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Subject[PATCH v9 4/7] x86/syscalls/32: Wire up arch_prctl on x86-32
Date
Hook up arch_prctl to call do_arch_prctl on x86-32, and in 32 bit compat
mode on x86-64. This allows us to have arch_prctls that are not specific to
64 bits.

On UML, simply stub out this syscall.

Signed-off-by: Kyle Huey <khuey@kylehuey.com>
---
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/kernel/process_32.c | 7 +++++++
arch/x86/kernel/process_64.c | 7 +++++++
arch/x86/um/Makefile | 2 +-
arch/x86/um/syscalls_32.c | 7 +++++++
include/linux/compat.h | 2 ++
6 files changed, 25 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/um/syscalls_32.c

diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 2b36185..d78c6b5 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -384,8 +384,9 @@
375 i386 membarrier sys_membarrier
376 i386 mlock2 sys_mlock2
377 i386 copy_file_range sys_copy_file_range
378 i386 preadv2 sys_preadv2 compat_sys_preadv2
379 i386 pwritev2 sys_pwritev2 compat_sys_pwritev2
380 i386 pkey_mprotect sys_pkey_mprotect
381 i386 pkey_alloc sys_pkey_alloc
382 i386 pkey_free sys_pkey_free
+385 i386 arch_prctl sys_arch_prctl compat_sys_arch_prctl
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index bd7be8e..95d3adc 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -30,16 +30,17 @@
#include <linux/ptrace.h>
#include <linux/personality.h>
#include <linux/percpu.h>
#include <linux/prctl.h>
#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/kdebug.h>
+#include <linux/syscalls.h>

#include <asm/pgtable.h>
#include <asm/ldt.h>
#include <asm/processor.h>
#include <asm/fpu/internal.h>
#include <asm/desc.h>
#ifdef CONFIG_MATH_EMULATION
#include <asm/math_emu.h>
@@ -49,16 +50,17 @@

#include <asm/tlbflush.h>
#include <asm/cpu.h>
#include <asm/idle.h>
#include <asm/syscalls.h>
#include <asm/debugreg.h>
#include <asm/switch_to.h>
#include <asm/vm86.h>
+#include <asm/proto.h>

void __show_regs(struct pt_regs *regs, int all)
{
unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
unsigned long d0, d1, d2, d3, d6, d7;
unsigned long sp;
unsigned short ss, gs;

@@ -296,8 +298,13 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
lazy_load_gs(next->gs);

switch_fpu_finish(next_fpu, fpu_switch);

this_cpu_write(current_task, next_p);

return prev_p;
}
+
+SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, arg2)
+{
+ return do_arch_prctl_common(current, code, arg2);
+}
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index bf75d26..3a2a84d 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -621,12 +621,19 @@ SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, arg2)

ret = do_arch_prctl_64(current, code, arg2);
if (ret == -EINVAL)
ret = do_arch_prctl_common(current, code, arg2);

return ret;
}

+#ifdef CONFIG_IA32_EMULATION
+COMPAT_SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, arg2)
+{
+ return do_arch_prctl_common(current, code, arg2);
+}
+#endif
+
unsigned long KSTK_ESP(struct task_struct *task)
{
return task_pt_regs(task)->sp;
}
diff --git a/arch/x86/um/Makefile b/arch/x86/um/Makefile
index e7e7055..69f0827 100644
--- a/arch/x86/um/Makefile
+++ b/arch/x86/um/Makefile
@@ -11,17 +11,17 @@ endif
obj-y = bug.o bugs_$(BITS).o delay.o fault.o ldt.o \
ptrace_$(BITS).o ptrace_user.o setjmp_$(BITS).o signal.o \
stub_$(BITS).o stub_segv.o \
sys_call_table_$(BITS).o sysrq_$(BITS).o tls_$(BITS).o \
mem_$(BITS).o subarch.o os-$(OS)/

ifeq ($(CONFIG_X86_32),y)

-obj-y += checksum_32.o
+obj-y += checksum_32.o syscalls_32.o
obj-$(CONFIG_ELF_CORE) += elfcore.o

subarch-y = ../lib/string_32.o ../lib/atomic64_32.o ../lib/atomic64_cx8_32.o
subarch-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += ../lib/rwsem.o

else

obj-y += syscalls_64.o vdso/
diff --git a/arch/x86/um/syscalls_32.c b/arch/x86/um/syscalls_32.c
new file mode 100644
index 0000000..ccf0598
--- /dev/null
+++ b/arch/x86/um/syscalls_32.c
@@ -0,0 +1,7 @@
+#include <linux/syscalls.h>
+#include <os.h>
+
+SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, arg2)
+{
+ return -EINVAL;
+}
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 6360939..500cdb3 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -716,16 +716,18 @@ int __compat_save_altstack(compat_stack_t __user *, unsigned long);
} while (0);

asmlinkage long compat_sys_sched_rr_get_interval(compat_pid_t pid,
struct compat_timespec __user *interval);

asmlinkage long compat_sys_fanotify_mark(int, unsigned int, __u32, __u32,
int, const char __user *);

+asmlinkage long compat_sys_arch_prctl(int, unsigned long);
+
/*
* For most but not all architectures, "am I in a compat syscall?" and
* "am I a compat task?" are the same question. For architectures on which
* they aren't the same question, arch code can override in_compat_syscall.
*/

#ifndef in_compat_syscall
static inline bool in_compat_syscall(void) { return is_compat_task(); }
--
2.10.2
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