[PATCH] lib: sbi: fix undefined behavior in signed shifts in sbi_hart.c, sbi_ecall_interface.h

[Marcos Oduardo]

UBSan detected undefined behavior in sbi_hart.c and sbi_fwft.c (in the case
of sbi_fwft.c, the bug comes from a macro call defined at sbi_ecall_interface.h)
caused by shifting a signed integer into the sign bit (1 << 31)

This can be fixed by using the 1UL literal, ensuring defined arithmetic.

Please let me know if there’s any other most suitable solution for this bug.

Signed-off-by: Marcos Oduardo <marcos.oduardo at gmail.com>
---
 include/sbi/sbi_ecall_interface.h | 2 +-
 lib/sbi/sbi_hart.c                | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/sbi/sbi_ecall_interface.h b/include/sbi/sbi_ecall_interface.h
index 76624e3f..9a776f79 100644
--- a/include/sbi/sbi_ecall_interface.h
+++ b/include/sbi/sbi_ecall_interface.h
@@ -144,7 +144,7 @@ enum sbi_fwft_feature_t {
 	SBI_FWFT_GLOBAL_PLATFORM_END		= 0xffffffff,
 };
 
-#define SBI_FWFT_GLOBAL_FEATURE_BIT		(1 << 31)
+#define SBI_FWFT_GLOBAL_FEATURE_BIT		(1UL << 31)
 #define SBI_FWFT_PLATFORM_FEATURE_BIT		(1 << 30)
 
 #define SBI_FWFT_SET_FLAG_LOCK			(1 << 0)
diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index 60e95bca..99e13990 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -70,7 +70,7 @@ static void mstatus_init(struct sbi_scratch *scratch)
 	 */
 	mhpmevent_init_val |= (MHPMEVENT_OF | MHPMEVENT_MINH);
 	for (cidx = 0; cidx <= 28; cidx++) {
-		if (!(mhpm_mask & 1 << (cidx + 3)))
+		if (!(mhpm_mask & 1UL << (cidx + 3)))
 			continue;
 #if __riscv_xlen == 32
 		csr_write_num(CSR_MHPMEVENT3 + cidx,
-- 
2.53.0