riscv: signal: fix signal frame size

commit aa49bc2 upstream.

The signal context of certain RISC-V extensions will be appended after
struct __riscv_extra_ext_header, which already includes an empty context
header. Therefore, there is no need to preserve a separate hdr for the
END of signal context.

Fixes: 8ee0b41 ("riscv: signal: Add sigcontext save/restore for vector")
Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Andy Chiu <AndybnAC@gmail.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20241220083926.19453-2-yongxuan.wang@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: yong-xuan

arch/riscv/kernel/signal.c

@@ -215,12 +215,6 @@ static size_t get_rt_frame_size(bool cal_all)
 		if (cal_all || riscv_v_vstate_query(task_pt_regs(current)))
 			total_context_size += riscv_v_sc_size;
 	}
-	/*
-	 * Preserved a __riscv_ctx_hdr for END signal context header if an
-	 * extension uses __riscv_extra_ext_header
-	 */
-	if (total_context_size)
-		total_context_size += sizeof(struct __riscv_ctx_hdr);
 
 	frame_size += total_context_size;