[v7,1/3] RISC-V: Enable cbo.clean/flush in usermode

Commit Message

Yunhui Cui Feb. 26, 2025, 6:32 a.m. UTC

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 <[e-mail]>
Signed-off-by: Yunhui Cui <[e-mail]>
---
 arch/riscv/kernel/cpufeature.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Patch

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 40ac72e407b6..a8b726d0dab8 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -32,6 +32,7 @@ 
 #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;
 
@@ -91,6 +92,8 @@  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;
 }
 
@@ -1001,6 +1004,11 @@  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