[RFT,v11,1/8] arm64/gcs: Return a success value from gcs_alloc_thread_stack()

Commit Message

Mark Brown Oct. 5, 2024, 10:31 a.m. UTC

Currently as a result of templating from x86 code gcs_alloc_thread_stack()
returns a pointer as an unsigned int however on arm64 we don't actually use
this pointer value as anything other than a pass/fail flag. Simplify the
interface to just return an int with 0 on success and a negative error code
on failure.

Signed-off-by: Mark Brown <[e-mail]>
---
 arch/arm64/include/asm/gcs.h | 8 ++++----
 arch/arm64/kernel/process.c  | 8 ++++----
 arch/arm64/mm/gcs.c          | 8 ++++----
 3 files changed, 12 insertions(+), 12 deletions(-)

Comments

Deepak Gupta Oct. 30, 2024, 9:11 p.m. UTC | #1

On Sat, Oct 05, 2024 at 11:31:28AM +0100, Mark Brown wrote:
>Currently as a result of templating from x86 code gcs_alloc_thread_stack()
>returns a pointer as an unsigned int however on arm64 we don't actually use
>this pointer value as anything other than a pass/fail flag. Simplify the
>interface to just return an int with 0 on success and a negative error code
>on failure.
>
>Signed-off-by: Mark Brown <[e-mail]>
Acked-by: Deepak Gupta <[e-mail]>

Patch

diff --git a/arch/arm64/include/asm/gcs.h b/arch/arm64/include/asm/gcs.h
index f50660603ecf5dc09a92740062df3a089b02b219..d8923b5f03b776252aca76ce316ef57399d71fa9 100644
--- a/arch/arm64/include/asm/gcs.h
+++ b/arch/arm64/include/asm/gcs.h
@@ -64,8 +64,8 @@  static inline bool task_gcs_el0_enabled(struct task_struct *task)
 void gcs_set_el0_mode(struct task_struct *task);
 void gcs_free(struct task_struct *task);
 void gcs_preserve_current_state(void);
-unsigned long gcs_alloc_thread_stack(struct task_struct *tsk,
-				     const struct kernel_clone_args *args);
+int gcs_alloc_thread_stack(struct task_struct *tsk,
+			   const struct kernel_clone_args *args);
 
 static inline int gcs_check_locked(struct task_struct *task,
 				   unsigned long new_val)
@@ -91,8 +91,8 @@  static inline bool task_gcs_el0_enabled(struct task_struct *task)
 static inline void gcs_set_el0_mode(struct task_struct *task) { }
 static inline void gcs_free(struct task_struct *task) { }
 static inline void gcs_preserve_current_state(void) { }
-static inline unsigned long gcs_alloc_thread_stack(struct task_struct *tsk,
-						   const struct kernel_clone_args *args)
+static inline int gcs_alloc_thread_stack(struct task_struct *tsk,
+					 const struct kernel_clone_args *args)
 {
 	return -ENOTSUPP;
 }
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index fdd095480c3ffb8c13fd4e7c9abc79e88143e08b..8ebd11c29792524dfeeade9cc7826b007329aa6a 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -297,7 +297,7 @@  static void flush_gcs(void)
 static int copy_thread_gcs(struct task_struct *p,
 			   const struct kernel_clone_args *args)
 {
-	unsigned long gcs;
+	int ret;
 
 	if (!system_supports_gcs())
 		return 0;
@@ -305,9 +305,9 @@  static int copy_thread_gcs(struct task_struct *p,
 	p->thread.gcs_base = 0;
 	p->thread.gcs_size = 0;
 
-	gcs = gcs_alloc_thread_stack(p, args);
-	if (IS_ERR_VALUE(gcs))
-		return PTR_ERR((void *)gcs);
+	ret = gcs_alloc_thread_stack(p, args);
+	if (ret != 0)
+		return ret;
 
 	p->thread.gcs_el0_mode = current->thread.gcs_el0_mode;
 	p->thread.gcs_el0_locked = current->thread.gcs_el0_locked;
diff --git a/arch/arm64/mm/gcs.c b/arch/arm64/mm/gcs.c
index 5c46ec527b1cdaa8f52cff445d70ba0f8509d086..1f633a482558b59aac5427963d42b37fce08c8a6 100644
--- a/arch/arm64/mm/gcs.c
+++ b/arch/arm64/mm/gcs.c
@@ -38,8 +38,8 @@  static unsigned long gcs_size(unsigned long size)
 	return max(PAGE_SIZE, size);
 }
 
-unsigned long gcs_alloc_thread_stack(struct task_struct *tsk,
-				     const struct kernel_clone_args *args)
+int gcs_alloc_thread_stack(struct task_struct *tsk,
+			   const struct kernel_clone_args *args)
 {
 	unsigned long addr, size;
 
@@ -59,13 +59,13 @@  unsigned long gcs_alloc_thread_stack(struct task_struct *tsk,
 	size = gcs_size(size);
 	addr = alloc_gcs(0, size);
 	if (IS_ERR_VALUE(addr))
-		return addr;
+		return PTR_ERR((void *)addr);
 
 	tsk->thread.gcs_base = addr;
 	tsk->thread.gcs_size = size;
 	tsk->thread.gcspr_el0 = addr + size - sizeof(u64);
 
-	return addr;
+	return 0;
 }
 
 SYSCALL_DEFINE3(map_shadow_stack, unsigned long, addr, unsigned long, size, unsigned int, flags)