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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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31
arch/m68k/include/asm/processor.h
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@@ -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, \
}
/*