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Commit be662a18 authored by Paolo 'Blaisorblade' Giarrusso's avatar Paolo 'Blaisorblade' Giarrusso Committed by Linus Torvalds
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[PATCH] uml: fix page faults in SKAS3 mode. 



I hadn't been running a SKAS3 host when testing the "uml: fix hang in TT mode
on fault" patch (commit 546fe1cb), and I
didn't think enough to the missing trap_no in SKAS3 mode.

In fact, the resulting kernel doesn't work at all in SKAS3 mode.

Signed-off-by: default avatarPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 79dfa4a5

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

+9 −1
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#ifndef __SYS_SIGCONTEXT_I386_H

#define __SYS_SIGCONTEXT_I386_H



#include "uml-config.h"

#include <sysdep/sc.h>



#define IP_RESTART_SYSCALL(ip) ((ip) -= 2)
@@ -28,6 +29,13 @@ 
/* This is Page Fault */

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



/* SKAS3 has no trap_no on i386, but get_skas_faultinfo() sets it to 0. */

#ifdef UML_CONFIG_MODE_SKAS

#define SEGV_MAYBE_FIXABLE(fi)	((fi)->trap_no == 0 && ptrace_faultinfo)

#else

#define SEGV_MAYBE_FIXABLE(fi)	0

#endif



extern unsigned long *sc_sigmask(void *sc_ptr);

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

arch/um/include/sysdep-x86_64/sigcontext.h

+4 −1
Original line number Diff line number Diff line
@@ -33,6 +33,9 @@ 
/* This is Page Fault */

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



/* No broken SKAS API, which doesn't pass trap_no, here. */

#define SEGV_MAYBE_FIXABLE(fi)	0



extern unsigned long *sc_sigmask(void *sc_ptr);



#endif

arch/um/kernel/trap_kern.c

+4 −1
Original line number Diff line number Diff line
@@ -26,6 +26,9 @@ 
#include "mconsole_kern.h"

#include "mem.h"

#include "mem_kern.h"

#ifdef CONFIG_MODE_SKAS

#include "skas.h"

#endif



/* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by segv(). */

int handle_page_fault(unsigned long address, unsigned long ip,
@@ -134,7 +137,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc) 
	else if(current->mm == NULL)

		panic("Segfault with no mm");



	if (SEGV_IS_FIXABLE(&fi))

	if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_FIXABLE(&fi))

		err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);

	else {

		err = -EFAULT;