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

Ben Dooks
2024-09-17T13:33:13Z

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 <ben.dooks@codethink.co.uk>
---
arch/riscv/include/asm/ptrace.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

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
--
2.37.2.352.g3c44437643