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authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>2022-08-09 12:54:25 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2022-11-24 13:31:46 +0100
commit7af82ff90a2b0690c2c45818fcce4c4ac3b187f3 (patch)
tree9341d7604ef37c7ffb553beb221507e507009e85 /arch/powerpc/include/asm/ftrace.h
parentpowerpc/pseries: Fix formatting to make code look more beautiful (diff)
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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 <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220809105425.424045-1-naveen.n.rao@linux.vnet.ibm.com
Diffstat (limited to 'arch/powerpc/include/asm/ftrace.h')
-rw-r--r--arch/powerpc/include/asm/ftrace.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index 3cee7115441b..ade406dc6504 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);