linux/arch/loongarch/kernel/lbt.S
Tiezhu Yang cb8a2ef084 LoongArch: Add ORC stack unwinder support
The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is
similar in concept to a DWARF unwinder. The difference is that the format
of the ORC data is much simpler than DWARF, which in turn allows the ORC
unwinder to be much simpler and faster.

The ORC data consists of unwind tables which are generated by objtool.
After analyzing all the code paths of a .o file, it determines information
about the stack state at each instruction address in the file and outputs
that information to the .orc_unwind and .orc_unwind_ip sections.

The per-object ORC sections are combined at link time and are sorted and
post-processed at boot time. The unwinder uses the resulting data to
correlate instruction addresses with their stack states at run time.

Most of the logic are similar with x86, in order to get ra info before ra
is saved into stack, add ra_reg and ra_offset into orc_entry. At the same
time, modify some arch-specific code to silence the objtool warnings.

Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-03-11 22:23:47 +08:00

159 lines
3.0 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Author: Qi Hu <huqi@loongson.cn>
* Huacai Chen <chenhuacai@loongson.cn>
*
* Copyright (C) 2020-2023 Loongson Technology Corporation Limited
*/
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/asm-extable.h>
#include <asm/asm-offsets.h>
#include <asm/errno.h>
#include <asm/regdef.h>
#include <asm/unwind_hints.h>
#define SCR_REG_WIDTH 8
.macro EX insn, reg, src, offs
.ex\@: \insn \reg, \src, \offs
_asm_extable .ex\@, .L_lbt_fault
.endm
/*
* Save a thread's lbt context.
*/
SYM_FUNC_START(_save_lbt)
movscr2gr t1, $scr0 # save scr
stptr.d t1, a0, THREAD_SCR0
movscr2gr t1, $scr1
stptr.d t1, a0, THREAD_SCR1
movscr2gr t1, $scr2
stptr.d t1, a0, THREAD_SCR2
movscr2gr t1, $scr3
stptr.d t1, a0, THREAD_SCR3
x86mfflag t1, 0x3f # save eflags
stptr.d t1, a0, THREAD_EFLAGS
jr ra
SYM_FUNC_END(_save_lbt)
EXPORT_SYMBOL(_save_lbt)
/*
* Restore a thread's lbt context.
*/
SYM_FUNC_START(_restore_lbt)
ldptr.d t1, a0, THREAD_SCR0 # restore scr
movgr2scr $scr0, t1
ldptr.d t1, a0, THREAD_SCR1
movgr2scr $scr1, t1
ldptr.d t1, a0, THREAD_SCR2
movgr2scr $scr2, t1
ldptr.d t1, a0, THREAD_SCR3
movgr2scr $scr3, t1
ldptr.d t1, a0, THREAD_EFLAGS # restore eflags
x86mtflag t1, 0x3f
jr ra
SYM_FUNC_END(_restore_lbt)
EXPORT_SYMBOL(_restore_lbt)
/*
* Load scr/eflag with zero.
*/
SYM_FUNC_START(_init_lbt)
movgr2scr $scr0, zero
movgr2scr $scr1, zero
movgr2scr $scr2, zero
movgr2scr $scr3, zero
x86mtflag zero, 0x3f
jr ra
SYM_FUNC_END(_init_lbt)
/*
* a0: scr
* a1: eflag
*/
SYM_FUNC_START(_save_lbt_context)
movscr2gr t1, $scr0 # save scr
EX st.d t1, a0, (0 * SCR_REG_WIDTH)
movscr2gr t1, $scr1
EX st.d t1, a0, (1 * SCR_REG_WIDTH)
movscr2gr t1, $scr2
EX st.d t1, a0, (2 * SCR_REG_WIDTH)
movscr2gr t1, $scr3
EX st.d t1, a0, (3 * SCR_REG_WIDTH)
x86mfflag t1, 0x3f # save eflags
EX st.w t1, a1, 0
li.w a0, 0 # success
jr ra
SYM_FUNC_END(_save_lbt_context)
/*
* a0: scr
* a1: eflag
*/
SYM_FUNC_START(_restore_lbt_context)
EX ld.d t1, a0, (0 * SCR_REG_WIDTH) # restore scr
movgr2scr $scr0, t1
EX ld.d t1, a0, (1 * SCR_REG_WIDTH)
movgr2scr $scr1, t1
EX ld.d t1, a0, (2 * SCR_REG_WIDTH)
movgr2scr $scr2, t1
EX ld.d t1, a0, (3 * SCR_REG_WIDTH)
movgr2scr $scr3, t1
EX ld.w t1, a1, 0 # restore eflags
x86mtflag t1, 0x3f
li.w a0, 0 # success
jr ra
SYM_FUNC_END(_restore_lbt_context)
/*
* a0: ftop
*/
SYM_FUNC_START(_save_ftop_context)
x86mftop t1
st.w t1, a0, 0
li.w a0, 0 # success
jr ra
SYM_FUNC_END(_save_ftop_context)
/*
* a0: ftop
*/
SYM_FUNC_START(_restore_ftop_context)
ld.w t1, a0, 0
andi t1, t1, 0x7
la.pcrel a0, 1f
alsl.d a0, t1, a0, 3
jr a0
1:
x86mttop 0
b 2f
x86mttop 1
b 2f
x86mttop 2
b 2f
x86mttop 3
b 2f
x86mttop 4
b 2f
x86mttop 5
b 2f
x86mttop 6
b 2f
x86mttop 7
2:
li.w a0, 0 # success
jr ra
SYM_FUNC_END(_restore_ftop_context)
.L_lbt_fault:
li.w a0, -EFAULT # failure
jr ra
STACK_FRAME_NON_STANDARD _restore_ftop_context