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signal: Deliver all of the siginfo perf data in _perf

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Don't abuse si_errno and deliver all of the perf data in _perf member
of siginfo_t.

Note: The data field in the perf data structures in a u64 to allow a
pointer to be encoded without needed to implement a 32bit and 64bit
version of the same structure.  There already exists a 32bit and 64bit
versions siginfo_t, and the 32bit version can not include a 64bit
member as it only has 32bit alignment.  So unsigned long is used in
siginfo_t instead of a u64 as unsigned long can encode a pointer on
all architectures linux supports.

v1: https://lkml.kernel.org/r/m11rarqqx2.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/20210503203814.25487-10-ebiederm@xmission.com
v3: https://lkml.kernel.org/r/20210505141101.11519-11-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20210517195748.8880-4-ebiederm@xmission.com
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2021-05-02 17:28:31 -05:00
parent af5eeab7e8
commit 0683b53197
9 changed files with 41 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
arch/m68k/kernel/signal.c
View file

@ -623,7 +623,8 @@ static inline void siginfo_build_tests(void)
BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x12);
/* _sigfault._perf */
BUILD_BUG_ON(offsetof(siginfo_t, si_perf) != 0x10);
BUILD_BUG_ON(offsetof(siginfo_t, si_perf_data) != 0x10);
BUILD_BUG_ON(offsetof(siginfo_t, si_perf_type) != 0x14);
/* _sigpoll */
BUILD_BUG_ON(offsetof(siginfo_t, si_band) != 0x0c);

6
arch/x86/kernel/signal_compat.c
View file

@ -141,8 +141,10 @@ static inline void signal_compat_build_tests(void)
BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x20);
BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pkey) != 0x14);
BUILD_BUG_ON(offsetof(siginfo_t, si_perf) != 0x18);
BUILD_BUG_ON(offsetof(compat_siginfo_t, si_perf) != 0x10);
BUILD_BUG_ON(offsetof(siginfo_t, si_perf_data) != 0x18);
BUILD_BUG_ON(offsetof(siginfo_t, si_perf_type) != 0x20);
BUILD_BUG_ON(offsetof(compat_siginfo_t, si_perf_data) != 0x10);
BUILD_BUG_ON(offsetof(compat_siginfo_t, si_perf_type) != 0x14);
CHECK_CSI_OFFSET(_sigpoll);
CHECK_CSI_SIZE (_sigpoll, 2*sizeof(int));

3
fs/signalfd.c
View file

@ -134,7 +134,8 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
break;
case SIL_PERF_EVENT:
new.ssi_addr = (long) kinfo->si_addr;
new.ssi_perf = kinfo->si_perf;
new.ssi_perf_type = kinfo->si_perf_type;
new.ssi_perf_data = kinfo->si_perf_data;
break;
case SIL_CHLD:
new.ssi_pid = kinfo->si_pid;

5
include/linux/compat.h
View file

@ -236,7 +236,10 @@ typedef struct compat_siginfo {
u32 _pkey;
} _addr_pkey;
/* used when si_code=TRAP_PERF */
compat_ulong_t _perf;
struct {
compat_ulong_t _data;
u32 _type;
} _perf;
};
} _sigfault;

8
include/uapi/asm-generic/siginfo.h
View file

@ -91,7 +91,10 @@ union __sifields {
__u32 _pkey;
} _addr_pkey;
/* used when si_code=TRAP_PERF */
unsigned long _perf;
struct {
unsigned long _data;
__u32 _type;
} _perf;
};
} _sigfault;
@ -154,7 +157,8 @@ typedef struct siginfo {
#define si_lower _sifields._sigfault._addr_bnd._lower
#define si_upper _sifields._sigfault._addr_bnd._upper
#define si_pkey _sifields._sigfault._addr_pkey._pkey
#define si_perf _sifields._sigfault._perf
#define si_perf_data _sifields._sigfault._perf._data
#define si_perf_type _sifields._sigfault._perf._type
#define si_band _sifields._sigpoll._band
#define si_fd _sifields._sigpoll._fd
#define si_call_addr _sifields._sigsys._call_addr

2
include/uapi/linux/perf_event.h
View file

@ -464,7 +464,7 @@ struct perf_event_attr {
/*
* User provided data if sigtrap=1, passed back to user via
* siginfo_t::si_perf, e.g. to permit user to identify the event.
* siginfo_t::si_perf_data, e.g. to permit user to identify the event.
*/
__u64 sig_data;
};

4
include/uapi/linux/signalfd.h
View file

@ -39,8 +39,8 @@ struct signalfd_siginfo {
__s32 ssi_syscall;
__u64 ssi_call_addr;
__u32 ssi_arch;
__u32 __pad3;
__u64 ssi_perf;
__u32 ssi_perf_type;
__u64 ssi_perf_data;
/*
* Pad strcture to 128 bytes. Remember to update the

21
kernel/signal.c
View file

@ -1768,11 +1768,13 @@ int force_sig_perf(void __user *addr, u32 type, u64 sig_data)
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = SIGTRAP;
info.si_errno = type;
info.si_code = TRAP_PERF;
info.si_addr = addr;
info.si_perf = sig_data;
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_PERF;
info.si_addr = addr;
info.si_perf_data = sig_data;
info.si_perf_type = type;
return force_sig_info(&info);
}
@ -3356,7 +3358,8 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
break;
case SIL_PERF_EVENT:
to->si_addr = ptr_to_compat(from->si_addr);
to->si_perf = from->si_perf;
to->si_perf_data = from->si_perf_data;
to->si_perf_type = from->si_perf_type;
break;
case SIL_CHLD:
to->si_pid = from->si_pid;
@ -3432,7 +3435,8 @@ static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
break;
case SIL_PERF_EVENT:
to->si_addr = compat_ptr(from->si_addr);
to->si_perf = from->si_perf;
to->si_perf_data = from->si_perf_data;
to->si_perf_type = from->si_perf_type;
break;
case SIL_CHLD:
to->si_pid = from->si_pid;
@ -4615,7 +4619,8 @@ static inline void siginfo_buildtime_checks(void)
CHECK_OFFSET(si_lower);
CHECK_OFFSET(si_upper);
CHECK_OFFSET(si_pkey);
CHECK_OFFSET(si_perf);
CHECK_OFFSET(si_perf_data);
CHECK_OFFSET(si_perf_type);
/* sigpoll */
CHECK_OFFSET(si_band);

14
tools/testing/selftests/perf_events/sigtrap_threads.c
View file

@ -43,7 +43,7 @@ static struct {
siginfo_t first_siginfo; /* First observed siginfo_t. */
} ctx;
/* Unique value to check si_perf is correctly set from perf_event_attr::sig_data. */
/* Unique value to check si_perf_data is correctly set from perf_event_attr::sig_data. */
#define TEST_SIG_DATA(addr) (~(unsigned long)(addr))
static struct perf_event_attr make_event_attr(bool enabled, volatile void *addr)
@ -164,8 +164,8 @@ TEST_F(sigtrap_threads, enable_event)
EXPECT_EQ(ctx.signal_count, NUM_THREADS);
EXPECT_EQ(ctx.tids_want_signal, 0);
EXPECT_EQ(ctx.first_siginfo.si_addr, &ctx.iterate_on);
EXPECT_EQ(ctx.first_siginfo.si_errno, PERF_TYPE_BREAKPOINT);
EXPECT_EQ(ctx.first_siginfo.si_perf, TEST_SIG_DATA(&ctx.iterate_on));
EXPECT_EQ(ctx.first_siginfo.si_perf_type, PERF_TYPE_BREAKPOINT);
EXPECT_EQ(ctx.first_siginfo.si_perf_data, TEST_SIG_DATA(&ctx.iterate_on));
/* Check enabled for parent. */
ctx.iterate_on = 0;
@ -183,8 +183,8 @@ TEST_F(sigtrap_threads, modify_and_enable_event)
EXPECT_EQ(ctx.signal_count, NUM_THREADS);
EXPECT_EQ(ctx.tids_want_signal, 0);
EXPECT_EQ(ctx.first_siginfo.si_addr, &ctx.iterate_on);
EXPECT_EQ(ctx.first_siginfo.si_errno, PERF_TYPE_BREAKPOINT);
EXPECT_EQ(ctx.first_siginfo.si_perf, TEST_SIG_DATA(&ctx.iterate_on));
EXPECT_EQ(ctx.first_siginfo.si_perf_type, PERF_TYPE_BREAKPOINT);
EXPECT_EQ(ctx.first_siginfo.si_perf_data, TEST_SIG_DATA(&ctx.iterate_on));
/* Check enabled for parent. */
ctx.iterate_on = 0;
@ -203,8 +203,8 @@ TEST_F(sigtrap_threads, signal_stress)
EXPECT_EQ(ctx.signal_count, NUM_THREADS * ctx.iterate_on);
EXPECT_EQ(ctx.tids_want_signal, 0);
EXPECT_EQ(ctx.first_siginfo.si_addr, &ctx.iterate_on);
EXPECT_EQ(ctx.first_siginfo.si_errno, PERF_TYPE_BREAKPOINT);
EXPECT_EQ(ctx.first_siginfo.si_perf, TEST_SIG_DATA(&ctx.iterate_on));
EXPECT_EQ(ctx.first_siginfo.si_perf_type, PERF_TYPE_BREAKPOINT);
EXPECT_EQ(ctx.first_siginfo.si_perf_data, TEST_SIG_DATA(&ctx.iterate_on));
}
TEST_HARNESS_MAIN