[PATCH -mm] x86 compat_binfmt_elf

From: Roland McGrath
Date: Wed Jan 02 2008 - 16:12:57 EST


This patch replaces the earlier patch by the same title already in x86/mm:

commit a9014d2dfcb253fb3ce5f4e3318849f743b85427
Author: Roland McGrath <roland@xxxxxxxxxx>

x86 compat_binfmt_elf

It requires the new patch I just posted, titled "compat_binfmt_elf Kconfig".


Thanks,
Roland
---
x86 compat_binfmt_elf

This switches x86-64's 32-bit ELF support to use the shared
fs/compat_binfmt_elf.c code instead of our own ia32_binfmt.c.

Signed-off-by: Roland McGrath <roland@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/Kconfig | 1 +
arch/x86/ia32/Makefile | 3 +-
arch/x86/vdso/vdso32-setup.c | 33 ++++++++++++++++
include/asm-x86/elf.h | 88 ++++++++++++++++++++++++++++++-----------
4 files changed, 99 insertions(+), 26 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 66d38bf..0000000 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1546,6 +1546,7 @@ source "fs/Kconfig.binfmt"
config IA32_EMULATION
bool "IA32 Emulation"
depends on X86_64
+ select COMPAT_BINFMT_ELF
help
Include code to run 32-bit programs under a 64-bit kernel. You should
likely turn this on, unless you're 100% sure that you don't have any
diff --git a/arch/x86/ia32/Makefile b/arch/x86/ia32/Makefile
index 93a6fda..0000000 100644
--- a/arch/x86/ia32/Makefile
+++ b/arch/x86/ia32/Makefile
@@ -2,8 +2,7 @@
# Makefile for the ia32 kernel emulation subsystem.
#

-obj-$(CONFIG_IA32_EMULATION) := ia32entry.o sys_ia32.o ia32_signal.o \
- ia32_binfmt.o
+obj-$(CONFIG_IA32_EMULATION) := ia32entry.o sys_ia32.o ia32_signal.o

sysv-$(CONFIG_SYSVIPC) := ipc32.o
obj-$(CONFIG_IA32_EMULATION) += $(sysv-y)
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index e0feb66..0000000 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -377,6 +377,39 @@ int arch_setup_additional_pages(struct l

__initcall(sysenter_setup);

+#ifdef CONFIG_SYSCTL
+/* Register vsyscall32 into the ABI table */
+#include <linux/sysctl.h>
+
+static ctl_table abi_table2[] = {
+ {
+ .procname = "vsyscall32",
+ .data = &sysctl_vsyscall32,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec
+ },
+ {}
+};
+
+static ctl_table abi_root_table2[] = {
+ {
+ .ctl_name = CTL_ABI,
+ .procname = "abi",
+ .mode = 0555,
+ .child = abi_table2
+ },
+ {}
+};
+
+static __init int ia32_binfmt_init(void)
+{
+ register_sysctl_table(abi_root_table2);
+ return 0;
+}
+__initcall(ia32_binfmt_init);
+#endif
+
#else /* CONFIG_X86_32 */

const char *arch_vma_name(struct vm_area_struct *vma)
diff --git a/include/asm-x86/elf.h b/include/asm-x86/elf.h
index d6bf742..0000000 100644
--- a/include/asm-x86/elf.h
+++ b/include/asm-x86/elf.h
@@ -73,6 +73,9 @@ typedef struct user_fxsr_struct elf_fpxr
#endif

#ifdef __KERNEL__
+#include <asm/vdso.h>
+
+extern unsigned int vdso_enabled;

/*
* This is used to ensure we don't load something for the wrong architecture.
@@ -84,7 +87,6 @@ typedef struct user_fxsr_struct elf_fpxr
#include <asm/processor.h>
#include <asm/system.h> /* for savesegment */
#include <asm/desc.h>
-#include <asm/vdso.h>

#define elf_check_arch(x) elf_check_arch_ia32(x)

@@ -106,7 +108,6 @@ typedef struct user_fxsr_struct elf_fpxr

#define ELF_PLATFORM (utsname()->machine)
#define set_personality_64bit() do { } while (0)
-extern unsigned int vdso_enabled;

#else /* CONFIG_X86_32 */

@@ -118,29 +119,57 @@ extern unsigned int vdso_enabled;
#define elf_check_arch(x) \
((x)->e_machine == EM_X86_64)

+#define compat_elf_check_arch(x) elf_check_arch_ia32(x)
+
+static inline void start_ia32_thread(struct pt_regs *regs, u32 ip, u32 sp)
+{
+ asm volatile("movl %0,%%fs" :: "r" (0));
+ asm volatile("movl %0,%%es; movl %0,%%ds" : : "r" (__USER32_DS));
+ load_gs_index(0);
+ regs->ip = ip;
+ regs->sp = sp;
+ regs->flags = X86_EFLAGS_IF;
+ regs->cs = __USER32_CS;
+ regs->ss = __USER32_DS;
+}
+
+static inline void elf_common_init(struct thread_struct *t,
+ struct pt_regs *regs, const u16 ds)
+{
+ regs->ax = regs->bx = regs->cx = regs->dx = 0;
+ regs->si = regs->di = regs->bp = 0;
+ regs->r8 = regs->r9 = regs->r10 = regs->r11 = 0;
+ regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
+ t->fs = t->gs = 0;
+ t->fsindex = t->gsindex = 0;
+ t->ds = t->es = ds;
+}
+
#define ELF_PLAT_INIT(_r, load_addr) do { \
- struct task_struct *cur = current; \
- (_r)->bx = 0; (_r)->cx = 0; (_r)->dx = 0; \
- (_r)->si = 0; (_r)->di = 0; (_r)->bp = 0; \
- (_r)->ax = 0; \
- (_r)->r8 = 0; \
- (_r)->r9 = 0; \
- (_r)->r10 = 0; \
- (_r)->r11 = 0; \
- (_r)->r12 = 0; \
- (_r)->r13 = 0; \
- (_r)->r14 = 0; \
- (_r)->r15 = 0; \
- cur->thread.fs = 0; cur->thread.gs = 0; \
- cur->thread.fsindex = 0; cur->thread.gsindex = 0; \
- cur->thread.ds = 0; cur->thread.es = 0; \
+ elf_common_init(&current->thread, _r, 0); \
clear_thread_flag(TIF_IA32); \
} while (0)

+#define COMPAT_ELF_PLAT_INIT(regs, load_addr) \
+ elf_common_init(&current->thread, regs, __USER_DS)
+#define compat_start_thread(regs, ip, sp) do { \
+ start_ia32_thread(regs, ip, sp); \
+ set_fs(USER_DS); \
+ } while (0)
+#define COMPAT_SET_PERSONALITY(ex, ibcs2) do { \
+ if (test_thread_flag(TIF_IA32)) \
+ clear_thread_flag(TIF_ABI_PENDING); \
+ else \
+ set_thread_flag(TIF_ABI_PENDING); \
+ current->personality |= force_personality32; \
+ } while (0)
+#define COMPAT_ELF_PLATFORM ("i686")
+
/* I'm not sure if we can use '-' here */
#define ELF_PLATFORM ("x86_64")
extern void set_personality_64bit(void);
-extern int vdso_enabled;
+extern unsigned int sysctl_vsyscall32;
+extern int force_personality32;

#endif /* !CONFIG_X86_32 */

@@ -179,17 +208,19 @@ extern int vdso_enabled;

struct task_struct;

+#define ARCH_DLINFO_IA32(vdso_enabled) \
+do if (vdso_enabled) { \
+ NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \
+ NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_CURRENT_BASE); \
+} while (0)
+
#ifdef CONFIG_X86_32

#define VDSO_HIGH_BASE (__fix_to_virt(FIX_VDSO))

-/* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
+#define ARCH_DLINFO ARCH_DLINFO_IA32(vdso_enabled)

-#define ARCH_DLINFO \
-do if (vdso_enabled) { \
- NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \
- NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_CURRENT_BASE); \
-} while (0)
+/* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */

#else /* CONFIG_X86_32 */

@@ -203,6 +234,12 @@ do if (vdso_enabled) { \
NEW_AUX_ENT(AT_SYSINFO_EHDR,(unsigned long)current->mm->context.vdso);\
} while (0)

+#define AT_SYSINFO 32
+
+#define COMPAT_ARCH_DLINFO ARCH_DLINFO_IA32(sysctl_vsyscall32)
+
+#define COMPAT_ELF_ET_DYN_BASE (TASK_UNMAPPED_BASE + 0x1000000)
+
#endif /* !CONFIG_X86_32 */

#define VDSO_CURRENT_BASE ((unsigned long)current->mm->context.vdso)
@@ -216,6 +253,9 @@ struct linux_binprm;
extern int arch_setup_additional_pages(struct linux_binprm *bprm,
int executable_stack);

+extern int syscall32_setup_pages(struct linux_binprm *, int exstack);
+#define compat_arch_setup_additional_pages syscall32_setup_pages
+
extern unsigned long arch_randomize_brk(struct mm_struct *mm);
#define arch_randomize_brk arch_randomize_brk

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