[PATCH v2 07/10] riscv: Add a getter for user PMLEN support

[Guodong Xu]

From: Andrew Jones <andrew.jones at oss.qualcomm.com>

Querying whether a given user PMLEN is supported is needed for
RVA23U64 base detection from outside arch/riscv/kernel/process.c.
Add riscv_have_user_pmlen() to expose this.

Link: https://lore.kernel.org/linux-riscv/rfuwa7a3ebe76udmnwyrssjy7shkkgxntvhwzn6oquysj4tuyp@xzvpylcfhz53/
Signed-off-by: Andrew Jones <andrew.jones at oss.qualcomm.com>
[Guodong: replace exported booleans with getter per Andrew's suggestion]
Signed-off-by: Guodong Xu <guodong at riscstar.com>
---
v2: Add a getter for user PMLEN.
---
 arch/riscv/include/asm/processor.h |  4 ++++
 arch/riscv/kernel/process.c        | 12 ++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 812517b2cec13..febf51e127f70 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -214,6 +214,10 @@ long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg);
 long get_tagged_addr_ctrl(struct task_struct *task);
 #define SET_TAGGED_ADDR_CTRL(arg)	set_tagged_addr_ctrl(current, arg)
 #define GET_TAGGED_ADDR_CTRL()		get_tagged_addr_ctrl(current)
+
+bool riscv_have_user_pmlen(u8 len);
+#else
+static inline bool riscv_have_user_pmlen(u8 len) { return false; }
 #endif
 
 #endif /* __ASSEMBLER__ */
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index b2df7f72241a5..5d9cb108a6232 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -302,6 +302,18 @@ enum {
 static bool have_user_pmlen_7;
 static bool have_user_pmlen_16;
 
+bool riscv_have_user_pmlen(u8 len)
+{
+	switch (len) {
+	case PMLEN_7:
+		return have_user_pmlen_7;
+	case PMLEN_16:
+		return have_user_pmlen_16;
+	default:
+		return false;
+	}
+}
+
 /*
  * Control the relaxed ABI allowing tagged user addresses into the kernel.
  */

-- 
2.43.0