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LoongArch: extable: Add `type` and `data` fields 

This is a LoongArch port of commit d6e2cc5647 ("arm64: extable: add
`type` and `data` fields").

Subsequent patches will add specialized handlers for fixups, in addition
to the simple PC fixup we have today. In preparation, this patch adds a
new `type` field to struct exception_table_entry, and uses this to
distinguish the fixup and other cases. A `data` field is also added so
that subsequent patches can associate data specific to each exception
site (e.g. register numbers).

Handlers are named ex_handler_*() for consistency, following the example
of x86. At the same time, get_ex_fixup() is split out into a helper so
that it can be used by other ex_handler_*() functions in the subsequent
patches.

Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Youling Tang 2022-12-10 22:39:59 +08:00 committed by Huacai Chen
parent 3d36f4298b
commit 26bc824412
5 changed files with 30 additions and 8 deletions
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15
arch/loongarch/include/asm/asm-extable.h
View File

@ -2,17 +2,22 @@
#ifndef __ASM_ASM_EXTABLE_H
#define __ASM_ASM_EXTABLE_H
#define EX_TYPE_NONE 0
#define EX_TYPE_FIXUP 1
#ifdef __ASSEMBLY__
#define __ASM_EXTABLE_RAW(insn, fixup) \
#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
.pushsection __ex_table, "a"; \
.balign 4; \
.long ((insn) - .); \
.long ((fixup) - .); \
.short (type); \
.short (data); \
.popsection;
.macro _asm_extable, insn, fixup
__ASM_EXTABLE_RAW(\insn, \fixup)
__ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0)
.endm
#else /* __ASSEMBLY__ */
@ -20,15 +25,17 @@
#include <linux/bits.h>
#include <linux/stringify.h>
#define __ASM_EXTABLE_RAW(insn, fixup) \
#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
".pushsection __ex_table, \"a\"\n" \
".balign 4\n" \
".long ((" insn ") - .)\n" \
".long ((" fixup ") - .)\n" \
".short (" type ")\n" \
".short (" data ")\n" \
".popsection\n"
#define _ASM_EXTABLE(insn, fixup) \
__ASM_EXTABLE_RAW(#insn, #fixup)
__ASM_EXTABLE_RAW(#insn, #fixup, __stringify(EX_TYPE_FIXUP), "0")
#endif /* __ASSEMBLY__ */

11
arch/loongarch/include/asm/extable.h
View File

@ -17,10 +17,21 @@
struct exception_table_entry {
int insn, fixup;
short type, data;
};
#define ARCH_HAS_RELATIVE_EXTABLE
#define swap_ex_entry_fixup(a, b, tmp, delta) \
do { \
(a)->fixup = (b)->fixup + (delta); \
(b)->fixup = (tmp).fixup - (delta); \
(a)->type = (b)->type; \
(b)->type = (tmp).type; \
(a)->data = (b)->data; \
(b)->data = (tmp).data; \
} while (0)
bool fixup_exception(struct pt_regs *regs);
#endif

3
arch/loongarch/kernel/vmlinux.lds.S
View File

@ -4,6 +4,7 @@
#include <asm/thread_info.h>
#define PAGE_SIZE _PAGE_SIZE
#define RO_EXCEPTION_TABLE_ALIGN 4
/*
* Put .bss..swapper_pg_dir as the first thing in .bss. This will
@ -53,8 +54,6 @@ SECTIONS
. = ALIGN(PECOFF_SEGMENT_ALIGN);
_etext = .;
EXCEPTION_TABLE(16)
.got : ALIGN(16) { *(.got) }
.plt : ALIGN(16) { *(.plt) }
.got.plt : ALIGN(16) { *(.got.plt) }

7
arch/loongarch/mm/extable.c
View File

@ -30,5 +30,10 @@ bool fixup_exception(struct pt_regs *regs)
if (!ex)
return false;
return ex_handler_fixup(ex, regs);
switch (ex->type) {
case EX_TYPE_FIXUP:
return ex_handler_fixup(ex, regs);
}
BUG();
}

2
scripts/sorttable.c
View File

@ -304,6 +304,7 @@ static int do_file(char const *const fname, void *addr)
switch (r2(&ehdr->e_machine)) {
case EM_386:
case EM_AARCH64:
case EM_LOONGARCH:
case EM_RISCV:
case EM_S390:
case EM_X86_64:
@ -312,7 +313,6 @@ static int do_file(char const *const fname, void *addr)
case EM_PARISC:
case EM_PPC:
case EM_PPC64:
case EM_LOONGARCH:
custom_sort = sort_relative_table;
break;
case EM_ARCOMPACT: