[PATCH v3 2/2] powerpc/fprobe: fix updated fprobe for function-graph tracer

From: Hari Bathini <hbathini@linux.ibm.com>

Since commit 4346ba160409 ("fprobe: Rewrite fprobe on function-graph
tracer"), FPROBE depends on HAVE_FUNCTION_GRAPH_FREGS. With previous
patch adding HAVE_FUNCTION_GRAPH_FREGS for powerpc, FPROBE can be
enabled on powerpc. But with the commit b5fa903b7f7c ("fprobe: Add
fprobe_header encoding feature"), asm/fprobe.h header is needed to
define arch dependent encode/decode macros. The fprobe header MSB
pattern on powerpc is not 0xf. So, define FPROBE_HEADER_MSB_PATTERN
expected on powerpc.

Also, commit 762abbc0d09f ("fprobe: Use ftrace_regs in fprobe exit
handler") introduced HAVE_FTRACE_REGS_HAVING_PT_REGS for archs that
have pt_regs in ftrace_regs. Advertise that on powerpc to reuse
common definitions like ftrace_partial_regs().

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Aditya Bodkhe <redacted>
---
 arch/powerpc/Kconfig              |  1 +
 arch/powerpc/include/asm/fprobe.h | 12 ++++++++++++
 2 files changed, 13 insertions(+)
 create mode 100644 arch/powerpc/include/asm/fprobe.h

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 451d0e140051..35d32cc43255 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig

@@ -243,6 +243,7 @@ config PPC
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
 	select HAVE_GUP_FAST
 	select HAVE_FTRACE_GRAPH_FUNC
+	select HAVE_FTRACE_REGS_HAVING_PT_REGS
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select HAVE_FUNCTION_DESCRIPTORS	if PPC64_ELF_ABI_V1
 	select HAVE_FUNCTION_ERROR_INJECTION

diff --git a/arch/powerpc/include/asm/fprobe.h b/arch/powerpc/include/asm/fprobe.h
new file mode 100644
index 000000000000..d64bc28fb3d3
--- /dev/null
+++ b/arch/powerpc/include/asm/fprobe.h

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_PPC_FPROBE_H
+#define _ASM_PPC_FPROBE_H
+
+#include <asm-generic/fprobe.h>
+
+#ifdef CONFIG_64BIT
+#undef FPROBE_HEADER_MSB_PATTERN
+#define FPROBE_HEADER_MSB_PATTERN	(PAGE_OFFSET & ~FPROBE_HEADER_MSB_MASK)
+#endif
+
+#endif /* _ASM_PPC_FPROBE_H */

-- 
2.51.0