[U-Boot] [PATCH 4/4] efi_loader: indent entry/exit prints to show nesting level

Rob Clark
2017-07-28T11:54:43Z

On Fri, Jul 28, 2017 at 6:22 AM, Alexander Graf <agraf@suse.de> wrote:
>
>
> On 28.07.17 12:11, Rob Clark wrote:
>>
>> On Fri, Jul 28, 2017 at 5:36 AM, Alexander Graf <agraf@suse.de> wrote:
>>>
>>>
>>>
>>> On 28.07.17 11:34, Rob Clark wrote:
>>>>
>>>>
>>>> On Fri, Jul 28, 2017 at 5:25 AM, Alexander Graf <agraf@suse.de> wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On 28.07.17 11:19, Rob Clark wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Fri, Jul 28, 2017 at 3:24 AM, Alexander Graf <agraf@suse.de> wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On 27.07.17 14:04, Rob Clark wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> This should make it easier to see when a callback back to UEFI world
>>>>>>>> calls back in to the u-boot world, and generally match up
>>>>>>>> EFI_ENTRY()
>>>>>>>> and EFI_EXIT() calls.
>>>>>>>>
>>>>>>>> Signed-off-by: Rob Clark <robdclark@gmail.com>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Doesn't the previous patch ensure that we're always only going 1
>>>>>>> level
>>>>>>> deep?
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> two separate counters for nesting and entry level. We can be more
>>>>>> deeply nested when EFI_CALL() is used :-)
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Ah, so this basically gives you the EFI_CALL nesting level? Wouldn't it
>>>>> make
>>>>> sense to also increase the nesting level on every application
>>>>> invocation?
>>>>
>>>>
>>>>
>>>> I specifically avoided that since (at least at what I was looking at)
>>>> each successive application invocation never returns.
>>>>
>>>> Maybe instead we should just do something like:
>>>> debug("========================================\n") to show the
>>>> application invocation boundaries more easily?
>>>
>>>
>>>
>>> Sounds like a good idea to me :). Ideally with a bit more information
>>> such
>>> as the file path.
>>>
>>
>> well, until my RFC patchset, there is no guarantee to be a file path ;-)
>>
>> And both the device and file path will be efi_device_path. I have
>> some thoughts to spiff out device_path_to_text a bit more to make it
>> more complete and also suitable for internal debugging use.. but that
>> is going to be post-MW. Once that happens we can add some more
>> information, but for now the boring "===========" is all we can do.
>
>
> No worries, we can introduce a fancy ========= when the time is ripe :).
>
>
>>
>>>
>>>>
>>>>>
>>>>>>
>>>>>>>
>>>>>>>> ---
>>>>>>>> include/efi_loader.h | 12 ++++++++----
>>>>>>>> lib/efi_loader/efi_boottime.c | 25 +++++++++++++++++++++++++
>>>>>>>> 2 files changed, 33 insertions(+), 4 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/include/efi_loader.h b/include/efi_loader.h
>>>>>>>> index 4262d0ac6b..037cc7c543 100644
>>>>>>>> --- a/include/efi_loader.h
>>>>>>>> +++ b/include/efi_loader.h
>>>>>>>> @@ -17,13 +17,16 @@
>>>>>>>> int __efi_entry_check(void);
>>>>>>>> int __efi_exit_check(void);
>>>>>>>> +const char *__efi_nesting_inc(void);
>>>>>>>> +const char *__efi_nesting_dec(void);
>>>>>>>> /*
>>>>>>>> * Enter the u-boot world from UEFI:
>>>>>>>> */
>>>>>>>> #define EFI_ENTRY(format, ...) do { \
>>>>>>>> assert(__efi_entry_check()); \
>>>>>>>> - debug("EFI: Entry %s(" format ")\n", __func__,
>>>>>>>> ##__VA_ARGS__);
>>>>>>>> \
>>>>>>>> + debug("%sEFI: Entry %s(" format ")\n", __efi_nesting_inc(),
>>>>>>>> \
>>>>>>>> + __func__, ##__VA_ARGS__); \
>>>>>>>> } while(0)
>>>>>>>> /*
>>>>>>>> @@ -31,7 +34,8 @@ int __efi_exit_check(void);
>>>>>>>> */
>>>>>>>> #define EFI_EXIT(ret) ({ \
>>>>>>>> efi_status_t _r = ret; \
>>>>>>>> - debug("EFI: Exit: %s: %u\n", __func__, (u32)(_r &
>>>>>>>> ~EFI_ERROR_MASK)); \
>>>>>>>> + debug("%sEFI: Exit: %s: %u\n", __efi_nesting_dec(), \
>>>>>>>> + __func__, (u32)(_r & ~EFI_ERROR_MASK)); \
>>>>>>>> assert(__efi_exit_check()); \
>>>>>>>> _r; \
>>>>>>>> })
>>>>>>>> @@ -40,11 +44,11 @@ int __efi_exit_check(void);
>>>>>>>> * Callback into UEFI world from u-boot:
>>>>>>>> */
>>>>>>>> #define EFI_CALL(exp) do { \
>>>>>>>> - debug("EFI: Call: %s\n", #exp); \
>>>>>>>> + debug("%sEFI: Call: %s\n", __efi_nesting_inc(), #exp); \
>>>>>>>> assert(__efi_exit_check()); \
>>>>>>>> exp; \
>>>>>>>> assert(__efi_entry_check()); \
>>>>>>>> - debug("EFI: Return From: %s\n", #exp); \
>>>>>>>> + debug("%sEFI: Return From: %s\n", __efi_nesting_dec(),
>>>>>>>> #exp);
>>>>>>>> \
>>>>>>>> } while(0)
>>>>>>>> extern struct efi_runtime_services efi_runtime_services;
>>>>>>>> diff --git a/lib/efi_loader/efi_boottime.c
>>>>>>>> b/lib/efi_loader/efi_boottime.c
>>>>>>>> index 66137d4ff9..de338f009c 100644
>>>>>>>> --- a/lib/efi_loader/efi_boottime.c
>>>>>>>> +++ b/lib/efi_loader/efi_boottime.c
>>>>>>>> @@ -50,6 +50,7 @@ static volatile void *efi_gd, *app_gd;
>>>>>>>> #endif
>>>>>>>> static int entry_count;
>>>>>>>> +static int nesting_level;
>>>>>>>> /* Called on every callback entry */
>>>>>>>> int __efi_entry_check(void)
>>>>>>>> @@ -96,6 +97,28 @@ void efi_restore_gd(void)
>>>>>>>> #endif
>>>>>>>> }
>>>>>>>> +/*
>>>>>>>> + * Two spaces per indent level, maxing out at 10.. which ought to
>>>>>>>> be
>>>>>>>> + * enough for anyone ;-)
>>>>>>>> + */
>>>>>>>> +static const char *indent_string(int level)
>>>>>>>> +{
>>>>>>>> + static const char *indent = " ";
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> There's no need for this to be static, no?
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> I suppose it doesn't *need* to be.. but it also doesn't need to have
>>>>>> scope outside the file, and usually static is a good hint to the
>>>>>> compiler to inline it. (If non-static the compiler needs to emit a
>>>>>> non-inlined version of it since it doesn't know it won't be called
>>>>>> outside of this object file.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> I don't mean the function, I mean the indent. If you do
>>>>>
>>>>> static const char *indent = <const value>;
>>>>>
>>>>> it should be practically the same as
>>>>>
>>>>> const char *indent = <const value>;
>>>>>
>>>>> no?
>>>>
>>>>
>>>>
>>>> hmm, I didn't want the compiler to instantiate the array on the stack.
>>>> But I suppose I need to check the generated asm to see how clever it
>>>> is.
>>>
>>>
>>>
>>> It really shouldn't do that. As long as you're just juggling pointers to
>>> a
>>> region in .rodata it should know exactly what's going on.
>>>
>>
>> I'll double check when I get to the office.. making it static doesn't
>> hurt and forces the compiler to do what we want (.rodata). Without
>> the 'static' it might end up doing the same thing.
>
>
> Well, every time i see a "static" declared variable inside a function scope
> my alarm bells ring :). So I'd prefer we had as few as possible.
>
> In fact, I *think* what your line does is it puts the pointer into a global
> in .data which really isn't what we want.
>

it seems to do the identical thing in both cases (based on diffing
objdump output)

BR,
-R