[1/3] riscv: ptrace: add regs_set_register()

Commit Message

Ben Dooks Sept. 17, 2024, 1:08 p.m. UTC

Since we have regs_get_register() and we could use the set counterpart
for things like fixing up traps, add regs_set_register() to set a pt_regs
value from offset.

Signed-off-by: Ben Dooks <[e-mail]>
---
 arch/riscv/include/asm/ptrace.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Patch

diff --git a/arch/riscv/include/asm/ptrace.h b/arch/riscv/include/asm/ptrace.h
index b5b0adcc85c1..66fc1795141d 100644
--- a/arch/riscv/include/asm/ptrace.h
+++ b/arch/riscv/include/asm/ptrace.h
@@ -143,6 +143,26 @@  static inline unsigned long regs_get_register(struct pt_regs *regs,
 	return *(unsigned long *)((unsigned long)regs + offset);
 }
 
+/**
+ * regs_set_register() - set register value from its offset
+ * @regs:	pt_regs from which register value is gotten
+ * @offset:	offset of the register.
+ * @to:		value to set register to
+ *
+ * regs_set_register sets the value @to to a register whose offset from @regs.
+ * The @offset is the offset of the register in struct pt_regs.
+ * If @offset is bigger than MAX_REG_OFFSET, this will ignore the write.
+ */
+static inline void regs_set_register(struct pt_regs *regs,
+				     unsigned int offset,
+				     unsigned long to)
+{
+	if (unlikely(offset > MAX_REG_OFFSET))
+		return;
+
+	*(unsigned long *)((unsigned long)regs + offset) = to;
+}
+
 /**
  * regs_get_kernel_argument() - get Nth function argument in kernel
  * @regs:       pt_regs of that context