starfive-tech/opensbi.git/firmware, branch debug

firmware/fw_payload: reduce the size by getting rid of padding

2021-04-28T18:22:36+00:00

Signed-off-by: Tekkaman Ninja

firmware: Support position independent execution

2021-03-19T09:30:50+00:00

Enable OpenSBI to support position independent execution. Because the position independent code will cause an additional GOT reference when accessing the global variables, it will reduce performance a bit. Therefore, the position independent execution is disabled by default. Users can through specifying "FW_PIC=y" on the make command to enable this feature. In theory, after enabling position-independent execution, the OpenSBI can run at arbitrary address with appropriate alignment. Therefore, the original relocation mechanism will be skipped. In other words, OpenSBI will directly run at the load address without any code movement. Signed-off-by: Vincent Chen Reviewed-by: Anup Patel

firmware: Use lla to access all global symbols

2021-03-19T09:27:45+00:00

When OpenSBI is compiled as fPIE mode, the assembler will translate "la" to GOT reference pattern. It will cause to cost an additional load instruction when obtaining the symbol address. However, if the symbol locates within the positive or negative 2GB region, we can use "lla" instead of "la" to avoid unneeded GOT references. This patch assumes that the OpenSBI image excluding the payload does not exceed 2GB. Based on this assumption, all "la" instructions are replaced by "lla" to avoid performance degradation when compiling as fPIE mode. Signed-off-by: Vincent Chen Reviewed-by: Anup Patel

lib: sbi: Introduce sbi_trap_exit() API

2021-01-07T04:23:17+00:00

We introduce sbi_trap_exit() API which can help non-firmware (i.e. generic or platform) code to force exit trap/interrupt handling and resume execution at context pointed by parameter "const struct sbi_trap_regs *regs". This new sbi_trap_exit() API will help Keystone Enclave project to resume execution of enclave from custom SBI call handler. Signed-off-by: Anup Patel Reviewed-by: Atish Patra

firmware: fw_base: Optimize trap handler for RV32 systems

2020-12-01T11:44:32+00:00

On RV32 systems, we have two CSRs for M-mode status (MSTATUS and MSTATUSH) when H-extension is implemented. This means we have to save/restore MSTATUSH for RV32 systems only when H-extension is implemented. The current _trap_handler() has extra instructions (roughly 10) for conditional save/restore of MSTATUSH CSR. These extra instructions in RV32 _trap_handler() can be avoided if we create separate low-level trap handler for RV32 systems having H-extension. This patch optimizes low-level trap handler for RV32 systems accordingly. Signed-off-by: Anup Patel Reviewed-by: Alistair Francis

firmware: Remove FW_PAYLOAD_FDT_PATH compile-time option

2020-10-18T04:59:59+00:00

The FW_PAYLOAD_FDT_PATH compile-time option is replaced by FW_FDT_PATH compile-time option which is more flexible and common across all OpenSBI firmwares. This patch removes FW_PAYLOAD_FDT_PATH and updates related documentation to use FW_FDT_PATH. Signed-off-by: Anup Patel Reviewed-by: Atish Patra

firmware: Add common FW_FDT_PATH compile-time option

2020-10-18T04:58:26+00:00

Currently, only FW_PAYLOAD has mechanism to embed external FDT using FW_PAYLOAD_FDT_PATH compile-time option. This patch adds a common FW_FDT_PATH compile-time option to embed external FDT for all OpenSBI firmwares (i.e FW_JUMP, FW_PAYLOAD, and FW_DYNAMIC). Signed-off-by: Anup Patel Reviewed-by: Atish Patra

firmware: fw_base: Improve exception stack setup in trap handler

2020-08-14T09:05:47+00:00

Currently, the low-level trap handler (i.e. _trap_handler()) uses branch instructions to conditionally setup exception stack based on which mode trap occured. This patch implements exception stack setup using xor instructions which is faster with same number of instructions due to lack of branch instructions. The new exception stack setup approach can be best described by the following pseudocode: Came_From_M_Mode = ((MSTATUS.MPP < PRV_M) ? 1 : 0) - 1; Exception_Stack = TP ^ (Came_From_M_Mode & (SP ^ TP)) Came_From_M_Mode = 0 ==> Exception_Stack = TP Came_From_M_Mode = -1 ==> Exception_Stack = SP Signed-off-by: Anup Patel Reviewed-by: Atish Patra

firmware: Remove FW_PAYLOAD_FDT and related documentation

2020-06-05T03:33:05+00:00

Now that no platform is using FW_PAYLOAD_FDT mechanism, we remove related code from Makefile and related documentation. Signed-off-by: Anup Patel Reviewed-by: Atish Patra

firmware: Allow fw_platform_init() to return updated FDT location

2020-06-05T03:32:34+00:00

Currently, the fw_platform_init() does not return anything but we can further improve by allowing fw_platform_init() to return updated FDT location. It is certainly not mandatory for fw_platform_init() to return a new location of FDT (or modify FDT). In fact, the fw_platform_init() can always return the original FDT location (i.e. 'arg1') unmodified. This new capability of fw_platform_init() will allow platforms to: 1. Have multiple built-in FDTs and select one 2. Modify FDT before using based on platform specific straps or OTP Signed-off-by: Anup Patel Reviewed-by: Atish Patra