MIPS: Extract schedule_mfi info from __schedule
schedule_mfi is supposed to be extracted from schedule(), and is used in thread_saved_pc and get_wchan. But, after optimization, schedule() is reduced to a sibling call to __schedule(), and no real frame info can be extracted. One solution is to compile schedule() with -fno-omit-frame-pointer and -fno-optimize-sibling-calls, but that will incur performance degradation. Another solution is to extract info from the real scheduler, __schedule, and this is the approache adopted here. This patch reads the __schedule address by either following the 'j' call in schedule if KALLSYMS is disabled or by using kallsyms_lookup_name to lookup __schedule if KALLSYMS is available, then, extracts schedule_mfi from __schedule frame info. This patch also fixes the "Can't analyze schedule() prologue" warning at boot time. Signed-off-by: Tony Wu <tung7970@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5237/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
parent
e7438c4b89
commit
5000653e92
|
@ -224,6 +224,9 @@ struct mips_frame_info {
|
|||
int pc_offset;
|
||||
};
|
||||
|
||||
#define J_TARGET(pc,target) \
|
||||
(((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
|
||||
|
||||
static inline int is_ra_save_ins(union mips_instruction *ip)
|
||||
{
|
||||
#ifdef CONFIG_CPU_MICROMIPS
|
||||
|
@ -395,15 +398,42 @@ err:
|
|||
|
||||
static struct mips_frame_info schedule_mfi __read_mostly;
|
||||
|
||||
#ifdef CONFIG_KALLSYMS
|
||||
static unsigned long get___schedule_addr(void)
|
||||
{
|
||||
return kallsyms_lookup_name("__schedule");
|
||||
}
|
||||
#else
|
||||
static unsigned long get___schedule_addr(void)
|
||||
{
|
||||
union mips_instruction *ip = (void *)schedule;
|
||||
int max_insns = 8;
|
||||
int i;
|
||||
|
||||
for (i = 0; i < max_insns; i++, ip++) {
|
||||
if (ip->j_format.opcode == j_op)
|
||||
return J_TARGET(ip, ip->j_format.target);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
#endif
|
||||
|
||||
static int __init frame_info_init(void)
|
||||
{
|
||||
unsigned long size = 0;
|
||||
#ifdef CONFIG_KALLSYMS
|
||||
unsigned long ofs;
|
||||
|
||||
kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);
|
||||
#endif
|
||||
schedule_mfi.func = schedule;
|
||||
unsigned long addr;
|
||||
|
||||
addr = get___schedule_addr();
|
||||
if (!addr)
|
||||
addr = (unsigned long)schedule;
|
||||
|
||||
#ifdef CONFIG_KALLSYMS
|
||||
kallsyms_lookup_size_offset(addr, &size, &ofs);
|
||||
#endif
|
||||
schedule_mfi.func = (void *)addr;
|
||||
schedule_mfi.func_size = size;
|
||||
|
||||
get_frame_info(&schedule_mfi);
|
||||
|
|
Loading…
Reference in a new issue