From: Quan Zhou <[email protected]> Expose orig_a0 to userspace to ensure that users can modify the actual value of `a0` in the traced process through the ptrace(PTRACE_SETREGSET, ...) path.
The addition of orig_a0 also requires the following adjustments: 1) Adjust the position of orig_a0 in pt_regs to ensure correct copying. 2) MAX_REG_OFFSET should match the new bottom of pt_regs. Suggested-by: Charlie Jenkins <[email protected]> Signed-off-by: Quan Zhou <[email protected]> --- arch/riscv/include/asm/ptrace.h | 7 ++++--- arch/riscv/include/uapi/asm/ptrace.h | 2 ++ 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/riscv/include/asm/ptrace.h b/arch/riscv/include/asm/ptrace.h index b5b0adcc85c1..380cf54c1f3d 100644 --- a/arch/riscv/include/asm/ptrace.h +++ b/arch/riscv/include/asm/ptrace.h @@ -12,6 +12,7 @@ #ifndef __ASSEMBLY__ +/* MAX_REG_OFFSET should match the bottom of pt_regs */ struct pt_regs { unsigned long epc; unsigned long ra; @@ -45,12 +46,12 @@ struct pt_regs { unsigned long t4; unsigned long t5; unsigned long t6; + /* a0 value before the syscall */ + unsigned long orig_a0; /* Supervisor/Machine CSRs */ unsigned long status; unsigned long badaddr; unsigned long cause; - /* a0 value before the syscall */ - unsigned long orig_a0; }; #define PTRACE_SYSEMU 0x1f @@ -64,7 +65,7 @@ struct pt_regs { #define user_mode(regs) (((regs)->status & SR_PP) == 0) -#define MAX_REG_OFFSET offsetof(struct pt_regs, orig_a0) +#define MAX_REG_OFFSET offsetof(struct pt_regs, cause) /* Helpers for working with the instruction pointer */ static inline unsigned long instruction_pointer(struct pt_regs *regs) diff --git a/arch/riscv/include/uapi/asm/ptrace.h b/arch/riscv/include/uapi/asm/ptrace.h index a38268b19c3d..3e37f80cb3e8 100644 --- a/arch/riscv/include/uapi/asm/ptrace.h +++ b/arch/riscv/include/uapi/asm/ptrace.h @@ -54,6 +54,8 @@ struct user_regs_struct { unsigned long t4; unsigned long t5; unsigned long t6; + /* a0 value before the syscall */ + unsigned long orig_a0; }; struct __riscv_f_ext_state { -- 2.34.1
