Commit c578455a authored by Bodo Stroesser's avatar Bodo Stroesser Committed by Linus Torvalds
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[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
......@@ -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);
......
/*
* 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
......@@ -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
......
......@@ -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);
......
/*
* 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
/*
* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#ifndef __SYSDEP_IA64_SKAS_PTRACE_H
#define __SYSDEP_IA64_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
/*
* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#ifndef __SYSDEP_PPC_SKAS_PTRACE_H
#define __SYSDEP_PPC_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
/*
* Copyright (C) 2004 Fujitsu Siemens Computers GmbH
* Author: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
* Licensed under the GPL
*/
#ifndef __FAULTINFO_X86_64_H
#define __FAULTINFO_X86_64_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 1
#endif
......@@ -9,6 +9,7 @@
#include "uml-config.h"
#include "user_constants.h"
#include "sysdep/faultinfo.h"
#define MAX_REG_OFFSET (UM_FRAME_SIZE)
#define MAX_REG_NR ((MAX_REG_OFFSET) / sizeof(unsigned long))
......@@ -83,6 +84,7 @@ union uml_pt_regs {
long syscall;
unsigned long orig_rax;
void *sc;
struct faultinfo faultinfo;
} tt;
#endif
#ifdef UML_CONFIG_MODE_SKAS
......@@ -90,9 +92,7 @@ union uml_pt_regs {
/* XXX */
unsigned long regs[27];
unsigned long fp[65];
unsigned long fault_addr;
unsigned long fault_type;
unsigned long trap_type;
struct faultinfo faultinfo;
long syscall;
int is_user;
} skas;
......@@ -241,14 +241,8 @@ struct syscall_args {
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_TRAP(r) __CHOOSE_MODE(SC_TRAP_TYPE(UPT_SC(r)), REGS_TRAP(&r->skas))
#define UPT_ERR(r) __CHOOSE_MODE(SC_FAULT_TYPE(UPT_SC(r)), REGS_ERR(&r->skas))
#define UPT_FAULTINFO(r) \
CHOOSE_MODE((&(r)->tt.faultinfo), (&(r)->skas.faultinfo))
#endif
......
......@@ -17,11 +17,12 @@
#define SC_FAULT_ADDR(sc) SC_CR2(sc)
#define SC_FAULT_TYPE(sc) SC_ERR(sc)
#define FAULT_WRITE(err) ((err) & 2)
#define SC_FAULT_WRITE(sc) FAULT_WRITE(SC_FAULT_TYPE(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.
......@@ -29,8 +30,8 @@
#define SC_START_SYSCALL(sc) do SC_RAX(sc) = -ENOSYS; while(0)
#define SEGV_IS_FIXABLE(trap) ((trap) == 14)
#define SC_SEGV_IS_FIXABLE(sc) SEGV_IS_FIXABLE(SC_TRAP_TYPE(sc))
/* This is Page Fault */
#define SEGV_IS_FIXABLE(fi) ((fi)->trap_no == 14)
extern unsigned long *sc_sigmask(void *sc_ptr);
......
/*
* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#ifndef __SYSDEP_X86_64_SKAS_PTRACE_H
#define __SYSDEP_X86_64_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
......@@ -252,13 +252,13 @@ long sys_ptrace(long request, long pid, long addr, long data)
break;
#endif
case PTRACE_FAULTINFO: {
struct ptrace_faultinfo fault;
fault = ((struct ptrace_faultinfo)
{ .is_write = child->thread.err,
.addr = child->thread.cr2 });
ret = copy_to_user((unsigned long __user *) data, &fault,
sizeof(fault));
/* Take the info from thread->arch->faultinfo,
* but transfer max. sizeof(struct ptrace_faultinfo).
* On i386, ptrace_faultinfo is smaller!
*/
ret = copy_to_user((unsigned long __user *) data,
&child->thread.arch.faultinfo,
sizeof(struct ptrace_faultinfo));
if(ret)
break;
break;
......@@ -269,6 +269,7 @@ long sys_ptrace(long request, long pid, long addr, long data)
sizeof(child->pending.signal));
break;
#ifdef PTRACE_LDT
case PTRACE_LDT: {
struct ptrace_ldt ldt;
......@@ -284,6 +285,7 @@ long sys_ptrace(long request, long pid, long addr, long data)
ret = -EIO;
break;
}
#endif
#ifdef CONFIG_PROC_MM
case PTRACE_SWITCH_MM: {
struct mm_struct *old = child->mm;
......
......@@ -27,9 +27,10 @@ extern void map(int fd, unsigned long virt, unsigned long len, int r, int w,
extern int unmap(int fd, void *addr, unsigned long len);
extern int protect(int fd, unsigned long addr, unsigned long len,
int r, int w, int x);
extern void user_signal(int sig, union uml_pt_regs *regs);
extern void user_signal(int sig, union uml_pt_regs *regs, int pid);
extern int new_mm(int from);
extern void start_userspace(int cpu);
extern void get_skas_faultinfo(int pid, struct faultinfo * fi);
extern long execute_syscall_skas(void *r);
#endif
......
......@@ -4,6 +4,7 @@
*/
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
......@@ -37,17 +38,26 @@ int is_skas_winch(int pid, int fd, void *data)
return(1);
}
static void handle_segv(int pid)
void get_skas_faultinfo(int pid, struct faultinfo * fi)
{
struct ptrace_faultinfo fault;
int err;
err = ptrace(PTRACE_FAULTINFO, pid, 0, &fault);
err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
if(err)
panic("handle_segv - PTRACE_FAULTINFO failed, errno = %d\n",
errno);
panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
"errno = %d\n", errno);
/* Special handling for i386, which has different structs */
if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
sizeof(struct faultinfo) -
sizeof(struct ptrace_faultinfo));
}
segv(fault.addr, 0, FAULT_WRITE(fault.is_write), 1, NULL);
static void handle_segv(int pid, union uml_pt_regs * regs)
{
get_skas_faultinfo(pid, &regs->skas.faultinfo);
segv(regs->skas.faultinfo, 0, 1, NULL);
}
/*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
......@@ -163,7 +173,7 @@ void userspace(union uml_pt_regs *regs)
if(WIFSTOPPED(status)){
switch(WSTOPSIG(status)){
case SIGSEGV:
handle_segv(pid);
handle_segv(pid, regs);
break;
case SIGTRAP + 0x80:
handle_trap(pid, regs, local_using_sysemu);
......@@ -177,7 +187,7 @@ void userspace(union uml_pt_regs *regs)
case SIGBUS:
case SIGFPE:
case SIGWINCH:
user_signal(WSTOPSIG(status), regs);
user_signal(WSTOPSIG(status), regs, pid);
break;
default:
printk("userspace - child stopped with signal "
......
......@@ -5,12 +5,15 @@
#include <signal.h>
#include <errno.h>
#include "sysdep/ptrace.h"
#include "signal_user.h"
#include "user_util.h"
#include "kern_util.h"
#include "task.h"
#include "sigcontext.h"
#include "skas.h"
#include "ptrace_user.h"
#include "sysdep/ptrace.h"
#include "sysdep/ptrace_user.h"
void sig_handler_common_skas(int sig, void *sc_ptr)
{
......@@ -31,9 +34,11 @@ void sig_handler_common_skas(int sig, void *sc_ptr)
r = &TASK_REGS(get_current())->skas;
save_user = r->is_user;
r->is_user = 0;
r->fault_addr = SC_FAULT_ADDR(sc);
r->fault_type = SC_FAULT_TYPE(sc);
r->trap_type = SC_TRAP_TYPE(sc);
if ( sig == SIGFPE || sig == SIGSEGV ||
sig == SIGBUS || sig == SIGILL ||
sig == SIGTRAP ) {
GET_FAULTINFO_FROM_SC(r->faultinfo, sc);
}
change_sig(SIGUSR1, 1);
info = &sig_info[sig];
......@@ -45,14 +50,17 @@ void sig_handler_common_skas(int sig, void *sc_ptr)
r->is_user = save_user;
}
void user_signal(int sig, union uml_pt_regs *regs)
extern int ptrace_faultinfo;
void user_signal(int sig, union uml_pt_regs *regs, int pid)
{
struct signal_info *info;
int segv = ((sig == SIGFPE) || (sig == SIGSEGV) || (sig == SIGBUS) ||
(sig == SIGILL) || (sig == SIGTRAP));
regs->skas.is_user = 1;
regs->skas.fault_addr = 0;
regs->skas.fault_type = 0;
regs->skas.trap_type = 0;
if (segv)
get_skas_faultinfo(pid, &regs->skas.faultinfo);
info = &sig_info[sig];
(*info->handler)(sig, regs);
......
......@@ -133,12 +133,19 @@ static int check_remapped_addr(unsigned long address, int is_write)
return(0);
}
unsigned long segv(unsigned long address, unsigned long ip, int is_write,
int is_user, void *sc)
/*
* We give a *copy* of the faultinfo in the regs to segv.
* This must be done, since nesting SEGVs could overwrite
* the info in the regs. A pointer to the info then would
* give us bad data!
*/
unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc)
{
struct siginfo si;
void *catcher;
int err;
int is_write = FAULT_WRITE(fi);
unsigned long address = FAULT_ADDRESS(fi);
if(!is_user && (address >= start_vm) && (address < end_vm)){
flush_tlb_kernel_vm();
......@@ -159,7 +166,7 @@ unsigned long segv(unsigned long address, unsigned long ip, int is_write,
}
else if(current->thread.fault_addr != NULL)
panic("fault_addr set but no fault catcher");
else if(arch_fixup(ip, sc))
else if(!is_user && arch_fixup(ip, sc))
return(0);
if(!is_user)
......@@ -171,6 +178,7 @@ unsigned long segv(unsigned long address, unsigned long ip, int is_write,
si.si_errno = 0;
si.si_code = BUS_ADRERR;
si.si_addr = (void *)address;
current->thread.arch.faultinfo = fi;
force_sig_info(SIGBUS, &si, current);
}
else if(err == -ENOMEM){
......@@ -180,22 +188,20 @@ unsigned long segv(unsigned long address, unsigned long ip, int is_write,
else {
si.si_signo = SIGSEGV;
si.si_addr = (void *) address;
current->thread.cr2 = address;
current->thread.err = is_write;
current->thread.arch.faultinfo = fi;
force_sig_info(SIGSEGV, &si, current);
}
return(0);
}
void bad_segv(unsigned long address, unsigned long ip, int is_write)
void bad_segv(struct faultinfo fi, unsigned long ip)
{
struct siginfo si;
si.si_signo = SIGSEGV;
si.si_code = SEGV_ACCERR;
si.si_addr = (void *) address;
current->thread.cr2 = address;
current->thread.err = is_write;
si.si_addr = (void *) FAULT_ADDRESS(fi);
current->thread.arch.faultinfo = fi;
force_sig_info(SIGSEGV, &si, current);
}
......@@ -204,6 +210,7 @@ void relay_signal(int sig, union uml_pt_regs *regs)
if(arch_handle_signal(sig, regs)) return;
if(!UPT_IS_USER(regs))
panic("Kernel mode signal %d", sig);
current->thread.arch.faultinfo = *UPT_FAULTINFO(regs);
force_sig(sig, current);
}
......
......@@ -54,23 +54,22 @@ struct {
void segv_handler(int sig, union uml_pt_regs *regs)
{
int index, max;
struct faultinfo * fi = UPT_FAULTINFO(regs);
if(UPT_IS_USER(regs) && !UPT_SEGV_IS_FIXABLE(regs)){
bad_segv(UPT_FAULT_ADDR(regs), UPT_IP(regs),
UPT_FAULT_WRITE(regs));
if(UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)){
bad_segv(*fi, UPT_IP(regs));
return;
}
max = sizeof(segfault_record)/sizeof(segfault_record[0]);
index = next_trap_index(max);
nsegfaults++;
segfault_record[index].address = UPT_FAULT_ADDR(regs);
segfault_record[index].address = FAULT_ADDRESS(*fi);
segfault_record[index].pid = os_getpid();
segfault_record[index].is_write = UPT_FAULT_WRITE(regs);
segfault_record[index].is_write = FAULT_WRITE(*fi);
segfault_record[index].sp = UPT_SP(regs);
segfault_record[index].is_user = UPT_IS_USER(regs);
segv(UPT_FAULT_ADDR(regs), UPT_IP(regs), UPT_FAULT_WRITE(regs),
UPT_IS_USER(regs), regs);
segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
}
void usr2_handler(int sig, union uml_pt_regs *regs)
......