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|
# This patch changes all cases where the ARM assembler mov pc,rx
# instructions are used to ensure that the thumb/arm interwork change of
# process more works - in essence mov pc,rx needs to become bx rc.
#
# The ldr pc or ldm rx, {pc} instructions are not changed - this is
# fine on ARM >=v5 but will fail to restore thumb mode on ARM v4T,
# i.e. this code will not provide support for thumb on ARM v4T.
#
# One mov pc is left in resolve.S, this is fixed in a different patch -
# thumb-resolve.patch
#
# The changes are protected by __THUMB_INTERWORK__ - the original
# mov instruction will work on newer architectures and is required on
# arch v4 (not v4t) and earlier - those which did not support thumb -
# so this is safe. See gcc lib1asmfuncs for a more exact test.
#
--- uClibc-0.9.28/.pc/thumb-mov-pc-bx.patch/ldso/ldso/arm/dl-startup.h 2005-08-17 15:49:41.000000000 -0700
+++ uClibc-0.9.28/ldso/ldso/arm/dl-startup.h 2005-09-16 23:38:34.266546180 -0700
@@ -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 @@
" 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 @@
" .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
--- uClibc/.pc/thumb-mov-pc-bx.patch/ldso/ldso/arm/dl-sysdep.h 2006-01-19 19:03:40.000000000 -0800
+++ uClibc/ldso/ldso/arm/dl-sysdep.h 2006-01-20 01:25:26.026727661 -0800
@@ -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;
}
--- uClibc/libc/sysdeps/linux/arm/clone.S.orig 2006-01-19 19:03:55.000000000 -0800
+++ uClibc/libc/sysdeps/linux/arm/clone.S 2006-01-19 19:30:30.969758100 -0800
@@ -52,7 +52,11 @@ clone:
swi __NR_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]
--- uClibc/libc/sysdeps/linux/arm/vfork.S.orig 2006-01-19 19:03:55.000000000 -0800
+++ uClibc/libc/sysdeps/linux/arm/vfork.S 2006-01-19 19:33:09.533757874 -0800
@@ -25,7 +25,11 @@ vfork:
#ifdef __NR_vfork
swi __NR_vfork
cmn r0, #4096
+#if defined(__THUMB_INTERWORK__)
+ bxcc lr
+#else
movcc pc, lr
+#endif
/* Check if vfork even exists. */
ldr r1, =-ENOSYS
@@ -38,7 +42,11 @@ 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
|
