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Date: Wed, 14 Sep 2016 14:08:09 -0700
From: Kyle Huey <me@...ehuey.com>
To: Robert O'Callahan <robert@...llahan.org>
Cc: linux-kernel@...r.kernel.org, Borislav Petkov <bp@...e.de>,
Andy Lutomirski <luto@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
Al Viro <viro@...iv.linux.org.uk>,
Milosz Tanski <milosz@...in.com>,
"Dmitry V. Levin" <ldv@...linux.org>,
David Howells <dhowells@...hat.com>,
Zach Brown <zab@...hat.com>,
Eric B Munson <emunson@...mai.com>,
Peter Zijlstra <peterz@...radead.org>,
Jiri Slaby <jslaby@...e.cz>,
"Michael S. Tsirkin" <mst@...hat.com>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Paul Gortmaker <paul.gortmaker@...driver.com>,
Borislav Petkov <bp@...en8.de>,
Dmitry Vyukov <dvyukov@...gle.com>,
Dmitry Safonov <dsafonov@...tuozzo.com>,
Mateusz Guzik <mguzik@...hat.com>
Subject: [RESEND][PATCH v2 1/3] syscalls,x86 Expose arch_prctl on x86-32.
Signed-off-by: Kyle Huey <khuey@...ehuey.com>
---
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/kernel/process.c | 80 ++++++++++++++++++++++++++++++++++
arch/x86/kernel/process_64.c | 66 ----------------------------
3 files changed, 81 insertions(+), 66 deletions(-)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index f848572..3b6965b 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -386,3 +386,4 @@
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 arch_prctl sys_arch_prctl
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 62c0b0e..0f857c3 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -20,6 +20,7 @@
#include <linux/cpuidle.h>
#include <trace/events/power.h>
#include <linux/hw_breakpoint.h>
+#include <linux/syscalls.h>
#include <asm/cpu.h>
#include <asm/apic.h>
#include <asm/syscalls.h>
@@ -32,6 +33,7 @@
#include <asm/tlbflush.h>
#include <asm/mce.h>
#include <asm/vm86.h>
+#include <asm/prctl.h>
/*
* per-CPU TSS segments. Threads are completely 'soft' on Linux,
@@ -567,3 +569,81 @@ unsigned long get_wchan(struct task_struct *p)
} while (count++ < 16 && p->state != TASK_RUNNING);
return 0;
}
+
+long do_arch_prctl(struct task_struct *task, int code, unsigned long arg2)
+{
+ int ret = 0;
+ int doit = task == current;
+ int is_32 = IS_ENABLED(CONFIG_IA32_EMULATION) && test_thread_flag(TIF_IA32);
+ int cpu;
+
+ switch (code) {
+#ifdef CONFIG_X86_64
+ case ARCH_SET_GS:
+ if (is_32)
+ return -EINVAL;
+ if (arg2 >= TASK_SIZE_MAX)
+ return -EPERM;
+ cpu = get_cpu();
+ task->thread.gsindex = 0;
+ task->thread.gsbase = arg2;
+ if (doit) {
+ load_gs_index(0);
+ ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, arg2);
+ }
+ put_cpu();
+ break;
+ case ARCH_SET_FS:
+ if (is_32)
+ return -EINVAL;
+ /* Not strictly needed for fs, but do it for symmetry
+ with gs */
+ if (arg2 >= TASK_SIZE_MAX)
+ return -EPERM;
+ cpu = get_cpu();
+ task->thread.fsindex = 0;
+ task->thread.fsbase = arg2;
+ if (doit) {
+ /* set the selector to 0 to not confuse __switch_to */
+ loadsegment(fs, 0);
+ ret = wrmsrl_safe(MSR_FS_BASE, arg2);
+ }
+ put_cpu();
+ break;
+ case ARCH_GET_FS: {
+ unsigned long base;
+
+ if (is_32)
+ return -EINVAL;
+ if (doit)
+ rdmsrl(MSR_FS_BASE, base);
+ else
+ base = task->thread.fsbase;
+ ret = put_user(base, (unsigned long __user *)arg2);
+ break;
+ }
+ case ARCH_GET_GS: {
+ unsigned long base;
+
+ if (is_32)
+ return -EINVAL;
+ if (doit)
+ rdmsrl(MSR_KERNEL_GS_BASE, base);
+ else
+ base = task->thread.gsbase;
+ ret = put_user(base, (unsigned long __user *)arg2);
+ break;
+ }
+#endif
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, arg2)
+{
+ return do_arch_prctl(current, code, arg2);
+}
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 63236d8..e8c6302 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -524,72 +524,6 @@ void set_personality_ia32(bool x32)
}
EXPORT_SYMBOL_GPL(set_personality_ia32);
-long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
-{
- int ret = 0;
- int doit = task == current;
- int cpu;
-
- switch (code) {
- case ARCH_SET_GS:
- if (addr >= TASK_SIZE_MAX)
- return -EPERM;
- cpu = get_cpu();
- task->thread.gsindex = 0;
- task->thread.gsbase = addr;
- if (doit) {
- load_gs_index(0);
- ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr);
- }
- put_cpu();
- break;
- case ARCH_SET_FS:
- /* Not strictly needed for fs, but do it for symmetry
- with gs */
- if (addr >= TASK_SIZE_MAX)
- return -EPERM;
- cpu = get_cpu();
- task->thread.fsindex = 0;
- task->thread.fsbase = addr;
- if (doit) {
- /* set the selector to 0 to not confuse __switch_to */
- loadsegment(fs, 0);
- ret = wrmsrl_safe(MSR_FS_BASE, addr);
- }
- put_cpu();
- break;
- case ARCH_GET_FS: {
- unsigned long base;
- if (doit)
- rdmsrl(MSR_FS_BASE, base);
- else
- base = task->thread.fsbase;
- ret = put_user(base, (unsigned long __user *)addr);
- break;
- }
- case ARCH_GET_GS: {
- unsigned long base;
- if (doit)
- rdmsrl(MSR_KERNEL_GS_BASE, base);
- else
- base = task->thread.gsbase;
- ret = put_user(base, (unsigned long __user *)addr);
- break;
- }
-
- default:
- ret = -EINVAL;
- break;
- }
-
- return ret;
-}
-
-long sys_arch_prctl(int code, unsigned long addr)
-{
- return do_arch_prctl(current, code, addr);
-}
-
unsigned long KSTK_ESP(struct task_struct *task)
{
return task_pt_regs(task)->sp;
--
2.7.4
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