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tracing: Add ftrace_partial_regs() for converting ftrace_regs to pt_regs

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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@kernel.org>
Acked-by: Florent Revest <revest@chromium.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Link: https://lore.kernel.org/173518996761.391279.4987911298206448122.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu (Google)
2024-12-26 14:12:47 +09:00
committed by Steven Rostedt (Google)
parent 762abbc0d0
commit b9b55c8912
3 changed files with 44 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
arch/arm64/include/asm/ftrace.h
View File

@@ -135,6 +135,19 @@ 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)
{
struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs);
memcpy(regs->regs, afregs->regs, sizeof(afregs->regs));
regs->sp = afregs->sp;
regs->pc = afregs->pc;
regs->regs[29] = afregs->fp;
regs->regs[30] = afregs->lr;
return regs;
}
int ftrace_regs_query_register_offset(const char *name);
int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);

14
arch/riscv/include/asm/ftrace.h
View File

@@ -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(&regs->a0, afregs->args, sizeof(afregs->args));
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,

17
include/linux/ftrace.h
View File

@@ -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.