opensbi.git/firmware/fw_base.S, branch v1.2

firmware: Minor optimization for relocate

2022-12-05T05:17:38Z

The t3 register stores the address of _load_end. If relocation is not required, it is unnecessary to calculate the address of _load_end. This can reduce the operation time of two instructions. Signed-off-by: Dongdong Zhang Reviewed-by: Bin Meng Reviewed-by: Anup Patel

firmware: Fix code for accessing hart_count and stack_size

2022-03-27T03:23:27Z

lwu exists under the current rv64 and should also exist under the rv128 in the future, so I modified the conditions of conditional compilation so that it can adapt to the future situation Signed-off-by: Xiang W Reviewed-by: Anup Patel

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