[ PATCH 1/4] UML - Tidy fault code

From: Jeff Dike
Date: Wed Apr 04 2007 - 20:39:41 EST

Tidying in preparation for the segfault register dumping patch which
follows.

void * pointers are changed to union uml_pt_regs *. This makes
the types match reality, except in arch_fixup, which is changed to
operate on a union uml_pt_regs. This fixes a bug in the call from
segv_handler, which passes a union uml_pt_regs, to segv, which expects
to pass a struct sigcontext to arch_fixup.

Whitespace and other style fixes.

There's also a errno printk fix.

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxxxxxx>
--
arch/um/include/arch.h | 2 +-
arch/um/include/kern_util.h | 2 +-
arch/um/kernel/trap.c | 35 ++++++++++++++++++-----------------
arch/um/os-Linux/skas/trap.c | 17 ++++++++---------
arch/um/sys-i386/fault.c | 18 ++----------------
arch/um/sys-i386/signal.c | 41 +++++++++++++++--------------------------
arch/um/sys-x86_64/fault.c | 30 +++++++++++++++++-------------
arch/um/sys-x86_64/signal.c | 2 +-
8 files changed, 63 insertions(+), 84 deletions(-)

Index: linux-2.6.21-mm/arch/um/include/arch.h
===================================================================
--- linux-2.6.21-mm.orig/arch/um/include/arch.h 2007-04-02 12:18:49.000000000 -0400
+++ linux-2.6.21-mm/arch/um/include/arch.h 2007-04-02 12:19:04.000000000 -0400
@@ -9,7 +9,7 @@
#include "sysdep/ptrace.h"

extern void arch_check_bugs(void);
-extern int arch_fixup(unsigned long address, void *sc_ptr);
+extern int arch_fixup(unsigned long address, union uml_pt_regs *regs);
extern int arch_handle_signal(int sig, union uml_pt_regs *regs);

#endif
Index: linux-2.6.21-mm/arch/um/include/kern_util.h
===================================================================
--- linux-2.6.21-mm.orig/arch/um/include/kern_util.h 2007-04-02 12:19:01.000000000 -0400
+++ linux-2.6.21-mm/arch/um/include/kern_util.h 2007-04-02 12:19:04.000000000 -0400
@@ -43,7 +43,7 @@ extern unsigned long alloc_stack(int ord
extern int do_signal(void);
extern int is_stack_fault(unsigned long sp);
extern unsigned long segv(struct faultinfo fi, unsigned long ip,
- int is_user, void *sc);
+ int is_user, union uml_pt_regs *regs);
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);
Index: linux-2.6.21-mm/arch/um/kernel/trap.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/kernel/trap.c 2007-04-02 12:18:49.000000000 -0400
+++ linux-2.6.21-mm/arch/um/kernel/trap.c 2007-04-02 12:19:04.000000000 -0400
@@ -72,8 +72,8 @@ good_area:
goto out;

/* Don't require VM_READ|VM_EXEC for write faults! */
- if(!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC)))
- goto out;
+ if(!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC)))
+ goto out;

do {
survive:
@@ -157,18 +157,19 @@ static void segv_handler(int sig, union
* 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)
+unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
+ union uml_pt_regs *regs)
{
struct siginfo si;
void *catcher;
int err;
- int is_write = FAULT_WRITE(fi);
- unsigned long address = FAULT_ADDRESS(fi);
+ 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();
- return(0);
- }
+ if(!is_user && (address >= start_vm) && (address < end_vm)){
+ flush_tlb_kernel_vm();
+ return 0;
+ }
else if(current->mm == NULL)
panic("Segfault with no mm");

@@ -183,17 +184,17 @@ unsigned long segv(struct faultinfo fi,

catcher = current->thread.fault_catcher;
if(!err)
- return(0);
+ return 0;
else if(catcher != NULL){
current->thread.fault_addr = (void *) address;
do_longjmp(catcher, 1);
}
else if(current->thread.fault_addr != NULL)
panic("fault_addr set but no fault catcher");
- else if(!is_user && arch_fixup(ip, sc))
- return(0);
+ else if(!is_user && arch_fixup(ip, regs))
+ return 0;

- if(!is_user)
+ if(!is_user)
panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
address, ip);

@@ -202,7 +203,7 @@ unsigned long segv(struct faultinfo fi,
si.si_errno = 0;
si.si_code = BUS_ADRERR;
si.si_addr = (void __user *)address;
- current->thread.arch.faultinfo = fi;
+ current->thread.arch.faultinfo = fi;
force_sig_info(SIGBUS, &si, current);
} else if (err == -ENOMEM) {
printk("VM: killing process %s\n", current->comm);
@@ -211,10 +212,10 @@ unsigned long segv(struct faultinfo fi,
BUG_ON(err != -EFAULT);
si.si_signo = SIGSEGV;
si.si_addr = (void __user *) address;
- current->thread.arch.faultinfo = fi;
+ current->thread.arch.faultinfo = fi;
force_sig_info(SIGSEGV, &si, current);
}
- return(0);
+ return 0;
}

void relay_signal(int sig, union uml_pt_regs *regs)
@@ -229,7 +230,7 @@ void relay_signal(int sig, union uml_pt_
panic("Kernel mode signal %d", sig);
}

- current->thread.arch.faultinfo = *UPT_FAULTINFO(regs);
+ current->thread.arch.faultinfo = *UPT_FAULTINFO(regs);
force_sig(sig, current);
}

Index: linux-2.6.21-mm/arch/um/os-Linux/skas/trap.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/os-Linux/skas/trap.c 2007-04-02 12:18:49.000000000 -0400
+++ linux-2.6.21-mm/arch/um/os-Linux/skas/trap.c 2007-04-02 12:19:04.000000000 -0400
@@ -18,10 +18,9 @@
void sig_handler_common_skas(int sig, void *sc_ptr)
{
struct sigcontext *sc = sc_ptr;
- struct skas_regs *r;
+ union uml_pt_regs *r;
void (*handler)(int, union uml_pt_regs *);
- int save_errno = errno;
- int save_user;
+ int save_user, save_errno = errno;

/* This is done because to allow SIGSEGV to be delivered inside a SEGV
* handler. This can happen in copy_user, and if SEGV is disabled,
@@ -31,13 +30,13 @@ void sig_handler_common_skas(int sig, vo
if(sig == SIGSEGV)
change_sig(SIGSEGV, 1);

- r = &TASK_REGS(get_current())->skas;
- save_user = r->is_user;
- r->is_user = 0;
+ r = TASK_REGS(get_current());
+ save_user = r->skas.is_user;
+ r->skas.is_user = 0;
if ( sig == SIGFPE || sig == SIGSEGV ||
sig == SIGBUS || sig == SIGILL ||
sig == SIGTRAP ) {
- GET_FAULTINFO_FROM_SC(r->faultinfo, sc);
+ GET_FAULTINFO_FROM_SC(r->skas.faultinfo, sc);
}

change_sig(SIGUSR1, 1);
@@ -49,10 +48,10 @@ void sig_handler_common_skas(int sig, vo
sig != SIGVTALRM && sig != SIGALRM)
unblock_signals();

- handler(sig, (union uml_pt_regs *) r);
+ handler(sig, r);

errno = save_errno;
- r->is_user = save_user;
+ r->skas.is_user = save_user;
}

extern int ptrace_faultinfo;
Index: linux-2.6.21-mm/arch/um/sys-i386/fault.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/sys-i386/fault.c 2007-04-02 12:18:49.000000000 -0400
+++ linux-2.6.21-mm/arch/um/sys-i386/fault.c 2007-04-02 12:19:04.000000000 -0400
@@ -3,9 +3,7 @@
* Licensed under the GPL
*/

-#include <signal.h>
#include "sysdep/ptrace.h"
-#include "sysdep/sigcontext.h"

/* These two are from asm-um/uaccess.h and linux/module.h, check them. */
struct exception_table_entry
@@ -17,26 +15,14 @@ struct exception_table_entry
const struct exception_table_entry *search_exception_tables(unsigned long add);

/* Compare this to arch/i386/mm/extable.c:fixup_exception() */
-int arch_fixup(unsigned long address, void *sc_ptr)
+int arch_fixup(unsigned long address, union uml_pt_regs *regs)
{
- struct sigcontext *sc = sc_ptr;
const struct exception_table_entry *fixup;

fixup = search_exception_tables(address);
if(fixup != 0){
- sc->eip = fixup->fixup;
+ UPT_IP(regs) = fixup->fixup;
return(1);
}
return(0);
}
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
Index: linux-2.6.21-mm/arch/um/sys-x86_64/fault.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/sys-x86_64/fault.c 2007-04-02 12:18:49.000000000 -0400
+++ linux-2.6.21-mm/arch/um/sys-x86_64/fault.c 2007-04-02 12:19:04.000000000 -0400
@@ -4,20 +4,24 @@
* Licensed under the GPL
*/

-#include "user.h"
+#include "sysdep/ptrace.h"

-int arch_fixup(unsigned long address, void *sc_ptr)
+/* These two are from asm-um/uaccess.h and linux/module.h, check them. */
+struct exception_table_entry
{
- /* XXX search_exception_tables() */
+ unsigned long insn;
+ unsigned long fixup;
+};
+
+const struct exception_table_entry *search_exception_tables(unsigned long add);
+int arch_fixup(unsigned long address, union uml_pt_regs *regs)
+{
+ const struct exception_table_entry *fixup;
+
+ fixup = search_exception_tables(address);
+ if(fixup != 0){
+ UPT_IP(regs) = fixup->fixup;
+ return(1);
+ }
return(0);
}
-
-/* Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
Index: linux-2.6.21-mm/arch/um/sys-x86_64/signal.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/sys-x86_64/signal.c 2007-04-02 12:18:49.000000000 -0400
+++ linux-2.6.21-mm/arch/um/sys-x86_64/signal.c 2007-04-02 12:19:04.000000000 -0400
@@ -51,7 +51,7 @@ static int copy_sc_from_user_skas(struct

#undef GETREG

- return(err);
+ return err;
}

int copy_sc_to_user_skas(struct sigcontext __user *to,
Index: linux-2.6.21-mm/arch/um/sys-i386/signal.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/sys-i386/signal.c 2007-04-02 12:18:49.000000000 -0400
+++ linux-2.6.21-mm/arch/um/sys-i386/signal.c 2007-04-02 12:19:04.000000000 -0400
@@ -28,7 +28,7 @@ static int copy_sc_from_user_skas(struct
err = copy_from_user(&sc, from, sizeof(sc));
err |= copy_from_user(fpregs, sc.fpstate, sizeof(fpregs));
if(err)
- return(err);
+ return err;

REGS_GS(regs->regs.skas.regs) = sc.gs;
REGS_FS(regs->regs.skas.regs) = sc.fs;
@@ -50,11 +50,11 @@ static int copy_sc_from_user_skas(struct
err = restore_fp_registers(userspace_pid[0], fpregs);
if(err < 0){
printk("copy_sc_from_user_skas - PTRACE_SETFPREGS failed, "
- "errno = %d\n", err);
- return(1);
+ "errno = %d\n", -err);
+ return err;
}

- return(0);
+ return 0;
}

int copy_sc_to_user_skas(struct sigcontext __user *to, struct _fpstate __user *to_fp,
@@ -90,16 +90,16 @@ int copy_sc_to_user_skas(struct sigconte
if(err < 0){
printk("copy_sc_to_user_skas - PTRACE_GETFPREGS failed, "
"errno = %d\n", err);
- return(1);
+ return 1;
}
to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
sc.fpstate = to_fp;

if(err)
- return(err);
+ return err;

- return(copy_to_user(to, &sc, sizeof(sc)) ||
- copy_to_user(to_fp, fpregs, sizeof(fpregs)));
+ return copy_to_user(to, &sc, sizeof(sc)) ||
+ copy_to_user(to_fp, fpregs, sizeof(fpregs));
}
#endif

@@ -129,7 +129,7 @@ int copy_sc_from_user_tt(struct sigconte
to->fpstate = to_fp;
if(to_fp != NULL)
err |= copy_from_user(to_fp, from_fp, fpsize);
- return(err);
+ return err;
}

int copy_sc_to_user_tt(struct sigcontext __user *to, struct _fpstate __user *fp,
@@ -164,15 +164,15 @@ static int copy_sc_from_user(struct pt_r
ret = CHOOSE_MODE(copy_sc_from_user_tt(UPT_SC(&to->regs), from,
sizeof(struct _fpstate)),
copy_sc_from_user_skas(to, from));
- return(ret);
+ return ret;
}

static int copy_sc_to_user(struct sigcontext __user *to, struct _fpstate __user *fp,
struct pt_regs *from, unsigned long sp)
{
- return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
+ return CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
sizeof(*fp), sp),
- copy_sc_to_user_skas(to, fp, from, sp)));
+ copy_sc_to_user_skas(to, fp, from, sp));
}

static int copy_ucontext_to_user(struct ucontext __user *uc, struct _fpstate __user *fp,
@@ -185,7 +185,7 @@ static int copy_ucontext_to_user(struct
err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, sp);
err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
- return(err);
+ return err;
}

struct sigframe
@@ -355,7 +355,7 @@ long sys_sigreturn(struct pt_regs regs)

/* Avoid ERESTART handling */
PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
- return(PT_REGS_SYSCALL_RET(&current->thread.regs));
+ return PT_REGS_SYSCALL_RET(&current->thread.regs);

segfault:
force_sig(SIGSEGV, current);
@@ -385,20 +385,9 @@ long sys_rt_sigreturn(struct pt_regs reg

/* Avoid ERESTART handling */
PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
- return(PT_REGS_SYSCALL_RET(&current->thread.regs));
+ return PT_REGS_SYSCALL_RET(&current->thread.regs);

segfault:
force_sig(SIGSEGV, current);
return 0;
}
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/