Add selftests to cbo.c to verify Zicbop extension behavior, and split
the previous `--sigill` mode into two options so they can be tested
independently.

The test checks:
- That hwprobe correctly reports Zicbop presence and block size.
- That prefetch instructions execute without exception on valid and NULL
  addresses when Zicbop is present.

Signed-off-by: Yao Zihong <[email protected]>
---
 tools/testing/selftests/riscv/hwprobe/cbo.c | 165 ++++++++++++++++----
 1 file changed, 136 insertions(+), 29 deletions(-)

diff --git a/tools/testing/selftests/riscv/hwprobe/cbo.c 
b/tools/testing/selftests/riscv/hwprobe/cbo.c
index 5e96ef785d0d..6d99726aceac 100644
--- a/tools/testing/selftests/riscv/hwprobe/cbo.c
+++ b/tools/testing/selftests/riscv/hwprobe/cbo.c
@@ -15,24 +15,31 @@
 #include <linux/compiler.h>
 #include <linux/kernel.h>
 #include <asm/ucontext.h>
+#include <getopt.h>
 
 #include "hwprobe.h"
 #include "../../kselftest.h"
 
 #define MK_CBO(fn) le32_bswap((uint32_t)(fn) << 20 | 10 << 15 | 2 << 12 | 0 << 
7 | 15)
+#define MK_PREFETCH(fn) \
+       le32_bswap(0 << 25 | (uint32_t)(fn) << 20 | 10 << 15 | 6 << 12 | 0 << 7 
| 19)
 
 static char mem[4096] __aligned(4096) = { [0 ... 4095] = 0xa5 };
 
-static bool illegal_insn;
+static bool got_fault;
 
-static void sigill_handler(int sig, siginfo_t *info, void *context)
+static void fault_handler(int sig, siginfo_t *info, void *context)
 {
        unsigned long *regs = (unsigned long *)&((ucontext_t 
*)context)->uc_mcontext;
        uint32_t insn = *(uint32_t *)regs[0];
 
-       assert(insn == MK_CBO(regs[11]));
+       if (sig == SIGILL)
+               assert(insn == MK_CBO(regs[11]));
 
-       illegal_insn = true;
+       if (sig == SIGSEGV || sig == SIGBUS)
+               assert(insn == MK_PREFETCH(regs[11]));
+
+       got_fault = true;
        regs[0] += 4;
 }
 
@@ -45,39 +52,51 @@ static void sigill_handler(int sig, siginfo_t *info, void 
*context)
        : : "r" (base), "i" (fn), "i" (MK_CBO(fn)) : "a0", "a1", "memory");     
\
 })
 
+#define prefetch_insn(base, fn)                                                
        \
+({                                                                             
\
+       asm volatile(                                                           
\
+       "mv     a0, %0\n"                                                       
\
+       "li     a1, %1\n"                                                       
\
+       ".4byte %2\n"                                                           
\
+       : : "r" (base), "i" (fn), "i" (MK_PREFETCH(fn)) : "a0", "a1");          
\
+})
+
 static void cbo_inval(char *base) { cbo_insn(base, 0); }
 static void cbo_clean(char *base) { cbo_insn(base, 1); }
 static void cbo_flush(char *base) { cbo_insn(base, 2); }
 static void cbo_zero(char *base)  { cbo_insn(base, 4); }
+static void prefetch_i(char *base) { prefetch_insn(base, 0); }
+static void prefetch_r(char *base) { prefetch_insn(base, 1); }
+static void prefetch_w(char *base) { prefetch_insn(base, 3); }
 
 static void test_no_cbo_inval(void *arg)
 {
        ksft_print_msg("Testing cbo.inval instruction remain privileged\n");
-       illegal_insn = false;
+       got_fault = false;
        cbo_inval(&mem[0]);
-       ksft_test_result(illegal_insn, "No cbo.inval\n");
+       ksft_test_result(got_fault, "No cbo.inval\n");
 }
 
 static void test_no_zicbom(void *arg)
 {
        ksft_print_msg("Testing Zicbom instructions remain privileged\n");
 
-       illegal_insn = false;
+       got_fault = false;
        cbo_clean(&mem[0]);
-       ksft_test_result(illegal_insn, "No cbo.clean\n");
+       ksft_test_result(got_fault, "No cbo.clean\n");
 
-       illegal_insn = false;
+       got_fault = false;
        cbo_flush(&mem[0]);
-       ksft_test_result(illegal_insn, "No cbo.flush\n");
+       ksft_test_result(got_fault, "No cbo.flush\n");
 }
 
 static void test_no_zicboz(void *arg)
 {
        ksft_print_msg("No Zicboz, testing cbo.zero remains privileged\n");
 
-       illegal_insn = false;
+       got_fault = false;
        cbo_zero(&mem[0]);
-       ksft_test_result(illegal_insn, "No cbo.zero\n");
+       ksft_test_result(got_fault, "No cbo.zero\n");
 }
 
 static bool is_power_of_2(__u64 n)
@@ -85,6 +104,51 @@ static bool is_power_of_2(__u64 n)
        return n != 0 && (n & (n - 1)) == 0;
 }
 
+static void test_zicbop(void *arg)
+{
+       struct riscv_hwprobe pair = {
+               .key = RISCV_HWPROBE_KEY_ZICBOP_BLOCK_SIZE,
+       };
+       struct sigaction act = {
+               .sa_sigaction = &fault_handler,
+               .sa_flags = SA_SIGINFO
+       };
+       struct sigaction dfl = {
+               .sa_handler = SIG_DFL
+       };
+       cpu_set_t *cpus = (cpu_set_t *)arg;
+       __u64 block_size;
+       long rc;
+
+       rc = sigaction(SIGSEGV, &act, NULL);
+       assert(rc == 0);
+       rc = sigaction(SIGBUS, &act, NULL);
+       assert(rc == 0);
+
+       rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long *)cpus, 
0);
+       block_size = pair.value;
+       ksft_test_result(rc == 0 && pair.key == 
RISCV_HWPROBE_KEY_ZICBOP_BLOCK_SIZE &&
+                        is_power_of_2(block_size), "Zicbop block size\n");
+       ksft_print_msg("Zicbop block size: %llu\n", block_size);
+
+       got_fault = false;
+       prefetch_i(&mem[0]);
+       prefetch_r(&mem[0]);
+       prefetch_w(&mem[0]);
+       ksft_test_result(!got_fault, "Zicbop prefetch.* on valid address\n");
+
+       got_fault = false;
+       prefetch_i(NULL);
+       prefetch_r(NULL);
+       prefetch_w(NULL);
+       ksft_test_result(!got_fault, "Zicbop prefetch.* on NULL\n");
+
+       rc = sigaction(SIGBUS, &dfl, NULL);
+       assert(rc == 0);
+       rc = sigaction(SIGSEGV, &dfl, NULL);
+       assert(rc == 0);
+}
+
 static void test_zicbom(void *arg)
 {
        struct riscv_hwprobe pair = {
@@ -100,13 +164,13 @@ static void test_zicbom(void *arg)
                         is_power_of_2(block_size), "Zicbom block size\n");
        ksft_print_msg("Zicbom block size: %llu\n", block_size);
 
-       illegal_insn = false;
+       got_fault = false;
        cbo_clean(&mem[block_size]);
-       ksft_test_result(!illegal_insn, "cbo.clean\n");
+       ksft_test_result(!got_fault, "cbo.clean\n");
 
-       illegal_insn = false;
+       got_fault = false;
        cbo_flush(&mem[block_size]);
-       ksft_test_result(!illegal_insn, "cbo.flush\n");
+       ksft_test_result(!got_fault, "cbo.flush\n");
 }
 
 static void test_zicboz(void *arg)
@@ -125,11 +189,11 @@ static void test_zicboz(void *arg)
                         is_power_of_2(block_size), "Zicboz block size\n");
        ksft_print_msg("Zicboz block size: %llu\n", block_size);
 
-       illegal_insn = false;
+       got_fault = false;
        cbo_zero(&mem[block_size]);
-       ksft_test_result(!illegal_insn, "cbo.zero\n");
+       ksft_test_result(!got_fault, "cbo.zero\n");
 
-       if (illegal_insn || !is_power_of_2(block_size)) {
+       if (got_fault || !is_power_of_2(block_size)) {
                ksft_test_result_skip("cbo.zero check\n");
                return;
        }
@@ -177,7 +241,19 @@ static void check_no_zicbo_cpus(cpu_set_t *cpus, __u64 cbo)
                rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long 
*)&one_cpu, 0);
                assert(rc == 0 && pair.key == RISCV_HWPROBE_KEY_IMA_EXT_0);
 
-               cbostr = cbo == RISCV_HWPROBE_EXT_ZICBOZ ? "Zicboz" : "Zicbom";
+               switch (cbo) {
+               case RISCV_HWPROBE_EXT_ZICBOZ:
+                       cbostr = "Zicboz";
+                       break;
+               case RISCV_HWPROBE_EXT_ZICBOM:
+                       cbostr = "Zicbom";
+                       break;
+               case RISCV_HWPROBE_EXT_ZICBOP:
+                       cbostr = "Zicbop";
+                       break;
+               default:
+                       ksft_exit_fail_msg("Internal error: invalid cbo 
%llu\n", cbo);
+               }
 
                if (pair.value & cbo)
                        ksft_exit_fail_msg("%s is only present on a subset of 
harts.\n"
@@ -194,6 +270,7 @@ enum {
        TEST_ZICBOM,
        TEST_NO_ZICBOM,
        TEST_NO_CBO_INVAL,
+       TEST_ZICBOP,
 };
 
 static struct test_info {
@@ -206,26 +283,51 @@ static struct test_info {
        [TEST_ZICBOM]           = { .nr_tests = 3, test_zicbom },
        [TEST_NO_ZICBOM]        = { .nr_tests = 2, test_no_zicbom },
        [TEST_NO_CBO_INVAL]     = { .nr_tests = 1, test_no_cbo_inval },
+       [TEST_ZICBOP]           = { .nr_tests = 3, test_zicbop },
+};
+
+static const struct option long_opts[] = {
+       {"zicbom-raises-sigill", no_argument, 0, 'm'},
+       {"zicboz-raises-sigill", no_argument, 0, 'z'},
+       {0, 0, 0, 0}
 };
 
 int main(int argc, char **argv)
 {
        struct sigaction act = {
-               .sa_sigaction = &sigill_handler,
+               .sa_sigaction = &fault_handler,
                .sa_flags = SA_SIGINFO,
        };
        struct riscv_hwprobe pair;
        unsigned int plan = 0;
        cpu_set_t cpus;
        long rc;
-       int i;
-
-       if (argc > 1 && !strcmp(argv[1], "--sigill")) {
-               rc = sigaction(SIGILL, &act, NULL);
-               assert(rc == 0);
-               tests[TEST_NO_ZICBOZ].enabled = true;
-               tests[TEST_NO_ZICBOM].enabled = true;
-               tests[TEST_NO_CBO_INVAL].enabled = true;
+       int i, opt, long_index;
+
+       long_index = 0;
+
+       while ((opt = getopt_long(argc, argv, "mz", long_opts, &long_index)) != 
-1) {
+               switch (opt) {
+               case 'm':
+                       tests[TEST_NO_ZICBOM].enabled = true;
+                       tests[TEST_NO_CBO_INVAL].enabled = true;
+                       rc = sigaction(SIGILL, &act, NULL);
+                       assert(rc == 0);
+                       break;
+               case 'z':
+                       tests[TEST_NO_ZICBOZ].enabled = true;
+                       tests[TEST_NO_CBO_INVAL].enabled = true;
+                       rc = sigaction(SIGILL, &act, NULL);
+                       assert(rc == 0);
+                       break;
+               case '?':
+                       fprintf(stderr,
+                               "Usage: %s [--zicbom-raises-sigill|-m] 
[--zicboz-raises-sigill|-z]\n",
+                               argv[0]);
+                       exit(1);
+               default:
+                       break;
+               }
        }
 
        rc = sched_getaffinity(0, sizeof(cpu_set_t), &cpus);
@@ -253,6 +355,11 @@ int main(int argc, char **argv)
                check_no_zicbo_cpus(&cpus, RISCV_HWPROBE_EXT_ZICBOM);
        }
 
+       if (pair.value & RISCV_HWPROBE_EXT_ZICBOP)
+               tests[TEST_ZICBOP].enabled = true;
+       else
+               check_no_zicbo_cpus(&cpus, RISCV_HWPROBE_EXT_ZICBOP);
+
        for (i = 0; i < ARRAY_SIZE(tests); ++i)
                plan += tests[i].enabled ? tests[i].nr_tests : 0;
 
-- 
2.47.2


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