr x1, . /* phys address */ > + bic x1, x1, #(1 << 30) - 1 /* 1GB block alignment */ Do you really want 1GB pages? You'll pretty much only be able to test valid memory operations with that. Which is also true until there's something other than an exit for the exception vector... but ya know what I mean. > + /* Setup some stack space and enter the test code. > + * Assume everthing except the return value is garbage when we > + * return, we won't need it. > + */ > + adrp x0, stack > + add x0, x0, :lo12:stack > + mov sp, x0 You need a pointer to the end of the stack, not the beginning. Again, I think this could be just adr sp, stack_end Also, there's tab/space confusion all through this file. IMO, this is assembly, so it *should* be tabs. > @@ -0,0 +1,22 @@ > +ENTRY(__start) > + > +SECTIONS > +{ > + /* virt machine, RAM starts at 1gb */ > + . = (1 << 30); > + .text : { > + *(.text) > + } > + .data : { > + *(.data) > + } > + .rodata : { > + *(.rodata) > + } If you ever wanted to make this read-only, swap .rodata before .data, so that it's next to .text. r~
Richard Henderson <richard.henderson@linaro.org> writes: > On 4/30/19 9:52 AM, Alex Bennée wrote: >> +.error: >> + .string "Terminated by exception.\n" > > Put it in .rodata just because we can? Sure. > >> + /* Page table setup (identity mapping). */ >> + adrp x0, ttb >> + add x0, x0, :lo12:ttb > > You are in control of the layout of the executable, > and adr has a 1MB range. Why use adrp+add? Ok. > >> + /* Create some (big) pages */ >> + adr x1, . /* phys address */ >> + bic x1, x1, #(1 << 30) - 1 /* 1GB block alignment */ > > Do you really want 1GB pages? You'll pretty much only be able to test valid > memory operations with that. Which is also true until there's something other > than an exit for the exception vector... but ya know what I mean. Yeah we can do better here. I mainly went with what libgloss had setup because I was finding it hard to get find a nice summary of the various page table formats. I want big enough that I don't have to futz around create multiple page entries and ideally have some fault-able regions as well. > >> + /* Setup some stack space and enter the test code. >> + * Assume everthing except the return value is garbage when we >> + * return, we won't need it. >> + */ >> + adrp x0, stack >> + add x0, x0, :lo12:stack >> + mov sp, x0 > > You need a pointer to the end of the stack, not the beginning. > Again, I think this could be just > > adr sp, stack_end lol, I guess the page table was being crapped over.... > > Also, there's tab/space confusion all through this file. > IMO, this is assembly, so it *should* be tabs. That will probably be my editor getting confused because .S implies cpp > >> @@ -0,0 +1,22 @@ >> +ENTRY(__start) >> + >> +SECTIONS >> +{ >> + /* virt machine, RAM starts at 1gb */ >> + . = (1 << 30); >> + .text : { >> + *(.text) >> + } >> + .data : { >> + *(.data) >> + } >> + .rodata : { >> + *(.rodata) >> + } > > If you ever wanted to make this read-only, swap .rodata before .data, so that > it's next to .text. OK > > > r~ -- Alex Bennée
Richard Henderson <richard.henderson@linaro.org> writes: > On 4/30/19 9:52 AM, Alex Bennée wrote: >> +.error: >> + .string "Terminated by exception.\n" > > Put it in .rodata just because we can? > >> + /* Page table setup (identity mapping). */ >> + adrp x0, ttb >> + add x0, x0, :lo12:ttb > > You are in control of the layout of the executable, > and adr has a 1MB range. Why use adrp+add? Well I have to now as I've aligned .data with: /* align r/w section to next 2mb */ . = ALIGN(1 << 21); > >> + /* Create some (big) pages */ >> + adr x1, . /* phys address */ >> + bic x1, x1, #(1 << 30) - 1 /* 1GB block alignment */ > > Do you really want 1GB pages? You'll pretty much only be able to test valid > memory operations with that. Which is also true until there's something other > than an exit for the exception vector... but ya know what I mean. Not using it for testing but I'm trying to set-up a 2 stage translation so we get: 1gb->1gb+2mb = .text/.rodata 1gb+2mb->1gb+4mb = .data/.bss > >> + /* Setup some stack space and enter the test code. >> + * Assume everthing except the return value is garbage when we >> + * return, we won't need it. >> + */ >> + adrp x0, stack >> + add x0, x0, :lo12:stack >> + mov sp, x0 > > You need a pointer to the end of the stack, not the beginning. > Again, I think this could be just > > adr sp, stack_end > > Also, there's tab/space confusion all through this file. > IMO, this is assembly, so it *should* be tabs. I'm adding an entry to editorconfig and fixing up the damage. > >> @@ -0,0 +1,22 @@ >> +ENTRY(__start) >> + >> +SECTIONS >> +{ >> + /* virt machine, RAM starts at 1gb */ >> + . = (1 << 30); >> + .text : { >> + *(.text) >> + } >> + .data : { >> + *(.data) >> + } >> + .rodata : { >> + *(.rodata) >> + } > > If you ever wanted to make this read-only, swap .rodata before .data, so that > it's next to .text. done. > > > r~ -- Alex Bennée
diff --git a/tests/tcg/aarch64/Makefile.softmmu-target b/tests/tcg/aarch64/Makefile.softmmu-target new file mode 100644 index 0000000000..e6aee856c8 --- /dev/null +++ b/tests/tcg/aarch64/Makefile.softmmu-target @@ -0,0 +1,32 @@ +# +# Aarch64 system tests +# + +AARCH64_SYSTEM_SRC=$(SRC_PATH)/tests/tcg/aarch64/system +VPATH+=$(AARCH64_SYSTEM_SRC) + +# These objects provide the basic boot code and helper functions for all tests +CRT_OBJS=boot.o + +AARCH64_TEST_SRCS=$(wildcard $(AARCH64_SYSTEM_SRC)/*.c) +AARCH64_TESTS = $(patsubst $(AARCH64_SYSTEM_SRC)/%.c, %, $(AARCH64_TEST_SRCS)) + +CRT_PATH=$(AARCH64_SYSTEM_SRC) +LINK_SCRIPT=$(AARCH64_SYSTEM_SRC)/kernel.ld +LDFLAGS=-Wl,-T$(LINK_SCRIPT) +TESTS+=$(AARCH64_TESTS) $(MULTIARCH_TESTS) +CFLAGS+=-nostdlib -ggdb -O0 $(MINILIB_INC) +LDFLAGS+=-static -nostdlib $(CRT_OBJS) $(MINILIB_OBJS) -lgcc + +# building head blobs +.PRECIOUS: $(CRT_OBJS) + +%.o: $(CRT_PATH)/%.S + $(CC) $(CFLAGS) -x assembler-with-cpp -c $< -o $@ + +# Build and link the tests +%: %.c $(LINK_SCRIPT) $(CRT_OBJS) $(MINILIB_OBJS) + $(CC) $(CFLAGS) $< -o $@ $(LDFLAGS) + +# Running +QEMU_OPTS+=-M virt -cpu max -display none -semihosting -kernel diff --git a/tests/tcg/aarch64/system/boot.S b/tests/tcg/aarch64/system/boot.S new file mode 100644 index 0000000000..03d319e07f --- /dev/null +++ b/tests/tcg/aarch64/system/boot.S @@ -0,0 +1,200 @@ +/* + * Minimal AArch64 system boot code. + * + * Copyright Linaro Ltd 2019 + * + * Loosely based on the newlib/libgloss setup stubs. Using semihosting + * for serial output and exit functions. + */ + +/* + * Semihosting interface on ARM AArch64 + * See "Semihosting for AArch32 and AArch64 Relase 2.0" by ARM + * w0 - semihosting call number + * x1 - semihosting parameter + */ +#define semihosting_call hlt 0xf000 +#define SYS_WRITEC 0x03 /* character to debug channel */ +#define SYS_WRITE0 0x04 /* string to debug channel */ +#define SYS_EXIT 0x18 + + .align 12 + + .macro ventry label + .align 7 + b \label + .endm + +vector_table: + /* Current EL with SP0. */ + ventry curr_sp0_sync /* Synchronous */ + ventry curr_sp0_irq /* Irq/vIRQ */ + ventry curr_sp0_fiq /* Fiq/vFIQ */ + ventry curr_sp0_serror /* SError/VSError */ + + /* Current EL with SPx. */ + ventry curr_spx_sync /* Synchronous */ + ventry curr_spx_irq /* IRQ/vIRQ */ + ventry curr_spx_fiq /* FIQ/vFIQ */ + ventry curr_spx_serror /* SError/VSError */ + + /* Lower EL using AArch64. */ + ventry lower_a64_sync /* Synchronous */ + ventry lower_a64_irq /* IRQ/vIRQ */ + ventry lower_a64_fiq /* FIQ/vFIQ */ + ventry lower_a64_serror /* SError/VSError */ + + /* Lower EL using AArch32. */ + ventry lower_a32_sync /* Synchronous */ + ventry lower_a32_irq /* IRQ/vIRQ */ + ventry lower_a32_fiq /* FIQ/vFIQ */ + ventry lower_a32_serror /* SError/VSError */ + + .text + .align 4 + + /* Common vector handling for now */ +curr_sp0_sync: +curr_sp0_irq: +curr_sp0_fiq: +curr_sp0_serror: +curr_spx_sync: +curr_spx_irq: +curr_spx_fiq: +curr_spx_serror: +lower_a64_sync: +lower_a64_irq: +lower_a64_fiq: +lower_a64_serror: +lower_a32_sync: +lower_a32_irq: +lower_a32_fiq: +lower_a32_serror: + mov x0, SYS_WRITE0 + adr x1, .error + semihosting_call + mov x0, SYS_EXIT + mov x1, 1 + semihosting_call + /* never returns */ + +.error: + .string "Terminated by exception.\n" + + .align 4 + .global __start +__start: + /* Installs a table of exception vectors to catch and handle all + exceptions by terminating the process with a diagnostic. */ + adr x0, vector_table + msr vbar_el1, x0 + + /* Page table setup (identity mapping). */ + adrp x0, ttb + add x0, x0, :lo12:ttb + msr ttbr0_el1, x0 + + /* Create some (big) pages */ + adr x1, . /* phys address */ + bic x1, x1, #(1 << 30) - 1 /* 1GB block alignment */ + + add x2, x0, x1, lsr #(30 - 3) /* page offset in l1 page table */ + + mov x3, #0x401 /* page table attributes (AF, block) */ + orr x1, x1, x3 + + str x1, [x2], #8 /* 1st GB */ + + mov x3, #(1 << 30) /* 1GB block */ + add x1, x1, x3 + + str x1, [x2] /* 2nd GB */ + + /* Setup/enable the MMU. */ + + /* + * TCR_EL1 - Translation Control Registers + * + * IPS[34:32] = 40-bit PA, 1TB + * ORGN0[11:10] = Outer: Normal, Outer Write-Back Read-Allocate No Write-Allocate Cacheable + * IRGN0[9:8] = Inner: Normal, Inner Write-Back Read-Allocate No Write-Allocate Cacheable. + * T0SZ[5:0] = 2^(64 - 25) + */ + ldr x0, = (2 << 32) | 25 | (3 << 10) | (3 << 8) + msr tcr_el1, x0 + + mov x0, #0xee /* Inner/outer cacheable WB */ + msr mair_el1, x0 + isb + + /* + * SCTLR_EL1 - System Control Register + * + * WXN[19] = 0 = no effect, Write does not imply XN (execute never) + * I[12] = Instruction cachability control + * SA[3] = SP alignment check + * C[2] = Data cachability control + * M[0] = 1, enable stage 1 address translation for EL0/1 + */ + mrs x0, sctlr_el1 + ldr x1, =0x100d /* bits I(12) SA(3) C(2) M(0) */ + bic x0, x0, #(1 << 1) /* clear bit A(1) */ + bic x0, x0, #(1 << 19) /* clear WXN */ + orr x0, x0, x1 /* set bits */ + + dsb sy + msr sctlr_el1, x0 + isb + + /* + * Enable FP registers. The standard C pre-amble will be + * saving these and A-profile compilers will use AdvSIMD + * registers unless we tell it not to. + */ + mrs x0, cpacr_el1 + orr x0, x0, #(3 << 20) + msr cpacr_el1, x0 + + /* Setup some stack space and enter the test code. + * Assume everthing except the return value is garbage when we + * return, we won't need it. + */ + adrp x0, stack + add x0, x0, :lo12:stack + + mov sp, x0 + bl main + + /* pass return value to sys exit */ + mov x1, x0 + ldr x0, =0x20026 /* ADP_Stopped_ApplicationExit */ + stp x0, x1, [sp, #-16]! + mov x1, sp + mov x0, SYS_EXIT + semihosting_call + /* never returns */ + + /* + * Helper Functions + */ + + /* Output a single character to serial port */ + .global __sys_outc +__sys_outc: + stp x0, x1, [sp, #-16]! + /* pass address of c on stack */ + mov x1, sp + mov x0, SYS_WRITEC + semihosting_call + ldp x0, x1, [sp], #16 + ret + + .data + .align 12 +ttb: + .space 4096, 0 + + .align 12 +stack: + .space 65536, 0 +stack_end: diff --git a/tests/tcg/aarch64/system/kernel.ld b/tests/tcg/aarch64/system/kernel.ld new file mode 100644 index 0000000000..73d75cae64 --- /dev/null +++ b/tests/tcg/aarch64/system/kernel.ld @@ -0,0 +1,22 @@ +ENTRY(__start) + +SECTIONS +{ + /* virt machine, RAM starts at 1gb */ + . = (1 << 30); + .text : { + *(.text) + } + .data : { + *(.data) + } + .rodata : { + *(.rodata) + } + .bss : { + *(.bss) + } + /DISCARD/ : { + *(.ARM.attributes) + } +}
This provides the bootstrap and low level helper functions for an aarch64 kernel. We use semihosting to handle test output and exiting the emulation. semihosting's parameter passing is a little funky so we end up using the stack and pointing to that as the parameter block. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- tests/tcg/aarch64/Makefile.softmmu-target | 32 ++++ tests/tcg/aarch64/system/boot.S | 200 ++++++++++++++++++++++ tests/tcg/aarch64/system/kernel.ld | 22 +++ 3 files changed, 254 insertions(+) create mode 100644 tests/tcg/aarch64/Makefile.softmmu-target create mode 100644 tests/tcg/aarch64/system/boot.S create mode 100644 tests/tcg/aarch64/system/kernel.ld -- 2.20.1