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ftrace: pass fregs to arch_ftrace_set_direct_caller()

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In subsequent patches we'll arrange for architectures to have an
ftrace_regs which is entirely distinct from pt_regs. In preparation for
this, we need to minimize the use of pt_regs to where strictly
necessary in the core ftrace code.

This patch changes the prototype of arch_ftrace_set_direct_caller() to
take ftrace_regs rather than pt_regs, and moves the extraction of the
pt_regs into arch_ftrace_set_direct_caller().

On x86, arch_ftrace_set_direct_caller() can be used even when
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=n, and <linux/ftrace.h> defines
struct ftrace_regs. Due to this, it's necessary to define
arch_ftrace_set_direct_caller() as a macro to avoid using an incomplete
type. I've also moved the body of arch_ftrace_set_direct_caller() after
the CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y defineidion of struct
ftrace_regs.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20221103170520.931305-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Mark Rutland 2022-11-03 17:05:17 +00:00 committed by Will Deacon
parent f0c4d9fc9c
commit 9705bc7096
4 changed files with 27 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/s390/include/asm/ftrace.h
View File

@ -60,6 +60,7 @@ static __always_inline void ftrace_instruction_pointer_set(struct ftrace_regs *f
fregs->regs.psw.addr = ip;
}
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/*
* When an ftrace registered caller is tracing a function that is
* also set by a register_ftrace_direct() call, it needs to be
@ -67,10 +68,12 @@ static __always_inline void ftrace_instruction_pointer_set(struct ftrace_regs *f
* place the direct caller in the ORIG_GPR2 part of pt_regs. This
* tells the ftrace_caller that there's a direct caller.
*/
static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr)
{
struct pt_regs *regs = &fregs->regs;
regs->orig_gpr2 = addr;
}
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
/*
* Even though the system call numbers are identical for s390/s390x a

31
arch/x86/include/asm/ftrace.h
View File

@ -34,19 +34,6 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
return addr;
}
/*
* When a ftrace registered caller is tracing a function that is
* also set by a register_ftrace_direct() call, it needs to be
* differentiated in the ftrace_caller trampoline. To do this, we
* place the direct caller in the ORIG_AX part of pt_regs. This
* tells the ftrace_caller that there's a direct caller.
*/
static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
{
/* Emulate a call */
regs->orig_ax = addr;
}
#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
struct ftrace_regs {
struct pt_regs regs;
@ -72,6 +59,24 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
#define FTRACE_GRAPH_TRAMP_ADDR FTRACE_GRAPH_ADDR
#endif
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/*
* When a ftrace registered caller is tracing a function that is
* also set by a register_ftrace_direct() call, it needs to be
* differentiated in the ftrace_caller trampoline. To do this, we
* place the direct caller in the ORIG_AX part of pt_regs. This
* tells the ftrace_caller that there's a direct caller.
*/
static inline void
__arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
{
/* Emulate a call */
regs->orig_ax = addr;
}
#define arch_ftrace_set_direct_caller(fregs, addr) \
__arch_ftrace_set_direct_caller(&(fregs)->regs, addr)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
#ifdef CONFIG_DYNAMIC_FTRACE
struct dyn_arch_ftrace {

9
include/linux/ftrace.h
View File

@ -37,9 +37,10 @@ extern void ftrace_boot_snapshot(void);
static inline void ftrace_boot_snapshot(void) { }
#endif
#ifdef CONFIG_FUNCTION_TRACER
struct ftrace_ops;
struct ftrace_regs;
#ifdef CONFIG_FUNCTION_TRACER
/*
* If the arch's mcount caller does not support all of ftrace's
* features, then it must call an indirect function that
@ -427,9 +428,7 @@ static inline int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsi
{
return -ENODEV;
}
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/*
* This must be implemented by the architecture.
* It is the way the ftrace direct_ops helper, when called
@ -443,9 +442,9 @@ static inline int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsi
* the return from the trampoline jump to the direct caller
* instead of going back to the function it just traced.
*/
static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs,
static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs,
unsigned long addr) { }
#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
#ifdef CONFIG_STACK_TRACER

3
kernel/trace/ftrace.c
View File

@ -2487,14 +2487,13 @@ ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
static void call_direct_funcs(unsigned long ip, unsigned long pip,
struct ftrace_ops *ops, struct ftrace_regs *fregs)
{
struct pt_regs *regs = ftrace_get_regs(fregs);
unsigned long addr;
addr = ftrace_find_rec_direct(ip);
if (!addr)
return;
arch_ftrace_set_direct_caller(regs, addr);
arch_ftrace_set_direct_caller(fregs, addr);
}
struct ftrace_ops direct_ops = {