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| 1 .hidden __sysinfo |
| 2 |
| 3 # The calling convention for __vsyscall has the syscall number |
| 4 # and 5 args arriving as: eax, edx, ecx, edi, esi, 4(%esp). |
| 5 # This ensures that the inline asm in the C code never has to touch |
| 6 # ebx or ebp (which are unavailable in PIC and frame-pointer-using |
| 7 # code, respectively), and optimizes for size/simplicity in the caller. |
| 8 |
| 9 .global __vsyscall |
| 10 .hidden __vsyscall |
| 11 .type __vsyscall,@function |
| 12 __vsyscall: |
| 13 push %edi |
| 14 push %ebx |
| 15 mov %edx,%ebx |
| 16 mov %edi,%edx |
| 17 mov 12(%esp),%edi |
| 18 push %eax |
| 19 call 1f |
| 20 2: mov %ebx,%edx |
| 21 pop %ebx |
| 22 pop %ebx |
| 23 pop %edi |
| 24 ret |
| 25 |
| 26 1: mov (%esp),%eax |
| 27 add $[__sysinfo-2b],%eax |
| 28 mov (%eax),%eax |
| 29 test %eax,%eax |
| 30 jz 1f |
| 31 push %eax |
| 32 mov 8(%esp),%eax |
| 33 ret # tail call to kernel vsyscall entry |
| 34 1: mov 4(%esp),%eax |
| 35 int $128 |
| 36 ret |
| 37 |
| 38 # The __vsyscall6 entry point is used only for 6-argument syscalls. |
| 39 # Instead of passing the 5th argument on the stack, a pointer to the |
| 40 # 5th and 6th arguments is passed. This is ugly, but there are no |
| 41 # register constraints the inline asm could use that would make it |
| 42 # possible to pass two arguments on the stack. |
| 43 |
| 44 .global __vsyscall6 |
| 45 .hidden __vsyscall6 |
| 46 .type __vsyscall6,@function |
| 47 __vsyscall6: |
| 48 push %ebp |
| 49 push %eax |
| 50 mov 12(%esp), %ebp |
| 51 mov (%ebp), %eax |
| 52 mov 4(%ebp), %ebp |
| 53 push %eax |
| 54 mov 4(%esp),%eax |
| 55 call __vsyscall |
| 56 pop %ebp |
| 57 pop %ebp |
| 58 pop %ebp |
| 59 ret |
| 60 |
| 61 .global __syscall |
| 62 .hidden __syscall |
| 63 .type __syscall,@function |
| 64 __syscall: |
| 65 lea 24(%esp),%eax |
| 66 push %esi |
| 67 push %edi |
| 68 push %eax |
| 69 mov 16(%esp),%eax |
| 70 mov 20(%esp),%edx |
| 71 mov 24(%esp),%ecx |
| 72 mov 28(%esp),%edi |
| 73 mov 32(%esp),%esi |
| 74 call __vsyscall6 |
| 75 pop %edi |
| 76 pop %edi |
| 77 pop %esi |
| 78 ret |
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