Signed-off-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Shuah Khan shuah@kernel.org Cc: linux-kselftest@vger.kernel.org --- tools/testing/selftests/rseq/.gitignore | 1 + tools/testing/selftests/rseq/Makefile | 3 +- tools/testing/selftests/rseq/rseq.c | 21 ++ tools/testing/selftests/rseq/rseq.h | 12 + .../selftests/rseq/rseq_ext_abort_at_ip.c | 285 ++++++++++++++++++ 5 files changed, 321 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/rseq/rseq_ext_abort_at_ip.c

diff --git a/tools/testing/selftests/rseq/.gitignore b/tools/testing/selftests/rseq/.gitignore index 5910888ebfe1..472152afab77 100644 --- a/tools/testing/selftests/rseq/.gitignore +++ b/tools/testing/selftests/rseq/.gitignore @@ -5,3 +5,4 @@ basic_rseq_op_test param_test param_test_benchmark param_test_compare_twice +rseq_ext_abort_at_ip diff --git a/tools/testing/selftests/rseq/Makefile b/tools/testing/selftests/rseq/Makefile index 2af9d39a9716..dae0dba7552b 100644 --- a/tools/testing/selftests/rseq/Makefile +++ b/tools/testing/selftests/rseq/Makefile @@ -13,7 +13,8 @@ LDLIBS += -lpthread OVERRIDE_TARGETS = 1

TEST_GEN_PROGS = basic_test basic_percpu_ops_test param_test \ - param_test_benchmark param_test_compare_twice + param_test_benchmark param_test_compare_twice \ + rseq_ext_abort_at_ip

TEST_GEN_PROGS_EXTENDED = librseq.so

diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c index 7159eb777fd3..3e012f581ddb 100644 --- a/tools/testing/selftests/rseq/rseq.c +++ b/tools/testing/selftests/rseq/rseq.c @@ -73,6 +73,27 @@ static int sys_rseq(volatile struct rseq *rseq_abi, uint32_t rseq_len, return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig); }

+/* + * Return 0 if extension is available, negative error otherwise. + */ +int rseq_query_extension(enum rseq_extension ext) +{ + int ret; + unsigned int flags; + + switch (ext) { + case RSEQ_EXT_ABORT_AT_IP: + flags = RSEQ_FLAG_QUERY_ABORT_AT_IP; + break; + default: + return -EINVAL; + } + ret = sys_rseq(NULL, 0, flags, 0); + if (!ret) + return 0; + return -errno; +} + int rseq_register_current_thread(void) { int rc, ret = 0; diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h index 3f63eb362b92..34c80402c078 100644 --- a/tools/testing/selftests/rseq/rseq.h +++ b/tools/testing/selftests/rseq/rseq.h @@ -67,6 +67,12 @@ extern int __rseq_handled; abort(); \ } while (0)

+enum rseq_extension { + RSEQ_EXT_ABORT_AT_IP = 0, +}; + +#define ASM_RSEQ_CS_FLAG_ABORT_AT_IP (1U << 3) + #if defined(__x86_64__) || defined(__i386__) #include <rseq-x86.h> #elif defined(__ARMEL__) @@ -162,4 +168,10 @@ static inline void rseq_prepare_unload(void) rseq_clear_rseq_cs(); }

+/* + * Query whether rseq extension is available. Return 0 if available, negative + * error value otherwise. + */ +int rseq_query_extension(enum rseq_extension ext); + #endif /* RSEQ_H_ */ diff --git a/tools/testing/selftests/rseq/rseq_ext_abort_at_ip.c b/tools/testing/selftests/rseq/rseq_ext_abort_at_ip.c new file mode 100644 index 000000000000..4cddf7433cc3 --- /dev/null +++ b/tools/testing/selftests/rseq/rseq_ext_abort_at_ip.c @@ -0,0 +1,285 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * RSEQ abort-at-ip extension test. + * + * The test test_abort_at_ip_loop() implements an infinite loop which only exits when + * aborted. This rseq critical section is defined with the abort-at-ip + * extension, which requires the userspace abort handler to reajust the stack pointer. + * This test validates that the abort-at-ip value is within the address range of the + * rseq critical section. + * + * The test test_abort_at_ip_undo() validates that when aborted between two + * consecutive increments of two distinct variables, those variables are indeed one + * value apart. This validates that abort undo operations based on the abort-at-ip + * work as expected. + */ + +#define _GNU_SOURCE +#include <assert.h> +#include <sched.h> +#include <signal.h> +#include <stdio.h> +#include <string.h> +#include <sys/time.h> + +#include "rseq.h" + +const int nr_iter = 10; + +#ifdef __x86_64__ +static void test_abort_at_ip_loop(void) +{ + void *abort_ip_addr, *abort_ip_start, *abort_ip_end; + + printf("Testing abort_at_ip infinite loop\n"); + + __asm__ __volatile__ goto ( + __RSEQ_ASM_DEFINE_TABLE(3, 0x0, ASM_RSEQ_CS_FLAG_ABORT_AT_IP, 1f, (2f - 1f), 4f) /* start, post_commit_offset, abort */ + /* Start rseq by storing table entry pointer into rseq_cs. */ + RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi])) + "rep; nop\n\t" /* cpu_relax for busy loop. */ + "jmp 1b\n\t" /* infinite loop. */ + "2:\n\t" + RSEQ_ASM_DEFINE_ABORT(4, + /* abort-at-ip must be pop from the stack. */ + "popq %%rcx\n\t" + "addq $128, %%rsp\n\t" /* x86-64 redzone */ + "movq %%rcx, %[abort_ip_addr]\n\t" + "lea 1b(%%rip), %%rcx\n\t" + "movq %%rcx, %[abort_ip_start]\n\t" + "lea 2b(%%rip), %%rcx\n\t" + "movq %%rcx, %[abort_ip_end]\n\t", + abort) + : /* gcc asm goto does not allow outputs */ + : [rseq_abi] "r" (&__rseq_abi), + [abort_ip_addr] "m" (abort_ip_addr), + [abort_ip_start] "m" (abort_ip_start), + [abort_ip_end] "m" (abort_ip_end) + : "memory", "cc", "rcx" + : abort + ); + fprintf(stderr, "Error: infinite loop should never exit gracefully.\n"); + abort(); + +abort: + printf("Critical section aborted (as expected) at ip %p, within range [%p,%p[\n", + abort_ip_addr, abort_ip_start, abort_ip_end); + if (abort_ip_addr < abort_ip_start || abort_ip_addr >= abort_ip_end) { + fprintf(stderr, "Error: abort-ip is outside of expected range\n"); + abort(); + } +} + +static void test_abort_at_ip_undo(void) +{ + void *abort_ip_addr, *abort_ip_start, *abort_ip_end, *ip_after_first_inc, *ip_after_second_inc; + unsigned long v[2] = { 0, 0 }; + + printf("Testing abort_at_ip undo\n"); + + __asm__ __volatile__ goto ( + __RSEQ_ASM_DEFINE_TABLE(3, 0x0, ASM_RSEQ_CS_FLAG_ABORT_AT_IP, 1f, (2f - 1f), 4f) /* start, post_commit_offset, abort */ + /* Start rseq by storing table entry pointer into rseq_cs. */ + RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi])) + "incq %[v0]\n\t" + "10:\n\t" + "rep; nop\n\t" + "incq %[v1]\n\t" + "20:\n\t" + "rep; nop\n\t" + "jmp 1b\n\t" /* infinite loop. */ + "2:\n\t" + RSEQ_ASM_DEFINE_ABORT(4, + /* abort-at-ip must be pop from the stack. */ + "popq %%rcx\n\t" + "addq $128, %%rsp\n\t" /* x86-64 redzone */ + "movq %%rcx, %[abort_ip_addr]\n\t" + "lea 1b(%%rip), %%rcx\n\t" + "movq %%rcx, %[abort_ip_start]\n\t" + "lea 2b(%%rip), %%rcx\n\t" + "movq %%rcx, %[abort_ip_end]\n\t" + "lea 10b(%%rip), %%rcx\n\t" + "movq %%rcx, %[ip_after_first_inc]\n\t" + "lea 20b(%%rip), %%rcx\n\t" + "movq %%rcx, %[ip_after_second_inc]\n\t", + abort) + : /* gcc asm goto does not allow outputs */ + : [rseq_abi] "r" (&__rseq_abi), + [abort_ip_addr] "m" (abort_ip_addr), + [abort_ip_start] "m" (abort_ip_start), + [abort_ip_end] "m" (abort_ip_end), + [ip_after_first_inc] "m" (ip_after_first_inc), + [ip_after_second_inc] "m" (ip_after_second_inc), + [v0] "m" (v[0]), + [v1] "m" (v[1]) + : "memory", "cc", "rcx" + : abort + ); + fprintf(stderr, "Error: infinite loop should never exit gracefully.\n"); + abort(); + +abort: + printf("Critical section aborted (as expected) at ip %p, within range [%p,%p[\n", + abort_ip_addr, abort_ip_start, abort_ip_end); + if (abort_ip_addr < abort_ip_start || abort_ip_addr >= abort_ip_end) { + fprintf(stderr, "Error: abort-ip is outside of expected range\n"); + abort(); + } + printf("ip after first inc: %p, ip after second inc: %p\n", + ip_after_first_inc, ip_after_second_inc); + printf("Counter values: v0: %lu v1: %lu\n", v[0], v[1]); + if (abort_ip_addr < ip_after_first_inc || abort_ip_addr >= ip_after_second_inc) { + if (v[0] != v[1]) + abort(); + } else { + if (v[0] != v[1] + 1) + abort(); + } +} +#elif defined (__i386__) +static void test_abort_at_ip_loop(void) +{ + void *abort_ip_addr, *abort_ip_start, *abort_ip_end; + + printf("Testing abort_at_ip infinite loop\n"); + + __asm__ __volatile__ goto ( + __RSEQ_ASM_DEFINE_TABLE(3, 0x0, ASM_RSEQ_CS_FLAG_ABORT_AT_IP, 1f, (2f - 1f), 4f) /* start, post_commit_offset, abort */ + /* Start rseq by storing table entry pointer into rseq_cs. */ + RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi])) + "rep; nop\n\t" /* cpu_relax for busy loop. */ + "jmp 1b\n\t" /* infinite loop. */ + "2:\n\t" + RSEQ_ASM_DEFINE_ABORT(4, + /* abort-at-ip must be pop from the stack. */ + "popl %%ecx\n\t" + "movl %%ecx, %[abort_ip_addr]\n\t" + "movl $1b, %%ecx\n\t" + "movl %%ecx, %[abort_ip_start]\n\t" + "movl $2b, %%ecx\n\t" + "movl %%ecx, %[abort_ip_end]\n\t", + abort) + : /* gcc asm goto does not allow outputs */ + : [rseq_abi] "r" (&__rseq_abi), + [abort_ip_addr] "m" (abort_ip_addr), + [abort_ip_start] "m" (abort_ip_start), + [abort_ip_end] "m" (abort_ip_end) + : "memory", "cc", "ecx" + : abort + ); + fprintf(stderr, "Error: infinite loop should never exit gracefully.\n"); + abort(); + +abort: + printf("Critical section aborted (as expected) at ip %p, within range [%p,%p[\n", + abort_ip_addr, abort_ip_start, abort_ip_end); + if (abort_ip_addr < abort_ip_start || abort_ip_addr >= abort_ip_end) { + fprintf(stderr, "Error: abort-ip is outside of expected range\n"); + abort(); + } +} + +static void test_abort_at_ip_undo(void) +{ + void *abort_ip_addr, *abort_ip_start, *abort_ip_end, *ip_after_first_inc, *ip_after_second_inc; + unsigned long v[2] = { 0, 0 }; + + printf("Testing abort_at_ip undo\n"); + + __asm__ __volatile__ goto ( + __RSEQ_ASM_DEFINE_TABLE(3, 0x0, ASM_RSEQ_CS_FLAG_ABORT_AT_IP, 1f, (2f - 1f), 4f) /* start, post_commit_offset, abort */ + /* Start rseq by storing table entry pointer into rseq_cs. */ + RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi])) + "incl %[v0]\n\t" + "10:\n\t" + "rep; nop\n\t" + "incl %[v1]\n\t" + "20:\n\t" + "rep; nop\n\t" + "jmp 1b\n\t" /* infinite loop. */ + "2:\n\t" + RSEQ_ASM_DEFINE_ABORT(4, + /* abort-at-ip must be pop from the stack. */ + "popl %%ecx\n\t" + "movl %%ecx, %[abort_ip_addr]\n\t" + "movl $1b, %%ecx\n\t" + "movl %%ecx, %[abort_ip_start]\n\t" + "movl $2b, %%ecx\n\t" + "movl %%ecx, %[abort_ip_end]\n\t" + "movl $10b, %%ecx\n\t" + "movl %%ecx, %[ip_after_first_inc]\n\t" + "movl $20b, %%ecx\n\t" + "movl %%ecx, %[ip_after_second_inc]\n\t", + abort) + : /* gcc asm goto does not allow outputs */ + : [rseq_abi] "r" (&__rseq_abi), + [abort_ip_addr] "m" (abort_ip_addr), + [abort_ip_start] "m" (abort_ip_start), + [abort_ip_end] "m" (abort_ip_end), + [ip_after_first_inc] "m" (ip_after_first_inc), + [ip_after_second_inc] "m" (ip_after_second_inc), + [v0] "m" (v[0]), + [v1] "m" (v[1]) + : "memory", "cc", "rcx" + : abort + ); + fprintf(stderr, "Error: infinite loop should never exit gracefully.\n"); + abort(); + +abort: + printf("Critical section aborted (as expected) at ip %p, within range [%p,%p[\n", + abort_ip_addr, abort_ip_start, abort_ip_end); + if (abort_ip_addr < abort_ip_start || abort_ip_addr >= abort_ip_end) { + fprintf(stderr, "Error: abort-ip is outside of expected range\n"); + abort(); + } + printf("ip after first inc: %p, ip after second inc: %p\n", + ip_after_first_inc, ip_after_second_inc); + printf("Counter values: v0: %lu v1: %lu\n", v[0], v[1]); + if (abort_ip_addr < ip_after_first_inc || abort_ip_addr >= ip_after_second_inc) { + if (v[0] != v[1]) + abort(); + } else { + if (v[0] != v[1] + 1) + abort(); + } +} +#else +static void test_abort_at_ip_loop(void) +{ + abort(); +} +static void test_abort_at_ip_undo(void) +{ + abort(); +} +#endif + +int main(int argc, char **argv) +{ + int i; + + if (rseq_register_current_thread()) { + fprintf(stderr, "Error: rseq_register_current_thread(...) failed(%d): %s\n", + errno, strerror(errno)); + goto init_thread_error; + } + printf("testing abort-at-ip extension\n"); + if (rseq_query_extension(RSEQ_EXT_ABORT_AT_IP) != 0) { + fprintf(stderr, "RSEQ abort-at-ip extension is not supported, skipping test.\n"); + return 0; + } + for (i = 0; i < nr_iter; i++) + test_abort_at_ip_loop(); + for (i = 0; i < nr_iter; i++) + test_abort_at_ip_undo(); + if (rseq_unregister_current_thread()) { + fprintf(stderr, "Error: rseq_unregister_current_thread(...) failed(%d): %s\n", + errno, strerror(errno)); + goto init_thread_error; + } + return 0; + +init_thread_error: + return -1; +}