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-rw-r--r--ldso/ldso/arm/dl-startup.h69
-rw-r--r--ldso/ldso/arm/dl-sysdep.h18
-rw-r--r--libc/sysdeps/linux/arm/clone.S6
-rw-r--r--libc/sysdeps/linux/arm/vfork.S8
4 files changed, 100 insertions, 1 deletions
diff --git a/ldso/ldso/arm/dl-startup.h b/ldso/ldso/arm/dl-startup.h
index 8ebc0b288..fa7c9651e 100644
--- a/ldso/ldso/arm/dl-startup.h
+++ b/ldso/ldso/arm/dl-startup.h
@@ -4,6 +4,7 @@
* Copyright (C) 2000-2004 by Erik Andersen <andersen@codepoet.org>
*/
+#if defined(__arm__)
asm(
" .text\n"
" .globl _start\n"
@@ -40,7 +41,11 @@ asm(
" ldr r0, .L_FINI_PROC\n"
" ldr r0, [sl, r0]\n"
" @ jump to the user_s entry point\n"
+#if defined(__THUMB_INTERWORK__)
+ " bx r6\n"
+#else
" mov pc, r6\n"
+#endif
".L_GET_GOT:\n"
" .word _GLOBAL_OFFSET_TABLE_ - .L_GOT_GOT - 4\n"
".L_SKIP_ARGS:\n"
@@ -51,6 +56,70 @@ asm(
" .size _start,.-_start\n"
".previous\n"
);
+#else
+asm(
+ " .text\n"
+ " .arm\n"
+ " .globl _start\n"
+ " .type _start,%function\n"
+ "_start:\n"
+ " @ dumb: can't persuade the linker to make the start address\n"
+ " @ odd, so use an arm function and change to thumb (_dl_start\n"
+ " @ is thumb)\n"
+ " adr r0, __dl_thumb_start+1\n"
+ " bx r0\n"
+ "\n\n"
+ " .thumb\n"
+ " .globl __dl_thumb_start\n"
+ " .thumb_func\n"
+ " .type __dl_thumb_start,%function\n"
+ "__dl_thumb_start:\n"
+ " @ at start time, all the args are on the stack\n"
+ " mov r0, sp\n"
+ " bl _dl_start\n"
+ " @ returns user entry point in r0\n"
+ " mov r6, r0\n"
+ " @ we are PIC code, so get global offset table\n"
+ " ldr r7, .L_GET_GOT\n"
+ ".L_GOT_GOT:\n"
+ " add r7, pc\n"
+ " @ See if we were run as a command with the executable file\n"
+ " @ name as an extra leading argument.\n"
+ " ldr r4, .L_SKIP_ARGS\n"
+ " ldr r4, [r7, r4]\n"
+ " @ get the original arg count\n"
+ " ldr r1, [sp]\n"
+ " @ subtract _dl_skip_args from it\n"
+ " sub r1, r1, r4\n"
+ " @ adjust the stack pointer to skip them\n"
+ " lsl r4, r4, #2\n"
+ " add sp, r4\n"
+ " @ get the argv address\n"
+ " add r2, sp, #4\n"
+ " @ store the new argc in the new stack location\n"
+ " str r1, [sp]\n"
+ " @ compute envp\n"
+ " lsl r3, r1, #2\n"
+ " add r3, r3, r2\n"
+ " add r3, #4\n"
+ "\n\n"
+ " @ load the finalizer function\n"
+ " ldr r0, .L_FINI_PROC\n"
+ " ldr r0, [r7, r0]\n"
+ " @ jump to the user_s entry point\n"
+ " bx r6\n"
+ "\n\n"
+ ".L_GET_GOT:\n"
+ " .word _GLOBAL_OFFSET_TABLE_ - .L_GOT_GOT - 4\n"
+ ".L_SKIP_ARGS:\n"
+ " .word _dl_skip_args(GOTOFF)\n"
+ ".L_FINI_PROC:\n"
+ " .word _dl_fini(GOT)\n"
+ "\n\n"
+ " .size _start,.-_start\n"
+ ".previous\n"
+);
+#endif
/* Get a pointer to the argv array. On many platforms this can be just
diff --git a/ldso/ldso/arm/dl-sysdep.h b/ldso/ldso/arm/dl-sysdep.h
index 794c86a0c..194fd2eb7 100644
--- a/ldso/ldso/arm/dl-sysdep.h
+++ b/ldso/ldso/arm/dl-sysdep.h
@@ -85,7 +85,25 @@ elf_machine_load_address (void)
extern void __dl_start asm ("_dl_start");
Elf32_Addr got_addr = (Elf32_Addr) &__dl_start;
Elf32_Addr pcrel_addr;
+#if !defined __thumb__
asm ("adr %0, _dl_start" : "=r" (pcrel_addr));
+#else
+ int tmp;
+ /* The above adr will not work on thumb because it
+ * is negative. The only safe way is to temporarily
+ * swap to arm.
+ */
+ asm( ".align 2\n"
+ " bx pc\n"
+ " nop \n"
+ " .arm \n"
+ " adr %0, _dl_start\n"
+ " .align 2\n"
+ " orr %1, pc, #1\n"
+ " bx %1\n"
+ " .force_thumb\n"
+ : "=r" (pcrel_addr), "=&r" (tmp));
+#endif
return pcrel_addr - got_addr;
}
diff --git a/libc/sysdeps/linux/arm/clone.S b/libc/sysdeps/linux/arm/clone.S
index 6672c7d6e..98b1296c0 100644
--- a/libc/sysdeps/linux/arm/clone.S
+++ b/libc/sysdeps/linux/arm/clone.S
@@ -52,7 +52,11 @@ clone:
DO_CALL (clone)
movs a1, a1
blt __error
- movne pc, lr
+#if defined(__THUMB_INTERWORK__)
+ bxne lr
+#else
+ movne pc, lr
+#endif
@ pick the function arg and call address off the stack and execute
ldr r0, [sp, #4]
diff --git a/libc/sysdeps/linux/arm/vfork.S b/libc/sysdeps/linux/arm/vfork.S
index e13636940..486a7e8e4 100644
--- a/libc/sysdeps/linux/arm/vfork.S
+++ b/libc/sysdeps/linux/arm/vfork.S
@@ -26,7 +26,11 @@ __vfork:
#ifdef __NR_vfork
DO_CALL (vfork)
cmn r0, #4096
+#if defined(__THUMB_INTERWORK__)
+ bxcc lr
+#else
movcc pc, lr
+#endif
/* Check if vfork even exists. */
ldr r1, =-ENOSYS
@@ -39,7 +43,11 @@ __vfork:
cmn r0, #4096
/* Syscall worked. Return to child/parent */
+#if defined(__THUMB_INTERWORK__)
+ bxcc lr
+#else
movcc pc, lr
+#endif
__error:
b __syscall_error