[PATCH v4 5/9] ftrace: Add ftrace_partial_regs() for converting ftrace_regs to pt_regs
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Date: 2023-08-23 15:18:13
Also in:
bpf, lkml
Subsystem:
arm64 port (aarch64 architecture), function hooks (ftrace), the rest · Maintainers:
Catalin Marinas, Will Deacon, Steven Rostedt, Masami Hiramatsu, Linus Torvalds
From: Masami Hiramatsu (Google) <mhiramat@kernel.org> Add ftrace_partial_regs() which converts the ftrace_regs to pt_regs. If the architecture defines its own ftrace_regs, this copies partial registers to pt_regs and returns it. If not, ftrace_regs is the same as pt_regs and ftrace_partial_regs() will return ftrace_regs::regs. Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Florent Revest <redacted> --- Changes in v3: - Fix to use pt_regs::regs instead of x. - Return ftrace_regs::regs forcibly if HAVE_PT_REGS_COMPAT_FTRACE_REGS=y. - Fix typo. - Fix to copy correct registers to the pt_regs on arm64. Changes in v4: - Change the patch order in the series so that fprobe event can use this. --- arch/arm64/include/asm/ftrace.h | 11 +++++++++++ include/linux/ftrace.h | 17 +++++++++++++++++ 2 files changed, 28 insertions(+)
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index ab158196480c..5ad24f315d52 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h@@ -137,6 +137,17 @@ ftrace_override_function_with_return(struct ftrace_regs *fregs) fregs->pc = fregs->lr; } +static __always_inline struct pt_regs * +ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs) +{ + memcpy(regs->regs, fregs->regs, sizeof(u64) * 9); + regs->sp = fregs->sp; + regs->pc = fregs->pc; + regs->regs[29] = fregs->fp; + regs->regs[30] = fregs->lr; + return regs; +} + int ftrace_regs_query_register_offset(const char *name); int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index c0a42d0860b8..a6ed2aa71efc 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h@@ -165,6 +165,23 @@ static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs return arch_ftrace_get_regs(fregs); } +#if !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS) || \ + defined(CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST) + +static __always_inline struct pt_regs * +ftrace_partial_regs(struct ftrace_regs *fregs, struct pt_regs *regs) +{ + /* + * If CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST=y, ftrace_regs memory + * layout is the same as pt_regs. So always returns that address. + * Since arch_ftrace_get_regs() will check some members and may return + * NULL, we can not use it. + */ + return &fregs->regs; +} + +#endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS || CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST */ + /* * When true, the ftrace_regs_{get,set}_*() functions may be used on fregs. * Note: this can be true even when ftrace_get_regs() cannot provide a pt_regs.