On 1/29/19 12:23 PM, Andrew Jones wrote:
> On Tue, Jan 29, 2019 at 11:16:05AM +0000, Alexandru Elisei wrote:
>> On 1/28/19 4:31 PM, Andrew Jones wrote:
>>> On Mon, Jan 28, 2019 at 02:24:29PM +0000, Alexandru Elisei wrote:
>>>> On 1/25/19 4:47 PM, Andrew Jones wrote:
>>>>> On Fri, Jan 25, 2019 at 04:36:13PM +0000, Alexandru Elisei wrote:
>>>>>> On 1/24/19 12:37 PM, Andrew Jones wrote:
>>>>>>> On Thu, Jan 24, 2019 at 11:59:43AM +0000, Andre Przywara wrote:
>>>>>>>> On Thu, 24 Jan 2019 11:16:29 +0000
>>>>>>>> Alexandru Elisei <alexandru.elisei@xxxxxxx> wrote:
>>>>>>>>
>>>>>>>>> A warning is displayed if uart0_base is different from what the code
>>>>>>>>> expects qemu to generate for the pl011 UART in the device tree.
>>>>>>>>> However, now we support the ns16550a UART emulated by kvmtool, which
>>>>>>>>> has a different address. This leads to the warning being displayed
>>>>>>>>> even though the UART is configured and working as expected.
>>>>>>>>>
>>>>>>>>> Now that we support multiple UARTs, the warning serves no purpose, so
>>>>>>>>> remove it.
>>>>>>>> Mmh, but we use that address before, right? So for anything not
>>>>>>>> emulating an UART at this QEMU specific address we write to some random
>>>>>>>> (device) memory?
>>>>>>>>
>>>>>>>> Drew, how important is this early print feature for kvm-unit-tests?
>>>>>>> The setup code passes through quite a few asserts before getting through
>>>>>>> io_init() (including in uart0_init), so I think there's still value in
>>>>>>> having a guessed UART address. Maybe we can provide guesses for both
>>>>>>> QEMU and kvmtool, and some selection method, that would be used until
>>>>>>> we've properly assigned uart0_base from DT?
>>>>>>>
>>>>>>>> Cheers,
>>>>>>>> Andre.
>>>>>>>>
>>>>>>>>> Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
>>>>>>>>> ---
>>>>>>>>> lib/arm/io.c | 6 ------
>>>>>>>>> 1 file changed, 6 deletions(-)
>>>>>>>>>
>>>>>>>>> diff --git a/lib/arm/io.c b/lib/arm/io.c
>>>>>>>>> index 35fc05aeb4db..87435150f73e 100644
>>>>>>>>> --- a/lib/arm/io.c
>>>>>>>>> +++ b/lib/arm/io.c
>>>>>>>>> @@ -61,12 +61,6 @@ static void uart0_init(void)
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> uart0_base = ioremap(base.addr, base.size);
>>>>>>>>> -
>>>>>>>>> - if (uart0_base != (u8 *)UART_EARLY_BASE) {
>>>>>>>>> - printf("WARNING: early print support may not work. "
>>>>>>>>> - "Found uart at %p, but early base is %p.\n",
>>>>>>>>> - uart0_base, (u8 *)UART_EARLY_BASE);
>>>>>>>>> - }
>>>>>>>>> }
>>>>>>> This warning is doing what it should, which is pointing out that the
>>>>>>> UART_EARLY_BASE guess appears to be wrong. If we can provide a way
>>>>>>> to support more than one guess, then we should keep this warning but
>>>>>>> adjust it to match one of any of the guesses.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> drew
>>>>>> I'm not really sure how to implement a selection method. I've looked at
>>>>>> splitting io_init() into uart0_init() and chr_testdev_init() and calling
>>>>>> uart0_init() very early in the setup process, but uart0_init() itself uses
>>>>>> printf() and assert().
>>>>>>
>>>>>> I've also thought about adding another function, something like
>>>>>> uart0_early_init(), that is called very early in setup() and gets the base
>>>>>> address from the dtb bootargs. But that means calling dt_init() and
>>>>>> dt_get_bootargs(), which can fail.
>>>>>>
>>>>>> One other option that could work is to make it a compile-time configuration.
>>>>>>
>>>>>> What do you think?
>>>>>>
>>>>> Compile-time is fine, which I guess will result in a new configure script
>>>>> option as well. I wonder if we shouldn't consider generating a config.h
>>>>> file with stuff like this rather than adding another -D to the compile
>>>>> line.
>>>>>
>>>>> drew
>>>> I propose a new configuration option called --vmm, with possible values qemu and
>>>> kvmtool, which defaults to qemu if not set.
>>>>
>>>> Another possibility would be to have an --uart-base option, but that means we
>>>> are expecting the user to be aware of the uart base address for the virtual
>>>> machine manager, which might be unreasonable.
>>>>
>>>> This is a quick prototype of how using -D for conditional compilation would look
>>>> like (the configure changes are included too):
>>>>
>>>> diff --git a/configure b/configure
>>>> index df8581e3a906..7a56ba47707f 100755
>>>> --- a/configure
>>>> +++ b/configure
>>>> @@ -70,6 +70,9 @@ while [[ "$1" = -* ]]; do
>>>> ;;
>>>> --ld)
>>>> ld="$arg"
>>>> + ;;
>>>> + --vmm)
>>>> + vmm="$arg"
>>>> ;;
>>>> --enable-pretty-print-stacks)
>>>> pretty_print_stacks=yes
>>>> @@ -108,6 +111,14 @@ if [ "$arch" = "i386" ] || [ "$arch" = "x86_64" ]; then
>>>> testdir=x86
>>>> elif [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then
>>>> testdir=arm
>>>> + if [ -z "$vmm" ] || [ "$vmm" = "qemu" ]; then
>>>> + uart_early_base=0x09000000UL
>>> You can drop the 'UL'.
>>>
>>>> + elif [ "$vmm" = "kvmtool" ]; then
>>>> + uart_early_base=0x3f8
>>>> + else
>>>> + echo '--vmm must be one of "qemu" or "kvmtool"'
>>>> + usage
>>> You're outputting usage here, but you didn't add vmm to the help text.
>>>
>>>> + fi
>>>> elif [ "$arch" = "ppc64" ]; then
>>>> testdir=powerpc
>>>> firmware="$testdir/boot_rom.bin"
>>>> @@ -197,4 +208,5 @@ PRETTY_PRINT_STACKS=$pretty_print_stacks
>>>> ENVIRON_DEFAULT=$environ_default
>>>> ERRATATXT=errata.txt
>>>> U32_LONG_FMT=$u32_long
>>>> +UART_EARLY_BASE=$uart_early_base
>>>> EOF
>>>> diff --git a/Makefile b/Makefile
>>>> index e9f02272e156..225c2a525cdf 100644
>>>> --- a/Makefile
>>>> +++ b/Makefile
>>>> @@ -72,6 +72,10 @@ COMMON_CFLAGS += $(fno_pic) $(no_pie)
>>>> CFLAGS += $(COMMON_CFLAGS)
>>>> CFLAGS += -Wmissing-parameter-type -Wold-style-declaration -Woverride-init
>>>>
>>>> +ifneq ($(UART_EARLY_BASE),)
>>>> +CFLAGS += -DUART_EARLY_BASE=$(UART_EARLY_BASE)
>>>> +endif
>>> This type of thing is what I would like to avoid by introducing a
>>> config.h file. In the least we shouldn't add this -D to CFLAGS for
>>> all architectures. It can be added to the %.elf rule in
>>> arm/Makefile.common
>>>
>>>> +
>>>> CXXFLAGS += $(COMMON_CFLAGS)
>>>>
>>>> autodepend-flags = -MMD -MF $(dir $*).$(notdir $*).d
>>>>
>>> You'll also want to patch lib/arm/io.c with
>>>
>>> -/*
>>> - * Use this guess for the pl011 base in order to make an attempt at
>>> - * having earlier printf support. We'll overwrite it with the real
>>> - * base address that we read from the device tree later. This is
>>> - * the address we expect QEMU's mach-virt machine type to put in
>>> - * its generated device tree.
>>> - */
>>> -#define UART_EARLY_BASE 0x09000000UL
>>> -
>>> static struct spinlock uart_lock;
>>> -static volatile u8 *uart0_base = (u8 *)UART_EARLY_BASE;
>>> +static volatile u8 *uart0_base = (u8 *)(unsigned long)UART_EARLY_BASE;
>>>
>>>
>>>
>>> This is all a bit on the ugly side, but I can't think of anything
>>> better.
>>>
>>> Thanks,
>>> drew
>> I've also tried doing it by generating config.h This is what I came up with:
>>
>> diff --git a/configure b/configure
>> index df8581e3a906..d77b8b0d82fa 100755
>> --- a/configure
>> +++ b/configure
>> @@ -16,6 +16,7 @@ endian=""
>> pretty_print_stacks=yes
>> environ_default=yes
>> u32_long=
>> +vmm=qemu
>>
>> usage() {
>> cat <<-EOF
>> @@ -23,6 +24,8 @@ usage() {
>>
>> Options include:
>> --arch=ARCH architecture to compile for ($arch)
>> + --vmm=VMM virtual machine monitor to compile for (qemu
>> or kvmtool,
> Long line?
I will fix it.
>
>> + arm/arm64 only, default is qemu)
> Why arm/arm64 only? No plans to use kvmtool for x86 tests?
The patches target only the arm and arm64 architectures.
>
>> --processor=PROCESSOR processor to compile for ($arch)
>> --cross-prefix=PREFIX cross compiler prefix
>> --cc=CC c compiler to use ($cc)
>> @@ -71,6 +74,9 @@ while [[ "$1" = -* ]]; do
>> --ld)
>> ld="$arg"
>> ;;
>> + --vmm)
>> + vmm="$arg"
>> + ;;
>> --enable-pretty-print-stacks)
>> pretty_print_stacks=yes
>> ;;
>> @@ -108,6 +114,14 @@ if [ "$arch" = "i386" ] || [ "$arch" = "x86_64" ]; then
>> testdir=x86
>> elif [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then
>> testdir=arm
>> + if [ "$vmm" = "qemu" ]; then
>> + uart_early_base=0x09000000
>> + elif [ "$vmm" = "kvmtool" ]; then
>> + uart_early_base=0x3f8
>> + else
>> + echo '--vmm must be one of "qemu" or "kvmtool"'
>> + usage
> Checking the vmm is qemu or kvmtool can be moved out of the if-arm block
> if we decide it can be for other architectures. If uart_early_base is only
> and arm thing, then 'arm' should probably be in its name. Could also
> rename 'base' to 'addr' to accommodate ioports.
It's arm only for now, I will rename the variable.
>
>
>> + fi
>> elif [ "$arch" = "ppc64" ]; then
>> testdir=powerpc
>> firmware="$testdir/boot_rom.bin"
>> @@ -198,3 +212,16 @@ ENVIRON_DEFAULT=$environ_default
>> ERRATATXT=errata.txt
>> U32_LONG_FMT=$u32_long
>> EOF
>> +
>> +cat <<EOF > lib/config.h
>> +#ifndef CONFIG_H
>> +#define CONFIG_H 1
> Should add a header stating this is a generated file like
> make_asm_offsets has in scripts/asm-offsets.mak
I will do that.
>
>> +EOF
>> +if [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then
>> +cat <<EOF >> lib/config.h
>> +#define UART_EARLY_BASE ${uart_early_base}UL
> Drop the 'UL'. If somebody attempted to supply it themselves it'd end up
> being ULUL. Just add another cast to where the value gets used to handle
> the type.
Good point.
>
>> +EOF
>> +fi
>> +cat <<EOF >> lib/config.h
>> +#endif
>> +EOF
> The one line appends could use 'echo' to take 2 less lines each.
I will change it to an echo.
>
>> diff --git a/lib/arm/io.c b/lib/arm/io.c
>> index 9fe9bd0bf659..0a3e8f237ab8 100644
>> --- a/lib/arm/io.c
>> +++ b/lib/arm/io.c
>> @@ -11,6 +11,7 @@
>> #include <libcflat.h>
>> #include <devicetree.h>
>> #include <chr-testdev.h>
>> +#include <config.h>
>> #include "arm/asm/psci.h"
>> #include <asm/spinlock.h>
>> #include <asm/io.h>
>> @@ -21,15 +22,6 @@ extern void halt(int code);
>>
>> static bool testdev_enabled;
>>
>> -/*
>> - * Use this guess for the pl011 base in order to make an attempt at
>> - * having earlier printf support. We'll overwrite it with the real
>> - * base address that we read from the device tree later. This is
>> - * the address we expect QEMU's mach-virt machine type to put in
>> - * its generated device tree.
>> - */
>> -#define UART_EARLY_BASE 0x09000000UL
>> -
>> static struct spinlock uart_lock;
>> static volatile u8 *uart0_base = (u8 *)UART_EARLY_BASE;
>>
>> Putting config.h in lib makes it available for other architectures, in case they
>> want to implement something similar. Please suggest another location if there is
>> a better one.
>>
>> I think this looks better than using architecture-specific compile-time defines
>> buried in arm/Makefile.common, what do you think?
>>
> Yes, I agree this looks better. You'll probably want to add a
> lib/.gitignore for the file too and also remove it when
> 'make distclean' is run.
>
> Thanks,
> drew
Thank you for the feedback, I will incorporate these changes into the next
version of the patches.
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