March 2021 - Linux-kselftest-mirror

[PATCH RFC v2 0/8] Add support for synchronous signals on perf events

by Marco Elver

The perf subsystem today unifies various tracing and monitoring features, from both software and hardware. One benefit of the perf subsystem is automatically inheriting events to child tasks, which enables process-wide events monitoring with low overheads. By default perf events are non-intrusive, not affecting behaviour of the tasks being monitored. For certain use-cases, however, it makes sense to leverage the generality of the perf events subsystem and optionally allow the tasks being monitored to receive signals on events they are interested in. This patch series adds the option to synchronously signal user space on events. To better support process-wide synchronous self-monitoring, without events propagating to children that do not share the current process's shared environment, two pre-requisite patches are added to optionally restrict inheritance to CLONE_THREAD, and remove events on exec (without affecting the parent). Examples how to use these features can be found in the two kselftests at the end of the series. The kselftests verify and stress test the basic functionality. The discussion at [1] led to the changes proposed in this series. The approach taken in patch "Add support for SIGTRAP on perf events" to use 'event_limit' to trigger the signal was kindly suggested by Peter Zijlstra in [2]. [1] https://lore.kernel.org/lkml/CACT4Y+YPrXGw+AtESxAgPyZ84TYkNZdP0xpocX2jwVAbZ… [2] https://lore.kernel.org/lkml/YBv3rAT566k+6zjg@hirez.programming.kicks-ass.n… Motivation and example uses: 1. Our immediate motivation is low-overhead sampling-based race detection for user space [3]. By using perf_event_open() at process initialization, we can create hardware breakpoint/watchpoint events that are propagated automatically to all threads in a process. As far as we are aware, today no existing kernel facility (such as ptrace) allows us to set up process-wide watchpoints with minimal overheads (that are comparable to mprotect() of whole pages). [3] https://llvm.org/devmtg/2020-09/slides/Morehouse-GWP-Tsan.pdf 2. Other low-overhead error detectors that rely on detecting accesses to certain memory locations or code, process-wide and also only in a specific set of subtasks or threads. Other ideas for use-cases we found interesting, but should only illustrate the range of potential to further motivate the utility (we're sure there are more): 3. Code hot patching without full stop-the-world. Specifically, by setting a code breakpoint to entry to the patched routine, then send signals to threads and check that they are not in the routine, but without stopping them further. If any of the threads will enter the routine, it will receive SIGTRAP and pause. 4. Safepoints without mprotect(). Some Java implementations use "load from a known memory location" as a safepoint. When threads need to be stopped, the page containing the location is mprotect()ed and threads get a signal. This could be replaced with a watchpoint, which does not require a whole page nor DTLB shootdowns. 5. Threads receiving signals on performance events to throttle/unthrottle themselves. 6. Tracking data flow globally. --- v2: * Patch "Support only inheriting events if cloned with CLONE_THREAD" added to series. * Patch "Add support for event removal on exec" added to series. * Patch "Add kselftest for process-wide sigtrap handling" added to series. * Patch "Add kselftest for remove_on_exec" added to series. * Implicitly restrict inheriting events if sigtrap, but the child was cloned with CLONE_CLEAR_SIGHAND, because it is not generally safe if the child cleared all signal handlers to continue sending SIGTRAP. * Various minor fixes (see details in patches). v1: https://lkml.kernel.org/r/20210223143426.2412737-1-elver@google.com Marco Elver (8): perf/core: Apply PERF_EVENT_IOC_MODIFY_ATTRIBUTES to children perf/core: Support only inheriting events if cloned with CLONE_THREAD perf/core: Add support for event removal on exec signal: Introduce TRAP_PERF si_code and si_perf to siginfo perf/core: Add support for SIGTRAP on perf events perf/core: Add breakpoint information to siginfo on SIGTRAP selftests/perf: Add kselftest for process-wide sigtrap handling selftests/perf: Add kselftest for remove_on_exec arch/m68k/kernel/signal.c | 3 + arch/x86/kernel/signal_compat.c | 5 +- fs/signalfd.c | 4 + include/linux/compat.h | 2 + include/linux/perf_event.h | 5 +- include/linux/signal.h | 1 + include/uapi/asm-generic/siginfo.h | 6 +- include/uapi/linux/perf_event.h | 5 +- include/uapi/linux/signalfd.h | 4 +- kernel/events/core.c | 130 ++++++++- kernel/fork.c | 2 +- kernel/signal.c | 11 + .../testing/selftests/perf_events/.gitignore | 3 + tools/testing/selftests/perf_events/Makefile | 6 + tools/testing/selftests/perf_events/config | 1 + .../selftests/perf_events/remove_on_exec.c | 256 ++++++++++++++++++ tools/testing/selftests/perf_events/settings | 1 + .../selftests/perf_events/sigtrap_threads.c | 202 ++++++++++++++ 18 files changed, 632 insertions(+), 15 deletions(-) create mode 100644 tools/testing/selftests/perf_events/.gitignore create mode 100644 tools/testing/selftests/perf_events/Makefile create mode 100644 tools/testing/selftests/perf_events/config create mode 100644 tools/testing/selftests/perf_events/remove_on_exec.c create mode 100644 tools/testing/selftests/perf_events/settings create mode 100644 tools/testing/selftests/perf_events/sigtrap_threads.c -- 2.30.1.766.gb4fecdf3b7-goog

3 years, 7 months

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[PATCH] kselftest: arm64: Add BTI tests

by Mark Brown

Add some tests that verify that BTI functions correctly for static binaries built with and without BTI support, verifying that SIGILL is generated when expected and is not generated in other situations. Since BTI support is still being rolled out in distributions these tests are built entirely free standing, no libc support is used at all so none of the standard helper functions for kselftest can be used and we open code everything. This also means we aren't testing the kernel support for the dynamic linker, though the test program can be readily adapted for that once it becomes something that we can reliably build and run. These tests were originally written by Dave Martin, I've adapted them for kselftest, mainly around the build system and the output format. Signed-off-by: Mark Brown <broonie(a)kernel.org> Cc: Dave Martin <Dave.Martin(a)arm.com> --- tools/testing/selftests/arm64/Makefile | 2 +- tools/testing/selftests/arm64/bti/.gitignore | 2 + tools/testing/selftests/arm64/bti/Makefile | 61 +++++ tools/testing/selftests/arm64/bti/assembler.h | 80 ++++++ tools/testing/selftests/arm64/bti/btitest.h | 23 ++ tools/testing/selftests/arm64/bti/compiler.h | 21 ++ .../selftests/arm64/bti/gen/.gitignore | 2 + tools/testing/selftests/arm64/bti/signal.c | 37 +++ tools/testing/selftests/arm64/bti/signal.h | 21 ++ tools/testing/selftests/arm64/bti/start.S | 14 ++ tools/testing/selftests/arm64/bti/syscall.S | 23 ++ tools/testing/selftests/arm64/bti/system.c | 22 ++ tools/testing/selftests/arm64/bti/system.h | 28 +++ tools/testing/selftests/arm64/bti/test.c | 234 ++++++++++++++++++ tools/testing/selftests/arm64/bti/teststubs.S | 39 +++ .../testing/selftests/arm64/bti/trampoline.S | 29 +++ 16 files changed, 637 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/arm64/bti/.gitignore create mode 100644 tools/testing/selftests/arm64/bti/Makefile create mode 100644 tools/testing/selftests/arm64/bti/assembler.h create mode 100644 tools/testing/selftests/arm64/bti/btitest.h create mode 100644 tools/testing/selftests/arm64/bti/compiler.h create mode 100644 tools/testing/selftests/arm64/bti/gen/.gitignore create mode 100644 tools/testing/selftests/arm64/bti/signal.c create mode 100644 tools/testing/selftests/arm64/bti/signal.h create mode 100644 tools/testing/selftests/arm64/bti/start.S create mode 100644 tools/testing/selftests/arm64/bti/syscall.S create mode 100644 tools/testing/selftests/arm64/bti/system.c create mode 100644 tools/testing/selftests/arm64/bti/system.h create mode 100644 tools/testing/selftests/arm64/bti/test.c create mode 100644 tools/testing/selftests/arm64/bti/teststubs.S create mode 100644 tools/testing/selftests/arm64/bti/trampoline.S diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile index 2c9d012797a7..ced910fb4019 100644 --- a/tools/testing/selftests/arm64/Makefile +++ b/tools/testing/selftests/arm64/Makefile @@ -4,7 +4,7 @@ ARCH ?= $(shell uname -m 2>/dev/null || echo not) ifneq (,$(filter $(ARCH),aarch64 arm64)) -ARM64_SUBTARGETS ?= tags signal pauth fp mte +ARM64_SUBTARGETS ?= tags signal pauth fp mte bti else ARM64_SUBTARGETS := endif diff --git a/tools/testing/selftests/arm64/bti/.gitignore b/tools/testing/selftests/arm64/bti/.gitignore new file mode 100644 index 000000000000..73869fabada4 --- /dev/null +++ b/tools/testing/selftests/arm64/bti/.gitignore @@ -0,0 +1,2 @@ +btitest +nobtitest diff --git a/tools/testing/selftests/arm64/bti/Makefile b/tools/testing/selftests/arm64/bti/Makefile new file mode 100644 index 000000000000..73e013c082a6 --- /dev/null +++ b/tools/testing/selftests/arm64/bti/Makefile @@ -0,0 +1,61 @@ +# SPDX-License-Identifier: GPL-2.0 + +TEST_GEN_PROGS := btitest nobtitest + +PROGS := $(patsubst %,gen/%,$(TEST_GEN_PROGS)) + +# These tests are built as freestanding binaries since otherwise BTI +# support in ld.so is required which is not currently widespread; when +# it is available it will still be useful to test this separately as the +# cases for statically linked and dynamically lined binaries are +# slightly different. + +CFLAGS_NOBTI = -DBTI=0 +CFLAGS_BTI = -mbranch-protection=standard -DBTI=1 + +CFLAGS_COMMON = -ffreestanding -Wall -Wextra $(CFLAGS) + +BTI_CC_COMMAND = $(CC) $(CFLAGS_BTI) $(CFLAGS_COMMON) -c -o $@ $< +NOBTI_CC_COMMAND = $(CC) $(CFLAGS_NOBTI) $(CFLAGS_COMMON) -c -o $@ $< + +%-bti.o: %.c + $(BTI_CC_COMMAND) + +%-bti.o: %.S + $(BTI_CC_COMMAND) + +%-nobti.o: %.c + $(NOBTI_CC_COMMAND) + +%-nobti.o: %.S + $(NOBTI_CC_COMMAND) + +BTI_OBJS = \ + test-bti.o \ + signal-bti.o \ + start-bti.o \ + syscall-bti.o \ + system-bti.o \ + teststubs-bti.o \ + trampoline-bti.o +gen/btitest: $(BTI_OBJS) + $(CC) $(CFLAGS_BTI) $(CFLAGS_COMMON) -nostdlib -o $@ $^ + +NOBTI_OBJS = \ + test-nobti.o \ + signal-nobti.o \ + start-nobti.o \ + syscall-nobti.o \ + system-nobti.o \ + teststubs-nobti.o \ + trampoline-nobti.o +gen/nobtitest: $(NOBTI_OBJS) + $(CC) $(CFLAGS_BTI) $(CFLAGS_COMMON) -nostdlib -o $@ $^ + +# Including KSFT lib.mk here will also mangle the TEST_GEN_PROGS list +# to account for any OUTPUT target-dirs optionally provided by +# the toplevel makefile +include ../../lib.mk + +$(TEST_GEN_PROGS): $(PROGS) + cp $(PROGS) $(OUTPUT)/ diff --git a/tools/testing/selftests/arm64/bti/assembler.h b/tools/testing/selftests/arm64/bti/assembler.h new file mode 100644 index 000000000000..04e7b72880ef --- /dev/null +++ b/tools/testing/selftests/arm64/bti/assembler.h @@ -0,0 +1,80 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#ifndef ASSEMBLER_H +#define ASSEMBLER_H + +#define NT_GNU_PROPERTY_TYPE_0 5 +#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000 + +/* Bits for GNU_PROPERTY_AARCH64_FEATURE_1_BTI */ +#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0) +#define GNU_PROPERTY_AARCH64_FEATURE_1_PAC (1U << 1) + + +.macro startfn name:req + .globl \name +\name: + .macro endfn + .size \name, . - \name + .type \name, @function + .purgem endfn + .endm +.endm + +.macro emit_aarch64_feature_1_and + .pushsection .note.gnu.property, "a" + .align 3 + .long 2f - 1f + .long 6f - 3f + .long NT_GNU_PROPERTY_TYPE_0 +1: .string "GNU" +2: + .align 3 +3: .long GNU_PROPERTY_AARCH64_FEATURE_1_AND + .long 5f - 4f +4: +#if BTI + .long GNU_PROPERTY_AARCH64_FEATURE_1_PAC | \ + GNU_PROPERTY_AARCH64_FEATURE_1_BTI +#else + .long 0 +#endif +5: + .align 3 +6: + .popsection +.endm + +.macro paciasp + hint 0x19 +.endm + +.macro autiasp + hint 0x1d +.endm + +.macro __bti_ + hint 0x20 +.endm + +.macro __bti_c + hint 0x22 +.endm + +.macro __bti_j + hint 0x24 +.endm + +.macro __bti_jc + hint 0x26 +.endm + +.macro bti what= + __bti_\what +.endm + +#endif /* ! ASSEMBLER_H */ diff --git a/tools/testing/selftests/arm64/bti/btitest.h b/tools/testing/selftests/arm64/bti/btitest.h new file mode 100644 index 000000000000..2aff9b10336e --- /dev/null +++ b/tools/testing/selftests/arm64/bti/btitest.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#ifndef BTITEST_H +#define BTITEST_H + +/* Trampolines for calling the test stubs: */ +void call_using_br_x0(void (*)(void)); +void call_using_br_x16(void (*)(void)); +void call_using_blr(void (*)(void)); + +/* Test stubs: */ +void nohint_func(void); +void bti_none_func(void); +void bti_c_func(void); +void bti_j_func(void); +void bti_jc_func(void); +void paciasp_func(void); + +#endif /* !BTITEST_H */ diff --git a/tools/testing/selftests/arm64/bti/compiler.h b/tools/testing/selftests/arm64/bti/compiler.h new file mode 100644 index 000000000000..ebb6204f447a --- /dev/null +++ b/tools/testing/selftests/arm64/bti/compiler.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#ifndef COMPILER_H +#define COMPILER_H + +#define __always_unused __attribute__((__unused__)) +#define __noreturn __attribute__((__noreturn__)) +#define __unreachable() __builtin_unreachable() + +/* curse(e) has value e, but the compiler cannot assume so */ +#define curse(e) ({ \ + __typeof__(e) __curse_e = (e); \ + asm ("" : "+r" (__curse_e)); \ + __curse_e; \ +}) + +#endif /* ! COMPILER_H */ diff --git a/tools/testing/selftests/arm64/bti/gen/.gitignore b/tools/testing/selftests/arm64/bti/gen/.gitignore new file mode 100644 index 000000000000..73869fabada4 --- /dev/null +++ b/tools/testing/selftests/arm64/bti/gen/.gitignore @@ -0,0 +1,2 @@ +btitest +nobtitest diff --git a/tools/testing/selftests/arm64/bti/signal.c b/tools/testing/selftests/arm64/bti/signal.c new file mode 100644 index 000000000000..f3fd29b91141 --- /dev/null +++ b/tools/testing/selftests/arm64/bti/signal.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#include "system.h" +#include "signal.h" + +int sigemptyset(sigset_t *s) +{ + unsigned int i; + + for (i = 0; i < _NSIG_WORDS; ++i) + s->sig[i] = 0; + + return 0; +} + +int sigaddset(sigset_t *s, int n) +{ + if (n < 1 || n > _NSIG) + return -EINVAL; + + s->sig[(n - 1) / _NSIG_BPW] |= 1UL << (n - 1) % _NSIG_BPW; + return 0; +} + +int sigaction(int n, struct sigaction *sa, const struct sigaction *old) +{ + return syscall(__NR_rt_sigaction, n, sa, old, sizeof(sa->sa_mask)); +} + +int sigprocmask(int how, const sigset_t *mask, sigset_t *old) +{ + return syscall(__NR_rt_sigprocmask, how, mask, old, sizeof(*mask)); +} diff --git a/tools/testing/selftests/arm64/bti/signal.h b/tools/testing/selftests/arm64/bti/signal.h new file mode 100644 index 000000000000..103457dc880e --- /dev/null +++ b/tools/testing/selftests/arm64/bti/signal.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#ifndef SIGNAL_H +#define SIGNAL_H + +#include <linux/signal.h> + +#include "system.h" + +typedef __sighandler_t sighandler_t; + +int sigemptyset(sigset_t *s); +int sigaddset(sigset_t *s, int n); +int sigaction(int n, struct sigaction *sa, const struct sigaction *old); +int sigprocmask(int how, const sigset_t *mask, sigset_t *old); + +#endif /* ! SIGNAL_H */ diff --git a/tools/testing/selftests/arm64/bti/start.S b/tools/testing/selftests/arm64/bti/start.S new file mode 100644 index 000000000000..831f952e0572 --- /dev/null +++ b/tools/testing/selftests/arm64/bti/start.S @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#include "assembler.h" + +startfn _start + mov x0, sp + b start +endfn + +emit_aarch64_feature_1_and diff --git a/tools/testing/selftests/arm64/bti/syscall.S b/tools/testing/selftests/arm64/bti/syscall.S new file mode 100644 index 000000000000..8dde8b6f3db1 --- /dev/null +++ b/tools/testing/selftests/arm64/bti/syscall.S @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#include "assembler.h" + +startfn syscall + bti c + mov w8, w0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + mov x3, x4 + mov x4, x5 + mov x5, x6 + mov x6, x7 + svc #0 + ret +endfn + +emit_aarch64_feature_1_and diff --git a/tools/testing/selftests/arm64/bti/system.c b/tools/testing/selftests/arm64/bti/system.c new file mode 100644 index 000000000000..6385d8d4973b --- /dev/null +++ b/tools/testing/selftests/arm64/bti/system.c @@ -0,0 +1,22 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#include "system.h" + +#include <asm/unistd.h> + +#include "compiler.h" + +void __noreturn exit(int n) +{ + syscall(__NR_exit, n); + __unreachable(); +} + +ssize_t write(int fd, const void *buf, size_t size) +{ + return syscall(__NR_write, fd, buf, size); +} diff --git a/tools/testing/selftests/arm64/bti/system.h b/tools/testing/selftests/arm64/bti/system.h new file mode 100644 index 000000000000..aca118589705 --- /dev/null +++ b/tools/testing/selftests/arm64/bti/system.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#ifndef SYSTEM_H +#define SYSTEM_H + +#include <linux/types.h> +#include <linux/stddef.h> + +typedef __kernel_size_t size_t; +typedef __kernel_ssize_t ssize_t; + +#include <linux/errno.h> +#include <asm/hwcap.h> +#include <asm/ptrace.h> +#include <asm/unistd.h> + +#include "compiler.h" + +long syscall(int nr, ...); + +void __noreturn exit(int n); +ssize_t write(int fd, const void *buf, size_t size); + +#endif /* ! SYSTEM_H */ diff --git a/tools/testing/selftests/arm64/bti/test.c b/tools/testing/selftests/arm64/bti/test.c new file mode 100644 index 000000000000..656b04976ccc --- /dev/null +++ b/tools/testing/selftests/arm64/bti/test.c @@ -0,0 +1,234 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019,2021 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#include "system.h" + +#include <linux/errno.h> +#include <linux/auxvec.h> +#include <linux/signal.h> +#include <asm/sigcontext.h> +#include <asm/ucontext.h> + +typedef struct ucontext ucontext_t; + +#include "btitest.h" +#include "compiler.h" +#include "signal.h" + +#define EXPECTED_TESTS 18 + +static volatile unsigned int test_num = 1; +static unsigned int test_passed; +static unsigned int test_failed; +static unsigned int test_skipped; + +static void fdputs(int fd, const char *str) +{ + size_t len = 0; + const char *p = str; + + while (*p++) + ++len; + + write(fd, str, len); +} + +static void putstr(const char *str) +{ + fdputs(1, str); +} + +static void putnum(unsigned int num) +{ + char c; + + if (num / 10) + putnum(num / 10); + + c = '0' + (num % 10); + write(1, &c, 1); +} + +#define puttestname(test_name, trampoline_name) do { \ + putstr(test_name); \ + putstr("/"); \ + putstr(trampoline_name); \ +} while (0) + +void print_summary(void) +{ + putstr("# Totals: pass:"); + putnum(test_passed); + putstr(" fail:"); + putnum(test_failed); + putstr(" xfail:0 xpass:0 skip:"); + putnum(test_skipped); + putstr(" error:0\n"); +} + +static const char *volatile current_test_name; +static const char *volatile current_trampoline_name; +static volatile int sigill_expected, sigill_received; + +static void handler(int n, siginfo_t *si __always_unused, + void *uc_ __always_unused) +{ + ucontext_t *uc = uc_; + + putstr("# \t[SIGILL in "); + puttestname(current_test_name, current_trampoline_name); + putstr(", BTYPE="); + write(1, &"00011011"[((uc->uc_mcontext.pstate & PSR_BTYPE_MASK) + >> PSR_BTYPE_SHIFT) * 2], 2); + if (!sigill_expected) { + putstr("]\n"); + putstr("not ok "); + putnum(test_num); + putstr(" "); + puttestname(current_test_name, current_trampoline_name); + putstr("(unexpected SIGILL)\n"); + print_summary(); + exit(128 + n); + } + + putstr(" (expected)]\n"); + sigill_received = 1; + /* zap BTYPE so that resuming the faulting code will work */ + uc->uc_mcontext.pstate &= ~PSR_BTYPE_MASK; +} + +static int skip_all; + +static void __do_test(void (*trampoline)(void (*)(void)), + void (*fn)(void), + const char *trampoline_name, + const char *name, + int expect_sigill) +{ + if (skip_all) { + test_skipped++; + putstr("ok "); + putnum(test_num); + putstr(" "); + puttestname(name, trampoline_name); + putstr(" # SKIP\n"); + + return; + } + + /* Branch Target exceptions should only happen in BTI binaries: */ + if (!BTI) + expect_sigill = 0; + + sigill_expected = expect_sigill; + sigill_received = 0; + current_test_name = name; + current_trampoline_name = trampoline_name; + + trampoline(fn); + + if (expect_sigill && !sigill_received) { + putstr("not ok "); + test_failed++; + } else { + putstr("ok "); + test_passed++; + } + putnum(test_num++); + putstr(" "); + puttestname(name, trampoline_name); + putstr("\n"); +} + +#define do_test(expect_sigill_br_x0, \ + expect_sigill_br_x16, \ + expect_sigill_blr, \ + name) \ +do { \ + __do_test(call_using_br_x0, name, "call_using_br_x0", #name, \ + expect_sigill_br_x0); \ + __do_test(call_using_br_x16, name, "call_using_br_x16", #name, \ + expect_sigill_br_x16); \ + __do_test(call_using_blr, name, "call_using_blr", #name, \ + expect_sigill_blr); \ +} while (0) + +void start(int *argcp) +{ + struct sigaction sa; + void *const *p; + const struct auxv_entry { + unsigned long type; + unsigned long val; + } *auxv; + unsigned long hwcap = 0, hwcap2 = 0; + + putstr("TAP version 13\n"); + putstr("1.."); + putnum(EXPECTED_TESTS); + putstr("\n"); + + /* Gross hack for finding AT_HWCAP2 from the initial process stack: */ + p = (void *const *)argcp + 1 + *argcp + 1; /* start of environment */ + /* step over environment */ + while (*p++) + ; + for (auxv = (const struct auxv_entry *)p; auxv->type != AT_NULL; ++auxv) { + switch (auxv->type) { + case AT_HWCAP: + hwcap = auxv->val; + break; + case AT_HWCAP2: + hwcap2 = auxv->val; + break; + default: + break; + } + } + + if (hwcap & HWCAP_PACA) + putstr("# HWCAP_PACA present\n"); + else + putstr("# HWCAP_PACA not present\n"); + + if (hwcap2 & HWCAP2_BTI) { + putstr("# HWCAP2_BTI present\n"); + if (!(hwcap & HWCAP_PACA)) + putstr("# Bad hardware? Expect problems.\n"); + } else { + putstr("# HWCAP2_BTI not present\n"); + skip_all = 1; + } + + putstr("# Test binary"); + if (!BTI) + putstr(" not"); + putstr(" built for BTI\n"); + + sa.sa_handler = (sighandler_t)(void *)handler; + sa.sa_flags = SA_SIGINFO; + sigemptyset(&sa.sa_mask); + sigaction(SIGILL, &sa, NULL); + sigaddset(&sa.sa_mask, SIGILL); + sigprocmask(SIG_UNBLOCK, &sa.sa_mask, NULL); + + do_test(1, 1, 1, nohint_func); + do_test(1, 1, 1, bti_none_func); + do_test(1, 0, 0, bti_c_func); + do_test(0, 0, 1, bti_j_func); + do_test(0, 0, 0, bti_jc_func); + do_test(1, 0, 0, paciasp_func); + + print_summary(); + + if (test_num - 1 != EXPECTED_TESTS) + putstr("# WARNING - EXPECTED TEST COUNT WRONG\n"); + + if (test_failed) + exit(1); + else + exit(0); +} diff --git a/tools/testing/selftests/arm64/bti/teststubs.S b/tools/testing/selftests/arm64/bti/teststubs.S new file mode 100644 index 000000000000..b62c8c35f67e --- /dev/null +++ b/tools/testing/selftests/arm64/bti/teststubs.S @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#include "assembler.h" + +startfn bti_none_func + bti + ret +endfn + +startfn bti_c_func + bti c + ret +endfn + +startfn bti_j_func + bti j + ret +endfn + +startfn bti_jc_func + bti jc + ret +endfn + +startfn paciasp_func + paciasp + autiasp + ret +endfn + +startfn nohint_func + ret +endfn + +emit_aarch64_feature_1_and diff --git a/tools/testing/selftests/arm64/bti/trampoline.S b/tools/testing/selftests/arm64/bti/trampoline.S new file mode 100644 index 000000000000..09beb3f361f1 --- /dev/null +++ b/tools/testing/selftests/arm64/bti/trampoline.S @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Arm Limited + * Original author: Dave Martin <Dave.Martin(a)arm.com> + */ + +#include "assembler.h" + +startfn call_using_br_x0 + bti c + br x0 +endfn + +startfn call_using_br_x16 + bti c + mov x16, x0 + br x16 +endfn + +startfn call_using_blr + paciasp + stp x29, x30, [sp, #-16]! + blr x0 + ldp x29, x30, [sp], #16 + autiasp + ret +endfn + +emit_aarch64_feature_1_and -- 2.20.1

3 years, 7 months

2
1
0 0

[PATCH 00/11] kselftest/arm64: mte: Fix feature detection and compilation

by Andre Przywara

When trying to run the arm64 MTE (Memory Tagging Extension) selftests on a model with the new FEAT_MTE3 capability, the MTE feature detection failed, because it was overzealously checking for one exact feature version only (0b0010). Trying to fix that (patch 06/11) led me into the rabbit hole of userland tool compilation, which triggered patches 01-05/11, to let me actually compile the selftests on an arm64 machine running Ubuntu 20.04. Before I actually fixed that, I tried some other compiler and distro; patches 07 and 08 are my witnesses. Then I got brave and tried clang: entering patches 09/11 and 10/11. Eventually I tried to run the whole thing on that model again, and, you guessed it, patch 11/11 concludes this apparent "2 minute job". Eventually I can now compile the mte selftests on Ubuntu 20.04 with both the native gcc and clang without warnings, also with some custom made cross compiler. And they even run now! Please have a look, also you may try to compile it on your setup, if you feel adventurous: $ make -C tools/testing/selftests TARGETS=arm64 ARM64_SUBTARGETS=mte Cheers, Andre Andre Przywara (11): kselftest/arm64: mte: Fix compilation with native compiler kselftest/arm64: mte: Fix pthread linking kselftest/arm64: mte: ksm_options: Fix fscanf warning kselftest/arm64: mte: user_mem: Fix write() warning kselftest/arm64: mte: common: Fix write() warnings kselftest/arm64: mte: Fix MTE feature detection kselftest/arm64: mte: Use cross-compiler if specified kselftest/arm64: mte: Output warning about failing compiler kselftest/arm64: mte: Makefile: Fix clang compilation kselftest/arm64: mte: Fix clang warning kselftest/arm64: mte: Report filename on failing temp file creation tools/testing/selftests/arm64/mte/Makefile | 15 +++++-- .../selftests/arm64/mte/check_ksm_options.c | 5 ++- .../selftests/arm64/mte/check_user_mem.c | 3 +- .../selftests/arm64/mte/mte_common_util.c | 39 +++++++++++-------- 4 files changed, 39 insertions(+), 23 deletions(-) -- 2.17.5

3 years, 7 months

4
15
0 0

[GIT PULL] KUnit fixes update for Linux 5.12-rc5

by Shuah Khan

Hi Linus, Please pull the following KUnit fixes update for Linux 5.12-rc5. This KUnit update for Linux 5.12-rc5 consists of two fixes to kunit tool from David Gow. diff is attached. thanks, -- Shuah ---------------------------------------------------------------- The following changes since commit a38fd8748464831584a19438cbb3082b5a2dab15: Linux 5.12-rc2 (2021-03-05 17:33:41 -0800) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux-kselftest-kunit-fixes-5.12-rc5.1 for you to fetch changes up to 7fd53f41f771d250eb08db08650940f017e37c26: kunit: tool: Disable PAGE_POISONING under --alltests (2021-03-11 14:37:37 -0700) ---------------------------------------------------------------- linux-kselftest-kunit-fixes-5.12-rc5.1 This KUnit update for Linux 5.12-rc5 consists of two fixes to kunit tool from David Gow. ---------------------------------------------------------------- David Gow (2): kunit: tool: Fix a python tuple typing error kunit: tool: Disable PAGE_POISONING under --alltests tools/testing/kunit/configs/broken_on_uml.config | 2 ++ tools/testing/kunit/kunit_config.py | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) ----------------------------------------------------------------

3 years, 7 months

2
1
0 0

[PATCH] tools: testing: Remove duplicate include of sched.h

by Wan Jiabing

sched.h has been included at line 33. So we remove the duplicate one at line 36. Signed-off-by: Wan Jiabing <wanjiabing(a)vivo.com> --- tools/testing/selftests/powerpc/mm/tlbie_test.c | 1 - 1 file changed, 1 deletion(-) diff --git a/tools/testing/selftests/powerpc/mm/tlbie_test.c b/tools/testing/selftests/powerpc/mm/tlbie_test.c index f85a0938ab25..48344a74b212 100644 --- a/tools/testing/selftests/powerpc/mm/tlbie_test.c +++ b/tools/testing/selftests/powerpc/mm/tlbie_test.c @@ -33,7 +33,6 @@ #include <sched.h> #include <time.h> #include <stdarg.h> -#include <sched.h> #include <pthread.h> #include <signal.h> #include <sys/prctl.h> -- 2.25.1

3 years, 7 months

2
1
0 0

[PATCH] tools: testing: inttypes.h is included twice

by Wan Jiabing

inttypes.h has been included at line 19. So we remove the duplicate one at line 23. Signed-off-by: Wan Jiabing <wanjiabing(a)vivo.com> --- tools/testing/selftests/powerpc/tm/tm-poison.c | 1 - 1 file changed, 1 deletion(-) diff --git a/tools/testing/selftests/powerpc/tm/tm-poison.c b/tools/testing/selftests/powerpc/tm/tm-poison.c index 29e5f26af7b9..27c083a03d1f 100644 --- a/tools/testing/selftests/powerpc/tm/tm-poison.c +++ b/tools/testing/selftests/powerpc/tm/tm-poison.c @@ -20,7 +20,6 @@ #include <sched.h> #include <sys/types.h> #include <signal.h> -#include <inttypes.h> #include "tm.h" -- 2.25.1

3 years, 7 months

1
0
0 0

[PATCH] tools: testing: pthread.h is included twice

by Wan Jiabing

pthread.h has been included at line 17. So we remove the duplicate one at line 20. Signed-off-by: Wan Jiabing <wanjiabing(a)vivo.com> --- tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c | 1 - 1 file changed, 1 deletion(-) diff --git a/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c b/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c index e2a0c07e8362..9ef37a9836ac 100644 --- a/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c +++ b/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c @@ -17,7 +17,6 @@ #include <pthread.h> #include <sys/mman.h> #include <unistd.h> -#include <pthread.h> #include "tm.h" #include "utils.h" -- 2.25.1

3 years, 7 months

1
0
0 0

[PATCH bpf-next v2 0/2] add support for batched ops in LPM trie

by Pedro Tammela

The patch itself is straightforward thanks to the infrastructure that is already in-place. The tests follows the other '*_map_batch_ops' tests with minor tweaks. v1 -> v2: Fixes for checkpatch warnings Pedro Tammela (2): bpf: add support for batched operations in LPM trie maps bpf: selftests: add tests for batched ops in LPM trie maps kernel/bpf/lpm_trie.c | 3 + .../map_tests/lpm_trie_map_batch_ops.c (new) | 158 ++++++++++++++++++ 2 files changed, 161 insertions(+) create mode 100644 tools/testing/selftests/bpf/map_tests/lpm_trie_map_batch_ops.c -- 2.25.1

3 years, 7 months

1
2
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Re: [selftests] e48d82b67a: BUG_TestSlub_RZ_alloc(Not_tainted):Redzone_overwritten

by Vlastimil Babka

On 3/17/21 9:36 AM, kernel test robot wrote: > > > Greeting, > > FYI, we noticed the following commit (built with gcc-9): > > commit: e48d82b67a2b760eedf7b95ca15f41267496386c ("[PATCH 1/2] selftests: add a kselftest for SLUB debugging functionality") > url: https://github.com/0day-ci/linux/commits/glittao-gmail-com/selftests-add-a-… > base: https://git.kernel.org/cgit/linux/kernel/git/shuah/linux-kselftest.git next > > in testcase: trinity > version: trinity-static-i386-x86_64-f93256fb_2019-08-28 > with following parameters: > > group: group-04 > > test-description: Trinity is a linux system call fuzz tester. > test-url: http://codemonkey.org.uk/projects/trinity/ > > > on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 8G > > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): > > > +---------------------------------------------------------------------------------------------------------------+-----------+------------+ > | | v5.12-rc2 | e48d82b67a | > +---------------------------------------------------------------------------------------------------------------+-----------+------------+ > | BUG_TestSlub_RZ_alloc(Not_tainted):Redzone_overwritten | 0 | 69 | > | INFO:0x(ptrval)-0x(ptrval)@offset=#.First_byte#instead_of | 0 | 69 | > | INFO:Allocated_in_resiliency_test_age=#cpu=#pid= | 0 | 69 | > | INFO:Slab0x(ptrval)objects=#used=#fp=0x(ptrval)flags= | 0 | 69 | > | INFO:Object0x(ptrval)@offset=#fp=0x(ptrval) | 0 | 69 | > | BUG_TestSlub_next_ptr_free(Tainted:G_B):Freechain_corrupt | 0 | 69 | > | INFO:Freed_in_resiliency_test_age=#cpu=#pid= | 0 | 69 | > | BUG_TestSlub_next_ptr_free(Tainted:G_B):Wrong_object_count.Counter_is#but_counted_were | 0 | 69 | > | BUG_TestSlub_next_ptr_free(Tainted:G_B):Redzone_overwritten | 0 | 69 | > | BUG_TestSlub_next_ptr_free(Tainted:G_B):Objects_remaining_in_TestSlub_next_ptr_free_on__kmem_cache_shutdown() | 0 | 69 | > | INFO:Object0x(ptrval)@offset= | 0 | 69 | > | BUG_TestSlub_1th_word_free(Tainted:G_B):Poison_overwritten | 0 | 69 | > | BUG_TestSlub_50th_word_free(Tainted:G_B):Poison_overwritten | 0 | 69 | > | BUG_TestSlub_RZ_free(Tainted:G_B):Redzone_overwritten | 0 | 69 | > +---------------------------------------------------------------------------------------------------------------+-----------+------------+ > > > If you fix the issue, kindly add following tag > Reported-by: kernel test robot <oliver.sang(a)intel.com> > > > > [ 22.154049] random: get_random_u32 called from __kmem_cache_create+0x23/0x3e0 with crng_init=0 > [ 22.154070] random: get_random_u32 called from cache_random_seq_create+0x7c/0x140 with crng_init=0 > [ 22.154167] random: get_random_u32 called from allocate_slab+0x155/0x5e0 with crng_init=0 > [ 22.154690] test_slub: 1. kmem_cache: Clobber Redzone 0x12->0x(ptrval) > [ 22.164499] ============================================================================= > [ 22.166629] BUG TestSlub_RZ_alloc (Not tainted): Redzone overwritten > [ 22.168179] ----------------------------------------------------------------------------- > [ 22.168179] > [ 22.168372] Disabling lock debugging due to kernel taint > [ 22.168372] INFO: 0x(ptrval)-0x(ptrval) @offset=1064. First byte 0x12 instead of 0xcc > [ 22.168372] INFO: Allocated in resiliency_test+0x47/0x1be age=3 cpu=0 pid=1 > [ 22.168372] __slab_alloc+0x57/0x80 > [ 22.168372] kmem_cache_alloc (kbuild/src/consumer/mm/slub.c:2871 kbuild/src/consumer/mm/slub.c:2915 kbuild/src/consumer/mm/slub.c:2920) > [ 22.168372] resiliency_test (kbuild/src/consumer/lib/test_slub.c:34 kbuild/src/consumer/lib/test_slub.c:107) > [ 22.168372] test_slub_init (kbuild/src/consumer/lib/test_slub.c:124) > [ 22.168372] do_one_initcall (kbuild/src/consumer/init/main.c:1226) > [ 22.168372] kernel_init_freeable (kbuild/src/consumer/init/main.c:1298 kbuild/src/consumer/init/main.c:1315 kbuild/src/consumer/init/main.c:1335 kbuild/src/consumer/init/main.c:1537) > [ 22.168372] kernel_init (kbuild/src/consumer/init/main.c:1426) > [ 22.168372] ret_from_fork (kbuild/src/consumer/arch/x86/entry/entry_32.S:856) > [ 22.168372] INFO: Slab 0x(ptrval) objects=16 used=1 fp=0x(ptrval) flags=0x40000201 > [ 22.168372] INFO: Object 0x(ptrval) @offset=1000 fp=0x(ptrval) > [ 22.168372] > [ 22.168372] Redzone (ptrval): cc cc cc cc cc cc cc cc ........ > [ 22.168372] Object (ptrval): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk > [ 22.168372] Object (ptrval): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk. > [ 22.168372] Redzone (ptrval): 12 cc cc cc .... > [ 22.168372] Padding (ptrval): 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ > [ 22.168372] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G B 5.12.0-rc2-00001-ge48d82b67a2b #1 > [ 22.168372] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 > [ 22.168372] Call Trace: > [ 22.168372] dump_stack (kbuild/src/consumer/lib/dump_stack.c:122) > [ 22.168372] print_trailer (kbuild/src/consumer/mm/slub.c:737) > [ 22.168372] check_bytes_and_report.cold (kbuild/src/consumer/mm/slub.c:807) > [ 22.168372] check_object (kbuild/src/consumer/mm/slub.c:914) > [ 22.168372] validate_slab (kbuild/src/consumer/mm/slub.c:4635) Hm but in this case the output means the tested functionality (slub debugging) is working as intended. So what can we do? Indicate/teach somehow to the bot that this is OK? Does kselftest have some support for this? Or silence the validation output for testing purposes? (I would prefer not to) Thanks, Vlastimil

3 years, 7 months

3
3
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[PATCH v5 1/2] mm: huge_memory: a new debugfs interface for splitting THP tests.

by Zi Yan

From: Zi Yan <ziy(a)nvidia.com> We did not have a direct user interface of splitting the compound page backing a THP and there is no need unless we want to expose the THP implementation details to users. Make <debugfs>/split_huge_pages accept a new command to do that. By writing "<pid>,<vaddr_start>,<vaddr_end>" to <debugfs>/split_huge_pages, THPs within the given virtual address range from the process with the given pid are split. It is used to test split_huge_page function. In addition, a selftest program is added to tools/testing/selftests/vm to utilize the interface by splitting PMD THPs and PTE-mapped THPs. This does not change the old behavior, i.e., writing 1 to the interface to split all THPs in the system. Changelog: >From v5: 1. Skipped special VMAs and other fixes. (suggested by Yang Shi) >From v4: 1. Fixed the error code return issue, spotted by kernel test robot <lkp(a)intel.com>. >From v3: 1. Factored out split huge pages in the given pid code to a separate function. 2. Added the missing put_page for not split pages. 3. pr_debug -> pr_info, make reading results simpler. >From v2: 1. Reused existing <debugfs>/split_huge_pages interface. (suggested by Yang Shi) >From v1: 1. Removed unnecessary calling to vma_migratable, spotted by kernel test robot <lkp(a)intel.com>. 2. Dropped the use of find_mm_struct and code it directly, since there is no need for the permission check in that function and the function is only available when migration is on. 3. Added some comments in the selftest program to clarify how PTE-mapped THPs are formed. Signed-off-by: Zi Yan <ziy(a)nvidia.com> --- mm/huge_memory.c | 143 +++++++- tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 1 + .../selftests/vm/split_huge_page_test.c | 318 ++++++++++++++++++ 4 files changed, 456 insertions(+), 7 deletions(-) create mode 100644 tools/testing/selftests/vm/split_huge_page_test.c diff --git a/mm/huge_memory.c b/mm/huge_memory.c index bff92dea5ab3..9bf9bc489228 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -7,6 +7,7 @@ #include <linux/mm.h> #include <linux/sched.h> +#include <linux/sched/mm.h> #include <linux/sched/coredump.h> #include <linux/sched/numa_balancing.h> #include <linux/highmem.h> @@ -2922,16 +2923,14 @@ static struct shrinker deferred_split_shrinker = { }; #ifdef CONFIG_DEBUG_FS -static int split_huge_pages_set(void *data, u64 val) +static void split_huge_pages_all(void) { struct zone *zone; struct page *page; unsigned long pfn, max_zone_pfn; unsigned long total = 0, split = 0; - if (val != 1) - return -EINVAL; - + pr_info("Split all THPs\n"); for_each_populated_zone(zone) { max_zone_pfn = zone_end_pfn(zone); for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { @@ -2959,11 +2958,141 @@ static int split_huge_pages_set(void *data, u64 val) } pr_info("%lu of %lu THP split\n", split, total); +} - return 0; +static int split_huge_pages_pid(int pid, unsigned long vaddr_start, + unsigned long vaddr_end) +{ + int ret = 0; + struct task_struct *task; + struct mm_struct *mm; + unsigned long total = 0, split = 0; + unsigned long addr; + + vaddr_start &= PAGE_MASK; + vaddr_end &= PAGE_MASK; + + /* Find the task_struct from pid */ + rcu_read_lock(); + task = find_task_by_vpid(pid); + if (!task) { + rcu_read_unlock(); + ret = -ESRCH; + goto out; + } + get_task_struct(task); + rcu_read_unlock(); + + /* Find the mm_struct */ + mm = get_task_mm(task); + put_task_struct(task); + + if (!mm) { + ret = -EINVAL; + goto out; + } + + pr_info("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", + pid, vaddr_start, vaddr_end); + + mmap_read_lock(mm); + /* + * always increase addr by PAGE_SIZE, since we could have a PTE page + * table filled with PTE-mapped THPs, each of which is distinct. + */ + for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { + struct vm_area_struct *vma = find_vma(mm, addr); + unsigned int follflags; + struct page *page; + + if (!vma || addr < vma->vm_start) + break; + + /* skip special VMA and hugetlb VMA */ + if (vma_is_special_huge(vma) || is_vm_hugetlb_page(vma)) { + addr = vma->vm_end; + continue; + } + + /* FOLL_DUMP to ignore special (like zero) pages */ + follflags = FOLL_GET | FOLL_DUMP; + page = follow_page(vma, addr, follflags); + + if (IS_ERR(page)) + continue; + if (!page) + continue; + + if (!is_transparent_hugepage(page)) + goto next; + + total++; + if (!can_split_huge_page(compound_head(page), NULL)) + goto next; + + if (!trylock_page(page)) + goto next; + + if (!split_huge_page(page)) + split++; + + unlock_page(page); +next: + put_page(page); + } + mmap_read_unlock(mm); + mmput(mm); + + pr_info("%lu of %lu THP split\n", split, total); + +out: + return ret; } -DEFINE_DEBUGFS_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, - "%llu\n"); + +static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppops) +{ + static DEFINE_MUTEX(split_debug_mutex); + ssize_t ret; + char input_buf[80]; /* hold pid, start_vaddr, end_vaddr */ + int pid; + unsigned long vaddr_start, vaddr_end; + + ret = mutex_lock_interruptible(&split_debug_mutex); + if (ret) + return ret; + + ret = -EFAULT; + + memset(input_buf, 0, 80); + if (copy_from_user(input_buf, buf, min_t(size_t, count, 80))) + goto out; + + input_buf[79] = '\0'; + ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); + if (ret == 1 && pid == 1) { + split_huge_pages_all(); + ret = strlen(input_buf); + goto out; + } else if (ret != 3) { + ret = -EINVAL; + goto out; + } + + ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); + if (!ret) + ret = strlen(input_buf); +out: + mutex_unlock(&split_debug_mutex); + return ret; + +} + +static const struct file_operations split_huge_pages_fops = { + .owner = THIS_MODULE, + .write = split_huge_pages_write, + .llseek = no_llseek, +}; static int __init split_huge_pages_debugfs(void) { diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore index 9a35c3f6a557..1f651e85ed60 100644 --- a/tools/testing/selftests/vm/.gitignore +++ b/tools/testing/selftests/vm/.gitignore @@ -22,3 +22,4 @@ map_fixed_noreplace write_to_hugetlbfs hmm-tests local_config.* +split_huge_page_test diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile index d42115e4284d..4cbc91d6869f 100644 --- a/tools/testing/selftests/vm/Makefile +++ b/tools/testing/selftests/vm/Makefile @@ -42,6 +42,7 @@ TEST_GEN_FILES += on-fault-limit TEST_GEN_FILES += thuge-gen TEST_GEN_FILES += transhuge-stress TEST_GEN_FILES += userfaultfd +TEST_GEN_FILES += split_huge_page_test ifeq ($(MACHINE),x86_64) CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_32bit_program.c -m32) diff --git a/tools/testing/selftests/vm/split_huge_page_test.c b/tools/testing/selftests/vm/split_huge_page_test.c new file mode 100644 index 000000000000..2c0c18e60c57 --- /dev/null +++ b/tools/testing/selftests/vm/split_huge_page_test.c @@ -0,0 +1,318 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A test of splitting PMD THPs and PTE-mapped THPs from a specified virtual + * address range in a process via <debugfs>/split_huge_pages interface. + */ + +#define _GNU_SOURCE +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <inttypes.h> +#include <string.h> +#include <fcntl.h> +#include <sys/mman.h> +#include <malloc.h> +#include <stdbool.h> + +uint64_t pagesize; +unsigned int pageshift; +uint64_t pmd_pagesize; + +#define PMD_SIZE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size" +#define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages" +#define SMAP_PATH "/proc/self/smaps" +#define INPUT_MAX 80 + +#define PFN_MASK ((1UL<<55)-1) +#define KPF_THP (1UL<<22) + +int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file) +{ + uint64_t paddr; + uint64_t page_flags; + + if (pagemap_file) { + pread(pagemap_file, &paddr, sizeof(paddr), + ((long)vaddr >> pageshift) * sizeof(paddr)); + + if (kpageflags_file) { + pread(kpageflags_file, &page_flags, sizeof(page_flags), + (paddr & PFN_MASK) * sizeof(page_flags)); + + return !!(page_flags & KPF_THP); + } + } + return 0; +} + + +static uint64_t read_pmd_pagesize(void) +{ + int fd; + char buf[20]; + ssize_t num_read; + + fd = open(PMD_SIZE_PATH, O_RDONLY); + if (fd == -1) { + perror("Open hpage_pmd_size failed"); + exit(EXIT_FAILURE); + } + num_read = read(fd, buf, 19); + if (num_read < 1) { + close(fd); + perror("Read hpage_pmd_size failed"); + exit(EXIT_FAILURE); + } + buf[num_read] = '\0'; + close(fd); + + return strtoul(buf, NULL, 10); +} + +static int write_file(const char *path, const char *buf, size_t buflen) +{ + int fd; + ssize_t numwritten; + + fd = open(path, O_WRONLY); + if (fd == -1) + return 0; + + numwritten = write(fd, buf, buflen - 1); + close(fd); + if (numwritten < 1) + return 0; + + return (unsigned int) numwritten; +} + +static void write_debugfs(int pid, uint64_t vaddr_start, uint64_t vaddr_end) +{ + char input[INPUT_MAX]; + int ret; + + ret = snprintf(input, INPUT_MAX, "%d,0x%lx,0x%lx", pid, vaddr_start, + vaddr_end); + if (ret >= INPUT_MAX) { + printf("%s: Debugfs input is too long\n", __func__); + exit(EXIT_FAILURE); + } + + if (!write_file(SPLIT_DEBUGFS, input, ret + 1)) { + perror(SPLIT_DEBUGFS); + exit(EXIT_FAILURE); + } +} + +#define MAX_LINE_LENGTH 500 + +static bool check_for_pattern(FILE *fp, const char *pattern, char *buf) +{ + while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) { + if (!strncmp(buf, pattern, strlen(pattern))) + return true; + } + return false; +} + +static uint64_t check_huge(void *addr) +{ + uint64_t thp = 0; + int ret; + FILE *fp; + char buffer[MAX_LINE_LENGTH]; + char addr_pattern[MAX_LINE_LENGTH]; + + ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-", + (unsigned long) addr); + if (ret >= MAX_LINE_LENGTH) { + printf("%s: Pattern is too long\n", __func__); + exit(EXIT_FAILURE); + } + + + fp = fopen(SMAP_PATH, "r"); + if (!fp) { + printf("%s: Failed to open file %s\n", __func__, SMAP_PATH); + exit(EXIT_FAILURE); + } + if (!check_for_pattern(fp, addr_pattern, buffer)) + goto err_out; + + /* + * Fetch the AnonHugePages: in the same block and check the number of + * hugepages. + */ + if (!check_for_pattern(fp, "AnonHugePages:", buffer)) + goto err_out; + + if (sscanf(buffer, "AnonHugePages:%10ld kB", &thp) != 1) { + printf("Reading smap error\n"); + exit(EXIT_FAILURE); + } + +err_out: + fclose(fp); + return thp; +} + +void split_pmd_thp(void) +{ + char *one_page; + size_t len = 4 * pmd_pagesize; + uint64_t thp_size; + size_t i; + + one_page = memalign(pmd_pagesize, len); + + if (!one_page) { + printf("Fail to allocate memory\n"); + exit(EXIT_FAILURE); + } + + madvise(one_page, len, MADV_HUGEPAGE); + + for (i = 0; i < len; i++) + one_page[i] = (char)i; + + thp_size = check_huge(one_page); + if (!thp_size) { + printf("No THP is allocated\n"); + exit(EXIT_FAILURE); + } + + /* split all THPs */ + write_debugfs(getpid(), (uint64_t)one_page, (uint64_t)one_page + len); + + for (i = 0; i < len; i++) + if (one_page[i] != (char)i) { + printf("%ld byte corrupted\n", i); + exit(EXIT_FAILURE); + } + + + thp_size = check_huge(one_page); + if (thp_size) { + printf("Still %ld kB AnonHugePages not split\n", thp_size); + exit(EXIT_FAILURE); + } + + printf("Split huge pages successful\n"); + free(one_page); +} + +void split_pte_mapped_thp(void) +{ + char *one_page, *pte_mapped, *pte_mapped2; + size_t len = 4 * pmd_pagesize; + uint64_t thp_size; + size_t i; + const char *pagemap_template = "/proc/%d/pagemap"; + const char *kpageflags_proc = "/proc/kpageflags"; + char pagemap_proc[255]; + int pagemap_fd; + int kpageflags_fd; + + if (snprintf(pagemap_proc, 255, pagemap_template, getpid()) < 0) { + perror("get pagemap proc error"); + exit(EXIT_FAILURE); + } + pagemap_fd = open(pagemap_proc, O_RDONLY); + + if (pagemap_fd == -1) { + perror("read pagemap:"); + exit(EXIT_FAILURE); + } + + kpageflags_fd = open(kpageflags_proc, O_RDONLY); + + if (kpageflags_fd == -1) { + perror("read kpageflags:"); + exit(EXIT_FAILURE); + } + + one_page = mmap((void *)(1UL << 30), len, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + + madvise(one_page, len, MADV_HUGEPAGE); + + for (i = 0; i < len; i++) + one_page[i] = (char)i; + + thp_size = check_huge(one_page); + if (!thp_size) { + printf("No THP is allocated\n"); + exit(EXIT_FAILURE); + } + + /* remap the first pagesize of first THP */ + pte_mapped = mremap(one_page, pagesize, pagesize, MREMAP_MAYMOVE); + + /* remap the Nth pagesize of Nth THP */ + for (i = 1; i < 4; i++) { + pte_mapped2 = mremap(one_page + pmd_pagesize * i + pagesize * i, + pagesize, pagesize, + MREMAP_MAYMOVE|MREMAP_FIXED, + pte_mapped + pagesize * i); + if (pte_mapped2 == (char *)-1) { + perror("mremap failed"); + exit(EXIT_FAILURE); + } + } + + /* smap does not show THPs after mremap, use kpageflags instead */ + thp_size = 0; + for (i = 0; i < pagesize * 4; i++) + if (i % pagesize == 0 && + is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) + thp_size++; + + if (thp_size != 4) { + printf("Some THPs are missing during mremap\n"); + exit(EXIT_FAILURE); + } + + /* split all remapped THPs */ + write_debugfs(getpid(), (uint64_t)pte_mapped, + (uint64_t)pte_mapped + pagesize * 4); + + /* smap does not show THPs after mremap, use kpageflags instead */ + thp_size = 0; + for (i = 0; i < pagesize * 4; i++) { + if (pte_mapped[i] != (char)i) { + printf("%ld byte corrupted\n", i); + exit(EXIT_FAILURE); + } + if (i % pagesize == 0 && + is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) + thp_size++; + } + + if (thp_size) { + printf("Still %ld THPs not split\n", thp_size); + exit(EXIT_FAILURE); + } + + printf("Split PTE-mapped huge pages successful\n"); + munmap(one_page, len); + close(pagemap_fd); + close(kpageflags_fd); +} + +int main(int argc, char **argv) +{ + if (geteuid() != 0) { + printf("Please run the benchmark as root\n"); + exit(EXIT_FAILURE); + } + + pagesize = getpagesize(); + pageshift = ffs(pagesize) - 1; + pmd_pagesize = read_pmd_pagesize(); + + split_pmd_thp(); + split_pte_mapped_thp(); + + return 0; +} -- 2.30.2

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Linux-kselftest-mirror March 2021