From: Qing Zhang <zhangqing@loongson.cn>
To: Huacai Chen <chenhuacai@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>,
loongarch@lists.linux.dev, linux-kernel@vger.kernel.org,
Jiaxun Yang <jiaxun.yang@flygoat.com>,
hejinyang@loongson.cn
Subject: [PATCH v2 8/9] LoongArch/ftrace: Add HAVE_FUNCTION_GRAPH_RET_ADDR_PTR support
Date: Fri, 26 Aug 2022 15:36:25 +0800 [thread overview]
Message-ID: <20220826073626.1716-2-zhangqing@loongson.cn> (raw)
In-Reply-To: <20220826073626.1716-1-zhangqing@loongson.cn>
Ftrace_graph_ret_addr can be called by stack unwinding code to convert
a found stack return address ('ret') to its original value, in case the
function graph tracer has modified it to be 'return_to_handler',If the
hasn't been modified, the unchanged value of 'ret' is returned.
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
---
arch/loongarch/include/asm/ftrace.h | 3 +++
arch/loongarch/include/asm/unwind.h | 1 +
arch/loongarch/kernel/ftrace_dyn.c | 2 +-
arch/loongarch/kernel/unwind_guess.c | 4 +++-
arch/loongarch/kernel/unwind_prologue.c | 10 +++++++++-
5 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
index ce119496c6d0..0c306f42a512 100644
--- a/arch/loongarch/include/asm/ftrace.h
+++ b/arch/loongarch/include/asm/ftrace.h
@@ -10,6 +10,8 @@
#define FTRACE_REGS_PLT_IDX 1
#define NR_FTRACE_PLTS 2
+#define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1]))
+
#ifdef CONFIG_FUNCTION_TRACER
#define MCOUNT_INSN_SIZE 4 /* sizeof mcount call */
@@ -20,6 +22,7 @@ extern void _mcount(void);
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
+#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
return addr;
diff --git a/arch/loongarch/include/asm/unwind.h b/arch/loongarch/include/asm/unwind.h
index 6af4718bdf01..f66b07c3e6a1 100644
--- a/arch/loongarch/include/asm/unwind.h
+++ b/arch/loongarch/include/asm/unwind.h
@@ -21,6 +21,7 @@ struct unwind_state {
struct stack_info stack_info;
struct task_struct *task;
bool first, error;
+ int graph_idx;
unsigned long sp, pc, ra;
};
diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c
index dd37185d446e..b070ce225989 100644
--- a/arch/loongarch/kernel/ftrace_dyn.c
+++ b/arch/loongarch/kernel/ftrace_dyn.c
@@ -219,7 +219,7 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent)
old = *parent;
- if (!function_graph_enter(old, self_addr, 0, NULL))
+ if (!function_graph_enter(old, self_addr, 0, parent))
*parent = return_hooker;
}
diff --git a/arch/loongarch/kernel/unwind_guess.c b/arch/loongarch/kernel/unwind_guess.c
index 5afa6064d73e..229ba014cea0 100644
--- a/arch/loongarch/kernel/unwind_guess.c
+++ b/arch/loongarch/kernel/unwind_guess.c
@@ -2,6 +2,7 @@
/*
* Copyright (C) 2022 Loongson Technology Corporation Limited
*/
+#include <linux/ftrace.h>
#include <linux/kernel.h>
#include <asm/unwind.h>
@@ -53,7 +54,8 @@ bool unwind_next_frame(struct unwind_state *state)
state->sp < info->end;
state->sp += sizeof(unsigned long)) {
addr = *(unsigned long *)(state->sp);
-
+ state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
if (__kernel_text_address(addr))
return true;
}
diff --git a/arch/loongarch/kernel/unwind_prologue.c b/arch/loongarch/kernel/unwind_prologue.c
index b206d9159205..03f8b31a90cc 100644
--- a/arch/loongarch/kernel/unwind_prologue.c
+++ b/arch/loongarch/kernel/unwind_prologue.c
@@ -2,6 +2,7 @@
/*
* Copyright (C) 2022 Loongson Technology Corporation Limited
*/
+#include <linux/ftrace.h>
#include <linux/kallsyms.h>
#include <asm/inst.h>
@@ -32,6 +33,8 @@ static bool unwind_by_guess(struct unwind_state *state)
state->sp < info->end;
state->sp += sizeof(unsigned long)) {
addr = *(unsigned long *)(state->sp);
+ state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
if (__kernel_text_address(addr))
return true;
}
@@ -146,8 +149,11 @@ bool unwind_next_frame(struct unwind_state *state)
break;
case UNWINDER_PROLOGUE:
- if (unwind_by_prologue(state))
+ if (unwind_by_prologue(state)) {
+ state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ state->pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
return true;
+ }
if (info->type == STACK_TYPE_IRQ &&
info->end == state->sp) {
@@ -159,6 +165,8 @@ bool unwind_next_frame(struct unwind_state *state)
state->pc = pc;
state->sp = regs->regs[3];
+ state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
state->ra = regs->regs[1];
state->first = true;
get_stack_info(state->sp, state->task, info);
--
2.20.1
next prev parent reply other threads:[~2022-08-26 7:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-26 7:36 [PATCH v2 7/9] LoongArch: modules/ftrace: Initialize PLT at load time Qing Zhang
2022-08-26 7:36 ` Qing Zhang [this message]
2022-08-26 7:36 ` [PATCH v2 9/9] LoongArch: Enable CONFIG_KALLSYMS_ALL and CONFIG_DEBUG_FS Qing Zhang
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