Messages in this thread | | | Subject | Re: [PATCH] Work around for enabling CONFIG_CMDLINE on ppc64le | From | Akshay Adiga <> | Date | Fri, 23 Sep 2016 09:45:24 +0530 |
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Hi Michael,
Anton found this bug and raised it against gcc v7.0 and a fix is available in upstream gcc.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71709
Currently, gcc v5.4.0 and v6.1.1 shipped with Ubuntu 16.04 and 16.10 respectively, are hitting this problem.
I have also raised bug against Ubuntu for fixing gcc for 16.04.
https://bugzilla.linux.ibm.com/show_bug.cgi?id=146668
On 09/22/2016 03:51 PM, Michael Ellerman wrote: > Akshay Adiga <akshay.adiga@linux.vnet.ibm.com> writes: > >> Observed that boot arguments (passed as CONFIG_CMDLINE) are not being >> picked up by kernel while using gcc-ppc64-linux-gnu v5.4.0 and v6.1.1. >> While it works as expected with v5.3.1 . >> >> Found that in init/main.c in setup_command_line() the pointers passed to >> strcpy() is messed up. > Hi Akshay, > > Thanks for debugging this. > >> The problem goes away when compiler optimization is restricted to -O1. >> diff --git a/init/main.c b/init/main.c >> index a8a58e2..4259c42 100644 >> --- a/init/main.c >> +++ b/init/main.c >> @@ -358,7 +358,13 @@ static inline void smp_prepare_cpus(unsigned int maxcpus) { } >> * parsing is performed in place, and we should allow a component to >> * store reference of name/value for future reference. >> */ >> -static void __init setup_command_line(char *command_line) >> +static void __init >> +#ifdef CONFIG_PPC64 >> + #if GCC_VERSION > 50301 >> + __attribute__((optimize("-O1"))) >> + #endif >> +#endif >> + setup_command_line(char *command_line) >> { >> saved_command_line = >> memblock_virt_alloc(strlen(boot_command_line) + 1, 0); > But I can't merge that patch. > > Our options are one or both of: > - get GCC fixed and backport the fix to the compilers we care about. > - blacklist the broken compiler versions. > > Is there a GCC bug filed for this? > > cheers >
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