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Commit e821fa42 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

signal/powerpc: Replace TRAP_FIXME with TRAP_UNK 

Using an si_code of 0 that aliases with SI_USER is clearly the wrong
thing todo, and causes problems in interesting ways.

For use in unknown_exception the recently defined TRAP_UNK
semantically is a perfect fit.  For use in RunModeException it looks
like something more specific than TRAP_UNK could be used.  No one has
bothered to find a better fit than the broken si_code of 0 in all of
these years and I don't see an obvious better fit so TRAP_UNK is
switching RunModeException to return TRAP_UNK is clearly an
improvement.

Recent history suggests no actually cares about crazy corner
cases of the kernel behavior like this so I don't expect any
regressions from changing this.  However if something does
happen this change is easy to revert.

Though I wonder if SIGKILL might not be a better fit.

Cc: Paul Mackerras <paulus@samba.org>
Cc: Kumar Gala <kumar.gala@freescale.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org
Fixes: 9bad068c24d7 ("[PATCH] ppc32: support for e500 and 85xx")
Fixes: 0ed70f6105ef ("PPC32: Provide proper siginfo information on various exceptions.")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git


Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 535906c6

arch/powerpc/include/uapi/asm/siginfo.h

+0 −8
Original line number Diff line number Diff line
@@ -15,12 +15,4 @@ 


#include <asm-generic/siginfo.h>



/*

 * SIGTRAP si_codes

 */

#ifdef __KERNEL__

#define TRAP_FIXME	0	/* Broken dup of SI_USER */

#endif /* __KERNEL__ */





#endif	/* _ASM_POWERPC_SIGINFO_H */

arch/powerpc/kernel/traps.c

+2 −2
Original line number Diff line number Diff line
@@ -969,7 +969,7 @@ void unknown_exception(struct pt_regs *regs) 
	printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",

	       regs->nip, regs->msr, regs->trap);



	_exception(SIGTRAP, regs, TRAP_FIXME, 0);

	_exception(SIGTRAP, regs, TRAP_UNK, 0);



	exception_exit(prev_state);

}
@@ -991,7 +991,7 @@ void instruction_breakpoint_exception(struct pt_regs *regs) 


void RunModeException(struct pt_regs *regs)

{

	_exception(SIGTRAP, regs, TRAP_FIXME, 0);

	_exception(SIGTRAP, regs, TRAP_UNK, 0);

}



void single_step_exception(struct pt_regs *regs)