[PATCH v4 0/3] Enable Zicbom in usermode

[PATCH v4 0/3] Enable Zicbom in usermode

[Yunhui Cui]

v1/v2: 
There is only the first patch: RISC-V: Enable cbo.clean/flush in usermode,
which mainly removes the enabling of cbo.inval in user mode.

v3:
Add the functionality of Expose Zicbom and selftests for Zicbom.

v4:
Modify the order of macros, The test_no_cbo_inval function is added
separately.

Yunhui Cui (3):
  RISC-V: Enable cbo.clean/flush in usermode
  RISC-V: hwprobe: Expose Zicbom extension and its block size
  RISC-V: selftests: Add TEST_ZICBOM into CBO tests

 Documentation/arch/riscv/hwprobe.rst        |  6 ++
 arch/riscv/include/asm/hwprobe.h            |  2 +-
 arch/riscv/include/uapi/asm/hwprobe.h       |  2 +
 arch/riscv/kernel/cpufeature.c              |  8 +++
 arch/riscv/kernel/sys_hwprobe.c             |  6 ++
 tools/testing/selftests/riscv/hwprobe/cbo.c | 66 +++++++++++++++++----
 6 files changed, 78 insertions(+), 12 deletions(-)

-- 
2.39.2

[PATCH v4 1/3] RISC-V: Enable cbo.clean/flush in usermode

[Yunhui Cui]

Enabling cbo.clean and cbo.flush in user mode makes it more
convenient to manage the cache state and achieve better performance.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
---
 arch/riscv/kernel/cpufeature.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index c0916ed318c2..60d180b98f52 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -30,6 +30,7 @@
 #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
 
 static bool any_cpu_has_zicboz;
+static bool any_cpu_has_zicbom;
 
 unsigned long elf_hwcap __read_mostly;
 
@@ -87,6 +88,8 @@ static int riscv_ext_zicbom_validate(const struct riscv_isa_ext_data *data,
 		pr_err("Zicbom disabled as cbom-block-size present, but is not a power-of-2\n");
 		return -EINVAL;
 	}
+
+	any_cpu_has_zicbom = true;
 	return 0;
 }
 
@@ -944,6 +947,11 @@ void __init riscv_user_isa_enable(void)
 		current->thread.envcfg |= ENVCFG_CBZE;
 	else if (any_cpu_has_zicboz)
 		pr_warn("Zicboz disabled as it is unavailable on some harts\n");
+
+	if (riscv_has_extension_unlikely(RISCV_ISA_EXT_ZICBOM))
+		current->thread.envcfg |= ENVCFG_CBCFE;
+	else if (any_cpu_has_zicbom)
+		pr_warn("Zicbom disabled as it is unavailable on some harts\n");
 }
 
 #ifdef CONFIG_RISCV_ALTERNATIVE
-- 
2.39.2

[PATCH v4 2/3] RISC-V: hwprobe: Expose Zicbom extension and its block size

[Yunhui Cui]

Expose Zicbom through hwprobe and also provide a key to extract its
respective block size.

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
---
 Documentation/arch/riscv/hwprobe.rst  | 6 ++++++
 arch/riscv/include/asm/hwprobe.h      | 2 +-
 arch/riscv/include/uapi/asm/hwprobe.h | 2 ++
 arch/riscv/kernel/sys_hwprobe.c       | 6 ++++++
 4 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
index 955fbcd19ce9..0ea7754b2049 100644
--- a/Documentation/arch/riscv/hwprobe.rst
+++ b/Documentation/arch/riscv/hwprobe.rst
@@ -242,6 +242,9 @@ The following keys are defined:
   * :c:macro:`RISCV_HWPROBE_EXT_SUPM`: The Supm extension is supported as
        defined in version 1.0 of the RISC-V Pointer Masking extensions.
 
+  * :c:macro:`RISCV_HWPROBE_EXT_ZICBOM`: The Zicbom extension is supported, as
+       ratified in commit 3dd606f ("Create cmobase-v1.0.pdf") of riscv-CMOs.
+
 * :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: Deprecated.  Returns similar values to
      :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_SCALAR_PERF`, but the key was
      mistakenly classified as a bitmask rather than a value.
@@ -281,6 +284,9 @@ The following keys are defined:
 * :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_VECTOR_PERF`: An enum value describing the
      performance of misaligned vector accesses on the selected set of processors.
 
+* :c:macro:`RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE`: An unsigned int which
+  represents the size of the Zicbom block in bytes.
+
   * :c:macro:`RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN`: The performance of misaligned
     vector accesses is unknown.
 
diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
index 1ce1df6d0ff3..89379f9a2e6e 100644
--- a/arch/riscv/include/asm/hwprobe.h
+++ b/arch/riscv/include/asm/hwprobe.h
@@ -8,7 +8,7 @@
 
 #include <uapi/asm/hwprobe.h>
 
-#define RISCV_HWPROBE_MAX_KEY 10
+#define RISCV_HWPROBE_MAX_KEY 11
 
 static inline bool riscv_hwprobe_key_is_valid(__s64 key)
 {
diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
index 3af142b99f77..b15c0bd83ef2 100644
--- a/arch/riscv/include/uapi/asm/hwprobe.h
+++ b/arch/riscv/include/uapi/asm/hwprobe.h
@@ -73,6 +73,7 @@ struct riscv_hwprobe {
 #define		RISCV_HWPROBE_EXT_ZCMOP		(1ULL << 47)
 #define		RISCV_HWPROBE_EXT_ZAWRS		(1ULL << 48)
 #define		RISCV_HWPROBE_EXT_SUPM		(1ULL << 49)
+#define		RISCV_HWPROBE_EXT_ZICBOM	(1ULL << 50)
 #define RISCV_HWPROBE_KEY_CPUPERF_0	5
 #define		RISCV_HWPROBE_MISALIGNED_UNKNOWN	(0 << 0)
 #define		RISCV_HWPROBE_MISALIGNED_EMULATED	(1 << 0)
@@ -94,6 +95,7 @@ struct riscv_hwprobe {
 #define		RISCV_HWPROBE_MISALIGNED_VECTOR_SLOW		2
 #define		RISCV_HWPROBE_MISALIGNED_VECTOR_FAST		3
 #define		RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED	4
+#define RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE	11
 /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
 
 /* Flags */
diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index cb93adfffc48..04150e62f998 100644
--- a/arch/riscv/kernel/sys_hwprobe.c
+++ b/arch/riscv/kernel/sys_hwprobe.c
@@ -106,6 +106,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
 		EXT_KEY(ZCA);
 		EXT_KEY(ZCB);
 		EXT_KEY(ZCMOP);
+		EXT_KEY(ZICBOM);
 		EXT_KEY(ZICBOZ);
 		EXT_KEY(ZICOND);
 		EXT_KEY(ZIHINTNTL);
@@ -278,6 +279,11 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
 		if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOZ))
 			pair->value = riscv_cboz_block_size;
 		break;
+	case RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE:
+		pair->value = 0;
+		if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOM))
+			pair->value = riscv_cbom_block_size;
+		break;
 	case RISCV_HWPROBE_KEY_HIGHEST_VIRT_ADDRESS:
 		pair->value = user_max_virt_addr();
 		break;
-- 
2.39.2

[PATCH v4 3/3] RISC-V: selftests: Add TEST_ZICBOM into CBO tests

[Yunhui Cui]

Add test for Zicbom and its block size into CBO tests, when
Zicbom is present, test that cbo.clean/flush may be issued and works.
As the software can't verify the clean/flush functions, we just judged
that cbo.clean/flush isn't executed illegally.

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
---
 tools/testing/selftests/riscv/hwprobe/cbo.c | 66 +++++++++++++++++----
 1 file changed, 55 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/riscv/hwprobe/cbo.c b/tools/testing/selftests/riscv/hwprobe/cbo.c
index a40541bb7c7d..dec510291ab8 100644
--- a/tools/testing/selftests/riscv/hwprobe/cbo.c
+++ b/tools/testing/selftests/riscv/hwprobe/cbo.c
@@ -50,6 +50,14 @@ 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 test_no_cbo_inval(void *arg)
+{
+	ksft_print_msg("Testing cbo.inval instruction remain privileged\n");
+	illegal_insn = false;
+	cbo_inval(&mem[0]);
+	ksft_test_result(illegal_insn, "No cbo.inval\n");
+}
+
 static void test_no_zicbom(void *arg)
 {
 	ksft_print_msg("Testing Zicbom instructions remain privileged\n");
@@ -61,10 +69,6 @@ static void test_no_zicbom(void *arg)
 	illegal_insn = false;
 	cbo_flush(&mem[0]);
 	ksft_test_result(illegal_insn, "No cbo.flush\n");
-
-	illegal_insn = false;
-	cbo_inval(&mem[0]);
-	ksft_test_result(illegal_insn, "No cbo.inval\n");
 }
 
 static void test_no_zicboz(void *arg)
@@ -81,6 +85,30 @@ static bool is_power_of_2(__u64 n)
 	return n != 0 && (n & (n - 1)) == 0;
 }
 
+static void test_zicbom(void *arg)
+{
+	struct riscv_hwprobe pair = {
+		.key = RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE,
+	};
+	cpu_set_t *cpus = (cpu_set_t *)arg;
+	__u64 block_size;
+	long rc;
+
+	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_ZICBOM_BLOCK_SIZE &&
+			 is_power_of_2(block_size), "Zicbom block size\n");
+	ksft_print_msg("Zicbom block size: %llu\n", block_size);
+
+	illegal_insn = false;
+	cbo_clean(&mem[block_size]);
+	ksft_test_result(!illegal_insn, "cbo.clean\n");
+
+	illegal_insn = false;
+	cbo_flush(&mem[block_size]);
+	ksft_test_result(!illegal_insn, "cbo.flush\n");
+}
+
 static void test_zicboz(void *arg)
 {
 	struct riscv_hwprobe pair = {
@@ -129,7 +157,7 @@ static void test_zicboz(void *arg)
 	ksft_test_result_pass("cbo.zero check\n");
 }
 
-static void check_no_zicboz_cpus(cpu_set_t *cpus)
+static void check_no_zicbo_cpus(cpu_set_t *cpus, __u64 cbo)
 {
 	struct riscv_hwprobe pair = {
 		.key = RISCV_HWPROBE_KEY_IMA_EXT_0,
@@ -137,6 +165,7 @@ static void check_no_zicboz_cpus(cpu_set_t *cpus)
 	cpu_set_t one_cpu;
 	int i = 0, c = 0;
 	long rc;
+	char *cbostr;
 
 	while (i++ < CPU_COUNT(cpus)) {
 		while (!CPU_ISSET(c, cpus))
@@ -148,10 +177,13 @@ static void check_no_zicboz_cpus(cpu_set_t *cpus)
 		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);
 
-		if (pair.value & RISCV_HWPROBE_EXT_ZICBOZ)
-			ksft_exit_fail_msg("Zicboz is only present on a subset of harts.\n"
-					   "Use taskset to select a set of harts where Zicboz\n"
-					   "presence (present or not) is consistent for each hart\n");
+		cbostr = cbo == RISCV_HWPROBE_EXT_ZICBOZ ? "Zicboz" : "Zicbom";
+
+		if (pair.value & cbo)
+			ksft_exit_fail_msg("%s is only present on a subset of harts.\n"
+					   "Use taskset to select a set of harts where %s\n"
+					   "presence (present or not) is consistent for each hart\n",
+					   cbostr, cbostr);
 		++c;
 	}
 }
@@ -159,7 +191,9 @@ static void check_no_zicboz_cpus(cpu_set_t *cpus)
 enum {
 	TEST_ZICBOZ,
 	TEST_NO_ZICBOZ,
+	TEST_ZICBOM,
 	TEST_NO_ZICBOM,
+	TEST_NO_ZICBOINVAL,
 };
 
 static struct test_info {
@@ -169,7 +203,9 @@ static struct test_info {
 } tests[] = {
 	[TEST_ZICBOZ]		= { .nr_tests = 3, test_zicboz },
 	[TEST_NO_ZICBOZ]	= { .nr_tests = 1, test_no_zicboz },
-	[TEST_NO_ZICBOM]	= { .nr_tests = 3, test_no_zicbom },
+	[TEST_ZICBOM]		= { .nr_tests = 3, test_zicbom },
+	[TEST_NO_ZICBOM]	= { .nr_tests = 2, test_no_zicbom },
+	[TEST_NO_ZICBOINVAL]	= { .nr_tests = 1, test_no_cbo_inval },
 };
 
 int main(int argc, char **argv)
@@ -189,6 +225,7 @@ int main(int argc, char **argv)
 		assert(rc == 0);
 		tests[TEST_NO_ZICBOZ].enabled = true;
 		tests[TEST_NO_ZICBOM].enabled = true;
+		tests[TEST_NO_ZICBOINVAL].enabled = true;
 	}
 
 	rc = sched_getaffinity(0, sizeof(cpu_set_t), &cpus);
@@ -206,7 +243,14 @@ int main(int argc, char **argv)
 		tests[TEST_ZICBOZ].enabled = true;
 		tests[TEST_NO_ZICBOZ].enabled = false;
 	} else {
-		check_no_zicboz_cpus(&cpus);
+		check_no_zicbo_cpus(&cpus, RISCV_HWPROBE_EXT_ZICBOZ);
+	}
+
+	if (pair.value & RISCV_HWPROBE_EXT_ZICBOM) {
+		tests[TEST_ZICBOM].enabled = true;
+		tests[TEST_NO_ZICBOM].enabled = false;
+	} else {
+		check_no_zicbo_cpus(&cpus, RISCV_HWPROBE_EXT_ZICBOM);
 	}
 
 	for (i = 0; i < ARRAY_SIZE(tests); ++i)
-- 
2.39.2

Re: [PATCH v4 2/3] RISC-V: hwprobe: Expose Zicbom extension and its block size

[Samuel Holland]

Hi Yunhui,

On 2025-01-13 8:19 PM, Yunhui Cui wrote:
> Expose Zicbom through hwprobe and also provide a key to extract its
> respective block size.
> 
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> ---
>  Documentation/arch/riscv/hwprobe.rst  | 6 ++++++
>  arch/riscv/include/asm/hwprobe.h      | 2 +-
>  arch/riscv/include/uapi/asm/hwprobe.h | 2 ++
>  arch/riscv/kernel/sys_hwprobe.c       | 6 ++++++
>  4 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> index 955fbcd19ce9..0ea7754b2049 100644
> --- a/Documentation/arch/riscv/hwprobe.rst
> +++ b/Documentation/arch/riscv/hwprobe.rst
> @@ -242,6 +242,9 @@ The following keys are defined:
>    * :c:macro:`RISCV_HWPROBE_EXT_SUPM`: The Supm extension is supported as
>         defined in version 1.0 of the RISC-V Pointer Masking extensions.
>  
> +  * :c:macro:`RISCV_HWPROBE_EXT_ZICBOM`: The Zicbom extension is supported, as
> +       ratified in commit 3dd606f ("Create cmobase-v1.0.pdf") of riscv-CMOs.
> +
>  * :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: Deprecated.  Returns similar values to
>       :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_SCALAR_PERF`, but the key was
>       mistakenly classified as a bitmask rather than a value.
> @@ -281,6 +284,9 @@ The following keys are defined:
>  * :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_VECTOR_PERF`: An enum value describing the
>       performance of misaligned vector accesses on the selected set of processors.
>  
> +* :c:macro:`RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE`: An unsigned int which
> +  represents the size of the Zicbom block in bytes.
> +
>    * :c:macro:`RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN`: The performance of misaligned
>      vector accesses is unknown.

The new key needs to go further down, below this list of possible values for the
previous key.

Regards,
Samuel

>  
> diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
> index 1ce1df6d0ff3..89379f9a2e6e 100644
> --- a/arch/riscv/include/asm/hwprobe.h
> +++ b/arch/riscv/include/asm/hwprobe.h
> @@ -8,7 +8,7 @@
>  
>  #include <uapi/asm/hwprobe.h>
>  
> -#define RISCV_HWPROBE_MAX_KEY 10
> +#define RISCV_HWPROBE_MAX_KEY 11
>  
>  static inline bool riscv_hwprobe_key_is_valid(__s64 key)
>  {
> diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> index 3af142b99f77..b15c0bd83ef2 100644
> --- a/arch/riscv/include/uapi/asm/hwprobe.h
> +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> @@ -73,6 +73,7 @@ struct riscv_hwprobe {
>  #define		RISCV_HWPROBE_EXT_ZCMOP		(1ULL << 47)
>  #define		RISCV_HWPROBE_EXT_ZAWRS		(1ULL << 48)
>  #define		RISCV_HWPROBE_EXT_SUPM		(1ULL << 49)
> +#define		RISCV_HWPROBE_EXT_ZICBOM	(1ULL << 50)
>  #define RISCV_HWPROBE_KEY_CPUPERF_0	5
>  #define		RISCV_HWPROBE_MISALIGNED_UNKNOWN	(0 << 0)
>  #define		RISCV_HWPROBE_MISALIGNED_EMULATED	(1 << 0)
> @@ -94,6 +95,7 @@ struct riscv_hwprobe {
>  #define		RISCV_HWPROBE_MISALIGNED_VECTOR_SLOW		2
>  #define		RISCV_HWPROBE_MISALIGNED_VECTOR_FAST		3
>  #define		RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED	4
> +#define RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE	11
>  /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
>  
>  /* Flags */
> diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> index cb93adfffc48..04150e62f998 100644
> --- a/arch/riscv/kernel/sys_hwprobe.c
> +++ b/arch/riscv/kernel/sys_hwprobe.c
> @@ -106,6 +106,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
>  		EXT_KEY(ZCA);
>  		EXT_KEY(ZCB);
>  		EXT_KEY(ZCMOP);
> +		EXT_KEY(ZICBOM);
>  		EXT_KEY(ZICBOZ);
>  		EXT_KEY(ZICOND);
>  		EXT_KEY(ZIHINTNTL);
> @@ -278,6 +279,11 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
>  		if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOZ))
>  			pair->value = riscv_cboz_block_size;
>  		break;
> +	case RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE:
> +		pair->value = 0;
> +		if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOM))
> +			pair->value = riscv_cbom_block_size;
> +		break;
>  	case RISCV_HWPROBE_KEY_HIGHEST_VIRT_ADDRESS:
>  		pair->value = user_max_virt_addr();
>  		break;

Re: [PATCH v4 3/3] RISC-V: selftests: Add TEST_ZICBOM into CBO tests

[Samuel Holland]

On 2025-01-13 8:19 PM, Yunhui Cui wrote:
> Add test for Zicbom and its block size into CBO tests, when
> Zicbom is present, test that cbo.clean/flush may be issued and works.
> As the software can't verify the clean/flush functions, we just judged
> that cbo.clean/flush isn't executed illegally.
> 
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> ---
>  tools/testing/selftests/riscv/hwprobe/cbo.c | 66 +++++++++++++++++----
>  1 file changed, 55 insertions(+), 11 deletions(-)

Reviewed-by: Samuel Holland <samuel.holland@sifive.com>

Re: [PATCH v4 3/3] RISC-V: selftests: Add TEST_ZICBOM into CBO tests

[Andrew Jones]

On Tue, Jan 14, 2025 at 10:19:36AM +0800, Yunhui Cui wrote:
> Add test for Zicbom and its block size into CBO tests, when
> Zicbom is present, test that cbo.clean/flush may be issued and works.
> As the software can't verify the clean/flush functions, we just judged
> that cbo.clean/flush isn't executed illegally.
> 
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> ---
>  tools/testing/selftests/riscv/hwprobe/cbo.c | 66 +++++++++++++++++----
>  1 file changed, 55 insertions(+), 11 deletions(-)
> 
> diff --git a/tools/testing/selftests/riscv/hwprobe/cbo.c b/tools/testing/selftests/riscv/hwprobe/cbo.c
> index a40541bb7c7d..dec510291ab8 100644
> --- a/tools/testing/selftests/riscv/hwprobe/cbo.c
> +++ b/tools/testing/selftests/riscv/hwprobe/cbo.c
> @@ -50,6 +50,14 @@ 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 test_no_cbo_inval(void *arg)
> +{
> +	ksft_print_msg("Testing cbo.inval instruction remain privileged\n");
> +	illegal_insn = false;
> +	cbo_inval(&mem[0]);
> +	ksft_test_result(illegal_insn, "No cbo.inval\n");
> +}
> +
>  static void test_no_zicbom(void *arg)
>  {
>  	ksft_print_msg("Testing Zicbom instructions remain privileged\n");
> @@ -61,10 +69,6 @@ static void test_no_zicbom(void *arg)
>  	illegal_insn = false;
>  	cbo_flush(&mem[0]);
>  	ksft_test_result(illegal_insn, "No cbo.flush\n");
> -
> -	illegal_insn = false;
> -	cbo_inval(&mem[0]);
> -	ksft_test_result(illegal_insn, "No cbo.inval\n");
>  }
>  
>  static void test_no_zicboz(void *arg)
> @@ -81,6 +85,30 @@ static bool is_power_of_2(__u64 n)
>  	return n != 0 && (n & (n - 1)) == 0;
>  }
>  
> +static void test_zicbom(void *arg)
> +{
> +	struct riscv_hwprobe pair = {
> +		.key = RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE,
> +	};
> +	cpu_set_t *cpus = (cpu_set_t *)arg;
> +	__u64 block_size;
> +	long rc;
> +
> +	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_ZICBOM_BLOCK_SIZE &&
> +			 is_power_of_2(block_size), "Zicbom block size\n");
> +	ksft_print_msg("Zicbom block size: %llu\n", block_size);
> +
> +	illegal_insn = false;
> +	cbo_clean(&mem[block_size]);
> +	ksft_test_result(!illegal_insn, "cbo.clean\n");
> +
> +	illegal_insn = false;
> +	cbo_flush(&mem[block_size]);
> +	ksft_test_result(!illegal_insn, "cbo.flush\n");
> +}
> +
>  static void test_zicboz(void *arg)
>  {
>  	struct riscv_hwprobe pair = {
> @@ -129,7 +157,7 @@ static void test_zicboz(void *arg)
>  	ksft_test_result_pass("cbo.zero check\n");
>  }
>  
> -static void check_no_zicboz_cpus(cpu_set_t *cpus)
> +static void check_no_zicbo_cpus(cpu_set_t *cpus, __u64 cbo)
>  {
>  	struct riscv_hwprobe pair = {
>  		.key = RISCV_HWPROBE_KEY_IMA_EXT_0,
> @@ -137,6 +165,7 @@ static void check_no_zicboz_cpus(cpu_set_t *cpus)
>  	cpu_set_t one_cpu;
>  	int i = 0, c = 0;
>  	long rc;
> +	char *cbostr;
>  
>  	while (i++ < CPU_COUNT(cpus)) {
>  		while (!CPU_ISSET(c, cpus))
> @@ -148,10 +177,13 @@ static void check_no_zicboz_cpus(cpu_set_t *cpus)
>  		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);
>  
> -		if (pair.value & RISCV_HWPROBE_EXT_ZICBOZ)
> -			ksft_exit_fail_msg("Zicboz is only present on a subset of harts.\n"
> -					   "Use taskset to select a set of harts where Zicboz\n"
> -					   "presence (present or not) is consistent for each hart\n");
> +		cbostr = cbo == RISCV_HWPROBE_EXT_ZICBOZ ? "Zicboz" : "Zicbom";
> +
> +		if (pair.value & cbo)
> +			ksft_exit_fail_msg("%s is only present on a subset of harts.\n"
> +					   "Use taskset to select a set of harts where %s\n"
> +					   "presence (present or not) is consistent for each hart\n",
> +					   cbostr, cbostr);
>  		++c;
>  	}
>  }
> @@ -159,7 +191,9 @@ static void check_no_zicboz_cpus(cpu_set_t *cpus)
>  enum {
>  	TEST_ZICBOZ,
>  	TEST_NO_ZICBOZ,
> +	TEST_ZICBOM,
>  	TEST_NO_ZICBOM,
> +	TEST_NO_ZICBOINVAL,

nit: TEST_NO_CBO_INVAL would be a better name.

>  };
>  
>  static struct test_info {
> @@ -169,7 +203,9 @@ static struct test_info {
>  } tests[] = {
>  	[TEST_ZICBOZ]		= { .nr_tests = 3, test_zicboz },
>  	[TEST_NO_ZICBOZ]	= { .nr_tests = 1, test_no_zicboz },
> -	[TEST_NO_ZICBOM]	= { .nr_tests = 3, test_no_zicbom },
> +	[TEST_ZICBOM]		= { .nr_tests = 3, test_zicbom },
> +	[TEST_NO_ZICBOM]	= { .nr_tests = 2, test_no_zicbom },
> +	[TEST_NO_ZICBOINVAL]	= { .nr_tests = 1, test_no_cbo_inval },
>  };
>  
>  int main(int argc, char **argv)
> @@ -189,6 +225,7 @@ int main(int argc, char **argv)
>  		assert(rc == 0);
>  		tests[TEST_NO_ZICBOZ].enabled = true;
>  		tests[TEST_NO_ZICBOM].enabled = true;
> +		tests[TEST_NO_ZICBOINVAL].enabled = true;
>  	}
>  
>  	rc = sched_getaffinity(0, sizeof(cpu_set_t), &cpus);
> @@ -206,7 +243,14 @@ int main(int argc, char **argv)
>  		tests[TEST_ZICBOZ].enabled = true;
>  		tests[TEST_NO_ZICBOZ].enabled = false;
>  	} else {
> -		check_no_zicboz_cpus(&cpus);
> +		check_no_zicbo_cpus(&cpus, RISCV_HWPROBE_EXT_ZICBOZ);
> +	}
> +
> +	if (pair.value & RISCV_HWPROBE_EXT_ZICBOM) {
> +		tests[TEST_ZICBOM].enabled = true;
> +		tests[TEST_NO_ZICBOM].enabled = false;
> +	} else {
> +		check_no_zicbo_cpus(&cpus, RISCV_HWPROBE_EXT_ZICBOM);
>  	}
>  
>  	for (i = 0; i < ARRAY_SIZE(tests); ++i)
> -- 
> 2.39.2
>

Besides the nit,

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

Re: [External] Re: [PATCH v4 2/3] RISC-V: hwprobe: Expose Zicbom extension and its block size

[yunhui cui]

Hi Samuel，

On Tue, Jan 14, 2025 at 1:28 PM Samuel Holland
<samuel.holland@sifive.com> wrote:
>
> Hi Yunhui,
>
> On 2025-01-13 8:19 PM, Yunhui Cui wrote:
> > Expose Zicbom through hwprobe and also provide a key to extract its
> > respective block size.
> >
> > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > ---
> >  Documentation/arch/riscv/hwprobe.rst  | 6 ++++++
> >  arch/riscv/include/asm/hwprobe.h      | 2 +-
> >  arch/riscv/include/uapi/asm/hwprobe.h | 2 ++
> >  arch/riscv/kernel/sys_hwprobe.c       | 6 ++++++
> >  4 files changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> > index 955fbcd19ce9..0ea7754b2049 100644
> > --- a/Documentation/arch/riscv/hwprobe.rst
> > +++ b/Documentation/arch/riscv/hwprobe.rst
> > @@ -242,6 +242,9 @@ The following keys are defined:
> >    * :c:macro:`RISCV_HWPROBE_EXT_SUPM`: The Supm extension is supported as
> >         defined in version 1.0 of the RISC-V Pointer Masking extensions.
> >
> > +  * :c:macro:`RISCV_HWPROBE_EXT_ZICBOM`: The Zicbom extension is supported, as
> > +       ratified in commit 3dd606f ("Create cmobase-v1.0.pdf") of riscv-CMOs.
> > +
> >  * :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: Deprecated.  Returns similar values to
> >       :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_SCALAR_PERF`, but the key was
> >       mistakenly classified as a bitmask rather than a value.
> > @@ -281,6 +284,9 @@ The following keys are defined:
> >  * :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_VECTOR_PERF`: An enum value describing the
> >       performance of misaligned vector accesses on the selected set of processors.
> >
> > +* :c:macro:`RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE`: An unsigned int which
> > +  represents the size of the Zicbom block in bytes.
> > +
> >    * :c:macro:`RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN`: The performance of misaligned
> >      vector accesses is unknown.
>
> The new key needs to go further down, below this list of possible values for the
> previous key.
I guess you mean to put it after
RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED, right?

>
> Regards,
> Samuel
>
> >
> > diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
> > index 1ce1df6d0ff3..89379f9a2e6e 100644
> > --- a/arch/riscv/include/asm/hwprobe.h
> > +++ b/arch/riscv/include/asm/hwprobe.h
> > @@ -8,7 +8,7 @@
> >
> >  #include <uapi/asm/hwprobe.h>
> >
> > -#define RISCV_HWPROBE_MAX_KEY 10
> > +#define RISCV_HWPROBE_MAX_KEY 11
> >
> >  static inline bool riscv_hwprobe_key_is_valid(__s64 key)
> >  {
> > diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> > index 3af142b99f77..b15c0bd83ef2 100644
> > --- a/arch/riscv/include/uapi/asm/hwprobe.h
> > +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> > @@ -73,6 +73,7 @@ struct riscv_hwprobe {
> >  #define              RISCV_HWPROBE_EXT_ZCMOP         (1ULL << 47)
> >  #define              RISCV_HWPROBE_EXT_ZAWRS         (1ULL << 48)
> >  #define              RISCV_HWPROBE_EXT_SUPM          (1ULL << 49)
> > +#define              RISCV_HWPROBE_EXT_ZICBOM        (1ULL << 50)
> >  #define RISCV_HWPROBE_KEY_CPUPERF_0  5
> >  #define              RISCV_HWPROBE_MISALIGNED_UNKNOWN        (0 << 0)
> >  #define              RISCV_HWPROBE_MISALIGNED_EMULATED       (1 << 0)
> > @@ -94,6 +95,7 @@ struct riscv_hwprobe {
> >  #define              RISCV_HWPROBE_MISALIGNED_VECTOR_SLOW            2
> >  #define              RISCV_HWPROBE_MISALIGNED_VECTOR_FAST            3
> >  #define              RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED     4
> > +#define RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE  11
> >  /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
> >
> >  /* Flags */
> > diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> > index cb93adfffc48..04150e62f998 100644
> > --- a/arch/riscv/kernel/sys_hwprobe.c
> > +++ b/arch/riscv/kernel/sys_hwprobe.c
> > @@ -106,6 +106,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
> >               EXT_KEY(ZCA);
> >               EXT_KEY(ZCB);
> >               EXT_KEY(ZCMOP);
> > +             EXT_KEY(ZICBOM);
> >               EXT_KEY(ZICBOZ);
> >               EXT_KEY(ZICOND);
> >               EXT_KEY(ZIHINTNTL);
> > @@ -278,6 +279,11 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
> >               if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOZ))
> >                       pair->value = riscv_cboz_block_size;
> >               break;
> > +     case RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE:
> > +             pair->value = 0;
> > +             if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOM))
> > +                     pair->value = riscv_cbom_block_size;
> > +             break;
> >       case RISCV_HWPROBE_KEY_HIGHEST_VIRT_ADDRESS:
> >               pair->value = user_max_virt_addr();
> >               break;
>

Thanks,
Yunhui

Re: [External] Re: [PATCH v4 2/3] RISC-V: hwprobe: Expose Zicbom extension and its block size

[Andrew Jones]

On Tue, Jan 14, 2025 at 08:17:02PM +0800, yunhui cui wrote:
> Hi Samuel，
> 
> On Tue, Jan 14, 2025 at 1:28 PM Samuel Holland
> <samuel.holland@sifive.com> wrote:
> >
> > Hi Yunhui,
> >
> > On 2025-01-13 8:19 PM, Yunhui Cui wrote:
> > > Expose Zicbom through hwprobe and also provide a key to extract its
> > > respective block size.
> > >
> > > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > > ---
> > >  Documentation/arch/riscv/hwprobe.rst  | 6 ++++++
> > >  arch/riscv/include/asm/hwprobe.h      | 2 +-
> > >  arch/riscv/include/uapi/asm/hwprobe.h | 2 ++
> > >  arch/riscv/kernel/sys_hwprobe.c       | 6 ++++++
> > >  4 files changed, 15 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> > > index 955fbcd19ce9..0ea7754b2049 100644
> > > --- a/Documentation/arch/riscv/hwprobe.rst
> > > +++ b/Documentation/arch/riscv/hwprobe.rst
> > > @@ -242,6 +242,9 @@ The following keys are defined:
> > >    * :c:macro:`RISCV_HWPROBE_EXT_SUPM`: The Supm extension is supported as
> > >         defined in version 1.0 of the RISC-V Pointer Masking extensions.
> > >
> > > +  * :c:macro:`RISCV_HWPROBE_EXT_ZICBOM`: The Zicbom extension is supported, as
> > > +       ratified in commit 3dd606f ("Create cmobase-v1.0.pdf") of riscv-CMOs.
> > > +
> > >  * :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: Deprecated.  Returns similar values to
> > >       :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_SCALAR_PERF`, but the key was
> > >       mistakenly classified as a bitmask rather than a value.
> > > @@ -281,6 +284,9 @@ The following keys are defined:
> > >  * :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_VECTOR_PERF`: An enum value describing the
> > >       performance of misaligned vector accesses on the selected set of processors.
> > >
> > > +* :c:macro:`RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE`: An unsigned int which
> > > +  represents the size of the Zicbom block in bytes.
> > > +
> > >    * :c:macro:`RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN`: The performance of misaligned
> > >      vector accesses is unknown.
> >
> > The new key needs to go further down, below this list of possible values for the
> > previous key.
> I guess you mean to put it after
> RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED, right?

Yes, notice how all the RISCV_HWPROBE_MISALIGNED_VECTOR_* defines are
indented under RISCV_HWPROBE_KEY_MISALIGNED_VECTOR_PERF indicating
they're part of the RISCV_HWPROBE_KEY_MISALIGNED_VECTOR_PERF group.

Thanks,
drew

> 
> >
> > Regards,
> > Samuel
> >
> > >
> > > diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
> > > index 1ce1df6d0ff3..89379f9a2e6e 100644
> > > --- a/arch/riscv/include/asm/hwprobe.h
> > > +++ b/arch/riscv/include/asm/hwprobe.h
> > > @@ -8,7 +8,7 @@
> > >
> > >  #include <uapi/asm/hwprobe.h>
> > >
> > > -#define RISCV_HWPROBE_MAX_KEY 10
> > > +#define RISCV_HWPROBE_MAX_KEY 11
> > >
> > >  static inline bool riscv_hwprobe_key_is_valid(__s64 key)
> > >  {
> > > diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> > > index 3af142b99f77..b15c0bd83ef2 100644
> > > --- a/arch/riscv/include/uapi/asm/hwprobe.h
> > > +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> > > @@ -73,6 +73,7 @@ struct riscv_hwprobe {
> > >  #define              RISCV_HWPROBE_EXT_ZCMOP         (1ULL << 47)
> > >  #define              RISCV_HWPROBE_EXT_ZAWRS         (1ULL << 48)
> > >  #define              RISCV_HWPROBE_EXT_SUPM          (1ULL << 49)
> > > +#define              RISCV_HWPROBE_EXT_ZICBOM        (1ULL << 50)
> > >  #define RISCV_HWPROBE_KEY_CPUPERF_0  5
> > >  #define              RISCV_HWPROBE_MISALIGNED_UNKNOWN        (0 << 0)
> > >  #define              RISCV_HWPROBE_MISALIGNED_EMULATED       (1 << 0)
> > > @@ -94,6 +95,7 @@ struct riscv_hwprobe {
> > >  #define              RISCV_HWPROBE_MISALIGNED_VECTOR_SLOW            2
> > >  #define              RISCV_HWPROBE_MISALIGNED_VECTOR_FAST            3
> > >  #define              RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED     4
> > > +#define RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE  11
> > >  /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
> > >
> > >  /* Flags */
> > > diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> > > index cb93adfffc48..04150e62f998 100644
> > > --- a/arch/riscv/kernel/sys_hwprobe.c
> > > +++ b/arch/riscv/kernel/sys_hwprobe.c
> > > @@ -106,6 +106,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
> > >               EXT_KEY(ZCA);
> > >               EXT_KEY(ZCB);
> > >               EXT_KEY(ZCMOP);
> > > +             EXT_KEY(ZICBOM);
> > >               EXT_KEY(ZICBOZ);
> > >               EXT_KEY(ZICOND);
> > >               EXT_KEY(ZIHINTNTL);
> > > @@ -278,6 +279,11 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
> > >               if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOZ))
> > >                       pair->value = riscv_cboz_block_size;
> > >               break;
> > > +     case RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE:
> > > +             pair->value = 0;
> > > +             if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOM))
> > > +                     pair->value = riscv_cbom_block_size;
> > > +             break;
> > >       case RISCV_HWPROBE_KEY_HIGHEST_VIRT_ADDRESS:
> > >               pair->value = user_max_virt_addr();
> > >               break;
> >
> 
> Thanks,
> Yunhui