[PATCH] lib: sbi: Fix sign-extension in sbi_misaligned_load_handler()

Anup Patel anup.patel at wdc.com
Sat Dec 19 23:17:37 EST 2020


The misaligned load emulation does not sign-extend values correctly
due to missing sign typecast in value passed to the SET_RD() macro.

A very easy way to reproduce this issue is to load 16-bit value
0xff1e from a byte aligned address using LH instruction on hardware
lacking misaligned load/store.

This patch fixes sbi_misaligned_load_handler() for above issue.

Signed-off-by: Anup Patel <anup.patel at wdc.com>
---
 lib/sbi/sbi_misaligned_ldst.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/sbi/sbi_misaligned_ldst.c b/lib/sbi/sbi_misaligned_ldst.c
index 964a372..77d6d46 100644
--- a/lib/sbi/sbi_misaligned_ldst.c
+++ b/lib/sbi/sbi_misaligned_ldst.c
@@ -128,7 +128,7 @@ int sbi_misaligned_load_handler(ulong addr, ulong tval2, ulong tinst,
 	}
 
 	if (!fp)
-		SET_RD(insn, regs, val.data_ulong << shift >> shift);
+		SET_RD(insn, regs, (long)val.data_ulong << shift >> shift);
 #ifdef __riscv_flen
 	else if (len == 8)
 		SET_F64_RD(insn, regs, val.data_u64);
-- 
2.25.1




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