Commit 82f69454 authored by Youling Tang's avatar Youling Tang Committed by Hongchen Zhang
Browse files

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

mainline inclusion
from mainline-v6.2-rc1
commit 26bc8244
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6BWFP


CVE: NA

--------------------------------

This is a LoongArch port of commit d6e2cc56 ("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: default avatarYouling Tang <tangyouling@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
Change-Id: I95ac7a755a8a3389b63b92c1e98a851c1993c0aa
parent a2603778

arch/loongarch/include/asm/asm-extable.h

+11 −4
Original line number Diff line number Diff line
@@ -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__ */

arch/loongarch/include/asm/extable.h

+11 −0
Original line number Diff line number Diff line
@@ -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

arch/loongarch/kernel/vmlinux.lds.S

+1 −2
Original line number Diff line number Diff line
@@ -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)



	. = ALIGN(PECOFF_SEGMENT_ALIGN);

	__init_begin = .;

	__inittext_begin = .;

arch/loongarch/mm/extable.c

+6 −1
Original line number Diff line number Diff line
@@ -30,5 +30,10 @@ bool fixup_exception(struct pt_regs *regs) 
	if (!ex)

		return false;



	switch (ex->type) {

	case EX_TYPE_FIXUP:

		return ex_handler_fixup(ex, regs);

	}



	BUG();

}

scripts/sorttable.c

+31 −1
Original line number Diff line number Diff line
@@ -231,6 +231,34 @@ static void sort_relative_table(char *extab_image, int image_size) 
	}

}



static void sort_relative_table_with_data(char *extab_image, int image_size)

{

	int i = 0;



	while (i < image_size) {

		uint32_t *loc = (uint32_t *)(extab_image + i);



		w(r(loc) + i, loc);

		w(r(loc + 1) + i + 4, loc + 1);

		/* Don't touch the fixup type or data */



		i += sizeof(uint32_t) * 3;

	}



	qsort(extab_image, image_size / 12, 12, compare_relative_table);



	i = 0;

	while (i < image_size) {

		uint32_t *loc = (uint32_t *)(extab_image + i);



		w(r(loc) - i, loc);

		w(r(loc + 1) - (i + 4), loc + 1);

		/* Don't touch the fixup type or data */



		i += sizeof(uint32_t) * 3;

	}

}



static void x86_sort_relative_table(char *extab_image, int image_size)

{

	int i = 0;
@@ -339,6 +367,9 @@ static int do_file(char const *const fname, void *addr) 
	case EM_X86_64:

		custom_sort = x86_sort_relative_table;

		break;

	case EM_LOONGARCH:

		custom_sort = sort_relative_table_with_data;

		break;

	case EM_S390:

		custom_sort = s390_sort_relative_table;

		break;
@@ -347,7 +378,6 @@ static int do_file(char const *const fname, void *addr) 
	case EM_PPC:

	case EM_ARM:

	case EM_PPC64:

	case EM_LOONGARCH:

		custom_sort = sort_relative_table;

		break;

	case EM_ARCOMPACT: