Re: [PATCH] Work around for enabling CONFIG_CMDLINE on ppc64le
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2016-09-22 10:21:40
Also in:
lkml
Akshay Adiga [off-list ref] 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.
quoted hunk ↗ jump to hunk
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