From: Naveen N. Rao Date: Tue, 9 Aug 2022 10:54:25 +0000 (+0530) Subject: powerpc/ftrace: Ignore weak functions X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7af82ff90a2b0690c2c45818fcce4c4ac3b187f3;p=linux.git powerpc/ftrace: Ignore weak functions Extend commit b39181f7c6907d ("ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function") to ppc32 and ppc64 -mprofile-kernel by defining FTRACE_MCOUNT_MAX_OFFSET. For ppc64 -mprofile-kernel ABI, we can have two instructions at function entry for TOC setup followed by 'mflr r0' and 'bl _mcount'. So, the mcount location is at most the 4th instruction in a function. For ppc32, mcount location is always the 3rd instruction in a function, preceded by 'mflr r0' and 'stw r0,4(r1)'. With this patch, and with ppc64le_guest_defconfig and some ftrace/bpf config items enabled: # grep __ftrace_invalid_address available_filter_functions | wc -l 79 Signed-off-by: Naveen N. Rao Acked-by: Steven Rostedt (Google) Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220809105425.424045-1-naveen.n.rao@linux.vnet.ibm.com --- diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 3cee7115441b4..ade406dc6504e 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -10,6 +10,13 @@ #define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR +/* Ignore unused weak functions which will have larger offsets */ +#ifdef CONFIG_MPROFILE_KERNEL +#define FTRACE_MCOUNT_MAX_OFFSET 12 +#elif defined(CONFIG_PPC32) +#define FTRACE_MCOUNT_MAX_OFFSET 8 +#endif + #ifndef __ASSEMBLY__ extern void _mcount(void);