From ee016a7bb098578a5d0d4bde01259fe3cd57b02f Mon Sep 17 00:00:00 2001 From: Gabriel Somlo Date: Thu, 30 Mar 2023 16:25:30 -0400 Subject: [PATCH] docs: Correct FW_JUMP_FDT_ADDR calculation example When using `PLATFORM=generic` defaults, the kernel is loaded at `FW_JUMP_ADDR`, and the FDT is loaded at `FW_JUMP_FDT_ADDR. Therefore, the maximum kernel size before `FW_JUMP_FDT_ADDR` must be increased is `$(( FW_JUMP_FDT_ADDR - FW_JUMP_ADDR ))`. The example calculation assumes `rv64`, and is wrong to boot (off by 0x200000). Fix it and update it for the general case. Signed-off-by: Gabriel Somlo Reviewed-by: Andrew Jones Reviewed-by: Xiang W --- docs/firmware/fw_jump.md | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/docs/firmware/fw_jump.md b/docs/firmware/fw_jump.md index 956897e..3e883fa 100644 --- a/docs/firmware/fw_jump.md +++ b/docs/firmware/fw_jump.md @@ -43,18 +43,18 @@ follows: When using the default *FW_JUMP_FDT_ADDR* with *PLATFORM=generic*, you must ensure *FW_JUMP_FDT_ADDR* is set high enough to avoid overwriting the kernel. - You can use the following method. + You can use the following method (e.g., using bash or zsh): ``` - ${CROSS_COMPILE}objdump -h $KERNEL_ELF | sort -k 5,5 | awk -n '/^ +[0-9]+ /\ - {addr="0x"$3; size="0x"$5; printf "0x""%x\n",addr+size}' \ - | (( `tail -1` > 0x2200000 )) && echo fdt overlaps kernel,\ - increase FW_JUMP_FDT_ADDR - - ${LLVM}objdump -h --show-lma $KERNEL_ELF | sort -k 5,5 | \ - awk -n '/^ +[0-9]+ / {addr="0x"$3; size="0x"$5; printf "0x""%x\n",addr+size}'\ - | (( `tail -1` > 0x2200000 )) && echo fdt overlaps kernel,\ - increase FW_JUMP_FDT_ADDR + ${CROSS_COMPILE}objdump -h $KERNEL_ELF | sort -k 5,5 | awk -n ' + /^ +[0-9]+ / {addr="0x"$3; size="0x"$5; printf "0x""%x\n",addr+size}' | + (( `tail -1` > (FW_JUMP_FDT_ADDR - FW_JUMP_ADDR) )) && + echo fdt overlaps kernel, increase FW_JUMP_FDT_ADDR + + ${LLVM}objdump -h --show-lma $KERNEL_ELF | sort -k 5,5 | awk -n ' + /^ +[0-9]+ / {addr="0x"$3; size="0x"$5; printf "0x""%x\n",addr+size}' | + (( `tail -1` > (FW_JUMP_FDT_ADDR - FW_JUMP_ADDR) )) && + echo fdt overlaps kernel, increase FW_JUMP_FDT_ADDR ``` *FW_JUMP* Example -- 2.34.1