Anton Blanchard 0e0ed6406e powerpc/modules: Module CRC relocation fix causes perf issues ... Module CRCs are implemented as absolute symbols that get resolved by a linker script. We build an intermediate .o that contains an unresolved symbol for each CRC. genksysms parses this .o, calculates the CRCs and writes a linker script that "resolves" the symbols to the calculated CRC. Unfortunately the ppc64 relocatable kernel sees these CRCs as symbols that need relocating and relocates them at boot. Commit d4703aef (module: handle ppc64 relocating kcrctabs when CONFIG_RELOCATABLE=y) added a hook to reverse the bogus relocations. Part of this patch created a symbol at 0x0: # head -2 /proc/kallsyms 0000000000000000 T reloc_start c000000000000000 T .__start This reloc_start symbol is causing lots of confusion to perf. It thinks reloc_start is a massive function that stretches from 0x0 to 0xc000000000000000 and we get various cryptic errors out of perf, including: problem incrementing symbol count, skipping event This patch removes the reloc_start linker script label and instead defines it as PHYSICAL_START. We also need to wrap it with CONFIG_PPC64 because the ppc32 kernel can set a non zero PHYSICAL_START at compile time and we wouldn't want to subtract it from the CRCs in that case. Signed-off-by: Anton Blanchard <anton@samba.org> Cc: <stable@kernel.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>		2013-07-24 14:18:43 +10:00
..
asm	powerpc/modules: Module CRC relocation fix causes perf issues	2013-07-24 14:18:43 +10:00
uapi/asm	net: rename busy poll socket op and globals	2013-07-10 17:08:27 -07:00