[PATCH 10/12] signal: Redefine signinfo so 64bit fields are possible
From: Eric W. Beiderman
Date: Mon May 03 2021 - 16:39:44 EST
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
The si_perf code really wants to add a u64 field. This change enables
that by reorganizing the definition of siginfo_t, so that a 64bit
field can be added without increasing the alignment of other fields.
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
arch/x86/kernel/signal_compat.c | 9 +++----
include/linux/compat.h | 28 +++++++++++++-------
include/uapi/asm-generic/siginfo.h | 42 ++++++++++++++++++++----------
3 files changed, 49 insertions(+), 30 deletions(-)
diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c
index a9fcabd8a5e5..a5cd01c52dfb 100644
--- a/arch/x86/kernel/signal_compat.c
+++ b/arch/x86/kernel/signal_compat.c
@@ -17,8 +17,6 @@
*/
static inline void signal_compat_build_tests(void)
{
- int _sifields_offset = offsetof(compat_siginfo_t, _sifields);
-
/*
* If adding a new si_code, there is probably new data in
* the siginfo. Make sure folks bumping the si_code
@@ -40,8 +38,7 @@ static inline void signal_compat_build_tests(void)
* in the ABI, of course. Make sure none of them ever
* move and are always at the beginning:
*/
- BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields) != 3 * sizeof(int));
-#define CHECK_CSI_OFFSET(name) BUILD_BUG_ON(_sifields_offset != offsetof(compat_siginfo_t, _sifields.name))
+#define CHECK_CSI_OFFSET(name) BUILD_BUG_ON(0 != offsetof(compat_siginfo_t, _sifields.name))
BUILD_BUG_ON(offsetof(siginfo_t, si_signo) != 0);
BUILD_BUG_ON(offsetof(siginfo_t, si_errno) != 4);
@@ -63,8 +60,8 @@ static inline void signal_compat_build_tests(void)
* structure stays within the padding size (checked
* above).
*/
-#define CHECK_CSI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((compat_siginfo_t *)0)->_sifields.name))
-#define CHECK_SI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((siginfo_t *)0)->_sifields.name))
+#define CHECK_CSI_SIZE(name, size) BUILD_BUG_ON(((3*sizeof(int))+(size)) != sizeof(((compat_siginfo_t *)0)->_sifields.name))
+#define CHECK_SI_SIZE(name, size) BUILD_BUG_ON(((4*sizeof(int))+(size)) != sizeof(((siginfo_t *)0)->_sifields.name))
CHECK_CSI_OFFSET(_kill);
CHECK_CSI_SIZE (_kill, 2*sizeof(int));
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 6af7bef15e94..d81493248bf3 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -158,27 +158,28 @@ typedef union compat_sigval {
compat_uptr_t sival_ptr;
} compat_sigval_t;
-typedef struct compat_siginfo {
- int si_signo;
-#ifndef __ARCH_HAS_SWAPPED_SIGINFO
- int si_errno;
- int si_code;
-#else
- int si_code;
- int si_errno;
-#endif
+#define __COMPAT_SIGINFO_COMMON \
+ ___SIGINFO_COMMON; \
+ int _common_pad[__alignof__(compat_uptr_t) != __alignof__(int)]
+typedef struct compat_siginfo {
+ union {
+ struct {
+ __COMPAT_SIGINFO_COMMON;
+ };
union {
- int _pad[128/sizeof(int) - 3];
+ int _pad[128/sizeof(int)];
/* kill() */
struct {
+ __COMPAT_SIGINFO_COMMON;
compat_pid_t _pid; /* sender's pid */
__compat_uid32_t _uid; /* sender's uid */
} _kill;
/* POSIX.1b timers */
struct {
+ __COMPAT_SIGINFO_COMMON;
compat_timer_t _tid; /* timer id */
int _overrun; /* overrun count */
compat_sigval_t _sigval; /* same as below */
@@ -186,6 +187,7 @@ typedef struct compat_siginfo {
/* POSIX.1b signals */
struct {
+ __COMPAT_SIGINFO_COMMON;
compat_pid_t _pid; /* sender's pid */
__compat_uid32_t _uid; /* sender's uid */
compat_sigval_t _sigval;
@@ -193,6 +195,7 @@ typedef struct compat_siginfo {
/* SIGCHLD */
struct {
+ __COMPAT_SIGINFO_COMMON;
compat_pid_t _pid; /* which child */
__compat_uid32_t _uid; /* sender's uid */
int _status; /* exit code */
@@ -203,6 +206,7 @@ typedef struct compat_siginfo {
#ifdef CONFIG_X86_X32_ABI
/* SIGCHLD (x32 version) */
struct {
+ __COMPAT_SIGINFO_COMMON;
compat_pid_t _pid; /* which child */
__compat_uid32_t _uid; /* sender's uid */
int _status; /* exit code */
@@ -213,6 +217,7 @@ typedef struct compat_siginfo {
/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */
struct {
+ __COMPAT_SIGINFO_COMMON;
compat_uptr_t _addr; /* faulting insn/memory ref. */
#define __COMPAT_ADDR_BND_PKEY_PAD (__alignof__(compat_uptr_t) < sizeof(short) ? \
sizeof(short) : __alignof__(compat_uptr_t))
@@ -242,16 +247,19 @@ typedef struct compat_siginfo {
/* SIGPOLL */
struct {
+ __COMPAT_SIGINFO_COMMON;
compat_long_t _band; /* POLL_IN, POLL_OUT, POLL_MSG */
int _fd;
} _sigpoll;
struct {
+ __COMPAT_SIGINFO_COMMON;
compat_uptr_t _call_addr; /* calling user insn */
int _syscall; /* triggering system call number */
unsigned int _arch; /* AUDIT_ARCH_* of syscall */
} _sigsys;
} _sifields;
+ };
} compat_siginfo_t;
struct compat_rlimit {
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index e663bf117b46..1fcede623a73 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -29,15 +29,33 @@ typedef union sigval {
#define __ARCH_SI_ATTRIBUTES
#endif
+#ifndef __ARCH_HAS_SWAPPED_SIGINFO
+#define ___SIGINFO_COMMON \
+ int si_signo; \
+ int si_errno; \
+ int si_code
+#else
+#define ___SIGINFO_COMMON \
+ int si_signo; \
+ int si_code; \
+ int si_errno
+#endif /* __ARCH_HAS_SWAPPED_SIGINFO */
+
+#define __SIGINFO_COMMON \
+ ___SIGINFO_COMMON; \
+ int _common_pad[__alignof__(void *) != __alignof(int)]
+
union __sifields {
/* kill() */
struct {
+ __SIGINFO_COMMON;
__kernel_pid_t _pid; /* sender's pid */
__kernel_uid32_t _uid; /* sender's uid */
} _kill;
/* POSIX.1b timers */
struct {
+ __SIGINFO_COMMON;
__kernel_timer_t _tid; /* timer id */
int _overrun; /* overrun count */
sigval_t _sigval; /* same as below */
@@ -46,6 +64,7 @@ union __sifields {
/* POSIX.1b signals */
struct {
+ __SIGINFO_COMMON;
__kernel_pid_t _pid; /* sender's pid */
__kernel_uid32_t _uid; /* sender's uid */
sigval_t _sigval;
@@ -53,6 +72,7 @@ union __sifields {
/* SIGCHLD */
struct {
+ __SIGINFO_COMMON;
__kernel_pid_t _pid; /* which child */
__kernel_uid32_t _uid; /* sender's uid */
int _status; /* exit code */
@@ -62,6 +82,7 @@ union __sifields {
/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */
struct {
+ __SIGINFO_COMMON;
void __user *_addr; /* faulting insn/memory ref. */
#ifdef __ia64__
int _imm; /* immediate value for "break" */
@@ -97,35 +118,28 @@ union __sifields {
/* SIGPOLL */
struct {
+ __SIGINFO_COMMON;
__ARCH_SI_BAND_T _band; /* POLL_IN, POLL_OUT, POLL_MSG */
int _fd;
} _sigpoll;
/* SIGSYS */
struct {
+ __SIGINFO_COMMON;
void __user *_call_addr; /* calling user insn */
int _syscall; /* triggering system call number */
unsigned int _arch; /* AUDIT_ARCH_* of syscall */
} _sigsys;
};
-#ifndef __ARCH_HAS_SWAPPED_SIGINFO
-#define __SIGINFO \
-struct { \
- int si_signo; \
- int si_errno; \
- int si_code; \
- union __sifields _sifields; \
-}
-#else
+
#define __SIGINFO \
-struct { \
- int si_signo; \
- int si_code; \
- int si_errno; \
+union { \
+ struct { \
+ __SIGINFO_COMMON; \
+ }; \
union __sifields _sifields; \
}
-#endif /* __ARCH_HAS_SWAPPED_SIGINFO */
typedef struct siginfo {
union {
--
2.30.1