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linux/arch/mips/lib/memset.S
James Hogan d6a428fb58 MIPS: uaccess: Take EVA into account in [__]clear_user 
__clear_user() (and clear_user() which uses it), always access the user
mode address space, which results in EVA store instructions when EVA is
enabled even if the current user address limit is KERNEL_DS.

Fix this by adding a new symbol __bzero_kernel for the normal kernel
address space bzero in EVA mode, and call that from __clear_user() if
eva_kernel_access().

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10844/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-12-22 11:58:43 +01:00

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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1998, 1999, 2000 by Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2007 by Maciej W. Rozycki
* Copyright (C) 2011, 2012 MIPS Technologies, Inc.
*/
#include <asm/asm.h>
#include <asm/asm-offsets.h>
#include <asm/regdef.h>
#if LONGSIZE == 4
#define LONG_S_L swl
#define LONG_S_R swr
#else
#define LONG_S_L sdl
#define LONG_S_R sdr
#endif
#ifdef CONFIG_CPU_MICROMIPS
#define STORSIZE (LONGSIZE * 2)
#define STORMASK (STORSIZE - 1)
#define FILL64RG t8
#define FILLPTRG t7
#undef LONG_S
#define LONG_S LONG_SP
#else
#define STORSIZE LONGSIZE
#define STORMASK LONGMASK
#define FILL64RG a1
#define FILLPTRG t0
#endif
#define LEGACY_MODE 1
#define EVA_MODE 2
/*
* No need to protect it with EVA #ifdefery. The generated block of code
* will never be assembled if EVA is not enabled.
*/
#define __EVAFY(insn, reg, addr) __BUILD_EVA_INSN(insn##e, reg, addr)
#define ___BUILD_EVA_INSN(insn, reg, addr) __EVAFY(insn, reg, addr)
#define EX(insn,reg,addr,handler) \
.if \mode == LEGACY_MODE; \
9: insn reg, addr; \
.else; \
9: ___BUILD_EVA_INSN(insn, reg, addr); \
.endif; \
.section __ex_table,"a"; \
PTR 9b, handler; \
.previous
.macro f_fill64 dst, offset, val, fixup, mode
EX(LONG_S, \val, (\offset + 0 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 1 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 2 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 3 * STORSIZE)(\dst), \fixup)
#if ((defined(CONFIG_CPU_MICROMIPS) && (LONGSIZE == 4)) || !defined(CONFIG_CPU_MICROMIPS))
EX(LONG_S, \val, (\offset + 4 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 5 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 6 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 7 * STORSIZE)(\dst), \fixup)
#endif
#if (!defined(CONFIG_CPU_MICROMIPS) && (LONGSIZE == 4))
EX(LONG_S, \val, (\offset + 8 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 9 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 10 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 11 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 12 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 13 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 14 * STORSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 15 * STORSIZE)(\dst), \fixup)
#endif
.endm
.set noreorder
.align 5
/*
* Macro to generate the __bzero{,_user} symbol
* Arguments:
* mode: LEGACY_MODE or EVA_MODE
*/
.macro __BUILD_BZERO mode
/* Initialize __memset if this is the first time we call this macro */
.ifnotdef __memset
.set __memset, 1
.hidden __memset /* Make sure it does not leak */
.endif
sltiu t0, a2, STORSIZE /* very small region? */
bnez t0, .Lsmall_memset\@
andi t0, a0, STORMASK /* aligned? */
#ifdef CONFIG_CPU_MICROMIPS
move t8, a1 /* used by 'swp' instruction */
move t9, a1
#endif
#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
beqz t0, 1f
PTR_SUBU t0, STORSIZE /* alignment in bytes */
#else
.set noat
li AT, STORSIZE
beqz t0, 1f
PTR_SUBU t0, AT /* alignment in bytes */
.set at
#endif
#ifndef CONFIG_CPU_MIPSR6
R10KCBARRIER(0(ra))
#ifdef __MIPSEB__
EX(LONG_S_L, a1, (a0), .Lfirst_fixup\@) /* make word/dword aligned */
#else
EX(LONG_S_R, a1, (a0), .Lfirst_fixup\@) /* make word/dword aligned */
#endif
PTR_SUBU a0, t0 /* long align ptr */
PTR_ADDU a2, t0 /* correct size */
#else /* CONFIG_CPU_MIPSR6 */
#define STORE_BYTE(N) \
EX(sb, a1, N(a0), .Lbyte_fixup\@); \
beqz t0, 0f; \
PTR_ADDU t0, 1;
PTR_ADDU a2, t0 /* correct size */
PTR_ADDU t0, 1
STORE_BYTE(0)
STORE_BYTE(1)
#if LONGSIZE == 4
EX(sb, a1, 2(a0), .Lbyte_fixup\@)
#else
STORE_BYTE(2)
STORE_BYTE(3)
STORE_BYTE(4)
STORE_BYTE(5)
EX(sb, a1, 6(a0), .Lbyte_fixup\@)
#endif
0:
ori a0, STORMASK
xori a0, STORMASK
PTR_ADDIU a0, STORSIZE
#endif /* CONFIG_CPU_MIPSR6 */
1: ori t1, a2, 0x3f /* # of full blocks */
xori t1, 0x3f
beqz t1, .Lmemset_partial\@ /* no block to fill */
andi t0, a2, 0x40-STORSIZE
PTR_ADDU t1, a0 /* end address */
.set reorder
1: PTR_ADDIU a0, 64
R10KCBARRIER(0(ra))
f_fill64 a0, -64, FILL64RG, .Lfwd_fixup\@, \mode
bne t1, a0, 1b
.set noreorder
.Lmemset_partial\@:
R10KCBARRIER(0(ra))
PTR_LA t1, 2f /* where to start */
#ifdef CONFIG_CPU_MICROMIPS
LONG_SRL t7, t0, 1
#endif
#if LONGSIZE == 4
PTR_SUBU t1, FILLPTRG
#else
.set noat
LONG_SRL AT, FILLPTRG, 1
PTR_SUBU t1, AT
.set at
#endif
jr t1
PTR_ADDU a0, t0 /* dest ptr */
.set push
.set noreorder
.set nomacro
/* ... but first do longs ... */
f_fill64 a0, -64, FILL64RG, .Lpartial_fixup\@, \mode
2: .set pop
andi a2, STORMASK /* At most one long to go */
beqz a2, 1f
#ifndef CONFIG_CPU_MIPSR6
PTR_ADDU a0, a2 /* What's left */
R10KCBARRIER(0(ra))
#ifdef __MIPSEB__
EX(LONG_S_R, a1, -1(a0), .Llast_fixup\@)
#else
EX(LONG_S_L, a1, -1(a0), .Llast_fixup\@)
#endif
#else
PTR_SUBU t0, $0, a2
PTR_ADDIU t0, 1
STORE_BYTE(0)
STORE_BYTE(1)
#if LONGSIZE == 4
EX(sb, a1, 2(a0), .Lbyte_fixup\@)
#else
STORE_BYTE(2)
STORE_BYTE(3)
STORE_BYTE(4)
STORE_BYTE(5)
EX(sb, a1, 6(a0), .Lbyte_fixup\@)
#endif
0:
#endif
1: jr ra
move a2, zero
.Lsmall_memset\@:
beqz a2, 2f
PTR_ADDU t1, a0, a2
1: PTR_ADDIU a0, 1 /* fill bytewise */
R10KCBARRIER(0(ra))
bne t1, a0, 1b
sb a1, -1(a0)
2: jr ra /* done */
move a2, zero
.if __memset == 1
END(memset)
.set __memset, 0
.hidden __memset
.endif
.Lbyte_fixup\@:
PTR_SUBU a2, $0, t0
jr ra
PTR_ADDIU a2, 1
.Lfirst_fixup\@:
jr ra
nop
.Lfwd_fixup\@:
PTR_L t0, TI_TASK($28)
andi a2, 0x3f
LONG_L t0, THREAD_BUADDR(t0)
LONG_ADDU a2, t1
jr ra
LONG_SUBU a2, t0
.Lpartial_fixup\@:
PTR_L t0, TI_TASK($28)
andi a2, STORMASK
LONG_L t0, THREAD_BUADDR(t0)
LONG_ADDU a2, t1
jr ra
LONG_SUBU a2, t0
.Llast_fixup\@:
jr ra
andi v1, a2, STORMASK
.endm
/*
* memset(void *s, int c, size_t n)
*
* a0: start of area to clear
* a1: char to fill with
* a2: size of area to clear
*/
LEAF(memset)
beqz a1, 1f
move v0, a0 /* result */
andi a1, 0xff /* spread fillword */
LONG_SLL t1, a1, 8
or a1, t1
LONG_SLL t1, a1, 16
#if LONGSIZE == 8
or a1, t1
LONG_SLL t1, a1, 32
#endif
or a1, t1
1:
#ifndef CONFIG_EVA
FEXPORT(__bzero)
#else
FEXPORT(__bzero_kernel)
#endif
__BUILD_BZERO LEGACY_MODE
#ifdef CONFIG_EVA
LEAF(__bzero)
__BUILD_BZERO EVA_MODE
END(__bzero)
#endif
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