23fc539e81
On some architectures, access_ok() does not do any argument type checking, so replacing the definition with a generic one causes a few warnings for harmless issues that were never caught before. Fix the ones that I found either through my own test builds or that were reported by the 0-day bot. Reported-by: kernel test robot <lkp@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Dinh Nguyen <dinguyen@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
115 lines
2.8 KiB
C
115 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
// Copyright (C) 2019 Hangzhou C-SKY Microsystems co.,ltd.
|
|
|
|
#include <linux/perf_event.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
/* Kernel callchain */
|
|
struct stackframe {
|
|
unsigned long fp;
|
|
unsigned long lr;
|
|
};
|
|
|
|
static int unwind_frame_kernel(struct stackframe *frame)
|
|
{
|
|
unsigned long low = (unsigned long)task_stack_page(current);
|
|
unsigned long high = low + THREAD_SIZE;
|
|
|
|
if (unlikely(frame->fp < low || frame->fp > high))
|
|
return -EPERM;
|
|
|
|
if (kstack_end((void *)frame->fp) || frame->fp & 0x3)
|
|
return -EPERM;
|
|
|
|
*frame = *(struct stackframe *)frame->fp;
|
|
|
|
if (__kernel_text_address(frame->lr)) {
|
|
int graph = 0;
|
|
|
|
frame->lr = ftrace_graph_ret_addr(NULL, &graph, frame->lr,
|
|
NULL);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void notrace walk_stackframe(struct stackframe *fr,
|
|
struct perf_callchain_entry_ctx *entry)
|
|
{
|
|
do {
|
|
perf_callchain_store(entry, fr->lr);
|
|
} while (unwind_frame_kernel(fr) >= 0);
|
|
}
|
|
|
|
/*
|
|
* Get the return address for a single stackframe and return a pointer to the
|
|
* next frame tail.
|
|
*/
|
|
static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry,
|
|
unsigned long fp, unsigned long reg_lr)
|
|
{
|
|
struct stackframe buftail;
|
|
unsigned long lr = 0;
|
|
unsigned long __user *user_frame_tail = (unsigned long __user *)fp;
|
|
|
|
/* Check accessibility of one struct frame_tail beyond */
|
|
if (!access_ok(user_frame_tail, sizeof(buftail)))
|
|
return 0;
|
|
if (__copy_from_user_inatomic(&buftail, user_frame_tail,
|
|
sizeof(buftail)))
|
|
return 0;
|
|
|
|
if (reg_lr != 0)
|
|
lr = reg_lr;
|
|
else
|
|
lr = buftail.lr;
|
|
|
|
fp = buftail.fp;
|
|
perf_callchain_store(entry, lr);
|
|
|
|
return fp;
|
|
}
|
|
|
|
/*
|
|
* This will be called when the target is in user mode
|
|
* This function will only be called when we use
|
|
* "PERF_SAMPLE_CALLCHAIN" in
|
|
* kernel/events/core.c:perf_prepare_sample()
|
|
*
|
|
* How to trigger perf_callchain_[user/kernel] :
|
|
* $ perf record -e cpu-clock --call-graph fp ./program
|
|
* $ perf report --call-graph
|
|
*
|
|
* On C-SKY platform, the program being sampled and the C library
|
|
* need to be compiled with * -mbacktrace, otherwise the user
|
|
* stack will not contain function frame.
|
|
*/
|
|
void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
|
|
struct pt_regs *regs)
|
|
{
|
|
unsigned long fp = 0;
|
|
|
|
fp = regs->regs[4];
|
|
perf_callchain_store(entry, regs->pc);
|
|
|
|
/*
|
|
* While backtrace from leaf function, lr is normally
|
|
* not saved inside frame on C-SKY, so get lr from pt_regs
|
|
* at the sample point. However, lr value can be incorrect if
|
|
* lr is used as temp register
|
|
*/
|
|
fp = user_backtrace(entry, fp, regs->lr);
|
|
|
|
while (fp && !(fp & 0x3) && entry->nr < entry->max_stack)
|
|
fp = user_backtrace(entry, fp, 0);
|
|
}
|
|
|
|
void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct stackframe fr;
|
|
|
|
fr.fp = regs->regs[4];
|
|
fr.lr = regs->lr;
|
|
walk_stackframe(&fr, entry);
|
|
}
|