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[PATCH] uml: fix page faults in SKAS3 mode.

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I hadn't been running a SKAS3 host when testing the "uml: fix hang in TT mode
on fault" patch (commit 546fe1cbf9), 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: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Paolo 'Blaisorblade' Giarrusso 2005-09-30 11:58:59 -07:00 committed by Linus Torvalds
parent 79dfa4a5a2
commit be662a18b7
3 changed files with 17 additions and 3 deletions
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10
arch/um/include/sysdep-i386/sigcontext.h
View file

@ -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)
@ -26,7 +27,14 @@
#define SC_START_SYSCALL(sc) do SC_EAX(sc) = -ENOSYS; while(0)
/* This is Page Fault */
#define SEGV_IS_FIXABLE(fi) ((fi)->trap_no == 14)
#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);

5
arch/um/include/sysdep-x86_64/sigcontext.h
View file

@ -31,7 +31,10 @@
#define SC_START_SYSCALL(sc) do SC_RAX(sc) = -ENOSYS; while(0)
/* This is Page Fault */
#define SEGV_IS_FIXABLE(fi) ((fi)->trap_no == 14)
#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);

5
arch/um/kernel/trap_kern.c
View file

@ -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;