d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Adjust the arm kernel entry point address properly regardless of whether the

Browse Source 
e_entry field holds a physical or a virtual address.  Add a comment block
that explains the assumptions being made by the adjustment code.
This commit is contained in:
ian 2013-02-26 03:24:45 +00:00
parent 6eb36900d3
commit d2e4d8580d
1 changed files with 17 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
sys/boot/common/load_elf.c
View File

@ -290,14 +290,25 @@ __elfN(loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
} else
off = 0;
#elif defined(__arm__)
if (off & 0xf0000000u) {
off = -(off & 0xf0000000u);
ehdr->e_entry += off;
/*
* The elf headers in some kernels specify virtual addresses in all
* header fields. More recently, the e_entry and p_paddr fields are the
* proper physical addresses. Even when the p_paddr fields are correct,
* the MI code below uses the p_vaddr fields with an offset added for
* loading (doing so is arguably wrong). To make loading work, we need
* an offset that represents the difference between physical and virtual
* addressing. ARM kernels are always linked at 0xC0000000. Depending
* on the headers, the offset value passed in may be physical or virtual
* (because it typically comes from e_entry), but we always replace
* whatever is passed in with the va<->pa offset. On the other hand, we
* only adjust the entry point if it's a virtual address to begin with.
*/
off = -0xc0000000u;
if ((ehdr->e_entry & 0xc0000000u) == 0xc000000u)
ehdr->e_entry += off;
#ifdef ELF_VERBOSE
printf("Converted entry 0x%08x\n", ehdr->e_entry);
printf("ehdr->e_entry 0x%08x, va<->pa off %llx\n", ehdr->e_entry, off);
#endif
} else
off = 0;
#else
off = 0; /* other archs use direct mapped kernels */
#endif