Commit c578455a authored by Bodo Stroesser's avatar Bodo Stroesser Committed by Linus Torvalds
Browse files

[PATCH] uml: S390 preparation, abstract host page fault data 



This patch removes the arch-specific fault/trap-infos from thread and
skas-regs.

It adds a new struct faultinfo, that is arch-specific defined in
sysdep/faultinfo.h.

The structure is inserted in thread.arch and thread.regs.skas and
thread.regs.tt

Now, segv and other trap-handlers can copy the contents from regs.X.faultinfo
to thread.arch.faultinfo with one simple assignment.

Also, the number of macros necessary is reduced to

FAULT_ADDRESS(struct faultinfo)
    extracts the faulting address from faultinfo

FAULT_WRITE(struct faultinfo)
    extracts the "is_write" flag

SEGV_IS_FIXABLE(struct faultinfo)
    is true for the fixable segvs, i.e. (TRAP == 14)
    on i386

UPT_FAULTINFO(regs)
    result is (struct faultinfo *) to the faultinfo
    in regs->skas.faultinfo

GET_FAULTINFO_FROM_SC(struct faultinfo, struct sigcontext *)
    copies the relevant parts of the sigcontext to
    struct faultinfo.

On SIGSEGV, call user_signal() instead of handle_segv(), if the architecture
provides the information needed in PTRACE_FAULTINFO, or if PTRACE_FAULTINFO is
missing, because segv-stub will provide the info.

The benefit of the change is, that in case of a non-fixable SIGSEGV, we can
give user processes a SIGSEGV, instead of possibly looping on pagefault
handling.

Since handle_segv() sikked arch_fixup() implicitly by passing ip==0 to segv(),
I changed segv() to call arch_fixup() only, if !is_user.

Signed-off-by: default avatarBodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: default avatarJeff Dike <jdike@addtoit.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ea66e8a3

arch/um/include/kern_util.h

+4 −3
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 


#include "linux/threads.h"

#include "sysdep/ptrace.h"

#include "sysdep/faultinfo.h"



extern int ncpus;

extern char *linux_prog;
@@ -31,8 +32,8 @@ extern int current_pid(void); 
extern unsigned long alloc_stack(int order, int atomic);

extern int do_signal(void);

extern int is_stack_fault(unsigned long sp);

extern unsigned long segv(unsigned long address, unsigned long ip, 

			  int is_write, int is_user, void *sc);

extern unsigned long segv(struct faultinfo fi, unsigned long ip,

			  int is_user, void *sc);

extern int handle_page_fault(unsigned long address, unsigned long ip,

			     int is_write, int is_user, int *code_out);

extern void syscall_ready(void);
@@ -82,7 +83,7 @@ extern void timer_irq(union uml_pt_regs *regs); 
extern void unprotect_stack(unsigned long stack);

extern void do_uml_exitcalls(void);

extern int attach_debugger(int idle_pid, int pid, int stop);

extern void bad_segv(unsigned long address, unsigned long ip, int is_write);

extern void bad_segv(struct faultinfo fi, unsigned long ip);

extern int config_gdb(char *str);

extern int remove_gdb(void);

extern char *uml_strdup(char *string);

arch/um/include/sysdep-i386/faultinfo.h

0 → 100644
+29 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2004 Fujitsu Siemens Computers GmbH

 * Author: Bodo Stroesser <bstroesser@fujitsu-siemens.com>

 * Licensed under the GPL

 */



#ifndef __FAULTINFO_I386_H

#define __FAULTINFO_I386_H



/* this structure contains the full arch-specific faultinfo

 * from the traps.

 * On i386, ptrace_faultinfo unfortunately doesn't provide

 * all the info, since trap_no is missing.

 * All common elements are defined at the same position in

 * both structures, thus making it easy to copy the

 * contents without knowledge about the structure elements.

 */

struct faultinfo {

        int error_code; /* in ptrace_faultinfo misleadingly called is_write */

        unsigned long cr2; /* in ptrace_faultinfo called addr */

        int trap_no; /* missing in ptrace_faultinfo */

};



#define FAULT_WRITE(fi) ((fi).error_code & 2)

#define FAULT_ADDRESS(fi) ((fi).cr2)



#define PTRACE_FULL_FAULTINFO 0



#endif

arch/um/include/sysdep-i386/ptrace.h

+5 −18
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ extern int sysemu_supported; 
#ifdef UML_CONFIG_MODE_SKAS



#include "skas_ptregs.h"

#include "sysdep/faultinfo.h"



#define REGS_IP(r) ((r)[HOST_IP])

#define REGS_SP(r) ((r)[HOST_SP])
@@ -53,12 +54,6 @@ extern int sysemu_supported; 


#define REGS_RESTART_SYSCALL(r) IP_RESTART_SYSCALL(REGS_IP(r))



#define REGS_SEGV_IS_FIXABLE(r) SEGV_IS_FIXABLE((r)->trap_type)



#define REGS_FAULT_ADDR(r) ((r)->fault_addr)



#define REGS_FAULT_WRITE(r) FAULT_WRITE((r)->fault_type)



#endif

#ifndef PTRACE_SYSEMU_SINGLESTEP

#define PTRACE_SYSEMU_SINGLESTEP 32
@@ -71,6 +66,7 @@ union uml_pt_regs { 
	struct tt_regs {

		long syscall;

		void *sc;

                struct faultinfo faultinfo;

	} tt;

#endif

#ifdef UML_CONFIG_MODE_SKAS
@@ -78,9 +74,7 @@ union uml_pt_regs { 
		unsigned long regs[HOST_FRAME_SIZE];

		unsigned long fp[HOST_FP_SIZE];

		unsigned long xfp[HOST_XFP_SIZE];

		unsigned long fault_addr;

		unsigned long fault_type;

		unsigned long trap_type;

                struct faultinfo faultinfo;

		long syscall;

		int is_user;

	} skas;
@@ -217,15 +211,8 @@ struct syscall_args { 
#define UPT_SYSCALL_NR(r) UPT_ORIG_EAX(r)

#define UPT_SYSCALL_RET(r) UPT_EAX(r)



#define UPT_SEGV_IS_FIXABLE(r) \

	CHOOSE_MODE(SC_SEGV_IS_FIXABLE(UPT_SC(r)), \

                    REGS_SEGV_IS_FIXABLE(&r->skas))



#define UPT_FAULT_ADDR(r) \

	__CHOOSE_MODE(SC_FAULT_ADDR(UPT_SC(r)), REGS_FAULT_ADDR(&r->skas))



#define UPT_FAULT_WRITE(r) \

	CHOOSE_MODE(SC_FAULT_WRITE(UPT_SC(r)), REGS_FAULT_WRITE(&r->skas))

#define UPT_FAULTINFO(r) \

        CHOOSE_MODE((&(r)->tt.faultinfo), (&(r)->skas.faultinfo))



#endif

arch/um/include/sysdep-i386/sigcontext.h

+7 −12
Original line number Diff line number Diff line
@@ -13,15 +13,12 @@ 
#define SC_RESTART_SYSCALL(sc) IP_RESTART_SYSCALL(SC_IP(sc))

#define SC_SET_SYSCALL_RETURN(sc, result) SC_EAX(sc) = (result)



#define SC_FAULT_ADDR(sc) SC_CR2(sc)

#define SC_FAULT_TYPE(sc) SC_ERR(sc)



#define FAULT_WRITE(err) (err & 2)

#define TO_SC_ERR(is_write) ((is_write) ? 2 : 0)



#define SC_FAULT_WRITE(sc) (FAULT_WRITE(SC_ERR(sc)))



#define SC_TRAP_TYPE(sc) SC_TRAPNO(sc)

#define GET_FAULTINFO_FROM_SC(fi,sc) \

	{ \

		(fi).cr2 = SC_CR2(sc); \

		(fi).error_code = SC_ERR(sc); \

		(fi).trap_no = SC_TRAPNO(sc); \

	}



/* ptrace expects that, at the start of a system call, %eax contains

 * -ENOSYS, so this makes it so.
@@ -29,9 +26,7 @@ 
#define SC_START_SYSCALL(sc) do SC_EAX(sc) = -ENOSYS; while(0)



/* This is Page Fault */

#define SEGV_IS_FIXABLE(trap) (trap == 14)



#define SC_SEGV_IS_FIXABLE(sc) (SEGV_IS_FIXABLE(SC_TRAPNO(sc)))

#define SEGV_IS_FIXABLE(fi) ((fi)->trap_no == 14)



extern unsigned long *sc_sigmask(void *sc_ptr);

extern int sc_get_fpregs(unsigned long buf, void *sc_ptr);

arch/um/include/sysdep-i386/skas_ptrace.h

0 → 100644
+22 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)

 * Licensed under the GPL

 */



#ifndef __SYSDEP_I386_SKAS_PTRACE_H

#define __SYSDEP_I386_SKAS_PTRACE_H



struct ptrace_faultinfo {

        int is_write;

        unsigned long addr;

};



struct ptrace_ldt {

        int func;

        void *ptr;

        unsigned long bytecount;

};



#define PTRACE_LDT 54



#endif

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