* [Linux-ia64] patching syscall into module
@ 2002-04-02 21:05 Joubert Berger
2002-04-02 21:46 ` Keith Owens
0 siblings, 1 reply; 2+ messages in thread
From: Joubert Berger @ 2002-04-02 21:05 UTC (permalink / raw)
To: linux-ia64
I am having some difficulty hooking a syscall from a module. I used
the work that Chas Williams did for openafs. But, I can't get my test
program to work.
Below is my test program and below that the stack trace.
=============< cut here >===============
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/types.h>
#include <sys/syscall.h>
#include <linux/init.h>
#include <linux/slab.h>
extern void *sys_call_table[];
struct fptr {
unsigned long ip;
unsigned long gp;
};
unsigned char *chmod_stub;
asmlinkage long (*sys_chmodp) (const char *, int, mode_t);
long my_chmod(const char *filename, int mode, mode_t dev)
{
printk("Original syscall\n");
// return (*sys_chmodp)(filename, mode, dev);
return 0;
}
unsigned char ia64_syscall_stub[] {
0x00, 0x50, 0x45, 0x16, 0x80, 0x05, // [MII] alloc r42=ar.pfs,8,3,6,0
0x90, 0x02, 0x00, 0x62, 0x00, 0x60, // mov r41°
0x05, 0x00, 0x01, 0x84, // mov r43=r32
0x00, 0x60, 0x01, 0x42, 0x00, 0x21, // [MII] mov r44=r33
0xd0, 0x02, 0x88, 0x00, 0x42, 0xc0, // mov r45=r34
0x05, 0x18, 0x01, 0x84, // mov r46=r35
0x0d, 0x78, 0x01, 0x48, 0x00, 0x21, // [MFI] mov r47=r36
0x00, 0x00, 0x00, 0x02, 0x00, 0x00, // nop.f 0x0
0x06, 0x08, 0x00, 0x84, // mov r48=gp;;
0x05, 0x00, 0x00, 0x00, 0x01, 0x00, // [MLX] nop.m 0x0
0x00, 0x00, 0x00, 0x00, 0x00, 0xe0, // movl r15=0x0;;
0x01, 0x00, 0x00, 0x60, //
0x0a, 0x80, 0x20, 0x1e, 0x18, 0x14, // [MMI] ld8 r16=[r15],8;;
0x10, 0x00, 0x3c, 0x30, 0x20, 0xc0, // ld8 gp=[r15]
0x00, 0x09, 0x00, 0x07, // mov b6=r16
0x1d, 0x00, 0x00, 0x00, 0x01, 0x00, // [MFB] nop.m 0x0
0x00, 0x00, 0x00, 0x02, 0x00, 0x00, // nop.f 0x0
0x68, 0x00, 0x00, 0x10, // br.call.sptk.many
b0¶;;
0x00, 0x00, 0x00, 0x00, 0x01, 0x00, // [MII] nop.m 0x0
0x00, 0x50, 0x01, 0x55, 0x00, 0x00, // mov.i ar.pfs=r42
0x90, 0x0a, 0x00, 0x07, // mov b0=r41
0x1d, 0x08, 0x00, 0x60, 0x00, 0x21, // [MFB] mov gp=r48
0x00, 0x00, 0x00, 0x02, 0x00, 0x80, // nop.f 0x0
0x08, 0x00, 0x84, 0x00 // br.ret.sptk.many b0;;
};
void ia64_imm64_fixup(unsigned long v, void *code)
{
unsigned long *bundle = (unsigned long *) code;
unsigned long insn;
unsigned long slot1;
insn = ((v & 0x8000000000000000) >> 27) | ((v &
0x0000000000200000)) |
((v & 0x00000000001f0000) << 6) | ((v & 0x000000000000ff80)
<< 20) | ((v & 0x000000000000007f) << 13);
slot1 = (v & 0x7fffffffffc00000) >> 22;
*bundle |= slot1 << 46;
*(bundle+1) |= insn << 23;
*(bundle+1) |= slot1 >> 18;
}
int __init
init_module(void)
{
unsigned long kernel_gp;
static struct fptr sys_chmod;
kernel_gp = ((struct fptr *) printk)->gp;
/* Setup the original call */
sys_chmodp = (void *) &sys_chmod;
((struct fptr *) sys_chmodp)->ip = (void *)
sys_call_table[__NR_chmod-1024];
((struct fptr *) sys_chmodp)->gp = kernel_gp;
/* Hook the syscall with our call */
chmod_stub = (void *) kmalloc(sizeof(ia64_syscall_stub), GFP_KERNEL);
memcpy(chmod_stub, ia64_syscall_stub, sizeof(ia64_syscall_stub));
ia64_imm64_fixup((unsigned long) my_chmod, chmod_stub+0x30);
sys_call_table[__NR_chmod-1024] = (void *) chmod_stub;
printk("Installing module\n");
return 0;
}
void __exit
cleanup_module(void)
{
printk("Removing module\n");
sys_call_table[__NR_chmod - 1024] = (void *) ((struct fptr *)
sys_chmodp)->ip;
}
==============< cut here >===========
But, here is the stack trace:
Apr 2 10:20:17 kong kernel: Installing module
Apr 2 10:20:31 kong kernel: Original syscall
Apr 2 10:20:31 kong kernel: chmod[865]: General Exception: IA-64
Reserved Register/Field fault (data access) 17179869232
Apr 2 10:20:31 kong kernel: --> schedule [kernel] 0x100 <--
Apr 2 10:20:31 kong kernel:
Apr 2 10:20:31 kong kernel: psr : 0000101008026018 ifs :
8000000000000894 ip : [schedule+256/4576] Tainted: P
Apr 2 10:20:31 kong kernel: psr : 0000101008026018 ifs :
8000000000000894 ip : [<e0000000044e6520>] Tainted: P
Apr 2 10:20:31 kong kernel: unat: 0000000000000000 pfs :
000000000000050a rsc : 0000000000000003
Apr 2 10:20:31 kong kernel: rnat: e00000003e6b66c8 bsps:
40000000000007e0 pr : 000000000002005b
Apr 2 10:20:31 kong kernel: ldrs: 0000000000000000 ccv :
0000000000000000 fpsr: 0009804c8a70033f
Apr 2 10:20:31 kong kernel: b0 : e0000000044923e0 b6 :
e0000000046e73c0 b7 : e000000004492050
Apr 2 10:20:31 kong kernel: f6 : 0fffafffffffff0000000 f7 :
0ffdee000000000000000
Apr 2 10:20:31 kong kernel: f8 : 10002e000000000000000 f9 :
100038000000000000000
Apr 2 10:20:31 kong kernel: r1 : e00000000454b1a0 r2 :
e00000003af1ff00 r3 : e00000003af18000
Apr 2 10:20:31 kong kernel: r8 : 0000000000000000 r9 :
0000000000000894 r10 : 0000000000000000
Apr 2 10:20:31 kong kernel: r11 : 000000000002029b r12 :
e00000003af1fe50 r13 : e00000003af18000
Apr 2 10:20:31 kong kernel: r14 : e00000003af18038 r15 :
8401190100420084 r16 : e000000004a9bb78
Apr 2 10:20:31 kong kernel: r17 : 0000000000000001 r18 :
0000000000000000 r19 : 0000000000000000
Apr 2 10:20:31 kong kernel: r20 : e000000004aff1b0 r21 :
e000000004aff1d0 r22 : 0000000000000000
Apr 2 10:20:31 kong kernel: r23 : e000000004aa6a90 r24 :
0000001008026018 r25 : e00000003cfd0040
Apr 2 10:20:31 kong kernel: r26 : e00000003cfd0050 r27 :
e00000003cfd0068 r28 : e00000003af18064
Apr 2 10:20:31 kong kernel: r29 : 0000000000000001 r30 :
0000000000000000 r31 : 0000000000000000
Apr 2 10:20:31 kong kernel: r32 : 6f732e6362696c00 r33 :
72747300312e362e r34 : 7478657400797063
Apr 2 10:20:31 kong kernel: r35 : 74730066746e6972 r36 :
7465670074756f64 r37 : 676e6f6c5f74706f
Apr 2 10:20:31 kong kernel: r38 : 646e6570665f5f00 r39 :
74635f5f00676e69 r40 : 656d00625f657079
Apr 2 10:20:31 kong kernel: r41 : 747570007970636d r42 :
776f7472626d0073 r43 : 636f6c6c616d0063
Apr 2 10:20:31 kong kernel: r44 : 0067726174706f00 r45 :
0072696464616572 r46 : 756f747274735f5f
Apr 2 10:20:31 kong kernel: r47 : 6e7265746e695f6c r48 :
74726f6261006c61 r49 : 5f00646f6d686300
Apr 2 10:20:31 kong kernel: r50 : 0074617473786c5f r51 : 746e697270777369
Apr 2 10:20:31 kong kernel: Call Trace: [show_stack+80/192]
sp=0xe00000003af1f9d0 bsp=0xe00000003af191d0
Apr 2 10:20:31 kong kernel: Call Trace: [<e000000004497710>]
sp=0xe00000003af1f9d0 bsp=0xe00000003af191d0
Apr 2 10:20:31 kong kernel: decoded to show_stack [kernel] 0x50
Apr 2 10:20:31 kong kernel: [show_regs+1968/2016] sp=0xe00000003af1fb90
bsp=0xe00000003af19178
Apr 2 10:20:31 kong kernel: [<e000000004497f30>] sp=0xe00000003af1fb90
bsp=0xe00000003af19178
Apr 2 10:20:31 kong kernel: decoded to show_regs [kernel] 0x7b0
Apr 2 10:20:31 kong kernel: [die_if_kernel+112/320]
sp=0xe00000003af1fbb0 bsp=0xe00000003af19150
Apr 2 10:20:31 kong kernel: [<e0000000044a8ef0>] sp=0xe00000003af1fbb0
bsp=0xe00000003af19150
Apr 2 10:20:31 kong kernel: decoded to die_if_kernel [kernel] 0x70
Apr 2 10:20:31 kong kernel: [ia64_fault+1936/1984]
sp=0xe00000003af1fbb0 bsp=0xe00000003af19118
Apr 2 10:20:31 kong kernel: [<e0000000044aa470>] sp=0xe00000003af1fbb0
bsp=0xe00000003af19118
Apr 2 10:20:31 kong kernel: decoded to ia64_fault [kernel] 0x790
Apr 2 10:20:31 kong kernel: [ia64_leave_kernel+0/640]
sp=0xe00000003af1fcb0 bsp=0xe00000003af19118
Apr 2 10:20:31 kong kernel: [<e000000004491fe0>] sp=0xe00000003af1fcb0
bsp=0xe00000003af19118
Apr 2 10:20:31 kong kernel: decoded to ia64_leave_kernel [kernel] 0x0
Apr 2 10:20:31 kong kernel: [schedule+256/4576] sp=0xe00000003af1fe50
bsp=0xe00000003af19078
Apr 2 10:20:31 kong kernel: [<e0000000044e6520>] sp=0xe00000003af1fe50
bsp=0xe00000003af19078
Apr 2 10:20:31 kong kernel: decoded to schedule [kernel] 0x100
Apr 2 10:20:31 kong kernel: [invoke_schedule+32/64]
sp=0xe00000003af1fe60 bsp=0xe00000003af19028
Apr 2 10:20:32 kong kernel: [<e0000000044923e0>] sp=0xe00000003af1fe60
bsp=0xe00000003af19028
Apr 2 10:20:32 kong kernel: decoded to invoke_schedule [kernel] 0x20
Apr 2 10:20:32 kong kernel: [ia64_leave_kernel+32/640]
sp=0xe00000003af1fe60 bsp=0xe00000003af19028
Apr 2 10:20:32 kong kernel: [<e000000004492000>] sp=0xe00000003af1fe60
bsp=0xe00000003af19028
Apr 2 10:20:32 kong kernel: decoded to ia64_leave_kernel [kernel] 0x20
Any help in figuring out what I am doing wrong would be greatly appreciated.
--joubert
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Linux-ia64] patching syscall into module
2002-04-02 21:05 [Linux-ia64] patching syscall into module Joubert Berger
@ 2002-04-02 21:46 ` Keith Owens
0 siblings, 0 replies; 2+ messages in thread
From: Keith Owens @ 2002-04-02 21:46 UTC (permalink / raw)
To: linux-ia64
On Tue, 02 Apr 2002 16:05:45 -0500,
Joubert Berger <joubert@issl.atl.hp.com> wrote:
>I am having some difficulty hooking a syscall from a module.
Syscalls are not allowed in modules. Linus forbids them (it allows
"extend and embrace") and there is no architecture independent way of
pointing the syscall table at module code. As you have found out,
syscalls in modules will break on IA64 and will also break on PPC64.
I cannot stop you doing this in your own code but I can guarantee that
syscalls in modules will not be accepted in the mainline kernel, nor
will it be supported by modutils.
^ permalink raw reply [flat|nested] 2+ messages in thread
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