RFC: Add 32bit x86-64 support to binutils
H.J. Lu
hjl.tools@gmail.com
Fri Dec 31 01:11:00 GMT 2010
On Thu, Dec 30, 2010 at 4:42 PM, H. Peter Anvin <hpa@zytor.com> wrote:
> On 12/30/2010 01:08 PM, Robert Millan wrote:
>> Hi folks,
>>
>> I had this unsubmitted patch in my local filesystem. It makes Linux
>> detect ELF32 AMD64 binaries and sets a flag to restrict them to
>> 32-bit address space.
>>
>> It's not rocket science but can save you some work in case you
>> haven't implemented this already.
>>
>
> I have pushed my old kernel patches to a git tree at:
>
> git://git.kernel.org//pub/scm/linux/kernel/git/hpa/linux-2.6-ilp32.git
>
> They are currently based on 2.6.31 since that was the released version
> when I first did this work; they are not intended to be mergeble but
> rather as a prototype.
>
> Note that we have no intention of supporting this ABI for the kernel
> itself. The kernel will be a normal x86-64 kernel.
>
Here is the updated ILP32 patch for 2.6.35.
--
H.J.
-------------- next part --------------
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 588a7aa..ae915c8 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -42,6 +42,14 @@
void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
+/* We use the standard 64-bit versions of these for the ILP32 variants */
+int
+restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
+ unsigned long *pax);
+int
+setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
+ struct pt_regs *regs, unsigned long mask);
+
int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
{
int err = 0;
@@ -565,3 +573,118 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
return 0;
}
+
+int ia32_setup_ilp32_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+ compat_sigset_t *set, struct pt_regs *regs)
+{
+ struct rt_sigframe_ilp32 __user *frame;
+ void __user *restorer;
+ int err = 0;
+ void __user *fpstate = NULL;
+
+ /* __copy_to_user optimizes that into a single 8 byte store */
+ static const struct {
+ u8 movl;
+ u32 val;
+ u16 int80;
+ u8 pad;
+ } __attribute__((packed)) code = {
+ 0xb8,
+ __NR_ia32_ilp32_sigreturn,
+ 0x80cd,
+ 0,
+ };
+
+ frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
+
+ if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+ return -EFAULT;
+
+ put_user_try {
+ put_user_ex(sig, &frame->sig);
+ put_user_ex(ptr_to_compat(&frame->info), &frame->pinfo);
+ put_user_ex(ptr_to_compat(&frame->uc), &frame->puc);
+ err |= copy_siginfo_to_user32(&frame->info, info);
+
+ /* Create the ucontext. */
+ if (cpu_has_xsave)
+ put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
+ else
+ put_user_ex(0, &frame->uc.uc_flags);
+ put_user_ex(0, &frame->uc.uc_link);
+ put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
+ put_user_ex(sas_ss_flags(regs->sp),
+ &frame->uc.uc_stack.ss_flags);
+ put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+ err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
+ regs, set->sig[0]);
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ if (ka->sa.sa_flags & SA_RESTORER)
+ restorer = ka->sa.sa_restorer;
+ else
+ restorer = VDSO32_SYMBOL(current->mm->context.vdso,
+ rt_sigreturn);
+ put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
+
+ /*
+ * Not actually used anymore, but left because some gdb
+ * versions need it.
+ */
+ put_user_ex(*((u64 *)&code), (u64 *)frame->retcode);
+ } put_user_catch(err);
+
+ if (err)
+ return -EFAULT;
+
+ /* Set up registers for signal handler */
+ regs->sp = (unsigned long) frame;
+ regs->ip = (unsigned long) ka->sa.sa_handler;
+
+ /* We use the 64-bit ILP32 calling convention here... */
+ regs->di = sig;
+ regs->si = (unsigned long) &frame->info;
+ regs->dx = (unsigned long) &frame->uc;
+
+ loadsegment(ds, __USER_DS);
+ loadsegment(es, __USER_DS);
+
+ regs->cs = __USER_CS;
+ regs->ss = __USER_DS;
+
+ return 0;
+}
+
+asmlinkage long sys32_ilp32_sigreturn(struct pt_regs *regs)
+{
+ struct rt_sigframe_ilp32 __user *frame;
+ sigset_t set;
+ unsigned long ax;
+ struct pt_regs tregs;
+
+ frame = (struct rt_sigframe_ilp32 __user *)(regs->sp - 4);
+
+ if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+ goto badframe;
+ if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ goto badframe;
+
+ sigdelsetmask(&set, ~_BLOCKABLE);
+ spin_lock_irq(¤t->sighand->siglock);
+ current->blocked = set;
+ recalc_sigpending();
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
+ goto badframe;
+
+ tregs = *regs;
+ if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)
+ goto badframe;
+
+ return ax;
+
+badframe:
+ signal_fault(regs, frame, "64bit ilp32 sigreturn");
+ return 0;
+}
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 4f5f71e..51f9951 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -475,6 +475,7 @@ quiet_ni_syscall:
CFI_STARTPROC32
+ PTREGSCALL stub32_ilp32_sigreturn, sys32_ilp32_sigreturn, %rdi
PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn, %rdi
PTREGSCALL stub32_sigreturn, sys32_sigreturn, %rdi
PTREGSCALL stub32_sigaltstack, sys32_sigaltstack, %rdx
@@ -761,7 +762,7 @@ ia32_sys_call_table:
.quad compat_sys_io_submit
.quad sys_io_cancel
.quad sys32_fadvise64 /* 250 */
- .quad quiet_ni_syscall /* free_huge_pages */
+ .quad stub32_ilp32_sigreturn
.quad sys_exit_group
.quad sys32_lookup_dcookie
.quad sys_epoll_create
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index f2ad216..7393347 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -5,6 +5,8 @@
* ELF register definitions..
*/
+#include <linux/thread_info.h>
+
#include <asm/ptrace.h>
#include <asm/user.h>
#include <asm/auxvec.h>
@@ -155,7 +157,12 @@ do { \
#define elf_check_arch(x) \
((x)->e_machine == EM_X86_64)
-#define compat_elf_check_arch(x) elf_check_arch_ia32(x)
+#define compat_elf_check_arch(x) \
+ (elf_check_arch_ia32(x) || (x)->e_machine == EM_X86_64)
+
+#if __USER32_DS != __USER_DS
+# error "The following code assumes __USER32_DS == __USER_DS"
+#endif
static inline void elf_common_init(struct thread_struct *t,
struct pt_regs *regs, const u16 ds)
@@ -178,8 +185,9 @@ static inline void elf_common_init(struct thread_struct *t,
void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp);
#define compat_start_thread start_thread_ia32
-void set_personality_ia32(void);
-#define COMPAT_SET_PERSONALITY(ex) set_personality_ia32()
+void set_personality_ia32(bool);
+#define COMPAT_SET_PERSONALITY(ex) \
+ set_personality_ia32((ex).e_machine == EM_X86_64)
#define COMPAT_ELF_PLATFORM ("i686")
@@ -277,7 +285,9 @@ do { \
#define VDSO_HIGH_BASE (__fix_to_virt(FIX_VDSO))
-#define ARCH_DLINFO ARCH_DLINFO_IA32(vdso_enabled)
+#define ARCH_DLINFO \
+if (!test_thread_flag(TIF_64BIT_ILP32)) \
+ ARCH_DLINFO_IA32(vdso_enabled)
/* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
diff --git a/arch/x86/include/asm/ia32.h b/arch/x86/include/asm/ia32.h
index 1f7e625..e19de80 100644
--- a/arch/x86/include/asm/ia32.h
+++ b/arch/x86/include/asm/ia32.h
@@ -43,6 +43,14 @@ struct ucontext_ia32 {
compat_sigset_t uc_sigmask; /* mask last for extensibility */
};
+struct ucontext_ilp32 {
+ unsigned int uc_flags;
+ unsigned int uc_link;
+ stack_ia32_t uc_stack;
+ struct sigcontext uc_mcontext; /* the 64-bit sigcontext type */
+ compat_sigset_t uc_sigmask; /* mask last for extensibility */
+};
+
/* This matches struct stat64 in glibc2.2, hence the absolutely
* insane amounts of padding around dev_t's.
*/
diff --git a/arch/x86/include/asm/ia32_unistd.h b/arch/x86/include/asm/ia32_unistd.h
index 976f6ec..cc11c64 100644
--- a/arch/x86/include/asm/ia32_unistd.h
+++ b/arch/x86/include/asm/ia32_unistd.h
@@ -8,11 +8,12 @@
* the number. This should be otherwise in sync with asm-x86/unistd_32.h. -AK
*/
-#define __NR_ia32_restart_syscall 0
-#define __NR_ia32_exit 1
-#define __NR_ia32_read 3
-#define __NR_ia32_write 4
-#define __NR_ia32_sigreturn 119
-#define __NR_ia32_rt_sigreturn 173
+#define __NR_ia32_restart_syscall 0
+#define __NR_ia32_exit 1
+#define __NR_ia32_read 3
+#define __NR_ia32_write 4
+#define __NR_ia32_sigreturn 119
+#define __NR_ia32_rt_sigreturn 173
+#define __NR_ia32_ilp32_sigreturn 251
#endif /* _ASM_X86_IA32_UNISTD_H */
diff --git a/arch/x86/include/asm/sigframe.h b/arch/x86/include/asm/sigframe.h
index 4e0fe26..1e31107 100644
--- a/arch/x86/include/asm/sigframe.h
+++ b/arch/x86/include/asm/sigframe.h
@@ -59,6 +59,21 @@ struct rt_sigframe_ia32 {
#endif /* defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) */
#ifdef CONFIG_X86_64
+
+#ifdef CONFIG_IA32_EMULATION
+struct rt_sigframe_ilp32 {
+ u32 pretcode;
+ int sig;
+ u32 pinfo;
+ u32 puc;
+ compat_siginfo_t info;
+ struct ucontext_ilp32 uc;
+ char retcode[8];
+ /* fp state follows here */
+};
+
+#endif /* CONFIG_IA32_EMULATION */
+
struct rt_sigframe {
char __user *pretcode;
struct ucontext uc;
diff --git a/arch/x86/include/asm/signal.h b/arch/x86/include/asm/signal.h
index 598457c..4922358 100644
--- a/arch/x86/include/asm/signal.h
+++ b/arch/x86/include/asm/signal.h
@@ -94,6 +94,10 @@ typedef unsigned long sigset_t;
*
* SA_ONESHOT and SA_NOMASK are the historical Linux names for the Single
* Unix names RESETHAND and NODEFER respectively.
+ *
+ * SA_GPR64 dumps the entire 64-bit GPR register set. This flag is only
+ * applicable to the 32-bit system calls when running on a 64-bit kernel,
+ * and only when SA_SIGINFO is specified.
*/
#define SA_NOCLDSTOP 0x00000001u
#define SA_NOCLDWAIT 0x00000002u
@@ -107,6 +111,7 @@ typedef unsigned long sigset_t;
#define SA_ONESHOT SA_RESETHAND
#define SA_RESTORER 0x04000000
+#define SA_GPR64 0x02000000
/*
* sigaltstack controls
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index f0b6e5d..7cf9feb 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -95,6 +95,7 @@ struct thread_info {
#define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */
#define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */
#define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */
+#define TIF_64BIT_ILP32 29 /* 32-bit native x86-64 binary */
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
@@ -117,6 +118,7 @@ struct thread_info {
#define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP)
#define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
+#define _TIF_64BIT_ILP32 (1 << TIF_64BIT_ILP32)
/* work to do in syscall_trace_enter() */
#define _TIF_WORK_SYSCALL_ENTRY \
diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h
index beb9b5f..ac96d72 100644
--- a/arch/x86/include/asm/unistd_32.h
+++ b/arch/x86/include/asm/unistd_32.h
@@ -256,7 +256,7 @@
#define __NR_io_submit 248
#define __NR_io_cancel 249
#define __NR_fadvise64 250
-/* 251 is available for reuse (was briefly sys_set_zone_reclaim) */
+#define __NR_ilp32_sigreturn 251
#define __NR_exit_group 252
#define __NR_lookup_dcookie 253
#define __NR_epoll_create 254
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 3c2422a..239ce5a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -355,7 +355,9 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp)
{
start_thread_common(regs, new_ip, new_sp,
- __USER32_CS, __USER32_DS, __USER32_DS);
+ test_thread_flag(TIF_64BIT_ILP32)
+ ? __USER_CS : __USER32_CS,
+ __USER_DS, __USER_DS);
}
#endif
@@ -507,12 +509,16 @@ void set_personality_64bit(void)
current->personality &= ~READ_IMPLIES_EXEC;
}
-void set_personality_ia32(void)
+void set_personality_ia32(bool ilp32)
{
/* inherit personality from parent */
/* Make sure to be in 32bit mode */
set_thread_flag(TIF_IA32);
+ if (ilp32)
+ set_thread_flag(TIF_64BIT_ILP32);
+ else
+ clear_thread_flag(TIF_64BIT_ILP32);
current->personality |= force_personality32;
/* Prepare the first "return" to user space */
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 70c4872..c20f6d1 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -1294,7 +1294,8 @@ void update_regset_xstate_info(unsigned int size, u64 xstate_mask)
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_IA32_EMULATION
- if (test_tsk_thread_flag(task, TIF_IA32))
+ if (test_tsk_thread_flag(task, TIF_IA32) &&
+ !test_tsk_thread_flag(task, TIF_64BIT_ILP32))
#endif
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
return &user_x86_32_view;
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 4fd173c..6512444 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -68,7 +68,7 @@
regs->seg = GET_SEG(seg) | 3; \
} while (0)
-static int
+int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
unsigned long *pax)
{
@@ -125,7 +125,7 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
return err;
}
-static int
+int
setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
struct pt_regs *regs, unsigned long mask)
{
@@ -647,10 +647,12 @@ static int signr_convert(int sig)
#define is_ia32 0
#endif /* CONFIG_IA32_EMULATION */
+int ia32_setup_ilp32_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+ sigset_t *set, struct pt_regs *regs);
int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
- sigset_t *set, struct pt_regs *regs);
+ sigset_t *set, struct pt_regs *regs);
int ia32_setup_frame(int sig, struct k_sigaction *ka,
- sigset_t *set, struct pt_regs *regs);
+ sigset_t *set, struct pt_regs *regs);
#endif /* CONFIG_X86_32 */
@@ -664,7 +666,14 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
/* Set up the stack frame */
if (is_ia32) {
if (ka->sa.sa_flags & SA_SIGINFO)
- ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
+#ifdef CONFIG_X86_64
+ if (ka->sa.sa_flags & SA_GPR64)
+ ret = ia32_setup_ilp32_frame(usig, ka, info,
+ set, regs);
+ else
+#endif
+ ret = ia32_setup_rt_frame(usig, ka, info,
+ set, regs);
else
ret = ia32_setup_frame(usig, ka, set, regs);
} else
diff --git a/scripts/checksyscalls.sh b/scripts/checksyscalls.sh
index 66ad375..9a96111 100755
--- a/scripts/checksyscalls.sh
+++ b/scripts/checksyscalls.sh
@@ -145,6 +145,7 @@ cat << EOF
#define __IGNORE_sysfs
#define __IGNORE_uselib
#define __IGNORE__sysctl
+#define __IGNORE_ilp32_sigreturn
/* ... including the "new" 32-bit uid syscalls */
#define __IGNORE_lchown32
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