[PATCH 8/15] misc: Make vm86 support optional

From: Matt Mackall
Date: Fri Nov 11 2005 - 03:41:55 EST

Make vm86 support optional

add/remove: 0/14 grow/shrink: 0/5 up/down: 0/-5221 (-5221)
function old new delta
do_simd_coprocessor_error 133 132 -1
irqbits 4 - -4
irqbits_lock 8 - -8
release_thread 72 52 -20
do_debug 212 186 -26
do_general_protection 475 428 -47
do_trap 196 140 -56
release_vm86_irqs 112 - -112
vm86_irqs 128 - -128
sys_vm86old 146 - -146
irq_handler 151 - -151
mark_screen_rdonly 159 - -159
sys_vm86 199 - -199
handle_vm86_trap 231 - -231
save_v86_state 339 - -339
do_sys_vm86 379 - -379
do_vm86_irq_handling 482 - -482
do_int 508 - -508
handle_vm86_fault 2225 - -2225

Signed-off-by: Matt Mackall <mpm@xxxxxxxxxxx>

Index: 2.6.14-misc/arch/i386/kernel/entry.S
===================================================================
--- 2.6.14-misc.orig/arch/i386/kernel/entry.S 2005-11-09 11:20:20.000000000 -0800
+++ 2.6.14-misc/arch/i386/kernel/entry.S 2005-11-09 11:20:21.000000000 -0800
@@ -313,15 +313,21 @@ work_resched:

work_notifysig: # deal with pending signals and
# notify-resume requests
- testl $VM_MASK, EFLAGS(%esp)
movl %esp, %eax
+
+#ifdef CONFIG_VM86
+ testl $VM_MASK, EFLAGS(%esp)
jne work_notifysig_v86 # returning to kernel-space or
# vm86-space
+#endif
+
xorl %edx, %edx
call do_notify_resume
jmp resume_userspace

ALIGN
+
+#ifdef CONFIG_VM86
work_notifysig_v86:
pushl %ecx # save ti_flags for do_notify_resume
call save_v86_state # %eax contains pt_regs pointer
@@ -333,6 +339,8 @@ work_notifysig_v86:

# perform syscall exit tracing
ALIGN
+#endif
+
syscall_trace_entry:
movl $-ENOSYS,EAX(%esp)
movl %esp, %eax
Index: 2.6.14-misc/arch/i386/kernel/process.c
===================================================================
--- 2.6.14-misc.orig/arch/i386/kernel/process.c 2005-11-09 11:20:20.000000000 -0800
+++ 2.6.14-misc/arch/i386/kernel/process.c 2005-11-09 11:20:21.000000000 -0800
@@ -428,7 +428,9 @@ void release_thread(struct task_struct *
}
}

+#ifdef CONFIG_VM86
release_vm86_irqs(dead_task);
+#endif
}

/*
Index: 2.6.14-misc/arch/i386/kernel/traps.c
===================================================================
--- 2.6.14-misc.orig/arch/i386/kernel/traps.c 2005-11-09 11:20:20.000000000 -0800
+++ 2.6.14-misc/arch/i386/kernel/traps.c 2005-11-09 11:20:21.000000000 -0800
@@ -371,8 +371,10 @@ static void __kprobes do_trap(int trapnr
tsk->thread.trap_no = trapnr;

if (regs->eflags & VM_MASK) {
+#ifdef CONFIG_VM86
if (vm86)
goto vm86_trap;
+#endif
goto trap_signal;
}

@@ -393,11 +395,13 @@ static void __kprobes do_trap(int trapnr
return;
}

+#ifdef CONFIG_VM86
vm86_trap: {
int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr);
if (ret) goto trap_signal;
return;
}
+#endif
}

#define DO_ERROR(trapnr, signr, str, name) \
@@ -452,6 +456,7 @@ DO_VM86_ERROR( 3, SIGTRAP, "int3", int3)
#endif
DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow)
DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds)
+
DO_ERROR_INFO( 6, SIGILL, "invalid operand", invalid_op, ILL_ILLOPN, regs->eip)
DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
@@ -497,8 +502,10 @@ fastcall void __kprobes do_general_prote
current->thread.error_code = error_code;
current->thread.trap_no = 13;

+#ifdef CONFIG_VM86
if (regs->eflags & VM_MASK)
goto gp_in_vm86;
+#endif

if (!user_mode(regs))
goto gp_in_kernel;
@@ -508,10 +515,12 @@ fastcall void __kprobes do_general_prote
force_sig(SIGSEGV, current);
return;

+#ifdef CONFIG_VM86
gp_in_vm86:
local_irq_enable();
handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
return;
+#endif

gp_in_kernel:
if (!fixup_exception(regs)) {
@@ -732,8 +741,10 @@ fastcall void __kprobes do_debug(struct
goto clear_dr7;
}

+#ifdef CONFIG_VM86
if (regs->eflags & VM_MASK)
goto debug_vm86;
+#endif

/* Save debug status register where ptrace can see it */
tsk->thread.debugreg[6] = condition;
@@ -762,9 +773,11 @@ clear_dr7:
set_debugreg(0, 7);
return;

+#ifdef CONFIG_VM86
debug_vm86:
handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
return;
+#endif

clear_TF_reenable:
set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
@@ -902,11 +915,13 @@ fastcall void do_simd_coprocessor_error(
* Handle strange cache flush from user space exception
* in all other cases. This is undocumented behaviour.
*/
+#ifdef CONFIG_VM86
if (regs->eflags & VM_MASK) {
handle_vm86_fault((struct kernel_vm86_regs *)regs,
error_code);
return;
}
+#endif
current->thread.trap_no = 19;
current->thread.error_code = error_code;
die_if_kernel("cache flush denied", regs, error_code);
Index: 2.6.14-misc/arch/i386/kernel/vm86.c
===================================================================
--- 2.6.14-misc.orig/arch/i386/kernel/vm86.c 2005-11-09 11:20:20.000000000 -0800
+++ 2.6.14-misc/arch/i386/kernel/vm86.c 2005-11-09 11:20:21.000000000 -0800
@@ -805,4 +805,3 @@ static int do_vm86_irq_handling(int subf
}
return -EINVAL;
}
-
Index: 2.6.14-misc/arch/i386/kernel/Makefile
===================================================================
--- 2.6.14-misc.orig/arch/i386/kernel/Makefile 2005-11-09 11:20:20.000000000 -0800
+++ 2.6.14-misc/arch/i386/kernel/Makefile 2005-11-09 11:20:21.000000000 -0800
@@ -4,7 +4,7 @@

extra-y := head.o init_task.o vmlinux.lds

-obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o vm86.o \
+obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o \
ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_i386.o \
pci-dma.o i386_ksyms.o i387.o dmi_scan.o bootflag.o \
quirks.o i8237.o
@@ -34,6 +34,7 @@ obj-$(CONFIG_ACPI_SRAT) += srat.o
obj-$(CONFIG_HPET_TIMER) += time_hpet.o
obj-$(CONFIG_EFI) += efi.o efi_stub.o
obj-$(CONFIG_DOUBLEFAULT) += doublefault.o
+obj-$(CONFIG_VM86) += vm86.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o

EXTRA_AFLAGS := -traditional
Index: 2.6.14-misc/arch/i386/kernel/sys_i386.c
===================================================================
--- 2.6.14-misc.orig/arch/i386/kernel/sys_i386.c 2005-11-09 11:20:20.000000000 -0800
+++ 2.6.14-misc/arch/i386/kernel/sys_i386.c 2005-11-09 11:20:21.000000000 -0800
@@ -22,6 +22,7 @@

#include <asm/uaccess.h>
#include <asm/ipc.h>
+#include <asm/unistd.h>

/*
* sys_pipe() is the normal C calling standard for creating
Index: 2.6.14-misc/init/Kconfig
===================================================================
--- 2.6.14-misc.orig/init/Kconfig 2005-11-09 11:20:20.000000000 -0800
+++ 2.6.14-misc/init/Kconfig 2005-11-09 11:20:39.000000000 -0800
@@ -347,6 +347,16 @@ config EPOLL
Disabling this option will cause the kernel to be built without
support for epoll family of system calls.

+config VM86
+ depends X86
+ default y
+ bool "Enable VM86 support" if EMBEDDED
+ help
+ This option is required by programs like DOSEMU to run 16-bit legacy
+ code on X86 processors. It also may be needed by software like
+ XFree86 to initialize some video cards via BIOS. Disabling this
+ option saves about 6k.
+
config CC_OPTIMIZE_FOR_SIZE
bool "Optimize for size" if EMBEDDED
default y if ARM || H8300
Index: 2.6.14-misc/kernel/sys_ni.c
===================================================================
--- 2.6.14-misc.orig/kernel/sys_ni.c 2005-11-09 11:20:20.000000000 -0800
+++ 2.6.14-misc/kernel/sys_ni.c 2005-11-09 11:20:21.000000000 -0800
@@ -82,6 +82,8 @@ cond_syscall(compat_sys_socketcall);
cond_syscall(sys_inotify_init);
cond_syscall(sys_inotify_add_watch);
cond_syscall(sys_inotify_rm_watch);
+cond_syscall(sys_vm86old);
+cond_syscall(sys_vm86);

/* arch-specific weak syscall entries */
cond_syscall(sys_pciconfig_read);
-
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