From 490571b6c05b9176886ce0b4241fc90d6b67c19b Mon Sep 17 00:00:00 2001 From: Michael Cardell Widerkrantz Date: Fri, 21 Oct 2022 16:27:23 +0200 Subject: [PATCH] Clear all RAM during start Since SRAM has some data remanence even without power it seems good hygien to clear all RAM when starting the device so as not to leak potential sensitive data between device apps. --- hw/application_fpga/fw/mta1_mkdf/start.S | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/hw/application_fpga/fw/mta1_mkdf/start.S b/hw/application_fpga/fw/mta1_mkdf/start.S index 7f34d3a..893b7ac 100644 --- a/hw/application_fpga/fw/mta1_mkdf/start.S +++ b/hw/application_fpga/fw/mta1_mkdf/start.S @@ -38,6 +38,14 @@ _start: li x30,0 li x31,0 + /* Clear all RAM */ + li a0, 0x40000000 // RAM base + li a1, 0x40020000 // To end of SRAM +clear: + sw zero, 0(a0) + addi a0, a0, 4 + blt a0, a1, clear + /* init stack to right under where we load app at 0x40010000 */ li sp, 0x4000fff0