Add a new MIPS_BE_FATAL_QUIET value which bus error handlers can return
to indicate that a bus error triggered by user code should be treated
the same way as MIPS_BE_FATAL, ie. we should deliver a SIGBUS, but the
kernel shouldn't print information about the bus error to the kernel
log.
This will be useful in a further commit which will silence kernel log
output from bus errors caused by user code performing smaller than 32
bit accesses to the GIC user page, which generates a bus error. Notably
this will silence a ton of output from crashme, which seems to be rather
eager to access the GIC user page in weird & wonderful ways.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
arch/mips/include/asm/traps.h | 1 +
arch/mips/kernel/traps.c | 5 ++++-
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/traps.h b/arch/mips/include/asm/traps.h
index f41cf3ee82a7..7594fb496001 100644
--- a/arch/mips/include/asm/traps.h
+++ b/arch/mips/include/asm/traps.h
@@ -17,6 +17,7 @@
#define MIPS_BE_DISCARD 0 /* return with no action */
#define MIPS_BE_FIXUP 1 /* return to the fixup code */
#define MIPS_BE_FATAL 2 /* treat as an unrecoverable error */
+#define MIPS_BE_FATAL_QUIET 3 /* treat as an unrecoverable error */
extern void (*board_be_init)(void);
extern int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 259e2d259204..2f4546e4abdb 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -465,6 +465,9 @@ asmlinkage void do_be(struct pt_regs *regs)
goto out;
}
break;
+ case MIPS_BE_FATAL_QUIET:
+ if (user_mode(regs))
+ goto out_sigbus;
default:
break;
}
@@ -480,8 +483,8 @@ asmlinkage void do_be(struct pt_regs *regs)
goto out;
die_if_kernel("Oops", regs);
+out_sigbus:
force_sig(SIGBUS, current);
-
out:
exception_exit(prev_state);
}
--
2.14.1
