Commit 30410373 authored by Heiko Carstens's avatar Heiko Carstens
Browse files

s390/acrs: cleanup access register handling 



save_access_regs() and restore_access_regs() are only available by
including switch_to.h. This is done by a couple of C files, which have
nothing to do with switch_to(), but only need these functions.

Move both functions to a new header file and improve the implementation:

- Get rid of typedef

- Add memory access instrumentation support

- Use long displacement instructions lamy/stamy instead of lam/stam - all
  current users end up with better code because of this

Reviewed-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent f78bcb2e

arch/s390/include/asm/access-regs.h

0 → 100644
+38 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright IBM Corp. 1999, 2024

 */



#ifndef __ASM_S390_ACCESS_REGS_H

#define __ASM_S390_ACCESS_REGS_H



#include <linux/instrumented.h>

#include <asm/sigcontext.h>



struct access_regs {

	unsigned int regs[NUM_ACRS];

};



static inline void save_access_regs(unsigned int *acrs)

{

	struct access_regs *regs = (struct access_regs *)acrs;



	instrument_write(regs, sizeof(*regs));

	asm volatile("stamy	0,15,%[regs]"

		     : [regs] "=QS" (*regs)

		     :

		     : "memory");

}



static inline void restore_access_regs(unsigned int *acrs)

{

	struct access_regs *regs = (struct access_regs *)acrs;



	instrument_read(regs, sizeof(*regs));

	asm volatile("lamy	0,15,%[regs]"

		     :

		     : [regs] "QS" (*regs)

		     : "memory");

}



#endif /* __ASM_S390_ACCESS_REGS_H */

arch/s390/include/asm/switch_to.h

+1 −14
Original line number Diff line number Diff line
@@ -10,26 +10,13 @@ 


#include <linux/thread_info.h>

#include <asm/fpu/api.h>

#include <asm/access-regs.h>

#include <asm/ptrace.h>

#include <asm/guarded_storage.h>



extern struct task_struct *__switch_to(void *, void *);

extern void update_cr_regs(struct task_struct *task);



static inline void save_access_regs(unsigned int *acrs)

{

	typedef struct { int _[NUM_ACRS]; } acrstype;



	asm volatile("stam 0,15,%0" : "=Q" (*(acrstype *)acrs));

}



static inline void restore_access_regs(unsigned int *acrs)

{

	typedef struct { int _[NUM_ACRS]; } acrstype;



	asm volatile("lam 0,15,%0" : : "Q" (*(acrstype *)acrs));

}



#define switch_to(prev, next, last) do {				\

	/* save_fpu_regs() sets the CIF_FPU flag, which enforces	\

	 * a restore of the floating point / vector registers as	\

arch/s390/kernel/compat_signal.c

+1 −1
Original line number Diff line number Diff line
@@ -24,10 +24,10 @@ 
#include <linux/tty.h>

#include <linux/personality.h>

#include <linux/binfmts.h>

#include <asm/access-regs.h>

#include <asm/ucontext.h>

#include <linux/uaccess.h>

#include <asm/lowcore.h>

#include <asm/switch_to.h>

#include <asm/vdso.h>

#include <asm/fpu/api.h>

#include "compat_linux.h"

arch/s390/kernel/early.c

+2 −1
Original line number Diff line number Diff line
@@ -19,6 +19,8 @@ 
#include <linux/kernel.h>

#include <asm/asm-extable.h>

#include <linux/memblock.h>

#include <asm/access-regs.h>

#include <asm/fpu/api.h>

#include <asm/diag.h>

#include <asm/ebcdic.h>

#include <asm/ipl.h>
@@ -31,7 +33,6 @@ 
#include <asm/sclp.h>

#include <asm/facility.h>

#include <asm/boot_data.h>

#include <asm/switch_to.h>

#include "entry.h"



#define decompressor_handled_param(param)			\

arch/s390/kernel/ptrace.c

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/seccomp.h>

#include <linux/compat.h>

#include <trace/syscall.h>

#include <asm/access-regs.h>

#include <asm/page.h>

#include <linux/uaccess.h>

#include <asm/unistd.h>