From: "Eric W. Beiderman" <ebiederm@xmission.com>
To: Marco Elver <elver@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
Florian Weimer <fweimer@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Collingbourne <pcc@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Alexander Potapenko <glider@google.com>,
sparclinux <sparclinux@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
kasan-dev <kasan-dev@googlegroups.com>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [PATCH v3 05/12] siginfo: Move si_trapno inside the union inside _si_fault
Date: Wed, 5 May 2021 09:10:54 -0500 [thread overview]
Message-ID: <20210505141101.11519-5-ebiederm@xmission.com> (raw)
In-Reply-To: <20210505141101.11519-1-ebiederm@xmission.com>
From: "Eric W. Biederman" <ebiederm@xmission.com>
It turns out that linux uses si_trapno very sparingly, and as such it
can be considered extra information for a very narrow selection of
signals, rather than information that is present with every fault
reported in siginfo.
As such move si_trapno inside the union inside of _si_fault. This
results in no change in placement, and makes it eaiser
to extend _si_fault in the future as this reduces the number of
special cases. In particular with si_trapno included in the union it
is no longer a concern that the union must be pointer alligned on most
architectures because the union followes immediately after si_addr
which is a pointer.
This change results in a difference in siginfo field placement on
sparc and alpha for the fields si_addr_lsb, si_lower, si_upper,
si_pkey, and si_perf. These architectures do not implement the
signals that would use si_addr_lsb, si_lower, si_upper, si_pkey, and
si_perf. Further these architecture have not yet implemented the
userspace that would use si_perf.
The point of this change is in fact to correct these placement issues
before sparc or alpha grow userspace that cares. This change was
discussed[1] and the agreement is that this change is currently safe.
[1]: https://lkml.kernel.org/r/CAK8P3a0+uKYwL1NhY6Hvtieghba2hKYGD6hcKx5n8=4Gtt+pHA@mail.gmail.com
Acked-by: Marco Elver <elver@google.com>
v1: https://lkml.kernel.org/r/m1tunns7yf.fsf_-_@fess.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
arch/sparc/kernel/signal32.c | 10 +++++-----
arch/sparc/kernel/signal_64.c | 10 +++++-----
arch/x86/kernel/signal_compat.c | 3 +++
include/linux/compat.h | 5 ++---
include/uapi/asm-generic/siginfo.h | 7 ++-----
kernel/signal.c | 1 +
6 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/arch/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c
index 32b977f253e3..5573722e34ad 100644
--- a/arch/sparc/kernel/signal32.c
+++ b/arch/sparc/kernel/signal32.c
@@ -774,10 +774,10 @@ static_assert(offsetof(compat_siginfo_t, si_int) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_ptr) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_addr) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_trapno) == 0x10);
-static_assert(offsetof(compat_siginfo_t, si_addr_lsb) == 0x14);
-static_assert(offsetof(compat_siginfo_t, si_lower) == 0x18);
-static_assert(offsetof(compat_siginfo_t, si_upper) == 0x1c);
-static_assert(offsetof(compat_siginfo_t, si_pkey) == 0x18);
-static_assert(offsetof(compat_siginfo_t, si_perf) == 0x14);
+static_assert(offsetof(compat_siginfo_t, si_addr_lsb) == 0x10);
+static_assert(offsetof(compat_siginfo_t, si_lower) == 0x14);
+static_assert(offsetof(compat_siginfo_t, si_upper) == 0x18);
+static_assert(offsetof(compat_siginfo_t, si_pkey) == 0x14);
+static_assert(offsetof(compat_siginfo_t, si_perf) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_band) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_fd) == 0x10);
diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c
index e9dda9db156c..a69a78984c36 100644
--- a/arch/sparc/kernel/signal_64.c
+++ b/arch/sparc/kernel/signal_64.c
@@ -584,10 +584,10 @@ static_assert(offsetof(siginfo_t, si_int) == 0x18);
static_assert(offsetof(siginfo_t, si_ptr) == 0x18);
static_assert(offsetof(siginfo_t, si_addr) == 0x10);
static_assert(offsetof(siginfo_t, si_trapno) == 0x18);
-static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x20);
-static_assert(offsetof(siginfo_t, si_lower) == 0x28);
-static_assert(offsetof(siginfo_t, si_upper) == 0x30);
-static_assert(offsetof(siginfo_t, si_pkey) == 0x28);
-static_assert(offsetof(siginfo_t, si_perf) == 0x20);
+static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x18);
+static_assert(offsetof(siginfo_t, si_lower) == 0x20);
+static_assert(offsetof(siginfo_t, si_upper) == 0x28);
+static_assert(offsetof(siginfo_t, si_pkey) == 0x20);
+static_assert(offsetof(siginfo_t, si_perf) == 0x18);
static_assert(offsetof(siginfo_t, si_band) == 0x10);
static_assert(offsetof(siginfo_t, si_fd) == 0x14);
diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c
index e735bc129331..c9601f092a1e 100644
--- a/arch/x86/kernel/signal_compat.c
+++ b/arch/x86/kernel/signal_compat.c
@@ -133,6 +133,9 @@ static inline void signal_compat_build_tests(void)
BUILD_BUG_ON(offsetof(siginfo_t, si_addr) != 0x10);
BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr) != 0x0C);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_trapno) != 0x18);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_trapno) != 0x10);
+
BUILD_BUG_ON(offsetof(siginfo_t, si_addr_lsb) != 0x18);
BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr_lsb) != 0x10);
diff --git a/include/linux/compat.h b/include/linux/compat.h
index f0d2dd35d408..6af7bef15e94 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -214,12 +214,11 @@ typedef struct compat_siginfo {
/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */
struct {
compat_uptr_t _addr; /* faulting insn/memory ref. */
-#ifdef __ARCH_SI_TRAPNO
- int _trapno; /* TRAP # which caused the signal */
-#endif
#define __COMPAT_ADDR_BND_PKEY_PAD (__alignof__(compat_uptr_t) < sizeof(short) ? \
sizeof(short) : __alignof__(compat_uptr_t))
union {
+ /* used on alpha and sparc */
+ int _trapno; /* TRAP # which caused the signal */
/*
* used when si_code=BUS_MCEERR_AR or
* used when si_code=BUS_MCEERR_AO
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 91c80d0c10c5..3503282021aa 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -68,9 +68,6 @@ union __sifields {
/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */
struct {
void __user *_addr; /* faulting insn/memory ref. */
-#ifdef __ARCH_SI_TRAPNO
- int _trapno; /* TRAP # which caused the signal */
-#endif
#ifdef __ia64__
int _imm; /* immediate value for "break" */
unsigned int _flags; /* see ia64 si_flags */
@@ -80,6 +77,8 @@ union __sifields {
#define __ADDR_BND_PKEY_PAD (__alignof__(void *) < sizeof(short) ? \
sizeof(short) : __alignof__(void *))
union {
+ /* used on alpha and sparc */
+ int _trapno; /* TRAP # which caused the signal */
/*
* used when si_code=BUS_MCEERR_AR or
* used when si_code=BUS_MCEERR_AO
@@ -155,9 +154,7 @@ typedef struct siginfo {
#define si_int _sifields._rt._sigval.sival_int
#define si_ptr _sifields._rt._sigval.sival_ptr
#define si_addr _sifields._sigfault._addr
-#ifdef __ARCH_SI_TRAPNO
#define si_trapno _sifields._sigfault._trapno
-#endif
#define si_addr_lsb _sifields._sigfault._addr_lsb
#define si_lower _sifields._sigfault._addr_bnd._lower
#define si_upper _sifields._sigfault._addr_bnd._upper
diff --git a/kernel/signal.c b/kernel/signal.c
index c3017aa8024a..65888aec65a0 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -4607,6 +4607,7 @@ static inline void siginfo_buildtime_checks(void)
/* sigfault */
CHECK_OFFSET(si_addr);
+ CHECK_OFFSET(si_trapno);
CHECK_OFFSET(si_addr_lsb);
CHECK_OFFSET(si_lower);
CHECK_OFFSET(si_upper);
--
2.30.1
next prev parent reply other threads:[~2021-05-05 14:11 UTC|newest]
Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-29 7:48 siginfo_t ABI break on sparc64 from si_addr_lsb move 3y ago Marco Elver
2021-04-29 17:23 ` Eric W. Biederman
2021-04-29 18:46 ` Marco Elver
2021-04-29 20:48 ` Arnd Bergmann
2021-04-30 17:08 ` Eric W. Biederman
2021-04-30 19:07 ` Marco Elver
2021-04-30 20:15 ` Eric W. Biederman
2021-04-30 23:50 ` Marco Elver
2021-04-30 22:49 ` [RFC][PATCH 0/3] signal: Move si_trapno into the _si_fault union Eric W. Biederman
2021-04-30 22:50 ` [PATCH 1/3] siginfo: Move si_trapno inside the union inside _si_fault Eric W. Biederman
2021-05-01 10:31 ` Marco Elver
2021-05-02 18:27 ` Eric W. Biederman
2021-04-30 22:54 ` [PATCH 2/3] signal: Implement SIL_FAULT_TRAPNO Eric W. Biederman
2021-04-30 23:19 ` Eric W. Biederman
2021-05-01 10:33 ` Marco Elver
2021-05-02 18:24 ` Eric W. Biederman
2021-04-30 22:55 ` [PATCH 3/3] signal: Use dedicated helpers to send signals with si_trapno set Eric W. Biederman
2021-05-01 10:33 ` Marco Elver
2021-04-30 22:56 ` [PATCH 4/3] signal: Remove __ARCH_SI_TRAPNO Eric W. Biederman
2021-04-30 23:23 ` Is perf_sigtrap synchronous? Eric W. Biederman
2021-05-01 0:28 ` Marco Elver
2021-04-30 23:42 ` [PATCH 5/3] signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency Eric W. Biederman
2021-05-01 10:35 ` Marco Elver
2021-04-30 23:43 ` [PATCH 6/3] signal: Factor force_sig_perf out of perf_sigtrap Eric W. Biederman
2021-05-01 10:45 ` Marco Elver
2021-04-30 23:43 ` [PATCH 7/3] signal: Deliver all of the perf_data in si_perf Eric W. Biederman
2021-05-01 10:47 ` Marco Elver
2021-05-02 18:39 ` Eric W. Biederman
2021-05-02 19:13 ` Marco Elver
2021-05-03 12:44 ` Peter Zijlstra
2021-05-03 19:38 ` Eric W. Biederman
2021-05-03 19:53 ` Marco Elver
2021-04-30 23:47 ` [RFC][PATCH 0/3] signal: Move si_trapno into the _si_fault union Eric W. Biederman
2021-05-01 0:37 ` Marco Elver
2021-05-01 15:16 ` Eric W. Biederman
2021-05-01 16:24 ` Marco Elver
2021-05-03 20:25 ` [PATCH 00/12] signal: sort out si_trapno and si_perf Eric W. Biederman
2021-05-03 20:38 ` [PATCH 01/12] sparc64: Add compile-time asserts for siginfo_t offsets Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 02/12] arm: " Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 03/12] arm64: " Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 04/12] siginfo: Move si_trapno inside the union inside _si_fault Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 05/12] signal: Implement SIL_FAULT_TRAPNO Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 06/12] signal: Use dedicated helpers to send signals with si_trapno set Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 07/12] signal: Remove __ARCH_SI_TRAPNO Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 08/12] signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 09/12] signal: Factor force_sig_perf out of perf_sigtrap Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 10/12] signal: Redefine signinfo so 64bit fields are possible Eric W. Beiderman
2021-05-03 21:04 ` Eric W. Biederman
2021-05-03 22:47 ` Marco Elver
2021-05-04 3:42 ` Eric W. Biederman
2021-05-04 4:03 ` Peter Collingbourne
2021-05-04 9:52 ` Marco Elver
2021-05-04 16:16 ` Eric W. Biederman
2021-05-03 20:38 ` [PATCH 11/12] signal: Deliver all of the siginfo perf data in _perf Eric W. Beiderman
2021-05-03 20:38 ` [PATCH 12/12] signalfd: Remove SIL_FAULT_PERF_EVENT fields from signalfd_siginfo Eric W. Beiderman
2021-05-04 21:13 ` [PATCH v3 00/12] signal: sort out si_trapno and si_perf Eric W. Biederman
2021-05-04 22:05 ` Marco Elver
2021-05-05 14:12 ` Eric W. Biederman
2021-05-05 14:10 ` [PATCH v3 01/12] sparc64: Add compile-time asserts for siginfo_t offsets Eric W. Beiderman
2021-05-05 14:10 ` [PATCH v3 02/12] arm: " Eric W. Beiderman
2021-05-05 14:10 ` [PATCH v3 03/12] arm64: " Eric W. Beiderman
2021-05-05 14:10 ` [PATCH v3 04/12] signal: Verify the alignment and size of siginfo_t Eric W. Beiderman
2021-05-05 17:24 ` Marco Elver
2021-05-05 14:10 ` Eric W. Beiderman [this message]
2021-05-05 14:10 ` [PATCH v3 06/12] signal: Implement SIL_FAULT_TRAPNO Eric W. Beiderman
2021-05-05 17:25 ` Marco Elver
2021-05-05 14:10 ` [PATCH v3 07/12] signal: Use dedicated helpers to send signals with si_trapno set Eric W. Beiderman
2021-05-05 17:25 ` Marco Elver
2021-05-05 14:10 ` [PATCH v3 08/12] signal: Remove __ARCH_SI_TRAPNO Eric W. Beiderman
2021-05-05 17:25 ` Marco Elver
2021-05-05 14:10 ` [PATCH v3 09/12] signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency Eric W. Beiderman
2021-05-05 17:26 ` Marco Elver
2021-05-05 14:10 ` [PATCH v3 10/12] signal: Factor force_sig_perf out of perf_sigtrap Eric W. Beiderman
2021-05-05 17:26 ` Marco Elver
2021-05-06 10:54 ` Peter Zijlstra
2021-05-05 14:11 ` [PATCH v3 11/12] signal: Deliver all of the siginfo perf data in _perf Eric W. Beiderman
2021-05-05 17:27 ` Marco Elver
2021-05-05 14:11 ` [PATCH v3 12/12] signalfd: Remove SIL_FAULT_PERF_EVENT fields from signalfd_siginfo Eric W. Beiderman
2021-05-05 17:27 ` Marco Elver
2021-05-05 17:28 ` [PATCH v3 00/12] signal: sort out si_trapno and si_perf Marco Elver
2021-05-06 7:00 ` Geert Uytterhoeven
2021-05-06 10:43 ` Marco Elver
2021-05-06 15:28 ` Eric W. Biederman
2021-05-06 15:14 ` Eric W. Biederman
2021-05-14 4:54 ` [GIT PULL] siginfo: ABI fixes for v5.13-rc2 Eric W. Biederman
2021-05-14 19:14 ` Linus Torvalds
2021-05-14 21:15 ` Eric W. Biederman
2021-05-14 22:38 ` Eric W. Biederman
2021-05-16 7:40 ` Ingo Molnar
2021-05-17 15:29 ` Eric W. Biederman
2021-05-21 14:59 ` [GIT PULL] siginfo: ABI fixes for v5.13-rc3 Eric W. Biederman
2021-05-21 16:34 ` pr-tracker-bot
2021-05-17 19:56 ` [PATCH v4 0/5] siginfo: ABI fixes for TRAP_PERF Eric W. Biederman
2021-05-17 19:57 ` [PATCH v4 1/5] siginfo: Move si_trapno inside the union inside _si_fault Eric W. Beiderman
2021-05-17 19:57 ` [PATCH v4 2/5] signal: Implement SIL_FAULT_TRAPNO Eric W. Beiderman
2021-05-17 19:57 ` [PATCH v4 3/5] signal: Factor force_sig_perf out of perf_sigtrap Eric W. Beiderman
2021-05-17 19:57 ` [PATCH v4 4/5] signal: Deliver all of the siginfo perf data in _perf Eric W. Beiderman
2021-05-17 19:57 ` [PATCH v4 5/5] signalfd: Remove SIL_PERF_EVENT fields from signalfd_siginfo Eric W. Beiderman
2021-05-17 20:53 ` [PATCH v4 0/5] siginfo: ABI fixes for TRAP_PERF Marco Elver
2021-05-18 3:46 ` Eric W. Biederman
2021-05-18 6:44 ` Marco Elver
2021-05-01 16:26 ` [RFC][PATCH 0/3] signal: Move si_trapno into the _si_fault union Marco Elver
2021-07-15 18:09 ` [PATCH 0/6] Final si_trapno bits Eric W. Biederman
2021-07-15 18:11 ` [PATCH 1/6] sparc64: Add compile-time asserts for siginfo_t offsets Eric W. Biederman
2021-07-15 18:11 ` [PATCH 2/6] arm: " Eric W. Biederman
2021-07-15 18:11 ` [PATCH 3/6] arm64: " Eric W. Biederman
2021-07-15 18:12 ` [PATCH 4/6] signal/sparc: si_trapno is only used with SIGILL ILL_ILLTRP Eric W. Biederman
2021-07-16 11:49 ` Marco Elver
2021-07-15 18:12 ` [PATCH 5/6] signal/alpha: si_trapno is only used with SIGFPE and SIGTRAP TRAP_UNK Eric W. Biederman
2021-07-16 11:48 ` Marco Elver
2021-07-15 18:13 ` [PATCH 6/6] signal: Remove the generic __ARCH_SI_TRAPNO support Eric W. Biederman
2021-07-16 11:48 ` Marco Elver
2021-07-16 11:50 ` [PATCH 0/6] Final si_trapno bits Marco Elver
2021-07-16 16:08 ` Eric W. Biederman
2021-07-16 17:15 ` Marco Elver
2021-07-16 16:06 ` [PATCH 7/7] signal: Verify the alignment and size of siginfo_t Eric W. Biederman
2021-07-16 16:07 ` [PATCH 8/6] signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency Eric W. Biederman
2021-04-30 20:43 ` siginfo_t ABI break on sparc64 from si_addr_lsb move 3y ago Arnd Bergmann
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