From b2db04d0a81a9784d4a007be3bfef21aee207f8f Mon Sep 17 00:00:00 2001 From: Christophe Lyon Date: Mon, 29 Oct 2018 14:34:25 +0000 Subject: Add support for Thumb-only processors. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * ldso/ldso/arm/aeabi_read_tp.S: Add Thumb version. * ldso/ldso/arm/dl-startup.h: Do not force ARM encoding, adjust for Thumb. * ldso/ldso/arm/resolve.S: Force Thumb encoding on Thumb-only processors. * libc/sysdeps/linux/arm/crt1.S: Do not force ARM encoding, adjust for Thumb. Signed-off-by: Mickaël Guêné Signed-off-by: Christophe Lyon --- ldso/ldso/arm/aeabi_read_tp.S | 14 ++++++++++++++ ldso/ldso/arm/dl-startup.h | 10 +++++++++- ldso/ldso/arm/resolve.S | 10 +++++++++- libc/sysdeps/linux/arm/crt1.S | 8 +++++++- 4 files changed, 39 insertions(+), 3 deletions(-) diff --git a/ldso/ldso/arm/aeabi_read_tp.S b/ldso/ldso/arm/aeabi_read_tp.S index 77e0d6ecc..5ab51257c 100644 --- a/ldso/ldso/arm/aeabi_read_tp.S +++ b/ldso/ldso/arm/aeabi_read_tp.S @@ -53,9 +53,23 @@ #else .hidden __aeabi_read_tp #endif +#if !defined(__ARM_ARCH_ISA_ARM) + .thumb_func + .thumb + .syntax unified + ENTRY (__aeabi_read_tp) + push {r7} + mov r7, #0x0f0000 + orr r7, r7, #6 + svc #0 + pop {r7} + bx lr +#else + .arm ENTRY (__aeabi_read_tp) mov r0, #0xffff0fff sub pc, r0, #31 +#endif END (__aeabi_read_tp) #endif /* __UCLIBC_HAS_THREADS_NATIVE__ */ diff --git a/ldso/ldso/arm/dl-startup.h b/ldso/ldso/arm/dl-startup.h index 06c95cb44..cacd461e1 100644 --- a/ldso/ldso/arm/dl-startup.h +++ b/ldso/ldso/arm/dl-startup.h @@ -11,10 +11,13 @@ #if defined(__FDPIC__) #if !defined(__thumb__) || defined(__thumb2__) __asm__( - " .arm\n" " .text\n" " .globl _start\n" " .type _start,%function\n" +#if defined(__thumb2__) + " .thumb_func\n" +#endif + " .align 2\n" "_start:\n" /* We compute the parameters for __self_reloc: - r0 is a pointer to the loadmap (either from r8 or r7 if rtld is @@ -25,12 +28,17 @@ __asm__( __self_reloc will fix indirect addresses in .rofixup section and will return the relocated GOT value. */ +#if defined(__thumb2__) + " sub r4, pc, #4\n" +#else " sub r4, pc, #8\n" +#endif " ldr r1, .L__ROFIXUP_LIST__\n" " add r1, r1, r4\n" " ldr r2, .L__ROFIXUP_END__\n" " add r2, r2, r4\n" " movs r0, r8\n" + " it eq\n" " moveq r0, r7\n" " push {r7, r8, r9, r10}\n" " bl __self_reloc;\n" diff --git a/ldso/ldso/arm/resolve.S b/ldso/ldso/arm/resolve.S index 039a6b788..801387255 100644 --- a/ldso/ldso/arm/resolve.S +++ b/ldso/ldso/arm/resolve.S @@ -101,7 +101,15 @@ .text .align 4 @ 16 byte boundary and there are 32 bytes below (arm case) #if 1 /*(!defined(__thumb__) || defined __THUMB_INTERWORK__) || defined(__thumb2__)*/ - .arm + /* On Thumb-only processors, force thumb encoding. These + processors support Thumb-2, so the same source code can be + used as in ARM mode. */ +#if !defined(__ARM_ARCH_ISA_ARM) + .thumb + .thumb_func +#else + .arm +#endif .hidden _dl_linux_resolve .globl _dl_linux_resolve .type _dl_linux_resolve,%function diff --git a/libc/sysdeps/linux/arm/crt1.S b/libc/sysdeps/linux/arm/crt1.S index 5da0fe19c..a1d7f0f23 100644 --- a/libc/sysdeps/linux/arm/crt1.S +++ b/libc/sysdeps/linux/arm/crt1.S @@ -97,12 +97,17 @@ ARM register quick reference: #if defined(__FDPIC__) .text - .arm .globl _start + .type _start,%function + .align 2 _start: /* Start by self relocation. */ +#if defined(__thumb2__) + sub r4, pc, #4 +#else sub r4, pc, #8 +#endif ldr r1, .L__ROFIXUP_LIST__ add r1, r1, r4 ldr r2, .L__ROFIXUP_END__ @@ -129,6 +134,7 @@ _start: ldr r4, [r9, r4] str r4, [sp, #0] /* sp + 0 GOT fini */ movs r4, r8 /* Test if static binary (r8 is 0 as there is no interpreter). */ + ite ne movne r4, r10 moveq r4, #0 str r4, [sp, #4] /* sp + 4 got rtld_fini */ -- cgit v1.2.3