uclibc: put ARM thumb patches from 0.9.27 into 0.9.28

Some of the thumb patches had already been pushed into the uclibc release,
this commit adds corrected/updated versions of most of the ones which had
not been accepted.  The controversial 'change the ldso symbol resolver'
patch is not in this set - it will be re-worked to match the changes being
made in binutils for the same problem.

4 files changed, 319 insertions, 1 deletions

diff --git a/packages/uclibc/uclibc-0.9.28/thumb-defined-arm-or-thumb.patch b/packages/uclibc/uclibc-0.9.28/thumb-defined-arm-or-thumb.patch
new file mode 100644
index 0000000000..502c8db86f
--- /dev/null
+++ b/packages/uclibc/uclibc-0.9.28/thumb-defined-arm-or-thumb.patch
@@ -0,0 +1,37 @@
+# in various places defined(__arm__) is used to protect/select code which
+# is ARM specific, that code must also be selected for __thumb__ because
+# __thumb__ is an ARM but __arm__ is not set...
+#
+--- ./ldso/include/dl-string.h.orig	2005-09-07 14:09:19.375564254 -0700
++++ ./ldso/include/dl-string.h	2005-09-07 14:09:52.045620051 -0700
+@@ -270,7 +270,7 @@
+ 
+ /* On some arches constant strings are referenced through the GOT.
+  * This requires that load_addr must already be defined... */
+-#if defined(mc68000) || defined(__arm__) || defined(__mips__)	\
++#if defined(mc68000) || defined(__arm__) || defined(__thumb__) || defined(__mips__)	\
+                      || defined(__sh__) ||  defined(__powerpc__)
+ # define CONSTANT_STRING_GOT_FIXUP(X) \
+ 	if ((X) < (const char *) load_addr) (X) += load_addr
+--- ./libc/sysdeps/linux/common/create_module.c.orig	2005-09-07 14:09:55.597843578 -0700
++++ ./libc/sysdeps/linux/common/create_module.c	2005-09-07 14:10:11.650853730 -0700
+@@ -31,7 +31,7 @@
+ 
+ #ifdef __NR_create_module
+ 
+-#if defined(__i386__) || defined(__m68k__) || defined(__arm__) || defined(__cris__) || defined(__i960__)
++#if defined(__i386__) || defined(__m68k__) || defined(__arm__) || defined(__thumb__) || defined(__cris__) || defined(__i960__)
+ #define __NR___create_module  __NR_create_module
+ #ifdef __STR_NR_create_module
+ #define __STR_NR___create_module  __STR_NR_create_module
+--- ./utils/ldd.c.orig	2005-09-07 14:10:32.368157388 -0700
++++ ./utils/ldd.c	2005-09-07 14:11:23.735389724 -0700
+@@ -51,7 +51,7 @@
+ #include <dmalloc.h>
+ #endif
+ 
+-#if defined(__arm__)
++#if defined(__arm__) || defined(__thumb__)
+ #define MATCH_MACHINE(x) (x == EM_ARM)
+ #define ELFCLASSM	ELFCLASS32
+ #endif
diff --git a/packages/uclibc/uclibc-0.9.28/thumb-mov-pc-bx.patch b/packages/uclibc/uclibc-0.9.28/thumb-mov-pc-bx.patch
new file mode 100644
index 0000000000..86713a7678
--- /dev/null
+++ b/packages/uclibc/uclibc-0.9.28/thumb-mov-pc-bx.patch
@@ -0,0 +1,102 @@
+# 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	2005-09-08 09:34:22.918316874 -0700
+@@ -8,6 +8,7 @@
+     "	.text\n"
+     "	.globl	_start\n"
+     "	.type	_start,%function\n"
++    "	.arm\n"
+ 	"_start:\n"
+ 	"	@ at start time, all the args are on the stack\n"
+ 	"	mov	r0, sp\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"
+--- uClibc-0.9.28/.pc/thumb-mov-pc-bx.patch/ldso/ldso/arm/dl-sysdep.h	2005-08-17 15:49:41.000000000 -0700
++++ uClibc-0.9.28/ldso/ldso/arm/dl-sysdep.h	2005-09-07 20:10:35.923583424 -0700
+@@ -85,7 +85,19 @@
+ 	extern void __dl_start asm ("_dl_start");
+ 	Elf32_Addr got_addr = (Elf32_Addr) &__dl_start;
+ 	Elf32_Addr pcrel_addr;
++#if !defined(__thumb__)
++	/* On thumb this has to be two instructions because
++	 * the offset is negative.
++	 */
+ 	asm ("adr %0, _dl_start" : "=r" (pcrel_addr));
++#else
++	/* This is dumb, gcc should support a thumb adrl
++	 * but it doesn't, so this is the same thing the
++	 * hard way.  If this code moves too far from _dl_start
++	 * it will fail.
++	 */
++	asm ("adr\t%0, 1f\n1:\tsub\t%0, #1b-_dl_start\n" : "=r" (pcrel_addr));
++#endif
+ 	return pcrel_addr - got_addr;
+ }
+ 
+--- uClibc-0.9.28/.pc/thumb-mov-pc-bx.patch/libc/sysdeps/linux/arm/clone.S	2005-08-17 15:49:41.000000000 -0700
++++ uClibc-0.9.28/libc/sysdeps/linux/arm/clone.S	2005-09-08 09:36:24.801986529 -0700
+@@ -51,7 +51,11 @@
+ 	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-0.9.28/.pc/thumb-mov-pc-bx.patch/libc/sysdeps/linux/arm/vfork.S	2005-08-17 15:49:41.000000000 -0700
++++ uClibc-0.9.28/libc/sysdeps/linux/arm/vfork.S	2005-09-08 09:51:13.377901086 -0700
+@@ -34,7 +34,11 @@
+ #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
+@@ -47,7 +51,11 @@
+ 	cmn     r0, #4096
+ 
+ 	/* Syscal worked.  Return to child/parent */
+-	movcc   pc, lr
++#if defined(__THUMB_INTERWORK__)
++	bxcc	lr
++#else
++	movcc	pc, lr
++#endif
+ 
+ __error:
+ 	b	__syscall_error
diff --git a/packages/uclibc/uclibc-0.9.28/thumb-resolve.patch b/packages/uclibc/uclibc-0.9.28/thumb-resolve.patch
new file mode 100644
index 0000000000..e088757590
--- /dev/null
+++ b/packages/uclibc/uclibc-0.9.28/thumb-resolve.patch
@@ -0,0 +1,172 @@
+# This change reimplements the ARM _dl_linux_resolve entry point - this is
+# called to resolve DLL PLT entries.  The assembler is changed to be thumb
+# compatible and slightly faster, the C function, _dl_linux_resolver (note
+# the extra r) is changed to take a byte address in place of an 8 byte
+# count (faster in caller and callee, and slightly easier to understand).
+#
+--- uClibc-0.9.28/.pc/thumb-resolve.patch/ldso/ldso/arm/elfinterp.c	2005-08-17 15:49:41.000000000 -0700
++++ uClibc-0.9.28/ldso/ldso/arm/elfinterp.c	2005-09-07 20:10:36.231602806 -0700
+@@ -55,7 +55,7 @@
+ 
+ 	rel_addr = (ELF_RELOC *) tpnt->dynamic_info[DT_JMPREL];
+ 
+-	this_reloc = rel_addr + (reloc_entry >> 3);
++	this_reloc = rel_addr + reloc_entry;
+ 	reloc_type = ELF32_R_TYPE(this_reloc->r_info);
+ 	symtab_index = ELF32_R_SYM(this_reloc->r_info);
+ 
+--- uClibc-0.9.28/.pc/thumb-resolve.patch/ldso/ldso/arm/resolve.S	2005-08-17 15:49:41.000000000 -0700
++++ uClibc-0.9.28/ldso/ldso/arm/resolve.S	2005-09-08 09:54:03.536608499 -0700
+@@ -1,43 +1,121 @@
+ /*
+- * This function is _not_ called directly.  It is jumped to (so no return
+- * address is on the stack) when attempting to use a symbol that has not yet
+- * been resolved.  The first time a jump symbol (such as a function call inside
+- * a shared library) is used (before it gets resolved) it will jump here to
+- * _dl_linux_resolve.  When we get called the stack looks like this:
+- *	reloc_entry
+- *	tpnt
+- *
+- * This function saves all the registers, puts a copy of reloc_entry and tpnt
+- * on the stack (as function arguments) then make the function call
+- * _dl_linux_resolver(tpnt, reloc_entry).  _dl_linux_resolver() figures out
+- * where the jump symbol is _really_ supposed to have jumped to and returns
+- * that to us.  Once we have that, we overwrite tpnt with this fixed up
+- * address. We then clean up after ourselves, put all the registers back how we
+- * found them, then we jump to the fixed up address, which is where the jump
+- * symbol that got us here really wanted to jump to in the first place.
+- *  -Erik Andersen
++ * On ARM the PLT contains the following three instructions (for ARM calls):
++ *
++ *	add   ip, pc, #0xNN00000
++ *	add   ip, ip, #0xNN000
++ *	ldr   pc, [ip, #0xNNN]!
++ *
++ * So that, effectively, causes the following to happen:
++ *
++ *	ip := pc+0x0NNNNNNN
++ *	pc := *ip
++ *
++ * For thumb the above fragment is preceded by "bx pc, nop" to switch to ARM
++ * mode and the thumb 'bl' must go to PLT-4 - the PLT entry is expanded by
++ * four bytes to accomodate the trampoline code.
++ *
++ * 0x0NNNNNNN is the offset of the GOT entry for this function relative to
++ * the PLT entry for this function (where the code is).  So the code in the
++ * PLT causes a branch to whatever is in the GOT, leaving the actual address
++ * of the GOT entry in ip.  (Note that the GOT must follow the PLT - the
++ * added value is 28 bit unsigned).
++ *
++ * ip is a pointer to the GOT entry for this function, the first time round
++ * *ip points to this code:
++ *
++ *	str   lr, [sp, #-4]!	@ save lr
++ *	ldr   lr, [pc, #4]	@ lr := *dat (&GOT_TABLE[0]-.)
++ *	add   lr, pc, lr	@ lr += &dat (so lr == &GOT_TABLE[0])
++ *	ldr   pc, [lr, #8]!	@ pc := GOT_TABLE[2]
++ *dat:	.long &GOT_TABLE[0] - .
++ *
++ * (this code is actually held in the first entry of the PLT).  The code
++ * preserves lr then uses it as a scratch register (this preserves the ip
++ * value calculated above).  GOT_TABLE[2] is initialized by INIT_GOT in
++ * dl-sysdep.h to point to _dl_linux_resolve - this function.  The first
++ * three entries in the GOT are reserved, then they are followed by the
++ * entries for the PLT entries, in order.
++ *
++ * The linker initialises the following (non-reserved) GOT entries to
++ * the offset of the PLT with an associated relocation so that on load
++ * the entry is relocated to point to the PLT - the above code.
++ *
++ * The net effect of all this is that on the first call to an external (as
++ * yet unresolved) function all seven of the above instructions are
++ * executed in sequence and the program ends up executing _dl_linux_resolve
++ * with the following important values in registers:
++ *
++ *	ip - a pointer to the GOT entry for the as yet unresolved function
++ *	lr - &GOT_TABLE[2]
++ *
++ * GOT_TABLE[2] has already been initialised to _dl_linux_resolve, and
++ * GOT_TABLE[1] is a pointer to the (elf_resolve*) from INIT_GOT.
++ * _dl_linux_resolve unfrobnicates the ip and lr values to obtain arguments
++ * for a call to _dl_linux_resolver (not the additional 'r' on the end) -
++ * this is in elfinterp.c in this directory.  The call takes arguments:
++ *
++ *	_dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
++ *
++ * And returns the address of the function, it also overwrites the GOT
++ * table entry so that the next time round only the first code fragment will
++ * be executed - it will call the function directly.
++ *
++ * [[Of course, this simply doesn't work on ARM 4T with a thumb target - because
++ * 4T did not do the thumb/arm change on ldr pc!  It can be made to work by
++ * changing _dl_linux_resolver to return __%s_from_arm for an STT_TFUNC, but
++ * this hasn't been done, and there is no guarantee that the linker generated
++ * that glue anyway.]]
++ *
++ * _dl_linux_resolve gets the arguments to call the resolver as follows:
++ *
++ *	tpnt		GOT_TABLE[1], [lr-4]
++ *	reloc-entry	&GOT-&GOT_TABLE[3], (ip - lr - 4)/4
++ *
++ * (I.e. 'GOT' means the table entry for this function, the thing for which
++ * ip holds the address.)  The reloc-entry is passed as an index, since
++ * since the GOT table has 4 byte entries the code needs to divide this by 4
++ * to get the actual index.
++ *
++ * John Bowler, August 13, 2005 - determined by experiment and examination
++ * of generated ARM code (there was no documentation...)
++ *
++ * This code is all ARM code - not thumb - _dl_linux_resolver may, itself,
++ * be thumb, in which case the linker will insert the appropriate glue.  A
++ * call from thumb to the PLT hits the trampoline code described above.
++ * This code (now) builds a proper stack frame.
++ *
++ * The code does *not* set sb (r9,v6) - to do that the basic PLT instructions
++ * would need to save sb and load the new value and that would require
++ * support in the linker since it generates those instructions.  (Also note
++ * that linux/uclibc seems to be using r10 - sl - as a PIC base register - see
++ * dl-startup.c).
+  */
+ 
+-#define sl r10
+-#define fp r11
+-#define ip r12
+-
+ .text
+ .globl _dl_linux_resolve
+ .type _dl_linux_resolve,%function
+-.align 4;
++.align 4	@ 16 byte boundary and there are 32 bytes below
+ 
+ _dl_linux_resolve:
+-	stmdb sp!, {r0, r1, r2, r3, sl, fp}
+-	sub r1, ip, lr
+-	sub r1, r1, #4
+-	add r1, r1, r1
+-	ldr r0, [lr, #-4]
+-	mov r3,r0
++	@ _dl_linux_resolver is a standard subroutine call, therefore it
++	@ preserves everything except r0-r3 (a1-a4), ip and lr.  This
++	@ function must branch to the real function, and that expects
++	@ r0-r3 and lr to be as they were before the whole PLT stuff -
++	@ ip can be trashed.
++	stmdb sp!, {r0-r3}
++	ldr r0, [lr, #-4]	@ r0 := [lr-4] (GOT_TABLE[1])
++	sub r1, lr, ip		@ r1 := (lr-ip) (a multple of 4)
++	mvn r1, r1, ASR #2	@ r1 := ~((lr-ip)>>2), since -x = (1+~x)
++				@ ~x = -x-1, therefore ~(r1>>2) = (-((lr-ip)>>2)-1)
++				@ = - ((lr-ip)/4) - 1 = (ip - lr - 4)/4, as required
+ 
+ 	bl _dl_linux_resolver
+ 
+-	mov ip, r0
+-	ldmia sp!, {r0, r1, r2, r3, sl, fp, lr}
+-	mov pc,ip
++	mov   ip, r0
++	ldmia sp!, {r0-r3, lr}
++#if defined(__THUMB_INTERWORK__)
++	bx    ip
++#else
++	mov   pc, ip
++#endif
+ .size _dl_linux_resolve, .-_dl_linux_resolve
diff --git a/packages/uclibc/uclibc_0.9.28.bb b/packages/uclibc/uclibc_0.9.28.bb
index ae3d576e4d..246e9bc772 100644
--- a/packages/uclibc/uclibc_0.9.28.bb
+++ b/packages/uclibc/uclibc_0.9.28.bb
@@ -1,5 +1,5 @@
 DEFAULT_PREFERENCE = "1"
-PR = "r0"
+PR = "r1"
 
 include uclibc.inc
 
@@ -20,3 +20,10 @@ S = "${WORKDIR}/uClibc-${PV}"
 # be necessary to add this for architectures which do not initially
 # have a 'good' set of kernel header files in the cross directory.
 #SRC_URI += "file://nokernelheadercheck.patch;patch=1"
+#
+# Thumb support
+SRC_URI += " file://thumb-defined-arm-or-thumb.patch;patch=1"
+#
+# Thumb interworking support
+SRC_URI += " file://thumb-mov-pc-bx.patch;patch=1"
+SRC_URI += " file://thumb-resolve.patch;patch=1"