[PATCH master] RISC-V: board-dt-2nd: move low level init into nonnaked function

[PATCH master] RISC-V: board-dt-2nd: move low level init into nonnaked function

[Ahmad Fatoum]

The generic DT image for RISC-V mimics a kernel image and specifies
a load offset that it expects to be honoured. The stack should then
grow down from the load address. This didn't work as intended though
with riscv64-linux-gnu-gcc (Debian 10.2.1-6), because of the entry
point's __naked attribute: local variables overwrote the first bytes
of the entry point. Fix this by using a noinline nonnaked function.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 arch/riscv/boot/board-dt-2nd.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/boot/board-dt-2nd.c b/arch/riscv/boot/board-dt-2nd.c
index f31c48a906c2..8b78e1b11d31 100644
--- a/arch/riscv/boot/board-dt-2nd.c
+++ b/arch/riscv/boot/board-dt-2nd.c
@@ -40,7 +40,8 @@ static const struct fdt_device_id console_ids[] = {
 	{ /* sentinel */ }
 };
 
-ENTRY_FUNCTION(start_dt_2nd, hartid, _fdt, a2)
+static void noinline __noreturn start_dt_2nd_nonnaked(unsigned long hartid,
+						      unsigned long _fdt)
 {
 	unsigned long membase, memsize, endmem, endfdt, uncompressed_len;
 	struct fdt_header *fdt = (void *)_fdt;
@@ -75,3 +76,8 @@ ENTRY_FUNCTION(start_dt_2nd, hartid, _fdt, a2)
 
 	barebox_riscv_supervisor_entry(membase, memsize, hartid, fdt);
 }
+
+ENTRY_FUNCTION(start_dt_2nd, hartid, _fdt, a2)
+{
+	start_dt_2nd_nonnaked(hartid, _fdt);
+}
-- 
2.30.2


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

Re: [PATCH master] RISC-V: board-dt-2nd: move low level init into nonnaked function

[Sascha Hauer]

On Thu, Sep 16, 2021 at 11:35:14AM +0200, Ahmad Fatoum wrote:
> The generic DT image for RISC-V mimics a kernel image and specifies
> a load offset that it expects to be honoured. The stack should then
> grow down from the load address. This didn't work as intended though
> with riscv64-linux-gnu-gcc (Debian 10.2.1-6), because of the entry
> point's __naked attribute: local variables overwrote the first bytes
> of the entry point. Fix this by using a noinline nonnaked function.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  arch/riscv/boot/board-dt-2nd.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)

Applied, thanks

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox