[PATCH v3 1/8] RISC-V: setup_c: avoid clearing BSS twice

[Stefan Kerkmann]

This commit duplicates what is already implemented for ARM(64)[1].
Currently setup_c() isn't called twice but might be in the future.

[1]: 11c389397c ("ARM: setup_c: avoid clearing BSS twice")

Signed-off-by: Stefan Kerkmann <s.kerkm...@pengutronix.de>
---
 arch/riscv/lib/setupc.S | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/lib/setupc.S b/arch/riscv/lib/setupc.S
index 423de4181e..5370e8a48e 100644
--- a/arch/riscv/lib/setupc.S
+++ b/arch/riscv/lib/setupc.S
@@ -10,13 +10,30 @@
  */
 .section .text.setup_c
 ENTRY(setup_c)
+       addi    sp, sp, -SZREG * 2
+       REG_S   ra, SZREG(sp)
+       lla     a0, bss_cleared
+       lw      a1, 0(a0)
+       bnez    a1, zeroed
        lla     a0, __bss_start
        li      a1, 0
        lla     a2, __bss_stop
        sub     a2, a2, a0
-       j       __memset
+       jal     __memset
+       lla     a0, bss_cleared
+       li      a1, 1
+       sw      a1, 0(a0)
+zeroed:
+       REG_L   ra, SZREG(sp)
+       addi    sp, sp, SZREG * 2
+       ret
 ENDPROC(setup_c)
 
+.section .data.bss_cleared
+.balign 4
+bss_cleared:
+       .word   0
+
 /*
  * void relocate_to_adr(unsigned long targetadr)
  *

-- 
2.47.3