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m68k: Remove set_fs()

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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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Link: https://lore.kernel.org/r/20210916070405.52750-7-hch@lst.de
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
This commit is contained in:
Christoph Hellwig 2021-09-16 09:04:05 +02:00 committed by Geert Uytterhoeven
parent 8ade833909
commit 9fde034864
22 changed files with 46 additions and 117 deletions
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1
arch/m68k/68000/entry.S
View file

@ -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>

1
arch/m68k/Kconfig
View file

@ -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

1
arch/m68k/coldfire/entry.S
View file

@ -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>

31
arch/m68k/include/asm/processor.h
View file

@ -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, \
}
/*

59
arch/m68k/include/asm/segment.h
View file

@ -1,59 +0,0 @@
/* 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 */

3
arch/m68k/include/asm/thread_info.h
View file

@ -4,7 +4,6 @@
#include <asm/types.h>
#include <asm/page.h>
#include <asm/segment.h>
/*
* On machines with 4k pages we default to an 8k thread size, though we
@ -27,7 +26,6 @@
struct thread_info {
struct task_struct *task; /* main task structure */
unsigned long flags;
mm_segment_t addr_limit; /* thread address space */
int preempt_count; /* 0 => preemptable, <0 => BUG */
__u32 cpu; /* should always be 0 on m68k */
unsigned long tp_value; /* thread pointer */
@ -37,7 +35,6 @@ struct thread_info {
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
.addr_limit = KERNEL_DS, \
.preempt_count = INIT_PREEMPT_COUNT, \
}

11
arch/m68k/include/asm/tlbflush.h
View file

@ -13,13 +13,12 @@ static inline void flush_tlb_kernel_page(void *addr)
if (CPU_IS_COLDFIRE) {
mmu_write(MMUOR, MMUOR_CNL);
} else if (CPU_IS_040_OR_060) {
mm_segment_t old_fs = get_fs();
set_fs(KERNEL_DS);
set_fc(SUPER_DATA);
__asm__ __volatile__(".chip 68040\n\t"
"pflush (%0)\n\t"
".chip 68k"
: : "a" (addr));
set_fs(old_fs);
set_fc(USER_DATA);
} else if (CPU_IS_020_OR_030)
__asm__ __volatile__("pflush #4,#4,(%0)" : : "a" (addr));
}
@ -84,12 +83,8 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
{
if (vma->vm_mm == current->active_mm) {
mm_segment_t old_fs = force_uaccess_begin();
if (vma->vm_mm == current->active_mm)
__flush_tlb_one(addr);
force_uaccess_end(old_fs);
}
}
static inline void flush_tlb_range(struct vm_area_struct *vma,

4
arch/m68k/include/asm/uaccess.h
View file

@ -9,7 +9,6 @@
*/
#include <linux/compiler.h>
#include <linux/types.h>
#include <asm/segment.h>
#include <asm/extable.h>
/* We let the MMU do all checking */
@ -451,9 +450,6 @@ do { \
goto err_label; \
} while (0)
#define user_addr_max() \
(uaccess_kernel() ? ~0UL : TASK_SIZE)
extern long strncpy_from_user(char *dst, const char __user *src, long count);
extern __must_check long strnlen_user(const char __user *str, long n);

2
arch/m68k/kernel/asm-offsets.c
View file

@ -31,7 +31,7 @@ int main(void)
DEFINE(THREAD_KSP, offsetof(struct thread_struct, ksp));
DEFINE(THREAD_USP, offsetof(struct thread_struct, usp));
DEFINE(THREAD_SR, offsetof(struct thread_struct, sr));
DEFINE(THREAD_FS, offsetof(struct thread_struct, fs));
DEFINE(THREAD_FC, offsetof(struct thread_struct, fc));
DEFINE(THREAD_CRP, offsetof(struct thread_struct, crp));
DEFINE(THREAD_ESP0, offsetof(struct thread_struct, esp0));
DEFINE(THREAD_FPREG, offsetof(struct thread_struct, fp));

5
arch/m68k/kernel/entry.S
View file

@ -36,7 +36,6 @@
#include <linux/linkage.h>
#include <asm/errno.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/traps.h>
#include <asm/unistd.h>
#include <asm/asm-offsets.h>
@ -337,7 +336,7 @@ resume:
/* save fs (sfc,%dfc) (may be pointing to kernel memory) */
movec %sfc,%d0
movew %d0,%a0@(TASK_THREAD+THREAD_FS)
movew %d0,%a0@(TASK_THREAD+THREAD_FC)
/* save usp */
/* it is better to use a movel here instead of a movew 8*) */
@ -423,7 +422,7 @@ resume:
movel %a0,%usp
/* restore fs (sfc,%dfc) */
movew %a1@(TASK_THREAD+THREAD_FS),%a0
movew %a1@(TASK_THREAD+THREAD_FC),%a0
movec %a0,%sfc
movec %a0,%dfc

4
arch/m68k/kernel/process.c
View file

@ -92,7 +92,7 @@ void show_regs(struct pt_regs * regs)
void flush_thread(void)
{
current->thread.fs = __USER_DS;
current->thread.fc = USER_DATA;
#ifdef CONFIG_FPU
if (!FPU_IS_EMU) {
unsigned long zero = 0;
@ -155,7 +155,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
* Must save the current SFC/DFC value, NOT the value when
* the parent was last descheduled - RGH 10-08-96
*/
p->thread.fs = get_fs().seg;
p->thread.fc = USER_DATA;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
/* kernel thread */

13
arch/m68k/kernel/traps.c
View file

@ -181,9 +181,8 @@ static inline void access_error060 (struct frame *fp)
static inline unsigned long probe040(int iswrite, unsigned long addr, int wbs)
{
unsigned long mmusr;
mm_segment_t old_fs = get_fs();
set_fs(MAKE_MM_SEG(wbs));
set_fc(wbs);
if (iswrite)
asm volatile (".chip 68040; ptestw (%0); .chip 68k" : : "a" (addr));
@ -192,7 +191,7 @@ static inline unsigned long probe040(int iswrite, unsigned long addr, int wbs)
asm volatile (".chip 68040; movec %%mmusr,%0; .chip 68k" : "=r" (mmusr));
set_fs(old_fs);
set_fc(USER_DATA);
return mmusr;
}
@ -201,10 +200,8 @@ static inline int do_040writeback1(unsigned short wbs, unsigned long wba,
unsigned long wbd)
{
int res = 0;
mm_segment_t old_fs = get_fs();
/* set_fs can not be moved, otherwise put_user() may oops */
set_fs(MAKE_MM_SEG(wbs));
set_fc(wbs);
switch (wbs & WBSIZ_040) {
case BA_SIZE_BYTE:
@ -218,9 +215,7 @@ static inline int do_040writeback1(unsigned short wbs, unsigned long wba,
break;
}
/* set_fs can not be moved, otherwise put_user() may oops */
set_fs(old_fs);
set_fc(USER_DATA);
pr_debug("do_040writeback1, res=%d\n", res);

1
arch/m68k/mac/misc.c
View file

@ -18,7 +18,6 @@
#include <linux/uaccess.h>
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/setup.h>
#include <asm/macintosh.h>
#include <asm/mac_via.h>

6
arch/m68k/mm/cache.c
View file

@ -90,11 +90,9 @@ void flush_icache_user_range(unsigned long address, unsigned long endaddr)
void flush_icache_range(unsigned long address, unsigned long endaddr)
{
mm_segment_t old_fs = get_fs();
set_fs(KERNEL_DS);
set_fc(SUPER_DATA);
flush_icache_user_range(address, endaddr);
set_fs(old_fs);
set_fc(USER_DATA);
}
EXPORT_SYMBOL(flush_icache_range);

6
arch/m68k/mm/init.c
View file

@ -72,12 +72,6 @@ void __init paging_init(void)
if (!empty_zero_page)
panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
__func__, PAGE_SIZE, PAGE_SIZE);
/*
* Set up SFC/DFC registers (user data space).
*/
set_fs (USER_DS);
max_zone_pfn[ZONE_DMA] = end_mem >> PAGE_SHIFT;
free_area_init(max_zone_pfn);
}

1
arch/m68k/mm/kmap.c
View file

@ -17,7 +17,6 @@
#include <linux/vmalloc.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/io.h>
#include <asm/tlbflush.h>

1
arch/m68k/mm/memory.c
View file

@ -15,7 +15,6 @@
#include <linux/gfp.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/traps.h>
#include <asm/machdep.h>

2
arch/m68k/mm/motorola.c
View file

@ -467,7 +467,7 @@ void __init paging_init(void)
/*
* Set up SFC/DFC registers
*/
set_fs(KERNEL_DS);
set_fc(USER_DATA);
#ifdef DEBUG
printk ("before free_area_init\n");

3
arch/m68k/sun3/config.c
View file

@ -31,7 +31,6 @@
#include <asm/intersil.h>
#include <asm/irq.h>
#include <asm/sections.h>
#include <asm/segment.h>
#include <asm/sun3ints.h>
char sun3_reserved_pmeg[SUN3_PMEGS_NUM];
@ -89,7 +88,7 @@ void __init sun3_init(void)
sun3_reserved_pmeg[249] = 1;
sun3_reserved_pmeg[252] = 1;
sun3_reserved_pmeg[253] = 1;
set_fs(KERNEL_DS);
set_fc(USER_DATA);
}
/* Without this, Bad Things happen when something calls arch_reset. */

6
arch/m68k/sun3/mmu_emu.c
View file

@ -23,7 +23,6 @@
#include <linux/uaccess.h>
#include <asm/page.h>
#include <asm/sun3mmu.h>
#include <asm/segment.h>
#include <asm/oplib.h>
#include <asm/mmu_context.h>
#include <asm/dvma.h>
@ -191,14 +190,13 @@ void __init mmu_emu_init(unsigned long bootmem_end)
for(seg = 0; seg < PAGE_OFFSET; seg += SUN3_PMEG_SIZE)
sun3_put_segmap(seg, SUN3_INVALID_PMEG);
set_fs(MAKE_MM_SEG(3));
set_fc(3);
for(seg = 0; seg < 0x10000000; seg += SUN3_PMEG_SIZE) {
i = sun3_get_segmap(seg);
for(j = 1; j < CONTEXTS_NUM; j++)
(*(romvec->pv_setctxt))(j, (void *)seg, i);
}
set_fs(KERNEL_DS);
set_fc(USER_DATA);
}
/* erase the mappings for a dead context. Uses the pg_dir for hints

1
arch/m68k/sun3/sun3ints.c
View file

@ -11,7 +11,6 @@
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <asm/segment.h>
#include <asm/intersil.h>
#include <asm/oplib.h>
#include <asm/sun3ints.h>

1
arch/m68k/sun3x/prom.c
View file

@ -14,7 +14,6 @@
#include <asm/traps.h>
#include <asm/sun3xprom.h>
#include <asm/idprom.h>
#include <asm/segment.h>
#include <asm/sun3ints.h>
#include <asm/openprom.h>
#include <asm/machines.h>