117 lines
2.6 KiB
C
117 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* ARM callchain support
|
|
*
|
|
* Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
|
|
* Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
|
|
*
|
|
* This code is based on the ARM OProfile backtrace code.
|
|
*/
|
|
#include <linux/perf_event.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
#include <asm/stacktrace.h>
|
|
|
|
/*
|
|
* The registers we're interested in are at the end of the variable
|
|
* length saved register structure. The fp points at the end of this
|
|
* structure so the address of this struct is:
|
|
* (struct frame_tail *)(xxx->fp)-1
|
|
*
|
|
* This code has been adapted from the ARM OProfile support.
|
|
*/
|
|
struct frame_tail {
|
|
struct frame_tail __user *fp;
|
|
unsigned long sp;
|
|
unsigned long lr;
|
|
} __attribute__((packed));
|
|
|
|
/*
|
|
* Get the return address for a single stackframe and return a pointer to the
|
|
* next frame tail.
|
|
*/
|
|
static struct frame_tail __user *
|
|
user_backtrace(struct frame_tail __user *tail,
|
|
struct perf_callchain_entry_ctx *entry)
|
|
{
|
|
struct frame_tail buftail;
|
|
unsigned long err;
|
|
|
|
if (!access_ok(tail, sizeof(buftail)))
|
|
return NULL;
|
|
|
|
pagefault_disable();
|
|
err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
|
|
pagefault_enable();
|
|
|
|
if (err)
|
|
return NULL;
|
|
|
|
perf_callchain_store(entry, buftail.lr);
|
|
|
|
/*
|
|
* Frame pointers should strictly progress back up the stack
|
|
* (towards higher addresses).
|
|
*/
|
|
if (tail + 1 >= buftail.fp)
|
|
return NULL;
|
|
|
|
return buftail.fp - 1;
|
|
}
|
|
|
|
void
|
|
perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
|
|
{
|
|
struct frame_tail __user *tail;
|
|
|
|
perf_callchain_store(entry, regs->ARM_pc);
|
|
|
|
if (!current->mm)
|
|
return;
|
|
|
|
tail = (struct frame_tail __user *)regs->ARM_fp - 1;
|
|
|
|
while ((entry->nr < entry->max_stack) &&
|
|
tail && !((unsigned long)tail & 0x3))
|
|
tail = user_backtrace(tail, entry);
|
|
}
|
|
|
|
/*
|
|
* Gets called by walk_stackframe() for every stackframe. This will be called
|
|
* whist unwinding the stackframe and is like a subroutine return so we use
|
|
* the PC.
|
|
*/
|
|
static bool
|
|
callchain_trace(void *data, unsigned long pc)
|
|
{
|
|
struct perf_callchain_entry_ctx *entry = data;
|
|
perf_callchain_store(entry, pc);
|
|
return true;
|
|
}
|
|
|
|
void
|
|
perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
|
|
{
|
|
struct stackframe fr;
|
|
|
|
arm_get_current_stackframe(regs, &fr);
|
|
walk_stackframe(&fr, callchain_trace, entry);
|
|
}
|
|
|
|
unsigned long perf_instruction_pointer(struct pt_regs *regs)
|
|
{
|
|
return instruction_pointer(regs);
|
|
}
|
|
|
|
unsigned long perf_misc_flags(struct pt_regs *regs)
|
|
{
|
|
int misc = 0;
|
|
|
|
if (user_mode(regs))
|
|
misc |= PERF_RECORD_MISC_USER;
|
|
else
|
|
misc |= PERF_RECORD_MISC_KERNEL;
|
|
|
|
return misc;
|
|
}
|