Re: [PATCH] ACPI: acenv: Permit compilation from within the kernel

[Dave Jiang]

On 11/20/23 09:38, Rafael J. Wysocki wrote:
> On Mon, Nov 20, 2023 at 5:19 PM Dave Jiang <dave.jiang@xxxxxxxxx> wrote:
>>
>>
>>
>> On 11/20/23 08:46, Rafael J. Wysocki wrote:
>>> On Tue, Nov 14, 2023 at 7:09 PM Sam Edwards <cfsworks@xxxxxxxxx> wrote:
>>>>
>>>> On 11/13/23 16:08, Linus Walleij wrote:
>>>>> After commit a103f46633fd the kernel stopped compiling for
>>>>> several ARM32 platforms that I am building with a bare metal
>>>>> compiler. Bare metal compilers (arm-none-eabi-) don't
>>>>> define __linux__.
>>>>
>>>> Hi Linus,
>>>>
>>>> I saw the same baremetal-compiler error here on the ARM64 side of the
>>>> fence, and narrowed the problem to the same commit as you.
>>>>
>>>>>
>>>>> This is because the header <acpi/platform/acenv.h> is now
>>>>> in the include path for <linux/irq.h>:
>>>>
>>>> More generally, I think it's because of this addition to linux/acpi.h:
>>>> +#include <linux/fw_table.h>
>>>>
>>>> linux/acpi.h is supposed to ensure _LINUX is defined (if it isn't
>>>> already done by a non-baremetal compiler) before we start pulling in
>>>> ACPICA includes, so that ACPICA knows the platform. But because
>>>> fw_table.h contains:
>>>> #include <linux/acpi.h>
>>>> #include <acpi/acpi.h>
>>>>
>>>> ...the circular include does nothing (linux/acpi.h's include guard stops
>>>> the include before _LINUX is defined) and we end up pulling in
>>>> acpi/acpi.h before we're ready.
>>
>> Not including either causes compile errors for me.
> 
> Interesting.  What errors do you get if you include linux/acpi.h only?
> 
> It should not be necessary to include acpi/acpi.h in addition to
> linux/acpi.h, because the latter is expected to include the former.
> If it doesn't do that, something is amiss.
> 


  CC      arch/x86/video/fbdev.o
In file included from ./include/linux/acpi.h:18,
                 from ./include/linux/tpm.h:21,
                 from ./include/keys/trusted-type.h:12,
                 from security/keys/encrypted-keys/encrypted.c:22:
./include/linux/fw_table.h:32:37: error: field ‘common’ has incomplete type
   32 |         struct acpi_subtable_header common;
      |                                     ^~~~~~
./include/linux/fw_table.h:33:36: error: field ‘hmat’ has incomplete type
   33 |         struct acpi_hmat_structure hmat;
      |                                    ^~~~
./include/linux/fw_table.h:34:40: error: field ‘prmt’ has incomplete type
   34 |         struct acpi_prmt_module_header prmt;
      |                                        ^~~~
./include/linux/fw_table.h:35:33: error: field ‘cedt’ has incomplete type
   35 |         struct acpi_cedt_header cedt;
      |                                 ^~~~


However, if I move fw_table.h in linux/acpi.h below include of asm/acpi.h, then we can build successfully w/o including acpi/acpi.h in fw_table.h.


diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 54189e0e5f41..2789beb26138 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -15,7 +15,6 @@
 #include <linux/mod_devicetable.h>
 #include <linux/property.h>
 #include <linux/uuid.h>
-#include <linux/fw_table.h>
 
 struct irq_domain;
 struct irq_domain_ops;
@@ -25,16 +24,6 @@ struct irq_domain_ops;
 #endif
 #include <acpi/acpi.h>
 
-#ifdef CONFIG_ACPI_TABLE_LIB
-#define EXPORT_SYMBOL_ACPI_LIB(x) EXPORT_SYMBOL_NS_GPL(x, ACPI)
-#define __init_or_acpilib
-#define __initdata_or_acpilib
-#else
-#define EXPORT_SYMBOL_ACPI_LIB(x)
-#define __init_or_acpilib __init
-#define __initdata_or_acpilib __initdata
-#endif
-
 #ifdef CONFIG_ACPI
 
 #include <linux/list.h>
@@ -48,6 +37,18 @@ struct irq_domain_ops;
 #include <acpi/acpi_io.h>
 #include <asm/acpi.h>
 
+#include <linux/fw_table.h>
+
+#ifdef CONFIG_ACPI_TABLE_LIB
+#define EXPORT_SYMBOL_ACPI_LIB(x) EXPORT_SYMBOL_NS_GPL(x, ACPI)
+#define __init_or_acpilib
+#define __initdata_or_acpilib
+#else
+#define EXPORT_SYMBOL_ACPI_LIB(x)
+#define __init_or_acpilib __init
+#define __initdata_or_acpilib __initdata
+#endif
+
 static inline acpi_handle acpi_device_handle(struct acpi_device *adev)
 {
        return adev ? adev->handle : NULL;
diff --git a/include/linux/fw_table.h b/include/linux/fw_table.h
index ff8fa58d5818..a722300c215b 100644
--- a/include/linux/fw_table.h
+++ b/include/linux/fw_table.h
@@ -26,7 +26,6 @@ struct acpi_subtable_proc {
 };
 
 #include <linux/acpi.h>
-#include <acpi/acpi.h>
 
 union acpi_subtable_headers {
        struct acpi_subtable_header common;



>> And directly including acpi/acpi.h w/o linux/acpi.h causes triggering the #error and some other stuff:
>>
>> ./include/acpi/platform/aclinux.h:18:2: error: #error "Please don't include <acpi/acpi.h> directly, include <linux/acpi.h> instead."
>>    18 | #error "Please don't include <acpi/acpi.h> directly, include <linux/acpi.h> instead."
>>       |  ^~~~~
>>
>>
>> Only including linux/acpi.h:
>> In file included from ./include/linux/acpi.h:18,
>>                  from init/main.c:30:
>> ./include/linux/fw_table.h:32:37: error: field ‘common’ has incomplete type
>>    32 |         struct acpi_subtable_header common;
>>       |                                     ^~~~~~
>> ./include/linux/fw_table.h:33:36: error: field ‘hmat’ has incomplete type
>>    33 |         struct acpi_hmat_structure hmat;
>>       |                                    ^~~~
>> ./include/linux/fw_table.h:34:40: error: field ‘prmt’ has incomplete type
>>    34 |         struct acpi_prmt_module_header prmt;
>>       |                                        ^~~~
>> ./include/linux/fw_table.h:35:33: error: field ‘cedt’ has incomplete type
>>    35 |         struct acpi_cedt_header cedt;
>>       |                                 ^~~~
>>
>>
>>>
>>> Yes, that's the problem AFAICS.  Dave?
>>>
>>> What about moving the fw_table.h include in linux/acpi.h below the
>>> mutex.h one, along with the EXPORT_SYMBOL_ACPI_LIB-related
>>> definitions?
>>
>> This builds cleanly for me.
> 
> OK, so I'm wondering if this also helps the other people in this thread.