opensbi.git/firmware/fw_base.S, branch v1.0

firmware: Move memcpy/memset mapping to fw_base.S

2021-12-23T12:16:09Z

Some of the external firmwares using OpenSBI as library are facing issues with the weak memcpy() and memset() aliases in libsbi.a so we move these to fw_base.S. This way mapping of implicit memcpy() or memset() calls to sbi_memcpy() or sbi_memset() will only be done for OpenSBI firmwares. (Refer, https://github.com/riscv-software-src/opensbi/issues/234) In addition, we also add memmove() and memcmp() mappings in fw_base.S because as-per the GCC documentation the freestanding environment must provide memcpy(), memmove(), memset(), and memcmp(). Signed-off-by: Anup Patel Reviewed-by: Atish Patra

firmware: use _fw_start for load address

2021-07-27T09:50:49Z

The previous code uses _start as the load address, this default .entry is the first segment, using _fw_start does not need to make this assumption. Signed-off-by: Xiang W Reviewed-by: Anup Patel

firmware: Remove the unhelpful alignment codes before fdt relocation

2021-07-17T11:43:43Z

If the device tree is at an address that is not __SIZEOF_POINTER__ aligned, the fdt relocation code tries to align both source and destination address to __SIZEOF_POINTER__ before the memory copy. But such alignment can lead to unexpected results if either source or destination address is not aligned. In fact libfdt requires that the device tree must be at an 8-byte aligned address. Hence remove the unhelpful alignment codes. Signed-off-by: Bin Meng Reviewed-by: Anup Patel

fw_base: Put data in .data rather than .text

2021-07-11T12:03:30Z

The -N linker option is supposed to make .text writable, but GNU ld and LLD differ in interpreting what that means. GNU ld will happily let you have relocations in it, but LLD will see that the input section is read-only (even though the output section is writable) and give an error. It's unclear if either of them intend to have that behaviour in this edge case, but regardless there's no reason not to just put the data in a writable .data section. Signed-off-by: Jessica Clarke Reviewed-by: Bin Meng Tested-by: Bin Meng Reviewed-by: Anup Patel

fw_base: Don't mark fw_platform_init as both global and weak

2021-07-11T11:50:42Z

These are mutually exclusive. GNU as and LLVM both let later binding directives override earlier ones so this works as intended, but LLVM 12 turned this into a warning as there's no good reason to do such a thing and could be a potential bug. Thus, remove the redundant and incorrect .globl directive for fw_platform_init. Signed-off-by: Jessica Clarke Reviewed-by: Bin Meng Tested-by: Bin Meng Reviewed-by: Anup Patel

firmware: Minor optimization in _scratch_init()

2021-07-11T06:11:50Z

Before entering _scratch_init(), register t3 already holds a copy of the firmware end address, hence there is no need to calculate it again. This reduces 3 instructions in each _scratch_init() loop. Signed-off-by: Bin Meng Reviewed-by: Xiang W Reviewed-by: Atish Patra

firmware: Remove redundant add instruction from trap restore path

2021-04-05T10:09:28Z

The "add sp, a0, zero" instruction in the trap restore path is redundant and can be avoided if TRAP_RESTORE_xyz() assembly macros use a0 as the base register instead of sp. Signed-off-by: Anup Patel Reviewed-by: Xiang W

firware: optimize the exception exit code

2021-04-01T05:18:35Z

There are two copies of the same abnormal exit code, this patch deletes one Signed-off-by: Xiang W Reviewed-by: Anup Patel

firmware: Support position independent execution

2021-03-19T09:30:50Z

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

2021-03-19T09:27:45Z

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