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[PATCH] uml: S390 preparation, abstract host page fault data

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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>
This commit is contained in:
Bodo Stroesser
2005-05-05 16:15:31 -07:00
committed by Linus Torvalds
parent ea66e8a3b6
commit c578455a3e
24 changed files with 279 additions and 115 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
arch/um/kernel/trap_kern.c
View File

@@ -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);
}