Commit 9fde0348 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Geert Uytterhoeven
Browse files

m68k: Remove set_fs() 



Add a m68k-only set_fc helper to set the SFC and DFC registers for the
few places that need to override it for special MM operations, but
disconnect that from the deprecated kernel-wide set_fs() API.

Note that the SFC/DFC registers are context switched, so there is no need
to disable preemption.

Partially based on an earlier patch from
Linus Torvalds <torvalds@linux-foundation.org>.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Tested-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Link: https://lore.kernel.org/r/20210916070405.52750-7-hch@lst.de


Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent 8ade8339

arch/m68k/68000/entry.S

+0 −1
Original line number Diff line number Diff line
@@ -15,7 +15,6 @@ 
#include <asm/unistd.h>

#include <asm/errno.h>

#include <asm/setup.h>

#include <asm/segment.h>

#include <asm/traps.h>

#include <asm/asm-offsets.h>

#include <asm/entry.h>

arch/m68k/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -29,7 +29,6 @@ config M68K 
	select NO_DMA if !MMU && !COLDFIRE

	select OLD_SIGACTION

	select OLD_SIGSUSPEND3

	select SET_FS

	select UACCESS_MEMCPY if !MMU

	select VIRT_TO_BUS

	select ZONE_DMA

arch/m68k/coldfire/entry.S

+0 −1
Original line number Diff line number Diff line
@@ -31,7 +31,6 @@ 
#include <asm/thread_info.h>

#include <asm/errno.h>

#include <asm/setup.h>

#include <asm/segment.h>

#include <asm/asm-offsets.h>

#include <asm/entry.h>

arch/m68k/include/asm/processor.h

+28 −3
Original line number Diff line number Diff line
@@ -9,7 +9,6 @@ 
#define __ASM_M68K_PROCESSOR_H



#include <linux/thread_info.h>

#include <asm/segment.h>

#include <asm/fpu.h>

#include <asm/ptrace.h>
@@ -75,11 +74,37 @@ static inline void wrusp(unsigned long usp) 
#define TASK_UNMAPPED_BASE	0

#endif



/* Address spaces (or Function Codes in Motorola lingo) */

#define USER_DATA     1

#define USER_PROGRAM  2

#define SUPER_DATA    5

#define SUPER_PROGRAM 6

#define CPU_SPACE     7



#ifdef CONFIG_CPU_HAS_ADDRESS_SPACES

/*

 * Set the SFC/DFC registers for special MM operations.  For most normal

 * operation these remain set to USER_DATA for the uaccess routines.

 */

static inline void set_fc(unsigned long val)

{

	WARN_ON_ONCE(in_interrupt());



	__asm__ __volatile__ ("movec %0,%/sfc\n\t"

			      "movec %0,%/dfc\n\t"

			      : /* no outputs */ : "r" (val) : "memory");

}

#else

static inline void set_fc(unsigned long val)

{

}

#endif /* CONFIG_CPU_HAS_ADDRESS_SPACES */



struct thread_struct {

	unsigned long  ksp;		/* kernel stack pointer */

	unsigned long  usp;		/* user stack pointer */

	unsigned short sr;		/* saved status register */

	unsigned short fs;		/* saved fs (sfc, dfc) */

	unsigned short fc;		/* saved fc (sfc, dfc) */

	unsigned long  crp[2];		/* cpu root pointer */

	unsigned long  esp0;		/* points to SR of stack frame */

	unsigned long  faddr;		/* info about last fault */
@@ -92,7 +117,7 @@ struct thread_struct { 
#define INIT_THREAD  {							\

	.ksp	= sizeof(init_stack) + (unsigned long) init_stack,	\

	.sr	= PS_S,							\

	.fs	= __KERNEL_DS,						\

	.fc	= USER_DATA,						\

}



/*

arch/m68k/include/asm/segment.h

deleted100644 → 0
+0 −59
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _M68K_SEGMENT_H

#define _M68K_SEGMENT_H



/* define constants */

/* Address spaces (FC0-FC2) */

#define USER_DATA     (1)

#ifndef __USER_DS

#define __USER_DS     (USER_DATA)

#endif

#define USER_PROGRAM  (2)

#define SUPER_DATA    (5)

#ifndef __KERNEL_DS

#define __KERNEL_DS   (SUPER_DATA)

#endif

#define SUPER_PROGRAM (6)

#define CPU_SPACE     (7)



#ifndef __ASSEMBLY__



typedef struct {

	unsigned long seg;

} mm_segment_t;



#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })



#ifdef CONFIG_CPU_HAS_ADDRESS_SPACES

/*

 * Get/set the SFC/DFC registers for MOVES instructions

 */

#define USER_DS		MAKE_MM_SEG(__USER_DS)

#define KERNEL_DS	MAKE_MM_SEG(__KERNEL_DS)



static inline mm_segment_t get_fs(void)

{

	mm_segment_t _v;

	__asm__ ("movec %/dfc,%0":"=r" (_v.seg):);

	return _v;

}



static inline void set_fs(mm_segment_t val)

{

	__asm__ __volatile__ ("movec %0,%/sfc\n\t"

			      "movec %0,%/dfc\n\t"

			      : /* no outputs */ : "r" (val.seg) : "memory");

}



#else

#define USER_DS		MAKE_MM_SEG(TASK_SIZE)

#define KERNEL_DS	MAKE_MM_SEG(0xFFFFFFFF)

#define get_fs()	(current_thread_info()->addr_limit)

#define set_fs(x)	(current_thread_info()->addr_limit = (x))

#endif



#define uaccess_kernel()	(get_fs().seg == KERNEL_DS.seg)



#endif /* __ASSEMBLY__ */



#endif /* _M68K_SEGMENT_H */