diff options
| author | Alexei Fedorov <Alexei.Fedorov@arm.com> | 2017-05-25 15:57:18 +0100 |
|---|---|---|
| committer | Evan Lloyd <evan.lloyd@arm.com> | 2018-09-07 11:51:22 +0100 |
| commit | 2431d00f34b513368100a39af4a4df20e25943ed (patch) | |
| tree | 45cc3dfb5d034c30292c57c9fdf49ef1bc04104d | |
| parent | e976e1fdb4f936352262122e5c3e80aff11bdc6b (diff) | |
| download | arm-trusted-firmware-2431d00f34b513368100a39af4a4df20e25943ed.tar.gz | |
ARM Platforms:Enable non-secure access to UART1
Adds an undocumented build option that enables non-secure access to
the PL011 UART1.
This allows a custom build where the UART can be used as a serial debug
port for WinDbg (or other debugger) connection.
This option is not documented in the user guide, as it is provided as a
convenience for Windows debugging, and not intended for general use.
In particular, enabling non-secure access to the UART might allow
a denial of service attack!
Change-Id: I4cd7d59c2cac897cc654ab5e1188ff031114ed3c
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>
| -rw-r--r-- | plat/arm/css/common/css_common.mk | 9 | ||||
| -rw-r--r-- | plat/arm/soc/common/soc_css_security.c | 8 |
2 files changed, 16 insertions, 1 deletions
diff --git a/plat/arm/css/common/css_common.mk b/plat/arm/css/common/css_common.mk index 29dd01d19..984c1da04 100644 --- a/plat/arm/css/common/css_common.mk +++ b/plat/arm/css/common/css_common.mk @@ -85,3 +85,12 @@ endif # Process CSS_USE_SCMI_SDS_DRIVER flag $(eval $(call assert_boolean,CSS_USE_SCMI_SDS_DRIVER)) $(eval $(call add_define,CSS_USE_SCMI_SDS_DRIVER)) + +# Process CSS_NON_SECURE_UART flag +# This undocumented build option is only to enable debug access to the UART +# from non secure code, which is useful on some platforms. +# Default (obviously) is off. +CSS_NON_SECURE_UART := 0 +$(eval $(call assert_boolean,CSS_NON_SECURE_UART)) +$(eval $(call add_define,CSS_NON_SECURE_UART)) + diff --git a/plat/arm/soc/common/soc_css_security.c b/plat/arm/soc/common/soc_css_security.c index 19bd76f80..f2296796c 100644 --- a/plat/arm/soc/common/soc_css_security.c +++ b/plat/arm/soc/common/soc_css_security.c @@ -23,7 +23,7 @@ void soc_css_init_nic400(void) /* * Allow non-secure access to some SOC regions, excluding UART1, which - * remains secure. + * remains secure (unless CSS_NON_SECURE_UART is set). * Note: This is the NIC-400 device on the SOC */ mmio_write_32(SOC_CSS_NIC400_BASE + @@ -36,9 +36,15 @@ void soc_css_init_nic400(void) NIC400_ADDR_CTRL_SECURITY_REG(SOC_CSS_NIC400_PL354_SMC), ~0); mmio_write_32(SOC_CSS_NIC400_BASE + NIC400_ADDR_CTRL_SECURITY_REG(SOC_CSS_NIC400_APB4_BRIDGE), ~0); +#if CSS_NON_SECURE_UART + /* Configure UART for non-secure access */ + mmio_write_32(SOC_CSS_NIC400_BASE + + NIC400_ADDR_CTRL_SECURITY_REG(SOC_CSS_NIC400_BOOTSEC_BRIDGE), ~0); +#else mmio_write_32(SOC_CSS_NIC400_BASE + NIC400_ADDR_CTRL_SECURITY_REG(SOC_CSS_NIC400_BOOTSEC_BRIDGE), ~SOC_CSS_NIC400_BOOTSEC_BRIDGE_UART1); +#endif /* CSS_NON_SECURE_UART */ } |