test fxsave

Signed-off-by: Hajime Tazaki <thehajime@gmail.com>

arch/x86/um/nommu/do_syscall_64.c

@@ -6,6 +6,7 @@
 #include <asm/prctl.h>
 #include <kern_util.h>
 #include <sysdep/syscalls.h>
+#include <shared/registers.h>
 #include <os.h>
 
 /*
@@ -52,6 +53,8 @@ static int os_x86_arch_prctl(int pid, int option, unsigned long *arg2)
 	return 0;
 }
 
+char fpstate_buf[2696];
+
 __visible void do_syscall_64(struct pt_regs *regs)
 {
 	int syscall;

arch/x86/um/nommu/entry_64.S

@@ -45,6 +45,9 @@ ENTRY(__kernel_vsyscall)
 
 	movq	%rsp, %r11
 
+	/* save fpregs */
+	fxsave fpstate_buf
+
 	/* Point rsp to the top of the ptregs array, so we can
            just fill it with a bunch of push'es. */
 	movq	current_ptregs, %rsp
@@ -106,6 +109,10 @@ ENTRY(userspace)
 	addq	$8, %rsp	/* skip flags */
 	popq	%rsp
 
+
+	/* restore fpregs */
+	fxrstor fpstate_buf
+
 	jmp	*%r11
 
 END(userspace)

arch/x86/um/os-Linux/mcontext.c

@@ -17,6 +17,10 @@ void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc)
 	COPY2(UESP, ESP); /* sic */
 	COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX);
 	COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS);
+#undef COPY2
+#undef COPY
+#undef COPY_SEG
+#undef COPY_SEG_CPL3
 #else
 #define COPY2(X,Y) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##Y]
 #define COPY(X) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##X]
@@ -29,5 +33,99 @@ void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc)
 	COPY2(CS, CSGSFS);
 	regs->gp[CS / sizeof(unsigned long)] &= 0xffff;
 	regs->gp[CS / sizeof(unsigned long)] |= 3;
+#undef COPY2
+#undef COPY
 #endif
 }
+
+/* Same thing, but the copy macros are turned around. */
+void get_mc_from_regs(struct uml_pt_regs *regs, mcontext_t *mc, int single_stepping)
+{
+#ifdef __i386__
+#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X]
+#define COPY(X) mc->gregs[REG_##X] = regs->gp[X]
+#define COPY_SEG(X) mc->gregs[REG_##X] = regs->gp[X] & 0xffff;
+#define COPY_SEG_CPL3(X) mc->gregs[REG_##X] = (regs->gp[X] & 0xffff) | 3;
+	COPY_SEG(GS); COPY_SEG(FS); COPY_SEG(ES); COPY_SEG(DS);
+	COPY(EDI); COPY(ESI); COPY(EBP);
+	COPY2(UESP, ESP); /* sic */
+	COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX);
+	COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS);
+#else
+#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X/sizeof(unsigned long)]
+#define COPY(X) mc->gregs[REG_##X] = regs->gp[X/sizeof(unsigned long)]
+	COPY(R8); COPY(R9); COPY(R10); COPY(R11);
+	COPY(R12); COPY(R13); COPY(R14); COPY(R15);
+	COPY(RDI); COPY(RSI); COPY(RBP); COPY(RBX);
+	COPY(RDX); COPY(RAX); COPY(RCX); COPY(RSP);
+	COPY(RIP);
+	COPY2(EFLAGS, EFL);
+	mc->gregs[REG_CSGSFS] = mc->gregs[REG_CSGSFS] & 0xffffffffffffl;
+	mc->gregs[REG_CSGSFS] |= (regs->gp[SS / sizeof(unsigned long)] & 0xffff) << 48;
+#endif
+
+	if (single_stepping)
+		mc->gregs[REG_EFL] |= X86_EFLAGS_TF;
+	else
+		mc->gregs[REG_EFL] &= ~X86_EFLAGS_TF;
+}
+#if 0
+
+#ifdef CONFIG_X86_32
+struct _xstate_64 {
+	struct _fpstate_64		fpstate;
+	struct _header			xstate_hdr;
+	struct _ymmh_state		ymmh;
+	/* New processor state extensions go here: */
+};
+
+/* Not quite the right structures as these contain more information */
+int um_i387_from_fxsr(struct _fpstate_32 *i387,
+		      const struct _fpstate_64 *fxsave);
+int um_fxsr_from_i387(struct _fpstate_64 *fxsave,
+		      const struct _fpstate_32 *from);
+#else
+#define _xstate_64 _xstate
+#endif
+
+struct _fpstate *get_fpstate(struct stub_data *data,
+				    mcontext_t *mcontext,
+				    int *fp_size)
+{
+	struct _fpstate *res;
+
+	/* Assume floating point registers are on the same page */
+	res = (void *)(((unsigned long)mcontext->fpregs &
+			(UM_KERN_PAGE_SIZE - 1)) +
+		       (unsigned long)&data->sigstack[0]);
+
+	if ((void *)res + sizeof(struct _fpstate) >
+	    (void *)data->sigstack + sizeof(data->sigstack))
+		return NULL;
+
+	if (res->sw_reserved.magic1 != FP_XSTATE_MAGIC1) {
+		*fp_size = sizeof(struct _fpstate);
+	} else {
+		char *magic2_addr;
+
+		magic2_addr = (void *)res;
+		magic2_addr += res->sw_reserved.extended_size;
+		magic2_addr -= FP_XSTATE_MAGIC2_SIZE;
+
+		/* We still need to be within our stack */
+		if ((void *)magic2_addr >
+		    (void *)data->sigstack + sizeof(data->sigstack))
+			return NULL;
+
+		/* If we do not read MAGIC2, then we did something wrong */
+		if (*(__u32 *)magic2_addr != FP_XSTATE_MAGIC2)
+			return NULL;
+
+		/* Remove MAGIC2 from the size, we do not save/restore it */
+		*fp_size = res->sw_reserved.extended_size -
+			   FP_XSTATE_MAGIC2_SIZE;
+	}
+
+	return res;
+ }
+#endif

arch/x86/um/shared/sysdep/mcontext.h

@@ -7,6 +7,8 @@
 #define __SYS_SIGCONTEXT_X86_H
 
 extern void get_regs_from_mc(struct uml_pt_regs *, mcontext_t *);
+extern void get_mc_from_regs(struct uml_pt_regs *regs, mcontext_t *mc,
+			     int single_stepping);
 #ifndef CONFIG_MMU
 extern void mc_set_sigsys_hook(mcontext_t *mc);
 extern void mc_set_regs_ip_relay(mcontext_t *mc);