FAILED: patch "[PATCH] riscv: add CALLER_ADDRx support" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 680341382da56bd192ebfa4e58eaf4fec2e5bca7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024030537-amiss-payable-3723@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

680341382da5 ("riscv: add CALLER_ADDRx support")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 680341382da56bd192ebfa4e58eaf4fec2e5bca7 Mon Sep 17 00:00:00 2001
From: Zong Li <[email protected]>
Date: Fri, 2 Feb 2024 01:51:02 +0000
Subject: [PATCH] riscv: add CALLER_ADDRx support

CALLER_ADDRx returns caller's address at specified level, they are used for several tracers. These macros eventually use __builtin_return_address(n) to get the caller's address if arch doesn't define their own implementation.

In RISC-V, __builtin_return_address(n) only works when n == 0, we need to walk the stack frame to get the caller's address at specified level.

data.level started from 'level + 3' due to the call flow of getting caller's address in RISC-V implementation. If we don't have additional three iteration, the level is corresponding to follows:

callsite -> return_address -> arch_stack_walk -> walk_stackframe

|           |                 |                  |
level 3     level 2           level 1            level 0

index 329172122952..15055f9df4da 100644
@@ -25,6 +25,11 @@
 
 #define ARCH_SUPPORTS_FTRACE_OPS 1
 #ifndef __ASSEMBLY__
+
+extern void *return_address(unsigned int level);
+
+#define ftrace_return_address(n) return_address(n)
+
 void MCOUNT_NAME(void);
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {

index f71910718053..604d6bf7e476 100644
@@ -7,6 +7,7 @@ ifdef CONFIG_FTRACE
 CFLAGS_REMOVE_ftrace.o	= $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_patch.o	= $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_sbi.o	= $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_return_address.o	= $(CC_FLAGS_FTRACE)
 endif
 CFLAGS_syscall_table.o	+= $(call cc-option,-Wno-override-init,)
 CFLAGS_compat_syscall_table.o += $(call cc-option,-Wno-override-init,)

@@ -46,6 +47,7 @@ obj-y	+= irq.o
 obj-y	+= process.o
 obj-y	+= ptrace.o
 obj-y	+= reset.o
+obj-y	+= return_address.o
 obj-y	+= setup.o
 obj-y	+= signal.o
 obj-y	+= syscall_table.o