[PATCH 4.9 115/223] um: Fix FP register size for XSTATE/XSAVE

Greg Kroah-Hartman
2019-08-02T09:45:52Z

From: Thomas Meyer <thomas@m3y3r.de>

commit 6f602afda7275c24c20ba38b5b6cd4ed08561fff upstream.

Hard code max size. Taken from
https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gdb/common/x86-xstate.h

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/um/include/asm/thread_info.h | 3 +++
arch/um/include/shared/os.h | 2 +-
arch/um/kernel/process.c | 4 ++--
arch/um/os-Linux/skas/process.c | 17 ++++++++---------
arch/x86/um/os-Linux/registers.c | 18 ++++++++++++------
arch/x86/um/user-offsets.c | 4 ++--
6 files changed, 28 insertions(+), 20 deletions(-)

--- a/arch/um/include/asm/thread_info.h
+++ b/arch/um/include/asm/thread_info.h
@@ -11,6 +11,7 @@
#include <asm/types.h>
#include <asm/page.h>
#include <asm/segment.h>
+#include <sysdep/ptrace_user.h>

struct thread_info {
struct task_struct *task; /* main task structure */
@@ -22,6 +23,8 @@ struct thread_info {
0-0xBFFFFFFF for user
0-0xFFFFFFFF for kernel */
struct thread_info *real_thread; /* Points to non-IRQ stack */
+ unsigned long aux_fp_regs[FP_SIZE]; /* auxiliary fp_regs to save/restore
+ them out-of-band */
};

#define INIT_THREAD_INFO(tsk) \
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -274,7 +274,7 @@ extern int protect(struct mm_id * mm_idp
extern int is_skas_winch(int pid, int fd, void *data);
extern int start_userspace(unsigned long stub_stack);
extern int copy_context_skas0(unsigned long stack, int pid);
-extern void userspace(struct uml_pt_regs *regs);
+extern void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs);
extern int map_stub_pages(int fd, unsigned long code, unsigned long data,
unsigned long stack);
extern void new_thread(void *stack, jmp_buf *buf, void (*handler)(void));
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -128,7 +128,7 @@ void new_thread_handler(void)
* callback returns only if the kernel thread execs a process
*/
n = fn(arg);
- userspace(&current->thread.regs.regs);
+ userspace(&current->thread.regs.regs, current_thread_info()->aux_fp_regs);
}

/* Called magically, see new_thread_handler above */
@@ -147,7 +147,7 @@ void fork_handler(void)

current->thread.prev_sched = NULL;

- userspace(&current->thread.regs.regs);
+ userspace(&current->thread.regs.regs, current_thread_info()->aux_fp_regs);
}

int copy_thread(unsigned long clone_flags, unsigned long sp,
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -87,12 +87,11 @@ bad_wait:

extern unsigned long current_stub_stack(void);

-static void get_skas_faultinfo(int pid, struct faultinfo *fi)
+static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux_fp_regs)
{
int err;
- unsigned long fpregs[FP_SIZE];

- err = get_fp_registers(pid, fpregs);
+ err = get_fp_registers(pid, aux_fp_regs);
if (err < 0) {
printk(UM_KERN_ERR "save_fp_registers returned %d\n",
err);
@@ -112,7 +111,7 @@ static void get_skas_faultinfo(int pid,
*/
memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));

- err = put_fp_registers(pid, fpregs);
+ err = put_fp_registers(pid, aux_fp_regs);
if (err < 0) {
printk(UM_KERN_ERR "put_fp_registers returned %d\n",
err);
@@ -120,9 +119,9 @@ static void get_skas_faultinfo(int pid,
}
}

-static void handle_segv(int pid, struct uml_pt_regs * regs)
+static void handle_segv(int pid, struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
{
- get_skas_faultinfo(pid, &regs->faultinfo);
+ get_skas_faultinfo(pid, &regs->faultinfo, aux_fp_regs);
segv(regs->faultinfo, 0, 1, NULL);
}

@@ -305,7 +304,7 @@ int start_userspace(unsigned long stub_s
return err;
}

-void userspace(struct uml_pt_regs *regs)
+void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
{
int err, status, op, pid = userspace_pid[0];
/* To prevent races if using_sysemu changes under us.*/
@@ -374,11 +373,11 @@ void userspace(struct uml_pt_regs *regs)
case SIGSEGV:
if (PTRACE_FULL_FAULTINFO) {
get_skas_faultinfo(pid,
- &regs->faultinfo);
+ &regs->faultinfo, aux_fp_regs);
(*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si,
regs);
}
- else handle_segv(pid, regs);
+ else handle_segv(pid, regs, aux_fp_regs);
break;
case SIGTRAP + 0x80:
handle_trap(pid, regs, local_using_sysemu);
--- a/arch/x86/um/os-Linux/registers.c
+++ b/arch/x86/um/os-Linux/registers.c
@@ -5,6 +5,7 @@
*/

#include <errno.h>
+#include <stdlib.h>
#include <sys/ptrace.h>
#ifdef __i386__
#include <sys/user.h>
@@ -31,7 +32,7 @@ int save_fp_registers(int pid, unsigned

if (have_xstate_support) {
iov.iov_base = fp_regs;
- iov.iov_len = sizeof(struct _xstate);
+ iov.iov_len = FP_SIZE * sizeof(unsigned long);
if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
return -errno;
return 0;
@@ -51,10 +52,9 @@ int restore_fp_registers(int pid, unsign
{
#ifdef PTRACE_SETREGSET
struct iovec iov;
-
if (have_xstate_support) {
iov.iov_base = fp_regs;
- iov.iov_len = sizeof(struct _xstate);
+ iov.iov_len = FP_SIZE * sizeof(unsigned long);
if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
return -errno;
return 0;
@@ -125,13 +125,19 @@ int put_fp_registers(int pid, unsigned l
void arch_init_registers(int pid)
{
#ifdef PTRACE_GETREGSET
- struct _xstate fp_regs;
+ void * fp_regs;
struct iovec iov;

- iov.iov_base = &fp_regs;
- iov.iov_len = sizeof(struct _xstate);
+ fp_regs = malloc(FP_SIZE * sizeof(unsigned long));
+ if(fp_regs == NULL)
+ return;
+
+ iov.iov_base = fp_regs;
+ iov.iov_len = FP_SIZE * sizeof(unsigned long);
if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0)
have_xstate_support = 1;
+
+ free(fp_regs);
#endif
}
#endif
--- a/arch/x86/um/user-offsets.c
+++ b/arch/x86/um/user-offsets.c
@@ -50,8 +50,8 @@ void foo(void)
DEFINE(HOST_GS, GS);
DEFINE(HOST_ORIG_AX, ORIG_EAX);
#else
-#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET)
- DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long));
+#ifdef FP_XSTATE_MAGIC1
+ DEFINE_LONGS(HOST_FP_SIZE, 2696);
#else
DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
#endif