Re: [U-Boot] [PATCH] riscv: tools: Fix prelink-riscv to work on big endian hosts

Hi Marcus
From: Marcus Comstedt [mailto:marcus@mc.pp.se] Sent: Monday, July 15, 2019 8:36 PM To: u-boot@lists.denx.de Cc: Marcus Comstedt; Rick Jian-Zhi Chen(陳建志) Subject: [PATCH] riscv: tools: Fix prelink-riscv to work on big endian hosts
All ELF fields whose values are inspected by the code are converted to CPU byteorder first. Values which are copied verbatim (relocation fixups) are not swapped to CPU byteorder and back as it is not needed.
Note that it is still assumed that the RISC-V ELF is little endian. In order to support big endian RISC-V targets as well, the calls to le*_to_cpu need to be replaced with macros target*_to_cpu defined by prelink-riscv.c, and prelink-riscv.inc included four times (32le, 64le, 32be, 32be) instead of two.
Signed-off-by: Marcus Comstedt marcus@mc.pp.se Cc: Rick Chen rick@andestech.com
tools/prelink-riscv.c | 5 +---- tools/prelink-riscv.inc | 41 +++++++++++++++++++++-------------------- 2 files changed, 22 insertions(+), 24 deletions(-)
diff --git a/tools/prelink-riscv.c b/tools/prelink-riscv.c index 52eb78e9d0..a900a1497a 100644 --- a/tools/prelink-riscv.c +++ b/tools/prelink-riscv.c @@ -8,10 +8,6 @@
- without fixup. Both RV32 and RV64 are supported.
*/
-#if __BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__ -#error "Only little-endian host is supported" -#endif
#include <errno.h> #include <stdbool.h> #include <stdint.h> @@ -25,6 +21,7 @@ #include <sys/stat.h> #include <sys/types.h> #include <unistd.h> +#include <compiler.h>
#ifndef EM_RISCV #define EM_RISCV 243 diff --git a/tools/prelink-riscv.inc b/tools/prelink-riscv.inc index d49258707d..e451159c03 100644 --- a/tools/prelink-riscv.inc +++ b/tools/prelink-riscv.inc @@ -23,14 +23,15 @@ #define Elf_Addr CONCAT3(Elf, PRELINK_INC_BITS, _Addr) #define ELF_R_TYPE CONCAT3(ELF, PRELINK_INC_BITS, _R_TYPE) #define ELF_R_SYM CONCAT3(ELF, PRELINK_INC_BITS, _R_SYM) +#define lenn_to_cpu CONCAT3(le, PRELINK_INC_BITS, _to_cpu)
static void* get_offset_nn (void* data, Elf_Phdr* phdrs, size_t phnum, Elf_Addr addr) { Elf_Phdr *p;
for (p = phdrs; p < phdrs + phnum; ++p)
if (p->p_vaddr <= addr && p->p_vaddr + p->p_memsz > addr)
return data + p->p_offset + (addr - p->p_vaddr);
if (lenn_to_cpu(p->p_vaddr) <= addr && lenn_to_cpu(p->p_vaddr) +
lenn_to_cpu(p->p_memsz) > addr)
return data + lenn_to_cpu(p->p_offset) + (addr -
+lenn_to_cpu(p->p_vaddr));
return NULL;
} @@ -42,15 +43,15 @@ static void prelink_nn(void *data) Elf_Dyn *dyn; Elf_Rela *r;
if (ehdr->e_machine != EM_RISCV)
if (le16_to_cpu(ehdr->e_machine) != EM_RISCV) die("Machine type is not RISC-V");
Elf_Phdr *phdrs = data + ehdr->e_phoff;
Elf_Phdr *phdrs = data + lenn_to_cpu(ehdr->e_phoff); Elf_Dyn *dyns = NULL;
for (p = phdrs; p < phdrs + ehdr->e_phnum; ++p) {
if (p->p_type == PT_DYNAMIC) {
dyns = data + p->p_offset;
for (p = phdrs; p < phdrs + le16_to_cpu(ehdr->e_phnum); ++p) {
if (le32_to_cpu(p->p_type) == PT_DYNAMIC) {
dyns = data + lenn_to_cpu(p->p_offset); break; } }
@@ -62,14 +63,14 @@ static void prelink_nn(void *data) size_t rela_count = 0; Elf_Sym *dynsym = NULL; for (dyn = dyns;; ++dyn) {
if (dyn->d_tag == DT_NULL)
if (lenn_to_cpu(dyn->d_tag) == DT_NULL) break;
else if (dyn->d_tag == DT_RELA)
rela_dyn = get_offset_nn(data, phdrs, ehdr->e_phnum, +
dyn->d_un.d_ptr);
else if (dyn->d_tag == DT_RELASZ)
rela_count = dyn->d_un.d_val / sizeof(Elf_Rela);
else if (dyn->d_tag == DT_SYMTAB)
dynsym = get_offset_nn(data, phdrs, ehdr->e_phnum, +
dyn->d_un.d_ptr);
else if (lenn_to_cpu(dyn->d_tag) == DT_RELA)
rela_dyn = get_offset_nn(data, phdrs,
le16_to_cpu(ehdr->e_phnum), + lenn_to_cpu(dyn->d_un.d_ptr));
else if (lenn_to_cpu(dyn->d_tag) == DT_RELASZ)
rela_count = lenn_to_cpu(dyn->d_un.d_val) / sizeof(Elf_Rela);
else if (lenn_to_cpu(dyn->d_tag) == DT_SYMTAB)
dynsym = get_offset_nn(data, phdrs,
le16_to_cpu(ehdr->e_phnum), + +lenn_to_cpu(dyn->d_un.d_ptr));
}
@@ -80,17 +81,17 @@ static void prelink_nn(void *data) die("No .dynsym found");
for (r = rela_dyn; r < rela_dyn + rela_count; ++r) {
void* buf = get_offset_nn(data, phdrs, ehdr->e_phnum, r->r_offset);
void* buf = get_offset_nn(data, phdrs,
le16_to_cpu(ehdr->e_phnum), +lenn_to_cpu(r->r_offset));
if (buf == NULL) continue;
if (ELF_R_TYPE(r->r_info) == R_RISCV_RELATIVE)
if (ELF_R_TYPE(lenn_to_cpu(r->r_info)) == R_RISCV_RELATIVE) *((uintnn_t*) buf) = r->r_addend;
else if (ELF_R_TYPE(r->r_info) == R_RISCV_32)
*((uint32_t*) buf) = dynsym[ELF_R_SYM(r->r_info)].st_value;
else if (ELF_R_TYPE(r->r_info) == R_RISCV_64)
*((uint64_t*) buf) = dynsym[ELF_R_SYM(r->r_info)].st_value;
else if (ELF_R_TYPE(lenn_to_cpu(r->r_info)) == R_RISCV_32)
*((uint32_t*) buf) =
dynsym[ELF_R_SYM(lenn_to_cpu(r->r_info))].st_value;
else if (ELF_R_TYPE(lenn_to_cpu(r->r_info)) == R_RISCV_64)
*((uint64_t*) buf) =
+dynsym[ELF_R_SYM(lenn_to_cpu(r->r_info))].st_value; } }
Nitpick: #undef lenn_to_cpu at the end of prelink-riscv.inc.
Other than that, Reviewed-by: Rick Chen rick@andestech.com
-- 2.21.0

Hi Rick,
Rick Chen rickchen36@gmail.com writes:
Nitpick: #undef lenn_to_cpu at the end of prelink-riscv.inc.
Other than that, Reviewed-by: Rick Chen rick@andestech.com
Thanks for reviewing!
Should I post a new version of the patch which adds the missing #undef?
In the meantime I have also implemented support for big endian ELFs if there is interest. :-D
// Marcus
participants (2)
-
Marcus Comstedt
-
Rick Chen