diff options
| author | Peter Crosthwaite <crosthwaitepeter@gmail.com> | 2016-03-04 11:30:21 +0000 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2016-03-04 11:30:21 +0000 |
| commit | 7ef295ea5b412cbaf82f719ccd49efb51296e841 (patch) | |
| tree | da99e5270fcf99285c0b5dfb787c4b304687843a /include | |
| parent | 140b7ce5fff6fc660b2484dfd9d33ed2e42ec5a9 (diff) | |
loader: Add data swap option to load-elf
Some CPUs are of an opposite data-endianness to other components in the
system. Sometimes elfs have the data sections layed out with this CPU
data-endianness accounting for when loaded via the CPU, so byte swaps
(relative to other system components) will occur.
The leading example, is ARM's BE32 mode, which is is basically LE with
address manipulation on half-word and byte accesses to access the
hw/byte reversed address. This means that word data is invariant
across LE and BE32. This also means that instructions are still LE.
The expectation is that the elf will be loaded via the CPU in this
endianness scheme, which means the data in the elf is reversed at
compile time.
As QEMU loads via the system memory directly, rather than the CPU, we
need a mechanism to reverse elf data endianness to implement this
possibility.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/hw/elf_ops.h | 22 | ||||
| -rw-r--r-- | include/hw/loader.h | 5 |
2 files changed, 25 insertions, 2 deletions
diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h index 0010c441d9..f510e7ec2a 100644 --- a/include/hw/elf_ops.h +++ b/include/hw/elf_ops.h @@ -263,7 +263,7 @@ static int glue(load_elf, SZ)(const char *name, int fd, void *translate_opaque, int must_swab, uint64_t *pentry, uint64_t *lowaddr, uint64_t *highaddr, - int elf_machine, int clear_lsb) + int elf_machine, int clear_lsb, int data_swab) { struct elfhdr ehdr; struct elf_phdr *phdr = NULL, *ph; @@ -366,6 +366,26 @@ static int glue(load_elf, SZ)(const char *name, int fd, addr = ph->p_paddr; } + if (data_swab) { + int j; + for (j = 0; j < file_size; j += (1 << data_swab)) { + uint8_t *dp = data + j; + switch (data_swab) { + case (1): + *(uint16_t *)dp = bswap16(*(uint16_t *)dp); + break; + case (2): + *(uint32_t *)dp = bswap32(*(uint32_t *)dp); + break; + case (3): + *(uint64_t *)dp = bswap64(*(uint64_t *)dp); + break; + default: + g_assert_not_reached(); + } + } + } + /* the entry pointer in the ELF header is a virtual * address, if the text segments paddr and vaddr differ * we need to adjust the entry */ diff --git a/include/hw/loader.h b/include/hw/loader.h index 5485906095..0ba780852c 100644 --- a/include/hw/loader.h +++ b/include/hw/loader.h @@ -56,6 +56,9 @@ const char *load_elf_strerror(int error); * @elf_machine: Expected ELF machine type * @clear_lsb: Set to mask off LSB of addresses (Some architectures use * this for non-address data) + * @data_swab: Set to order of byte swapping for data. 0 for no swap, 1 + * for swapping bytes within halfwords, 2 for bytes within + * words and 3 for within doublewords. * * Load an ELF file's contents to the emulated system's address space. * Clients may optionally specify a callback to perform address @@ -70,7 +73,7 @@ const char *load_elf_strerror(int error); int load_elf(const char *filename, uint64_t (*translate_fn)(void *, uint64_t), void *translate_opaque, uint64_t *pentry, uint64_t *lowaddr, uint64_t *highaddr, int big_endian, int elf_machine, - int clear_lsb); + int clear_lsb, int data_swab); /** load_elf_hdr: * @filename: Path of ELF file |