* [PATCH 0/3] arm64: Fix invalid si_codes for fault signals
@ 2018-02-21 16:02 Dave Martin
2018-02-21 16:02 ` [PATCH 1/3] signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions Dave Martin
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Dave Martin @ 2018-02-21 16:02 UTC (permalink / raw)
To: linux-arm-kernel
Cc: linux-arch, linux-api, Will Deacon, James Morse,
Eric W. Biederman, Catalin Marinas
Changes since RFC v2:
* Fold in reverts of the relevant parts of Eric's *_FIXME changes,
since this series removes all cases of those dummy si_code values
from arm64.
* Propagated the new signal/si_code assignments for synchronous
external aborts correctly to signals thrown from do_sea().
Original blurb:
As reported by Eric Biederman, [1], [2], [3] etc., several architectures
are inappropriately setting si_code to 0 when signaling faults to
userspace, which will interpret this value as SI_USER leading to garbage
being read out of siginfo fields that the kernel doesn't initialise.
This seems not to be a huge problem in practice, since many affected
faults should only happen if the kernel or hardware is buggy or broken.
However, there are some cases that don't fall under this.
This RFC series proposes fixes to eliminate these si_code == 0 cases
from arm64. Some of the changes may be controversial.
There are two main headlines here, which may be applicable to other
architectures:
* addition of a new code FPE_UNKNOWN for undiagnosable floating-point
exception traps;
* delivering SIGKILL instead of SIGSEGV/BUS/TRAP etc. for "impossible"
exceptions that are not feasible to recover from and likely indicate
a kernel or system bug or failure.
In particular there is likely to be a fair amount of overlap between arm
and arm64 here, but due to the longer history and evolution of the arm
tree and 32-bit architecture I'm less confident in making correct
judgements for that case. This series doesn't touch arm, for now.
Boot-tested on Arm Juno r0.
Floating-point exception traps tested on the Arm Fast Model.
[1] [PATCH 00/11] siginfo fixes/cleanups esp SI_USER
https://marc.info/?l=linux-kernel&m=151571871109016&w=2
[2] [PATCH 08/11] signal/arm: Document conflicts with SI_USER and SIGFPE
http://lists.infradead.org/pipermail/linux-arm-kernel/2018-January/553574.html
[3] [PATCH 07/11] signal/arm64: Document conflicts with SI_USER and SIGFPE, SIGTRAP, SIGBUS
lists.infradead.org/pipermail/linux-arm-kernel/2018-January/553573.html
---
Dave Martin (3):
signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions
arm64: fpsimd: Fix bad si_code for undiagnosed SIGFPE
arm64: signal: Ensure si_code is valid for all fault signals
arch/arm64/include/asm/esr.h | 9 +++
arch/arm64/include/uapi/asm/siginfo.h | 21 ------
arch/arm64/kernel/fpsimd.c | 31 +++++----
arch/arm64/mm/fault.c | 116 +++++++++++++++++-----------------
include/uapi/asm-generic/siginfo.h | 3 +-
kernel/signal.c | 4 --
6 files changed, 86 insertions(+), 98 deletions(-)
--
2.1.4
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/3] signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions
2018-02-21 16:02 [PATCH 0/3] arm64: Fix invalid si_codes for fault signals Dave Martin
@ 2018-02-21 16:02 ` Dave Martin
2018-02-22 12:14 ` James Morse
2018-02-21 16:02 ` [PATCH 2/3] arm64: fpsimd: Fix bad si_code for undiagnosed SIGFPE Dave Martin
2018-02-21 16:02 ` [PATCH 3/3] arm64: signal: Ensure si_code is valid for all fault signals Dave Martin
2 siblings, 1 reply; 6+ messages in thread
From: Dave Martin @ 2018-02-21 16:02 UTC (permalink / raw)
To: linux-arm-kernel
Cc: linux-arch, linux-api, Will Deacon, James Morse,
Eric W. Biederman, Catalin Marinas
Some architectures cannot always report accurately what kind of
floating-point exception triggered a floating-point exception trap.
This can occur with fp exceptions occuring on lanes in a vector
instruction on arm64 for example.
Rather than have every architecture come up with its own way of
descrbing such a condition, this patch adds a common FPE_FLTUNK do
report that an fp exception caused a trap but we cannot be certain
which kind of fp exception it was.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
include/uapi/asm-generic/siginfo.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 85dc965..10304de 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -229,7 +229,8 @@ typedef struct siginfo {
# define __FPE_INVASC 12 /* invalid ASCII digit */
# define __FPE_INVDEC 13 /* invalid decimal digit */
#endif
-#define NSIGFPE 13
+#define FPE_FLTUNK 14 /* undiagnosed floating-point exception */
+#define NSIGFPE 14
/*
* SIGSEGV si_codes
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/3] arm64: fpsimd: Fix bad si_code for undiagnosed SIGFPE
2018-02-21 16:02 [PATCH 0/3] arm64: Fix invalid si_codes for fault signals Dave Martin
2018-02-21 16:02 ` [PATCH 1/3] signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions Dave Martin
@ 2018-02-21 16:02 ` Dave Martin
2018-02-21 16:02 ` [PATCH 3/3] arm64: signal: Ensure si_code is valid for all fault signals Dave Martin
2 siblings, 0 replies; 6+ messages in thread
From: Dave Martin @ 2018-02-21 16:02 UTC (permalink / raw)
To: linux-arm-kernel
Cc: linux-arch, linux-api, Will Deacon, James Morse,
Eric W. Biederman, Catalin Marinas
Currently a SIGFPE delivered in response to a floating-point
exception trap may have si_code set to 0 on arm64. As reported by
Eric, this is a bad idea since this is the value of SI_USER -- yet
this signal is definitely not the result of kill(2), tgkill(2) etc.
and si_uid and si_pid make limited sense whereas we do want to
yield a value for si_addr (which doesn't exist for SI_USER).
It's not entirely clear whether the architecure permits a
"spurious" fp exception trap where none of the exception flag bits
in ESR_ELx is set. (IMHO the architectural intent is to forbid
this.) However, it does permit those bits to contain garbage if
the TFV bit in ESR_ELx is 0. That case isn't currently handled at
all and may result in si_code == 0 or si_code containing a FPE_FLT*
constant corresponding to an exception that did not in fact happen.
There is nothing sensible we can return for si_code in such cases,
but SI_USER is certainly not appropriate and will lead to violation
of legitimate userspace assumptions.
This patch allocates a new si_code value FPE_UNKNOWN that at least
does not conflict with any existing SI_* or FPE_* code, and yields
this in si_code for undiagnosable cases. This is probably the best
simplicity/incorrectness tradeoff achieveable without relying on
implementation-dependent features or adding a lot of code. In any
case, there appears to be no perfect solution possible that would
justify a lot of effort here.
Yielding FPE_UNKNOWN when some well-defined fp exception caused the
trap is a violation of POSIX, but this is forced by the
architecture. We have no realistic prospect of yielding the
correct code in such cases. At present I am not aware of any ARMv8
implementation that supports trapped floating-point exceptions in
any case.
The new code may be applicable to other architectures for similar
reasons.
No attempt is made to provide ESR_ELx to userspace in the signal
frame, since architectural limitations mean that it is unlikely to
provide much diagnostic value, doesn't benefit existing software
and would create ABI with no proven purpose. The existing
mechanism for passing it also has problems of its own which may
result in the wrong value being passed to userspace due to
interaction with mm faults. The implied rework does not appear
justified.
Reported-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
arch/arm64/include/asm/esr.h | 9 +++++++++
arch/arm64/include/uapi/asm/siginfo.h | 7 -------
arch/arm64/kernel/fpsimd.c | 27 +++++++++++++++------------
3 files changed, 24 insertions(+), 19 deletions(-)
diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index 803443d..ce70c3f 100644
--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -240,6 +240,15 @@
(((e) & ESR_ELx_SYS64_ISS_OP2_MASK) >> \
ESR_ELx_SYS64_ISS_OP2_SHIFT))
+/*
+ * ISS field definitions for floating-point exception traps
+ * (FP_EXC_32/FP_EXC_64).
+ *
+ * (The FPEXC_* constants are used instead for common bits.)
+ */
+
+#define ESR_ELx_FP_EXC_TFV (UL(1) << 23)
+
#ifndef __ASSEMBLY__
#include <asm/types.h>
diff --git a/arch/arm64/include/uapi/asm/siginfo.h b/arch/arm64/include/uapi/asm/siginfo.h
index 9b4d912..157e6a8 100644
--- a/arch/arm64/include/uapi/asm/siginfo.h
+++ b/arch/arm64/include/uapi/asm/siginfo.h
@@ -22,13 +22,6 @@
#include <asm-generic/siginfo.h>
/*
- * SIGFPE si_codes
- */
-#ifdef __KERNEL__
-#define FPE_FIXME 0 /* Broken dup of SI_USER */
-#endif /* __KERNEL__ */
-
-/*
* SIGBUS si_codes
*/
#ifdef __KERNEL__
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index e7226c4..9040038 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -39,6 +39,7 @@
#include <linux/slab.h>
#include <linux/sysctl.h>
+#include <asm/esr.h>
#include <asm/fpsimd.h>
#include <asm/cputype.h>
#include <asm/simd.h>
@@ -867,18 +868,20 @@ asmlinkage void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
asmlinkage void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
{
siginfo_t info;
- unsigned int si_code = FPE_FIXME;
-
- if (esr & FPEXC_IOF)
- si_code = FPE_FLTINV;
- else if (esr & FPEXC_DZF)
- si_code = FPE_FLTDIV;
- else if (esr & FPEXC_OFF)
- si_code = FPE_FLTOVF;
- else if (esr & FPEXC_UFF)
- si_code = FPE_FLTUND;
- else if (esr & FPEXC_IXF)
- si_code = FPE_FLTRES;
+ unsigned int si_code = FPE_FLTUNK;
+
+ if (esr & ESR_ELx_FP_EXC_TFV) {
+ if (esr & FPEXC_IOF)
+ si_code = FPE_FLTINV;
+ else if (esr & FPEXC_DZF)
+ si_code = FPE_FLTDIV;
+ else if (esr & FPEXC_OFF)
+ si_code = FPE_FLTOVF;
+ else if (esr & FPEXC_UFF)
+ si_code = FPE_FLTUND;
+ else if (esr & FPEXC_IXF)
+ si_code = FPE_FLTRES;
+ }
memset(&info, 0, sizeof(info));
info.si_signo = SIGFPE;
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 3/3] arm64: signal: Ensure si_code is valid for all fault signals
2018-02-21 16:02 [PATCH 0/3] arm64: Fix invalid si_codes for fault signals Dave Martin
2018-02-21 16:02 ` [PATCH 1/3] signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions Dave Martin
2018-02-21 16:02 ` [PATCH 2/3] arm64: fpsimd: Fix bad si_code for undiagnosed SIGFPE Dave Martin
@ 2018-02-21 16:02 ` Dave Martin
2 siblings, 0 replies; 6+ messages in thread
From: Dave Martin @ 2018-02-21 16:02 UTC (permalink / raw)
To: linux-arm-kernel
Cc: linux-arch, linux-api, Will Deacon, James Morse,
Eric W. Biederman, Catalin Marinas
Currently, as reported by Eric, an invalid si_code value 0 is
passed in many signals delivered to userspace in response to faults
and other kernel errors. Typically 0 is passed when the fault is
insufficiently diagnosable or when there does not appear to be any
sensible alternative value to choose.
This appears to violate POSIX, and is intuitively wrong for at
least two reasons arising from the fact that 0 == SI_USER:
1) si_code is a union selector, and SI_USER (and si_code <= 0 in
general) implies the existence of a different set of fields
(siginfo._kill) from that which exists for a fault signal
(siginfo._sigfault). However, the code raising the signal
typically writes only the _sigfault fields, and the _kill
fields make no sense in this case.
Thus when userspace sees si_code == 0 (SI_USER) it may
legitimately inspect fields in the inactive union member _kill
and obtain garbage as a result.
There appears to be software in the wild relying on this,
albeit generally only for printing diagnostic messages.
2) Software that wants to be robust against spurious signals may
discard signals where si_code == SI_USER (or <= 0), or may
filter such signals based on the si_uid and si_pid fields of
siginfo._sigkill. In the case of fault signals, this means
that important (and usually fatal) error conditions may be
silently ignored.
In practice, many of the faults for which arm64 passes si_code == 0
are undiagnosable conditions such as exceptions with syndrome
values in ESR_ELx to which the architecture does not yet assign any
meaning, or conditions indicative of a bug or error in the kernel
or system and thus that are unrecoverable and should never occur in
normal operation.
The approach taken in this patch is to translate all such
undiagnosable or "impossible" synchronous fault conditions to
SIGKILL, since these are at least probably localisable to a single
process. Some of these conditions should really result in a kernel
panic, but due to the lack of diagnostic information it is
difficult to be certain: this patch does not add any calls to
panic(), but this could change later if justified.
Although si_code will not reach userspace in the case of SIGKILL,
it is still desirable to pass a nonzero value so that the common
siginfo handling code can detect incorrect use of si_code == 0
without false positives. In this case the si_code dependent
siginfo fields will not be correctly initialised, but since they
are not passed to userspace I deem this not to matter.
A few faults can reasonably occur in realistic userspace scenarios,
and _should_ raise a regular, handleable (but perhaps not
ignorable/blockable) signal: for these, this patch attempts to
choose a suitable standard si_code value for the raised signal in
each case instead of 0.
arm64 was the only arch to define a BUS_FIXME code, so after this
patch nobody defines it. This patch therefore also removes the
relevant code from siginfo_layout().
Cc: James Morse <james.morse@arm.com>
Reported-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
Changes since RFC v2:
* Squashed in revert of the appropriate bits of Eric's BUS_/TRAP_FIXME
stuff.
* Propagated the fault_info[] sig and code vaules through do_sea(),
which previously was ignoring them.
---
arch/arm64/include/uapi/asm/siginfo.h | 14 ----
arch/arm64/kernel/fpsimd.c | 4 +-
arch/arm64/mm/fault.c | 116 +++++++++++++++++-----------------
kernel/signal.c | 4 --
4 files changed, 60 insertions(+), 78 deletions(-)
diff --git a/arch/arm64/include/uapi/asm/siginfo.h b/arch/arm64/include/uapi/asm/siginfo.h
index 157e6a8..574d12f 100644
--- a/arch/arm64/include/uapi/asm/siginfo.h
+++ b/arch/arm64/include/uapi/asm/siginfo.h
@@ -21,18 +21,4 @@
#include <asm-generic/siginfo.h>
-/*
- * SIGBUS si_codes
- */
-#ifdef __KERNEL__
-#define BUS_FIXME 0 /* Broken dup of SI_USER */
-#endif /* __KERNEL__ */
-
-/*
- * SIGTRAP si_codes
- */
-#ifdef __KERNEL__
-#define TRAP_FIXME 0 /* Broken dup of SI_USER */
-#endif /* __KERNEL__ */
-
#endif
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 9040038..dc93aa4 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -286,8 +286,8 @@ static void task_fpsimd_save(void)
* re-enter user with corrupt state.
* There's no way to recover, so kill it:
*/
- force_signal_inject(
- SIGKILL, 0, current_pt_regs(), 0);
+ force_signal_inject(SIGKILL, SI_KERNEL,
+ current_pt_regs(), 0);
return;
}
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index bff1155..c7c85c3 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -600,9 +600,9 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
nmi_exit();
}
- info.si_signo = SIGBUS;
+ info.si_signo = inf->sig;
info.si_errno = 0;
- info.si_code = BUS_FIXME;
+ info.si_code = inf->code;
if (esr & ESR_ELx_FnV)
info.si_addr = NULL;
else
@@ -613,70 +613,70 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
}
static const struct fault_info fault_info[] = {
- { do_bad, SIGBUS, BUS_FIXME, "ttbr address size fault" },
- { do_bad, SIGBUS, BUS_FIXME, "level 1 address size fault" },
- { do_bad, SIGBUS, BUS_FIXME, "level 2 address size fault" },
- { do_bad, SIGBUS, BUS_FIXME, "level 3 address size fault" },
+ { do_bad, SIGKILL, SI_KERNEL, "ttbr address size fault" },
+ { do_bad, SIGKILL, SI_KERNEL, "level 1 address size fault" },
+ { do_bad, SIGKILL, SI_KERNEL, "level 2 address size fault" },
+ { do_bad, SIGKILL, SI_KERNEL, "level 3 address size fault" },
{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 0 translation fault" },
{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" },
{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" },
{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 8" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 8" },
{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" },
{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" },
{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 12" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 12" },
{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" },
{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" },
{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" },
- { do_sea, SIGBUS, BUS_FIXME, "synchronous external abort" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 17" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 18" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 19" },
- { do_sea, SIGBUS, BUS_FIXME, "level 0 (translation table walk)" },
- { do_sea, SIGBUS, BUS_FIXME, "level 1 (translation table walk)" },
- { do_sea, SIGBUS, BUS_FIXME, "level 2 (translation table walk)" },
- { do_sea, SIGBUS, BUS_FIXME, "level 3 (translation table walk)" },
- { do_sea, SIGBUS, BUS_FIXME, "synchronous parity or ECC error" }, // Reserved when RAS is implemented
- { do_bad, SIGBUS, BUS_FIXME, "unknown 25" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 26" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 27" },
- { do_sea, SIGBUS, BUS_FIXME, "level 0 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
- { do_sea, SIGBUS, BUS_FIXME, "level 1 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
- { do_sea, SIGBUS, BUS_FIXME, "level 2 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
- { do_sea, SIGBUS, BUS_FIXME, "level 3 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
- { do_bad, SIGBUS, BUS_FIXME, "unknown 32" },
+ { do_sea, SIGBUS, BUS_OBJERR, "synchronous external abort" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 17" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 18" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 19" },
+ { do_sea, SIGKILL, SI_KERNEL, "level 0 (translation table walk)" },
+ { do_sea, SIGKILL, SI_KERNEL, "level 1 (translation table walk)" },
+ { do_sea, SIGKILL, SI_KERNEL, "level 2 (translation table walk)" },
+ { do_sea, SIGKILL, SI_KERNEL, "level 3 (translation table walk)" },
+ { do_sea, SIGBUS, BUS_OBJERR, "synchronous parity or ECC error" }, // Reserved when RAS is implemented
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 25" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 26" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 27" },
+ { do_sea, SIGKILL, SI_KERNEL, "level 0 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
+ { do_sea, SIGKILL, SI_KERNEL, "level 1 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
+ { do_sea, SIGKILL, SI_KERNEL, "level 2 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
+ { do_sea, SIGKILL, SI_KERNEL, "level 3 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 32" },
{ do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 34" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 35" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 36" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 37" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 38" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 39" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 40" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 41" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 42" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 43" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 44" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 45" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 46" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 47" },
- { do_bad, SIGBUS, BUS_FIXME, "TLB conflict abort" },
- { do_bad, SIGBUS, BUS_FIXME, "Unsupported atomic hardware update fault" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 50" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 51" },
- { do_bad, SIGBUS, BUS_FIXME, "implementation fault (lockdown abort)" },
- { do_bad, SIGBUS, BUS_FIXME, "implementation fault (unsupported exclusive)" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 54" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 55" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 56" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 57" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 58" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 59" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 60" },
- { do_bad, SIGBUS, BUS_FIXME, "section domain fault" },
- { do_bad, SIGBUS, BUS_FIXME, "page domain fault" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 63" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 34" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 35" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 36" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 37" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 38" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 39" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 40" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 41" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 42" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 43" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 44" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 45" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 46" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 47" },
+ { do_bad, SIGKILL, SI_KERNEL, "TLB conflict abort" },
+ { do_bad, SIGKILL, SI_KERNEL, "Unsupported atomic hardware update fault" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 50" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 51" },
+ { do_bad, SIGKILL, SI_KERNEL, "implementation fault (lockdown abort)" },
+ { do_bad, SIGBUS, BUS_OBJERR, "implementation fault (unsupported exclusive)" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 54" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 55" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 56" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 57" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 58" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 59" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 60" },
+ { do_bad, SIGKILL, SI_KERNEL, "section domain fault" },
+ { do_bad, SIGKILL, SI_KERNEL, "page domain fault" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 63" },
};
int handle_guest_sea(phys_addr_t addr, unsigned int esr)
@@ -774,11 +774,11 @@ static struct fault_info __refdata debug_fault_info[] = {
{ do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" },
{ do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" },
{ do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 3" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 3" },
{ do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" },
- { do_bad, SIGTRAP, TRAP_FIXME, "aarch32 vector catch" },
+ { do_bad, SIGKILL, SI_KERNEL, "aarch32 vector catch" },
{ early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" },
- { do_bad, SIGBUS, BUS_FIXME, "unknown 7" },
+ { do_bad, SIGKILL, SI_KERNEL, "unknown 7" },
};
void __init hook_debug_fault_code(int nr,
diff --git a/kernel/signal.c b/kernel/signal.c
index c6e4c83d..049a482 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2844,10 +2844,6 @@ enum siginfo_layout siginfo_layout(int sig, int si_code)
if ((sig == SIGFPE) && (si_code == FPE_FIXME))
layout = SIL_FAULT;
#endif
-#ifdef BUS_FIXME
- if ((sig == SIGBUS) && (si_code == BUS_FIXME))
- layout = SIL_FAULT;
-#endif
}
return layout;
}
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 1/3] signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions
2018-02-21 16:02 ` [PATCH 1/3] signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions Dave Martin
@ 2018-02-22 12:14 ` James Morse
2018-02-22 13:13 ` Dave Martin
0 siblings, 1 reply; 6+ messages in thread
From: James Morse @ 2018-02-22 12:14 UTC (permalink / raw)
To: Dave Martin
Cc: linux-arch, linux-api, Will Deacon, Eric W. Biederman,
Catalin Marinas, linux-arm-kernel
Hi Dave,
On 21/02/18 16:02, Dave Martin wrote:
> Some architectures cannot always report accurately what kind of
> floating-point exception triggered a floating-point exception trap.
>
> This can occur with fp exceptions occuring on lanes in a vector
(Nit: occurring)
> instruction on arm64 for example.
>
> Rather than have every architecture come up with its own way of
> descrbing such a condition, this patch adds a common FPE_FLTUNK do
(Nits: describing; 'to report')
> report that an fp exception caused a trap but we cannot be certain
> which kind of fp exception it was.
> diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
> index 85dc965..10304de 100644
> --- a/include/uapi/asm-generic/siginfo.h
> +++ b/include/uapi/asm-generic/siginfo.h
> @@ -229,7 +229,8 @@ typedef struct siginfo {
> # define __FPE_INVASC 12 /* invalid ASCII digit */
> # define __FPE_INVDEC 13 /* invalid decimal digit */
> #endif
> -#define NSIGFPE 13
> +#define FPE_FLTUNK 14 /* undiagnosed floating-point exception */
> +#define NSIGFPE 14
It looks like x86's compat relies on this value not changing:
| arch/x86/kernel/signal_compat.c: BUILD_BUG_ON(NSIGFPE != 13);
| include/uapi/asm-generic/siginfo.h:#define NSIGFPE 13
(from v4.16-rc2)
Thanks,
James
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/3] signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions
2018-02-22 12:14 ` James Morse
@ 2018-02-22 13:13 ` Dave Martin
0 siblings, 0 replies; 6+ messages in thread
From: Dave Martin @ 2018-02-22 13:13 UTC (permalink / raw)
To: James Morse
Cc: linux-arch, linux-api, Will Deacon, Eric W. Biederman,
Catalin Marinas, linux-arm-kernel
On Thu, Feb 22, 2018 at 12:14:17PM +0000, James Morse wrote:
> Hi Dave,
>
> On 21/02/18 16:02, Dave Martin wrote:
> > Some architectures cannot always report accurately what kind of
> > floating-point exception triggered a floating-point exception trap.
> >
> > This can occur with fp exceptions occuring on lanes in a vector
>
> (Nit: occurring)
>
> > instruction on arm64 for example.
> >
> > Rather than have every architecture come up with its own way of
> > descrbing such a condition, this patch adds a common FPE_FLTUNK do
>
> (Nits: describing; 'to report')
>
> > report that an fp exception caused a trap but we cannot be certain
Hmmm, this wasn't my best effort...
> > which kind of fp exception it was.
>
>
> > diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
> > index 85dc965..10304de 100644
> > --- a/include/uapi/asm-generic/siginfo.h
> > +++ b/include/uapi/asm-generic/siginfo.h
> > @@ -229,7 +229,8 @@ typedef struct siginfo {
> > # define __FPE_INVASC 12 /* invalid ASCII digit */
> > # define __FPE_INVDEC 13 /* invalid decimal digit */
> > #endif
> > -#define NSIGFPE 13
> > +#define FPE_FLTUNK 14 /* undiagnosed floating-point exception */
> > +#define NSIGFPE 14
>
> It looks like x86's compat relies on this value not changing:
> | arch/x86/kernel/signal_compat.c: BUILD_BUG_ON(NSIGFPE != 13);
> | include/uapi/asm-generic/siginfo.h:#define NSIGFPE 13
>
> (from v4.16-rc2)
Hmmm, that's embarrassing -- thanks for spotting!
I think we can justifiably bump the number there, since x86 won't use
FPT_FLTUNK (for now, perhaps for ever) and anyway it doesn't add any new
information to siginfo.
I'll respin with these changes.
Cheers
---Dave
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-02-22 13:13 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-02-21 16:02 [PATCH 0/3] arm64: Fix invalid si_codes for fault signals Dave Martin
2018-02-21 16:02 ` [PATCH 1/3] signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions Dave Martin
2018-02-22 12:14 ` James Morse
2018-02-22 13:13 ` Dave Martin
2018-02-21 16:02 ` [PATCH 2/3] arm64: fpsimd: Fix bad si_code for undiagnosed SIGFPE Dave Martin
2018-02-21 16:02 ` [PATCH 3/3] arm64: signal: Ensure si_code is valid for all fault signals Dave Martin
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