From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Add ftrace_partial_regs() which converts the ftrace_regs to pt_regs.
This is for the eBPF which needs this to keep the same pt_regs interface
to access registers.
Thus when replacing the pt_regs with ftrace_regs in fprobes (which is
used by kprobe_multi eBPF event), this will be used.
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@xxxxxxxxxx>
Acked-by: Florent Revest <revest@xxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
---
Changes in v14:
- Add riscv change.
Changes in v8:
- Add the reason why this required in changelog.
Changes from previous series: NOTHING, just forward ported.
---
arch/arm64/include/asm/ftrace.h | 11 +++++++++++
arch/riscv/include/asm/ftrace.h | 14 ++++++++++++++
include/linux/ftrace.h | 17 +++++++++++++++++
3 files changed, 42 insertions(+)
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index b5fa57b61378..d344c69eb01e 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -135,6 +135,17 @@ ftrace_regs_get_frame_pointer(const struct ftrace_regs *fregs)
return arch_ftrace_regs(fregs)->fp;
}
+static __always_inline struct pt_regs *
+ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs)
+{
+ memcpy(regs->regs, arch_ftrace_regs(fregs)->regs, sizeof(u64) * 9);
+ regs->sp = arch_ftrace_regs(fregs)->sp;
+ regs->pc = arch_ftrace_regs(fregs)->pc;
+ regs->regs[29] = arch_ftrace_regs(fregs)->fp;
+ regs->regs[30] = arch_ftrace_regs(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/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
index 9372f8d7036f..17e0a13cc386 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -197,6 +197,20 @@ static __always_inline void ftrace_override_function_with_return(struct ftrace_r
arch_ftrace_regs(fregs)->epc = arch_ftrace_regs(fregs)->ra;
}
+static __always_inline struct pt_regs *
+ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs)
+{
+ struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs);
+
+ memcpy(®s->a0, afregs->args, sizeof(u64) * 8);
+ regs->epc = afregs->epc;
+ regs->ra = afregs->ra;
+ regs->sp = afregs->sp;
+ regs->s0 = afregs->s0;
+ regs->t1 = afregs->t1;
+ return regs;
+}
+
int ftrace_regs_query_register_offset(const char *name);
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index bf8bb6c10553..ad2b46e1d5b0 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -190,6 +190,23 @@ 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_FTRACE_REGS_HAVING_PT_REGS)
+
+static __always_inline struct pt_regs *
+ftrace_partial_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
+{
+ /*
+ * If CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS=y, ftrace_regs memory
+ * layout is including 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 &arch_ftrace_regs(fregs)->regs;
+}
+
+#endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS || CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS */
+
/*
* 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.
