From 1446b26f7652124f0e3e98c348cdbc4fc55eb0cb Mon Sep 17 00:00:00 2001 From: Lukas Auer Date: Sun, 17 Mar 2019 19:28:36 +0100 Subject: [PATCH] riscv: save hart ID in register tp instead of s0 The hart ID passed by the previous boot stage is currently stored in register s0. If we divert the control flow inside a function, which is required as part of multi-hart support, the function epilog may not be called, clobbering register s0. Save the hart ID in the unallocatable register tp instead to protect the hart ID. Signed-off-by: Lukas Auer Reviewed-by: Bin Meng Reviewed-by: Rick Chen Reviewed-by: Anup Patel --- arch/riscv/cpu/start.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index a30f6f7194..bcc0ff696d 100644 --- a/arch/riscv/cpu/start.S +++ b/arch/riscv/cpu/start.S @@ -36,7 +36,7 @@ .globl _start _start: /* save hart id and dtb pointer */ - mv s0, a0 + mv tp, a0 mv s1, a1 la t0, trap_entry @@ -64,7 +64,7 @@ call_board_init_f_0: jal board_init_f_init_reserve /* save the boot hart id to global_data */ - SREG s0, GD_BOOT_HART(gp) + SREG tp, GD_BOOT_HART(gp) /* Enable cache */ jal icache_enable