On 11/15/2016 08:43 AM, Moore, Robert wrote: > The design for all of this is as follows: > > 1) OS-dependent includes > 2) Compiler-specific includes > 3) acenv.h is the master file that pulls in the correct headers (one compiler, and one OS) Sure, that's understood from the current structure. The issue is #3 -- there is no OS, in the sense of a run-time environment, so that assumption is incorrect in this case. All we know is that we're compiling the kernel and it needs to be able to run in complete isolation. > So, I think I see a couple of possible solutions for you: > > 1) If you are using GCC, the __GNUC__ symbol should already be defined. Right, which is what this patch is relying on. > 2) If "aclinux.h" works for you, we can either add a conditional case that would apply to your environment, or: I'm confused; I thought that was what this patch was doing. What is being suggested instead? > 2a) You could define _LINUX in your gcc invocations. This option might force changes in the kernel build which is otherwise not affected; this is only an issue with drivers/acpi/acpica/*. It may also cause ACPICA to build incorrectly for other OSs, but I'll have to look at that. Off hand, it seems like this would cause more problems with acenv.h. > > Because ACPICA supports many different environments, we don't want to have a "default" case which in a sense would only be an attempt to guess what the user intended. We want to have a clear error that tells the user that something important needs to be done before the code can be compiled. Understood, which is why I left the #error case; the intent is only to have a default when compiling Linux for bare-metal environments using GCC. Perhaps this is just a Linux-only modification... > Bob > > >> -----Original Message----- >> From: Al Stone [mailto:ahs3@xxxxxxxxxx] >> Sent: Monday, November 14, 2016 3:09 PM >> To: linux-acpi@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; linux- >> kernel@xxxxxxxxxxxxxxx >> Cc: Al Stone <ahs3@xxxxxxxxxx>; Rafael J . Wysocki <rjw@xxxxxxxxxxxxx>; >> Len Brown <lenb@xxxxxxxxxx>; Moore, Robert <robert.moore@xxxxxxxxx>; >> Zheng, Lv <lv.zheng@xxxxxxxxx> >> Subject: [PATCH] ACPI: allow compilation with bare metal compilers >> >> The ACPICA subsystem of the ACPI driver sets up a compilation >> environment for itself, adding in multiple typedefs unique to ACPICA >> that depend on where ACPICA will be used. >> >> The vast majority of such environments (Linux, QNX, ...) have an >> environment defined by the acenv.h header file. When using a Linaro >> compiler [1] specifically built to be used in an embedded environment >> with perhaps a kernel and an init process as the only things running, >> there is no environment defined for ACPICA so the typedefs it needs are >> not set up, causing compilation to fail badly unless ACPI is completely >> disabled. >> Since ACPI is enabled in the default config for the kernel, the >> compilation failure is fairly obvious. >> >> This may not be the optimal solution, but add in to the ACPI header file >> include/acpi/platform/acenv.h a default so that if GCC is being used, >> and all else fails, assume that we are going to be in a Linux-like >> environment and re-use the environment definition for Linux. This >> allows us to build a kernel using this compiler [1] with or without >> ACPI. >> >> [1] >> https://releases.linaro.org/components/toolchain/binaries/latest/aarch64 >> -elff/gcc-linaro-6.1.1-2016-08-x86_64_aarch64-elf.tar.xz >> >> Signed-off-by: Al Stone <ahs3@xxxxxxxxxx> >> Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> >> Cc: Len Brown <lenb@xxxxxxxxxx> >> Cc: Robert Moore <robert.moore@xxxxxxxxx> >> Cc: Lv Zheng <lv.zheng@xxxxxxxxx> >> --- >> include/acpi/platform/acenv.h | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/include/acpi/platform/acenv.h >> b/include/acpi/platform/acenv.h index 34cce72..cdd1cd6 100644 >> --- a/include/acpi/platform/acenv.h >> +++ b/include/acpi/platform/acenv.h >> @@ -234,6 +234,21 @@ >> #elif defined(_AED_EFI) || defined(_GNU_EFI) || defined(_EDK2_EFI) >> #include "acefi.h" >> >> +/* >> + * Up to this point, we've been looking for specific environments. In >> + * some cases, there is no environment, and we're just working on bare >> + * metal. However, since we're compiling the Linux kernel, let's just >> + * pretend we're in a Linux environment. >> + */ >> +#elif defined(__GNUC__) && !defined(__INTEL_COMPILER) #if >> +!defined(_LINUX) #define _LINUX #endif #if !defined(__linux__) #define >> +__linux__ #endif #include <acpi/platform/aclinux.h> >> + >> #else >> >> /* Unknown environment */ >> -- >> 2.10.2 > -- ciao, al ----------------------------------- Al Stone Software Engineer Red Hat, Inc. ahs3@xxxxxxxxxx ----------------------------------- -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
