diff options
Diffstat (limited to 'packages/uclibc/uclibc-cvs/thumb-mov-pc-bx.patch')
| -rw-r--r-- | packages/uclibc/uclibc-cvs/thumb-mov-pc-bx.patch | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/packages/uclibc/uclibc-cvs/thumb-mov-pc-bx.patch b/packages/uclibc/uclibc-cvs/thumb-mov-pc-bx.patch new file mode 100644 index 0000000000..342fbb1aee --- /dev/null +++ b/packages/uclibc/uclibc-cvs/thumb-mov-pc-bx.patch @@ -0,0 +1,178 @@ +# 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 |