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Bae" Cc: linux-kernel@vger.kernel.org, criu@lists.linux.dev, Dave Hansen , x86@kernel.org, Andrei Vagin , "H. Peter Anvin" Content-Type: text/plain; charset="UTF-8" Extend sigframe_portability test to include a consistency check. Verify that the kernel correctly rejects signal frames where the xstate_size is too small for the enabled features in the xfeatures mask. Signed-off-by: Andrei Vagin --- .../selftests/x86/sigframe_portability.c | 77 +++++++++++++++---- 1 file changed, 63 insertions(+), 14 deletions(-) diff --git a/tools/testing/selftests/x86/sigframe_portability.c b/tools/testing/selftests/x86/sigframe_portability.c index 54ba182a792f..04685a1c3aaa 100644 --- a/tools/testing/selftests/x86/sigframe_portability.c +++ b/tools/testing/selftests/x86/sigframe_portability.c @@ -17,13 +17,14 @@ #include "xstate.h" /* - * This test verifies the portability of the signal frame. - * It simulates a scenario where a signal frame is created on a system with - * fewer xstate features and restored on a system with more features. + * This test verifies the portability and consistency of the signal frame. + * Portability: A frame created on a system with fewer features can be + * restored on a system with more features. + * Consistency: The kernel rejects frames where xstate_size is insufficient + * for the features enabled in xfeatures. */ #define SIGFRAME_XSTATE_HDR_OFFSET 512 - #define XSTATE_SSE_ONLY_SIZE (SIGFRAME_XSTATE_HDR_OFFSET + XSAVE_HDR_SIZE) #define XFEATURE_MASK_FPSSE ((1 << XFEATURE_FP) | (1 << XFEATURE_SSE)) @@ -83,8 +84,7 @@ static void write_ymm0(uint64_t *v) asm volatile ("vmovdqu %0, %%ymm0" : : "m" (*(char (*)[32])v)); } - -static void handle_signal(int sig, siginfo_t *si, void *ucp) +static void handle_portability(int sig, siginfo_t *si, void *ucp) { ucontext_t *uc = ucp; void *fp = uc->uc_mcontext.fpregs; @@ -119,16 +119,12 @@ static void handle_signal(int sig, siginfo_t *si, void *ucp) memset(fp + sw->xstate_size + 4, 0, sw->extended_size - sw->xstate_size - 4); } -int main(void) +static void test_portability(void) { uint64_t v[4] = {0, 0, 0, 0}; - ksft_print_header(); - ksft_set_plan(1); - - check_avx_support(); - - sethandler(SIGUSR1, handle_signal, 0); + sig_err_buf[0] = 0; + sethandler(SIGUSR1, handle_portability, 0); v[0] = 0x1111111111111111ULL; v[1] = 0x2222222222222222ULL; @@ -143,13 +139,66 @@ int main(void) if (sig_err_buf[0]) ksft_test_result_fail("%s\n", sig_err_buf); else if (v[2] == TEST_YMMH_VAL && v[3] == (TEST_YMMH_VAL + 1)) - ksft_test_result_pass("YMM state restored correctly\n"); + ksft_test_result_pass("YMM state restored correctly from shrunk frame\n"); else ksft_test_result_fail( "Got upper bits: 0x%lx 0x%lx (expected %lx %lx)\n", v[2], v[3], TEST_YMMH_VAL, TEST_YMMH_VAL + 1); clearhandler(SIGUSR1); +} + +static void handle_consistency(int sig, siginfo_t *si, void *ucp) +{ + ucontext_t *uc = ucp; + void *fp = uc->uc_mcontext.fpregs; + struct _fpx_sw_bytes *sw = get_fpx_sw_bytes(fp); + + /* The origin frame contains an AVX state. */ + sw->xstate_size = XSTATE_SSE_ONLY_SIZE; + + *(uint32_t *)(fp + sw->xstate_size) = FP_XSTATE_MAGIC2; +} + +static void test_consistency(void) +{ + uint64_t v[4] = {0, 0, 0, 0}; + + sig_err_buf[0] = 0; + sethandler(SIGUSR2, handle_consistency, 0); + + v[0] = 0x1111111111111111ULL; + v[1] = 0x2222222222222222ULL; + v[2] = 0x3333333333333333ULL; + v[3] = 0x4444444444444444ULL; + write_ymm0(v); + + raise(SIGUSR2); + v[0] = v[1] = v[2] = v[3] = 0; + read_ymm0(v); + + /* + * When inconsistent, the kernel should have fallen back to + * FX-only mode, so YMM upper bits should be zero (init state). + */ + if (v[2] == 0 && v[3] == 0) + ksft_test_result_pass("Inconsistent size correctly rejected\n"); + else + ksft_test_result_fail("Inconsistent size was NOT rejected: 0x%lx 0x%lx\n", + v[2], v[3]); + + clearhandler(SIGUSR2); +} + +int main(void) +{ + ksft_print_header(); + ksft_set_plan(2); + + check_avx_support(); + + test_portability(); + test_consistency(); ksft_finished(); return 0; -- 2.54.0.1032.g2f8565e1d1-goog