| Message ID | 20250521164250.135776-4-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Maintainer updates for May (testing, plugins, virtio-gpu) - pre-PR | expand |
On 2025/05/22 1:42, Alex Bennée wrote: > Currently the boot.S code assumes everything starts at EL1. This will > break things like the memory test which will barf on unaligned memory > access when run at a higher level. > > Adapt the boot code to do some basic verification of the starting mode > and the minimal configuration to move to the lower exception levels. > With this we can run the memory test with: > > -M virt,secure=on > -M virt,secure=on,virtualization=on > -M virt,virtualisation=on > > If a test needs to be at a particular EL it can use the semihosting > command line to indicate the level we should execute in. > > Cc: Julian Armistead <julian.armistead@linaro.org> > Cc: Jim MacArthur <jim.macarthur@linaro.org> > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > > --- > v3 > - create system stack so we _exit cleanly > - normalise EL string before compares > - catch when we start in a lower EL than we asked for > - default to EL1 when arg unclear > v2 > - allow tests to control the final EL we end up at > - use tabs consistently > - validate command line arg is between 1 and 3 > --- > tests/tcg/aarch64/Makefile.softmmu-target | 3 +- > tests/tcg/aarch64/system/boot.S | 171 +++++++++++++++++++++- > 2 files changed, 168 insertions(+), 6 deletions(-) > > diff --git a/tests/tcg/aarch64/Makefile.softmmu-target b/tests/tcg/aarch64/Makefile.softmmu-target > index 9c52475b7a..f7a7d2b800 100644 > --- a/tests/tcg/aarch64/Makefile.softmmu-target > +++ b/tests/tcg/aarch64/Makefile.softmmu-target > @@ -68,7 +68,8 @@ run-plugin-semiconsole-with-%: semiconsole > > # vtimer test needs EL2 > QEMU_EL2_MACHINE=-machine virt,virtualization=on,gic-version=2 -cpu cortex-a57 -smp 4 > -run-vtimer: QEMU_OPTS=$(QEMU_EL2_MACHINE) $(QEMU_BASE_ARGS) -kernel > +QEMU_EL2_BASE_ARGS=-semihosting-config enable=on,target=native,chardev=output,arg="2" > +run-vtimer: QEMU_OPTS=$(QEMU_EL2_MACHINE) $(QEMU_EL2_BASE_ARGS) -kernel > > # Simple Record/Replay Test > .PHONY: memory-record > diff --git a/tests/tcg/aarch64/system/boot.S b/tests/tcg/aarch64/system/boot.S > index a5df9c173d..78380a6f75 100644 > --- a/tests/tcg/aarch64/system/boot.S > +++ b/tests/tcg/aarch64/system/boot.S > @@ -16,6 +16,7 @@ > #define semihosting_call hlt 0xf000 > #define SYS_WRITEC 0x03 /* character to debug channel */ > #define SYS_WRITE0 0x04 /* string to debug channel */ > +#define SYS_GET_CMDLINE 0x15 /* get command line */ > #define SYS_EXIT 0x18 > > .align 12 > @@ -70,21 +71,171 @@ lower_a32_sync: > lower_a32_irq: > lower_a32_fiq: > lower_a32_serror: > + adr x1, .unexp_excp > +exit_msg: > mov x0, SYS_WRITE0 > - adr x1, .error > semihosting_call > mov x0, 1 /* EXIT_FAILURE */ > bl _exit > /* never returns */ > > .section .rodata > -.error: > - .string "Terminated by exception.\n" > +.unexp_excp: > + .string "Unexpected exception.\n" > +.high_el_msg: > + .string "Started in lower EL than requested.\n" > + > + .align 8 .get_cmd may be put before strings to avoid unnecessary padding for alignment. > +.get_cmd: I pointed out a style problem with this label in the last review: > This label is prefixed with a dot, which is inconsistent with the other > labels except ".error". > > I guess ".error" is prefixed with a dot to make it local, but a local > symbol needs to be prefixed with ".L" instead according to: > https://sourceware.org/binutils/docs-2.41/as/Symbol-Names.html#Local- > Symbol-Names > > > A local symbol is any symbol beginning with certain local label > > prefixes. By default, the local label prefix is ‘.L’ for ELF systems > > or ‘L’ for traditional a.out systems, but each target may have its own > > set of local label prefixes. On the HPPA local symbols begin with > > ‘L$’. > + .quad cmdline > + .quad 128 > > .text > .align 4 > .global __start > __start: > + /* > + * Initialise the stack for whatever EL we are in before > + * anything else, we need it to be able to _exit cleanly. > + * It's smaller than the stack we pass to the C code but we > + * don't need much. > + */ > + adrp x0, system_stack_end > + add x0, x0, :lo12:system_stack_end > + mov sp, x0 > + > + /* > + * The test can set the semihosting command line to the target > + * EL needed for the test. However if no semihosting args are set we will > + * end up with -kernel/-append data (see semihosting_arg_fallback). > + * Keep the normalised target in w11. > + */ > + mov x0, SYS_GET_CMDLINE > + adr x1, .get_cmd > + semihosting_call > + adrp x10, cmdline > + add x10, x10, :lo12:cmdline > + ldrb w11, [x10] > + > + /* sanity check, normalise char to EL, clamp to 1 if outside range */ > + subs w11, w11, #'0' > + b.lt el_default > + cmp w11, #3 > + b.gt el_default > + b 1f > + > +el_high: > + adr x1, .high_el_msg > + b exit_msg > + > +el_default: > + mov w11, #1 > + > +1: > + /* Determine current Exception Level */ > + mrs x0, CurrentEL > + lsr x0, x0, #2 /* CurrentEL[3:2] contains the current EL */ > + > + /* Are we already in a lower EL than we want? */ > + cmp w11, w0 > + bgt el_high Shorter: /* sanity check, normalise char to EL, clamp to 1 if outside range */ subs w11, w11, #'0' mov w0, #1 cmp w11, #3 csel w11, w11, w0, GT /* Determine current Exception Level */ mrs x0, CurrentEL lsr x0, x0, #2 cmp w11, w0 ble el_correct adr x1, high_el_msg b exit_msg el_correct: > + > + /* Branch based on current EL */ > + cmp x0, #3 > + b.eq setup_el3 > + cmp x0, #2 > + b.eq setup_el2 > + cmp x0, #1 > + b.eq at_testel /* Already at EL1, skip transition */ > + /* Should not be at EL0 - error out */ > + b curr_sp0_sync This still says "Unexpected exception." > + > +setup_el3: > + /* Ensure we trap if we get anything wrong */ > + adr x0, vector_table > + msr vbar_el3, x0 > + > + /* Does the test want to be at EL3? */ > + cmp w11, #3 > + beq at_testel > + > + /* Configure EL3 to for lower states (EL2 or EL1) */ > + mrs x0, scr_el3 > + orr x0, x0, #(1 << 10) /* RW = 1: EL2/EL1 execution state is AArch64 */ > + orr x0, x0, #(1 << 0) /* NS = 1: Non-secure state */ > + msr scr_el3, x0 > + > + /* > + * We need to check if EL2 is actually enabled via ID_AA64PFR0_EL1, > + * otherwise we should just jump straight to EL1. > + */ > + mrs x0, id_aa64pfr0_el1 > + ubfx x0, x0, #8, #4 /* Extract EL2 field (bits 11:8) */ > + cbz x0, el2_not_present /* If field is 0 no EL2 */ > + > + > + /* Prepare SPSR for exception return to EL2 */ > + mov x0, #0x3c9 /* DAIF bits and EL2h mode (9) */ > + msr spsr_el3, x0 > + > + /* Set EL2 entry point */ > + adr x0, setup_el2 > + msr elr_el3, x0 > + > + /* Return to EL2 */ > + eret > + nop NOP is still present here. > + > +el2_not_present: > + /* Initialize SCTLR_EL1 with reset value */ > + msr sctlr_el1, xzr > + > + /* Set EL1 entry point */ > + adr x0, at_testel > + msr elr_el3, x0 > + > + /* Prepare SPSR for exception return to EL1h with interrupts masked */ > + mov x0, #0x3c5 /* DAIF bits and EL1h mode (5) */ > + msr spsr_el3, x0 > + > + isb /* Synchronization barrier */ > + eret /* Jump to EL1 */ > + > +setup_el2: > + /* Ensure we trap if we get anything wrong */ > + adr x0, vector_table > + msr vbar_el2, x0 > + > + /* Does the test want to be at EL2? */ > + cmp w11, #2 > + beq at_testel > + > + /* Configure EL2 to allow transition to EL1 */ > + mrs x0, hcr_el2 > + orr x0, x0, #(1 << 31) /* RW = 1: EL1 execution state is AArch64 */ > + msr hcr_el2, x0 > + > + /* Initialize SCTLR_EL1 with reset value */ > + msr sctlr_el1, xzr > + > + /* Set EL1 entry point */ > + adr x0, at_testel > + msr elr_el2, x0 > + > + /* Prepare SPSR for exception return to EL1 */ > + mov x0, #(0x5 << 0) /* EL1h (SPx), with interrupts disabled */ > + msr spsr_el2, x0 > + > + /* Return to EL1 */ > + eret > + > + nop > + > + /* > + * At the target EL for the test, usually EL1. Note we still > + * set everything up as if we were at EL1. > + */ > +at_testel: > /* Installs a table of exception vectors to catch and handle all > exceptions by terminating the process with a diagnostic. */ > adr x0, vector_table > @@ -100,7 +251,7 @@ __start: > * maps RAM to the first Gb. The stage2 tables have two 2mb > * translation block entries covering a series of adjacent > * 4k pages. > - */ > + */ > > /* Stage 1 entry: indexed by IA[38:30] */ > adr x1, . /* phys address */ > @@ -198,7 +349,8 @@ __start: > orr x0, x0, #(3 << 16) > msr cpacr_el1, x0 > > - /* Setup some stack space and enter the test code. > + /* > + * Setup some stack space before we enter the test code. > * Assume everything except the return value is garbage when we > * return, we won't need it. > */ > @@ -233,6 +385,11 @@ __sys_outc: > ret > > .data > + > + .align 8 > +cmdline: > + .space 128, 0 > + > .align 12 > > /* Translation table > @@ -246,6 +403,10 @@ ttb_stage2: > .space 4096, 0 > > .align 12 > +system_stack: > + .space 4096, 0 > +system_stack_end: > + > stack: > .space 65536, 0 > stack_end:
diff --git a/tests/tcg/aarch64/Makefile.softmmu-target b/tests/tcg/aarch64/Makefile.softmmu-target index 9c52475b7a..f7a7d2b800 100644 --- a/tests/tcg/aarch64/Makefile.softmmu-target +++ b/tests/tcg/aarch64/Makefile.softmmu-target @@ -68,7 +68,8 @@ run-plugin-semiconsole-with-%: semiconsole # vtimer test needs EL2 QEMU_EL2_MACHINE=-machine virt,virtualization=on,gic-version=2 -cpu cortex-a57 -smp 4 -run-vtimer: QEMU_OPTS=$(QEMU_EL2_MACHINE) $(QEMU_BASE_ARGS) -kernel +QEMU_EL2_BASE_ARGS=-semihosting-config enable=on,target=native,chardev=output,arg="2" +run-vtimer: QEMU_OPTS=$(QEMU_EL2_MACHINE) $(QEMU_EL2_BASE_ARGS) -kernel # Simple Record/Replay Test .PHONY: memory-record diff --git a/tests/tcg/aarch64/system/boot.S b/tests/tcg/aarch64/system/boot.S index a5df9c173d..78380a6f75 100644 --- a/tests/tcg/aarch64/system/boot.S +++ b/tests/tcg/aarch64/system/boot.S @@ -16,6 +16,7 @@ #define semihosting_call hlt 0xf000 #define SYS_WRITEC 0x03 /* character to debug channel */ #define SYS_WRITE0 0x04 /* string to debug channel */ +#define SYS_GET_CMDLINE 0x15 /* get command line */ #define SYS_EXIT 0x18 .align 12 @@ -70,21 +71,171 @@ lower_a32_sync: lower_a32_irq: lower_a32_fiq: lower_a32_serror: + adr x1, .unexp_excp +exit_msg: mov x0, SYS_WRITE0 - adr x1, .error semihosting_call mov x0, 1 /* EXIT_FAILURE */ bl _exit /* never returns */ .section .rodata -.error: - .string "Terminated by exception.\n" +.unexp_excp: + .string "Unexpected exception.\n" +.high_el_msg: + .string "Started in lower EL than requested.\n" + + .align 8 +.get_cmd: + .quad cmdline + .quad 128 .text .align 4 .global __start __start: + /* + * Initialise the stack for whatever EL we are in before + * anything else, we need it to be able to _exit cleanly. + * It's smaller than the stack we pass to the C code but we + * don't need much. + */ + adrp x0, system_stack_end + add x0, x0, :lo12:system_stack_end + mov sp, x0 + + /* + * The test can set the semihosting command line to the target + * EL needed for the test. However if no semihosting args are set we will + * end up with -kernel/-append data (see semihosting_arg_fallback). + * Keep the normalised target in w11. + */ + mov x0, SYS_GET_CMDLINE + adr x1, .get_cmd + semihosting_call + adrp x10, cmdline + add x10, x10, :lo12:cmdline + ldrb w11, [x10] + + /* sanity check, normalise char to EL, clamp to 1 if outside range */ + subs w11, w11, #'0' + b.lt el_default + cmp w11, #3 + b.gt el_default + b 1f + +el_high: + adr x1, .high_el_msg + b exit_msg + +el_default: + mov w11, #1 + +1: + /* Determine current Exception Level */ + mrs x0, CurrentEL + lsr x0, x0, #2 /* CurrentEL[3:2] contains the current EL */ + + /* Are we already in a lower EL than we want? */ + cmp w11, w0 + bgt el_high + + /* Branch based on current EL */ + cmp x0, #3 + b.eq setup_el3 + cmp x0, #2 + b.eq setup_el2 + cmp x0, #1 + b.eq at_testel /* Already at EL1, skip transition */ + /* Should not be at EL0 - error out */ + b curr_sp0_sync + +setup_el3: + /* Ensure we trap if we get anything wrong */ + adr x0, vector_table + msr vbar_el3, x0 + + /* Does the test want to be at EL3? */ + cmp w11, #3 + beq at_testel + + /* Configure EL3 to for lower states (EL2 or EL1) */ + mrs x0, scr_el3 + orr x0, x0, #(1 << 10) /* RW = 1: EL2/EL1 execution state is AArch64 */ + orr x0, x0, #(1 << 0) /* NS = 1: Non-secure state */ + msr scr_el3, x0 + + /* + * We need to check if EL2 is actually enabled via ID_AA64PFR0_EL1, + * otherwise we should just jump straight to EL1. + */ + mrs x0, id_aa64pfr0_el1 + ubfx x0, x0, #8, #4 /* Extract EL2 field (bits 11:8) */ + cbz x0, el2_not_present /* If field is 0 no EL2 */ + + + /* Prepare SPSR for exception return to EL2 */ + mov x0, #0x3c9 /* DAIF bits and EL2h mode (9) */ + msr spsr_el3, x0 + + /* Set EL2 entry point */ + adr x0, setup_el2 + msr elr_el3, x0 + + /* Return to EL2 */ + eret + nop + +el2_not_present: + /* Initialize SCTLR_EL1 with reset value */ + msr sctlr_el1, xzr + + /* Set EL1 entry point */ + adr x0, at_testel + msr elr_el3, x0 + + /* Prepare SPSR for exception return to EL1h with interrupts masked */ + mov x0, #0x3c5 /* DAIF bits and EL1h mode (5) */ + msr spsr_el3, x0 + + isb /* Synchronization barrier */ + eret /* Jump to EL1 */ + +setup_el2: + /* Ensure we trap if we get anything wrong */ + adr x0, vector_table + msr vbar_el2, x0 + + /* Does the test want to be at EL2? */ + cmp w11, #2 + beq at_testel + + /* Configure EL2 to allow transition to EL1 */ + mrs x0, hcr_el2 + orr x0, x0, #(1 << 31) /* RW = 1: EL1 execution state is AArch64 */ + msr hcr_el2, x0 + + /* Initialize SCTLR_EL1 with reset value */ + msr sctlr_el1, xzr + + /* Set EL1 entry point */ + adr x0, at_testel + msr elr_el2, x0 + + /* Prepare SPSR for exception return to EL1 */ + mov x0, #(0x5 << 0) /* EL1h (SPx), with interrupts disabled */ + msr spsr_el2, x0 + + /* Return to EL1 */ + eret + + nop + + /* + * At the target EL for the test, usually EL1. Note we still + * set everything up as if we were at EL1. + */ +at_testel: /* Installs a table of exception vectors to catch and handle all exceptions by terminating the process with a diagnostic. */ adr x0, vector_table @@ -100,7 +251,7 @@ __start: * maps RAM to the first Gb. The stage2 tables have two 2mb * translation block entries covering a series of adjacent * 4k pages. - */ + */ /* Stage 1 entry: indexed by IA[38:30] */ adr x1, . /* phys address */ @@ -198,7 +349,8 @@ __start: orr x0, x0, #(3 << 16) msr cpacr_el1, x0 - /* Setup some stack space and enter the test code. + /* + * Setup some stack space before we enter the test code. * Assume everything except the return value is garbage when we * return, we won't need it. */ @@ -233,6 +385,11 @@ __sys_outc: ret .data + + .align 8 +cmdline: + .space 128, 0 + .align 12 /* Translation table @@ -246,6 +403,10 @@ ttb_stage2: .space 4096, 0 .align 12 +system_stack: + .space 4096, 0 +system_stack_end: + stack: .space 65536, 0 stack_end:
Currently the boot.S code assumes everything starts at EL1. This will break things like the memory test which will barf on unaligned memory access when run at a higher level. Adapt the boot code to do some basic verification of the starting mode and the minimal configuration to move to the lower exception levels. With this we can run the memory test with: -M virt,secure=on -M virt,secure=on,virtualization=on -M virt,virtualisation=on If a test needs to be at a particular EL it can use the semihosting command line to indicate the level we should execute in. Cc: Julian Armistead <julian.armistead@linaro.org> Cc: Jim MacArthur <jim.macarthur@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- v3 - create system stack so we _exit cleanly - normalise EL string before compares - catch when we start in a lower EL than we asked for - default to EL1 when arg unclear v2 - allow tests to control the final EL we end up at - use tabs consistently - validate command line arg is between 1 and 3 --- tests/tcg/aarch64/Makefile.softmmu-target | 3 +- tests/tcg/aarch64/system/boot.S | 171 +++++++++++++++++++++- 2 files changed, 168 insertions(+), 6 deletions(-)