[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: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c
index ffc599b..ec19fed 100644
--- a/arch/um/kernel/ptrace.c
+++ b/arch/um/kernel/ptrace.c
@@ -252,13 +252,13 @@
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 @@
sizeof(child->pending.signal));
break;
+#ifdef PTRACE_LDT
case PTRACE_LDT: {
struct ptrace_ldt ldt;
@@ -284,6 +285,7 @@
ret = -EIO;
break;
}
+#endif
#ifdef CONFIG_PROC_MM
case PTRACE_SWITCH_MM: {
struct mm_struct *old = child->mm;
diff --git a/arch/um/kernel/skas/include/skas.h b/arch/um/kernel/skas/include/skas.h
index f0702c2..96b51db 100644
--- a/arch/um/kernel/skas/include/skas.h
+++ b/arch/um/kernel/skas/include/skas.h
@@ -27,9 +27,10 @@
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
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index b4ffaaa..c0b3051 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -4,6 +4,7 @@
*/
#include <stdlib.h>
+#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
@@ -37,17 +38,26 @@
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);
- segv(fault.addr, 0, FAULT_WRITE(fault.is_write), 1, NULL);
+ /* 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));
+}
+
+static void handle_segv(int pid, union uml_pt_regs * regs)
+{
+ get_skas_faultinfo(pid, ®s->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 @@
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 @@
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 "
diff --git a/arch/um/kernel/skas/trap_user.c b/arch/um/kernel/skas/trap_user.c
index 8e9b46d..0dee1d9 100644
--- a/arch/um/kernel/skas/trap_user.c
+++ b/arch/um/kernel/skas/trap_user.c
@@ -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 @@
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 @@
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, ®s->skas.faultinfo);
info = &sig_info[sig];
(*info->handler)(sig, regs);
diff --git a/arch/um/kernel/trap_kern.c b/arch/um/kernel/trap_kern.c
index 47e766e..54e2ec3 100644
--- a/arch/um/kernel/trap_kern.c
+++ b/arch/um/kernel/trap_kern.c
@@ -133,12 +133,19 @@
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 @@
}
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 @@
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 @@
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 @@
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);
}
diff --git a/arch/um/kernel/trap_user.c b/arch/um/kernel/trap_user.c
index 50a4042..f825a6e 100644
--- a/arch/um/kernel/trap_user.c
+++ b/arch/um/kernel/trap_user.c
@@ -54,23 +54,22 @@
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)
diff --git a/arch/um/kernel/tt/tracer.c b/arch/um/kernel/tt/tracer.c
index 7b5d937..f7b1753 100644
--- a/arch/um/kernel/tt/tracer.c
+++ b/arch/um/kernel/tt/tracer.c
@@ -89,8 +89,10 @@
static void tracer_segv(int sig, struct sigcontext sc)
{
+ struct faultinfo fi;
+ GET_FAULTINFO_FROM_SC(fi, &sc);
printf("Tracing thread segfault at address 0x%lx, ip 0x%lx\n",
- SC_FAULT_ADDR(&sc), SC_IP(&sc));
+ FAULT_ADDRESS(fi), SC_IP(&sc));
while(1)
pause();
}
diff --git a/arch/um/kernel/tt/trap_user.c b/arch/um/kernel/tt/trap_user.c
index 92a3820..fc10861 100644
--- a/arch/um/kernel/tt/trap_user.c
+++ b/arch/um/kernel/tt/trap_user.c
@@ -7,6 +7,7 @@
#include <errno.h>
#include <signal.h>
#include "sysdep/ptrace.h"
+#include "sysdep/sigcontext.h"
#include "signal_user.h"
#include "user_util.h"
#include "kern_util.h"
@@ -28,6 +29,11 @@
change_sig(SIGSEGV, 1);
r = &TASK_REGS(get_current())->tt;
+ if ( sig == SIGFPE || sig == SIGSEGV ||
+ sig == SIGBUS || sig == SIGILL ||
+ sig == SIGTRAP ) {
+ GET_FAULTINFO_FROM_SC(r->faultinfo, sc);
+ }
save_regs = *r;
is_user = user_context(SC_SP(sc));
r->sc = sc;