mirror of
https://github.com/torvalds/linux.git
synced 2025-04-11 04:53:02 +00:00
14d4a7b516
Since __attribute__((naked)) cannot be used with functions
containing C statements, just generate the few instructions
it needs in assembly directly.
While at it, fix the stack usage ("1 + 2*x - 1" is odd) and
document what it must do, and why it must adjust the stack.
Fixes: 8508a5e0e9db ("um: Fix misaligned stack in stub_exe")
Link: https://lore.kernel.org/linux-um/CABVgOSntH-uoOFMP5HwMXjx_f1osMnVdhgKRKm4uz6DFm2Lb8Q@mail.gmail.com/
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
135 lines
2.6 KiB
C
135 lines
2.6 KiB
C
/*
|
|
* Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
|
|
* Licensed under the GPL
|
|
*/
|
|
|
|
#ifndef __SYSDEP_STUB_H
|
|
#define __SYSDEP_STUB_H
|
|
|
|
#include <stddef.h>
|
|
#include <asm/ptrace.h>
|
|
#include <generated/asm-offsets.h>
|
|
|
|
#define STUB_MMAP_NR __NR_mmap2
|
|
#define MMAP_OFFSET(o) ((o) >> UM_KERN_PAGE_SHIFT)
|
|
|
|
static __always_inline long stub_syscall0(long syscall)
|
|
{
|
|
long ret;
|
|
|
|
__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall)
|
|
: "memory");
|
|
|
|
return ret;
|
|
}
|
|
|
|
static __always_inline long stub_syscall1(long syscall, long arg1)
|
|
{
|
|
long ret;
|
|
|
|
__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1)
|
|
: "memory");
|
|
|
|
return ret;
|
|
}
|
|
|
|
static __always_inline long stub_syscall2(long syscall, long arg1, long arg2)
|
|
{
|
|
long ret;
|
|
|
|
__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
|
|
"c" (arg2)
|
|
: "memory");
|
|
|
|
return ret;
|
|
}
|
|
|
|
static __always_inline long stub_syscall3(long syscall, long arg1, long arg2,
|
|
long arg3)
|
|
{
|
|
long ret;
|
|
|
|
__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
|
|
"c" (arg2), "d" (arg3)
|
|
: "memory");
|
|
|
|
return ret;
|
|
}
|
|
|
|
static __always_inline long stub_syscall4(long syscall, long arg1, long arg2,
|
|
long arg3, long arg4)
|
|
{
|
|
long ret;
|
|
|
|
__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
|
|
"c" (arg2), "d" (arg3), "S" (arg4)
|
|
: "memory");
|
|
|
|
return ret;
|
|
}
|
|
|
|
static __always_inline long stub_syscall5(long syscall, long arg1, long arg2,
|
|
long arg3, long arg4, long arg5)
|
|
{
|
|
long ret;
|
|
|
|
__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
|
|
"c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
|
|
: "memory");
|
|
|
|
return ret;
|
|
}
|
|
|
|
static __always_inline long stub_syscall6(long syscall, long arg1, long arg2,
|
|
long arg3, long arg4, long arg5,
|
|
long arg6)
|
|
{
|
|
struct syscall_args {
|
|
int ebx, ebp;
|
|
} args = { arg1, arg6 };
|
|
long ret;
|
|
|
|
__asm__ volatile ("pushl %%ebp;"
|
|
"movl 0x4(%%ebx),%%ebp;"
|
|
"movl (%%ebx),%%ebx;"
|
|
"int $0x80;"
|
|
"popl %%ebp"
|
|
: "=a" (ret)
|
|
: "0" (syscall), "b" (&args),
|
|
"c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
|
|
: "memory");
|
|
|
|
return ret;
|
|
}
|
|
|
|
static __always_inline void trap_myself(void)
|
|
{
|
|
__asm("int3");
|
|
}
|
|
|
|
static __always_inline void *get_stub_data(void)
|
|
{
|
|
unsigned long ret;
|
|
|
|
asm volatile (
|
|
"call _here_%=;"
|
|
"_here_%=:"
|
|
"popl %0;"
|
|
"andl %1, %0 ;"
|
|
"addl %2, %0 ;"
|
|
: "=a" (ret)
|
|
: "g" (~(UM_KERN_PAGE_SIZE - 1)),
|
|
"g" (UM_KERN_PAGE_SIZE));
|
|
|
|
return (void *)ret;
|
|
}
|
|
|
|
#define stub_start(fn) \
|
|
asm volatile ( \
|
|
"subl %0,%%esp ;" \
|
|
"movl %1, %%eax ; " \
|
|
"call *%%eax ;" \
|
|
:: "i" ((1 + STUB_DATA_PAGES) * UM_KERN_PAGE_SIZE), \
|
|
"i" (&fn))
|
|
#endif
|