[PATCH] RISC-V: fix stack clobbering in relocate_to_adr

[PATCH] RISC-V: fix stack clobbering in relocate_to_adr

[Ahmad Fatoum]

relocate_to_adr is decrementing two SZREG worth of stack space to be able
to spill two registers. An off-by-one led us to reference the word after
the reserved stack space, clobbering one word from the previous
function's stack frame unintentionally.

This this by decrementing the offsets by 1.

Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
 arch/riscv/lib/setupc.S | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/lib/setupc.S b/arch/riscv/lib/setupc.S
index d225186c79fd..423de4181ea6 100644
--- a/arch/riscv/lib/setupc.S
+++ b/arch/riscv/lib/setupc.S
@@ -32,14 +32,14 @@ ENTRY(relocate_to_adr)
 	/* adjust return address */
 	sub	ra, ra, a1		/* sub address where we are actually running */
 	add	ra, ra, a0		/* add address where we are going to run */
-	REG_S	ra, (SZREG * 2)(sp)
+	REG_S	ra, SZREG(sp)
 
 	beq	a0, a1, copied		/* skip if already at new address */
 
 	lla	a2, copied
 	sub	a2, a2, a1
 	add	a2, a2, a0
-	REG_S	a2, (SZREG * 1)(sp)
+	REG_S	a2, (sp)
 
 	lla	a2, __bss_start
 	sub	a2, a2, a1		 /* a2: size */
@@ -48,10 +48,10 @@ ENTRY(relocate_to_adr)
 
 	jal	sync_caches_for_execution
 
-	REG_L	a0, (SZREG * 1)(sp)
+	REG_L	a0, (sp)
 	jr	a0 			/* jump to relocated address */
 copied:
-	REG_L	ra, (SZREG * 2)(sp)
+	REG_L	ra, SZREG(sp)
 	addi	sp, sp, SZREG * 2
 	j	relocate_to_current_adr	/* relocate binary */
 ENDPROC(relocate_to_adr)
-- 
2.47.3