Commit a3616a3c authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die 

In the fpsp040 code when copyin or copyout fails call
force_sigsegv(SIGSEGV) instead of do_exit(SIGSEGV).

This solves a couple of problems.  Because do_exit embeds the ptrace
stop PTRACE_EVENT_EXIT a complete stack frame needs to be present for
that to work correctly.  There is always the information needed for a
ptrace stop where get_signal is called.  So exiting with a signal
solves the ptrace issue.

Further exiting with a signal ensures that all of the threads in a
process are killed not just the thread that malfunctioned.  Which
avoids confusing userspace.

To make force_sigsegv(SIGSEGV) work in fpsp040_die modify the code to
save all of the registers and jump to ret_from_exception (which
ultimately calls get_signal) after fpsp040_die returns.

v2: Updated the branches to use gas's pseudo ops that automatically
    calculate the best branch instruction to use for the purpose.

v1: https://lkml.kernel.org/r/87a6m8kgtx.fsf_-_@disp2133
Link: https://lkml.kernel.org/r/87tukghjfs.fsf_-_@disp2133


Acked-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent b48c7236

arch/m68k/fpsp040/skeleton.S

+2 −1
Original line number Diff line number Diff line
@@ -502,7 +502,8 @@ in_ea: 
	.section .fixup,#alloc,#execinstr

	.even

1:

	jbra	fpsp040_die

	jbsr	fpsp040_die

	jbra	.Lnotkern



	.section __ex_table,#alloc

	.align	4

arch/m68k/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -1150,7 +1150,7 @@ asmlinkage void set_esp0(unsigned long ssp) 
 */

asmlinkage void fpsp040_die(void)

{

	do_exit(SIGSEGV);

	force_sigsegv(SIGSEGV);

}



#ifdef CONFIG_M68KFPU_EMU