From ab12c95d3f1999648d70bca54ebcc0588a07dd3e Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Wed, 17 Aug 2022 17:05:04 +0200 Subject: [PATCH] target/s390x: Make translator stop before the end of a page Right now translator stops right *after* the end of a page, which breaks reporting of fault locations when the last instruction of a multi-insn translation block crosses a page boundary. Signed-off-by: Ilya Leoshkevich Reviewed-by: Richard Henderson Message-Id: <20220817150506.592862-3-iii@linux.ibm.com> Signed-off-by: Richard Henderson --- target/s390x/tcg/translate.c | 15 +++- tests/tcg/multiarch/noexec.c.inc | 139 +++++++++++++++++++++++++++++++ tests/tcg/s390x/Makefile.target | 1 + tests/tcg/s390x/noexec.c | 106 +++++++++++++++++++++++ 4 files changed, 257 insertions(+), 4 deletions(-) create mode 100644 tests/tcg/multiarch/noexec.c.inc create mode 100644 tests/tcg/s390x/noexec.c diff --git a/target/s390x/tcg/translate.c b/target/s390x/tcg/translate.c index d4c0b9b3a2..1d2dddab1c 100644 --- a/target/s390x/tcg/translate.c +++ b/target/s390x/tcg/translate.c @@ -6609,6 +6609,14 @@ static void s390x_tr_insn_start(DisasContextBase *dcbase, CPUState *cs) dc->insn_start = tcg_last_op(); } +static target_ulong get_next_pc(CPUS390XState *env, DisasContext *s, + uint64_t pc) +{ + uint64_t insn = ld_code2(env, s, pc); + + return pc + get_ilen((insn >> 8) & 0xff); +} + static void s390x_tr_translate_insn(DisasContextBase *dcbase, CPUState *cs) { CPUS390XState *env = cs->env_ptr; @@ -6616,10 +6624,9 @@ static void s390x_tr_translate_insn(DisasContextBase *dcbase, CPUState *cs) dc->base.is_jmp = translate_one(env, dc); if (dc->base.is_jmp == DISAS_NEXT) { - uint64_t page_start; - - page_start = dc->base.pc_first & TARGET_PAGE_MASK; - if (dc->base.pc_next - page_start >= TARGET_PAGE_SIZE || dc->ex_value) { + if (!is_same_page(dcbase, dc->base.pc_next) || + !is_same_page(dcbase, get_next_pc(env, dc, dc->base.pc_next)) || + dc->ex_value) { dc->base.is_jmp = DISAS_TOO_MANY; } } diff --git a/tests/tcg/multiarch/noexec.c.inc b/tests/tcg/multiarch/noexec.c.inc new file mode 100644 index 0000000000..2ef539b721 --- /dev/null +++ b/tests/tcg/multiarch/noexec.c.inc @@ -0,0 +1,139 @@ +/* + * Common code for arch-specific MMU_INST_FETCH fault testing. + */ + +#define _GNU_SOURCE + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Forward declarations. */ + +static void *arch_mcontext_pc(const mcontext_t *ctx); +static int arch_mcontext_arg(const mcontext_t *ctx); +static void arch_flush(void *p, int len); + +/* Testing infrastructure. */ + +struct noexec_test { + const char *name; + const char *test_code; + int test_len; + int page_ofs; + int entry_ofs; + int expected_si_ofs; + int expected_pc_ofs; + int expected_arg; +}; + +static void *page_base; +static int page_size; +static const struct noexec_test *current_noexec_test; + +static void handle_err(const char *syscall) +{ + printf("[ FAILED ] %s: %s\n", syscall, strerror(errno)); + exit(EXIT_FAILURE); +} + +static void handle_segv(int sig, siginfo_t *info, void *ucontext) +{ + const struct noexec_test *test = current_noexec_test; + const mcontext_t *mc = &((ucontext_t *)ucontext)->uc_mcontext; + void *expected_si; + void *expected_pc; + void *pc; + int arg; + + if (test == NULL) { + printf("[ FAILED ] unexpected SEGV\n"); + exit(EXIT_FAILURE); + } + current_noexec_test = NULL; + + expected_si = page_base + test->expected_si_ofs; + if (info->si_addr != expected_si) { + printf("[ FAILED ] wrong si_addr (%p != %p)\n", + info->si_addr, expected_si); + exit(EXIT_FAILURE); + } + + pc = arch_mcontext_pc(mc); + expected_pc = page_base + test->expected_pc_ofs; + if (pc != expected_pc) { + printf("[ FAILED ] wrong pc (%p != %p)\n", pc, expected_pc); + exit(EXIT_FAILURE); + } + + arg = arch_mcontext_arg(mc); + if (arg != test->expected_arg) { + printf("[ FAILED ] wrong arg (%d != %d)\n", arg, test->expected_arg); + exit(EXIT_FAILURE); + } + + if (mprotect(page_base, page_size, + PROT_READ | PROT_WRITE | PROT_EXEC) < 0) { + handle_err("mprotect"); + } +} + +static void test_noexec_1(const struct noexec_test *test) +{ + void *start = page_base + test->page_ofs; + void (*fn)(int arg) = page_base + test->entry_ofs; + + memcpy(start, test->test_code, test->test_len); + arch_flush(start, test->test_len); + + /* Trigger TB creation in order to test invalidation. */ + fn(0); + + if (mprotect(page_base, page_size, PROT_NONE) < 0) { + handle_err("mprotect"); + } + + /* Trigger SEGV and check that handle_segv() ran. */ + current_noexec_test = test; + fn(0); + assert(current_noexec_test == NULL); +} + +static int test_noexec(struct noexec_test *tests, size_t n_tests) +{ + struct sigaction act; + size_t i; + + memset(&act, 0, sizeof(act)); + act.sa_sigaction = handle_segv; + act.sa_flags = SA_SIGINFO; + if (sigaction(SIGSEGV, &act, NULL) < 0) { + handle_err("sigaction"); + } + + page_size = getpagesize(); + page_base = mmap(NULL, 2 * page_size, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (page_base == MAP_FAILED) { + handle_err("mmap"); + } + page_base += page_size; + + for (i = 0; i < n_tests; i++) { + struct noexec_test *test = &tests[i]; + + printf("[ RUN ] %s\n", test->name); + test_noexec_1(test); + printf("[ OK ]\n"); + } + + printf("[ PASSED ]\n"); + return EXIT_SUCCESS; +} diff --git a/tests/tcg/s390x/Makefile.target b/tests/tcg/s390x/Makefile.target index 1a7a4a2f59..5e13a41c3f 100644 --- a/tests/tcg/s390x/Makefile.target +++ b/tests/tcg/s390x/Makefile.target @@ -16,6 +16,7 @@ TESTS+=shift TESTS+=trap TESTS+=signals-s390x TESTS+=branch-relative-long +TESTS+=noexec Z14_TESTS=vfminmax vfminmax: LDFLAGS+=-lm diff --git a/tests/tcg/s390x/noexec.c b/tests/tcg/s390x/noexec.c new file mode 100644 index 0000000000..15d007d07f --- /dev/null +++ b/tests/tcg/s390x/noexec.c @@ -0,0 +1,106 @@ +#include "../multiarch/noexec.c.inc" + +static void *arch_mcontext_pc(const mcontext_t *ctx) +{ + return (void *)ctx->psw.addr; +} + +static int arch_mcontext_arg(const mcontext_t *ctx) +{ + return ctx->gregs[2]; +} + +static void arch_flush(void *p, int len) +{ +} + +extern char noexec_1[]; +extern char noexec_2[]; +extern char noexec_end[]; + +asm("noexec_1:\n" + " lgfi %r2,1\n" /* %r2 is 0 on entry, set 1. */ + "noexec_2:\n" + " lgfi %r2,2\n" /* %r2 is 0/1; set 2. */ + " br %r14\n" /* return */ + "noexec_end:"); + +extern char exrl_1[]; +extern char exrl_2[]; +extern char exrl_end[]; + +asm("exrl_1:\n" + " exrl %r0, exrl_2\n" + " br %r14\n" + "exrl_2:\n" + " lgfi %r2,2\n" + "exrl_end:"); + +int main(void) +{ + struct noexec_test noexec_tests[] = { + { + .name = "fallthrough", + .test_code = noexec_1, + .test_len = noexec_end - noexec_1, + .page_ofs = noexec_1 - noexec_2, + .entry_ofs = noexec_1 - noexec_2, + .expected_si_ofs = 0, + .expected_pc_ofs = 0, + .expected_arg = 1, + }, + { + .name = "jump", + .test_code = noexec_1, + .test_len = noexec_end - noexec_1, + .page_ofs = noexec_1 - noexec_2, + .entry_ofs = 0, + .expected_si_ofs = 0, + .expected_pc_ofs = 0, + .expected_arg = 0, + }, + { + .name = "exrl", + .test_code = exrl_1, + .test_len = exrl_end - exrl_1, + .page_ofs = exrl_1 - exrl_2, + .entry_ofs = exrl_1 - exrl_2, + .expected_si_ofs = 0, + .expected_pc_ofs = exrl_1 - exrl_2, + .expected_arg = 0, + }, + { + .name = "fallthrough [cross]", + .test_code = noexec_1, + .test_len = noexec_end - noexec_1, + .page_ofs = noexec_1 - noexec_2 - 2, + .entry_ofs = noexec_1 - noexec_2 - 2, + .expected_si_ofs = 0, + .expected_pc_ofs = -2, + .expected_arg = 1, + }, + { + .name = "jump [cross]", + .test_code = noexec_1, + .test_len = noexec_end - noexec_1, + .page_ofs = noexec_1 - noexec_2 - 2, + .entry_ofs = -2, + .expected_si_ofs = 0, + .expected_pc_ofs = -2, + .expected_arg = 0, + }, + { + .name = "exrl [cross]", + .test_code = exrl_1, + .test_len = exrl_end - exrl_1, + .page_ofs = exrl_1 - exrl_2 - 2, + .entry_ofs = exrl_1 - exrl_2 - 2, + .expected_si_ofs = 0, + .expected_pc_ofs = exrl_1 - exrl_2 - 2, + .expected_arg = 0, + }, + }; + + return test_noexec(noexec_tests, + sizeof(noexec_tests) / sizeof(noexec_tests[0])); +}