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score: add generic sys_call_table

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This adds back a sys_call_table to the score architecture, which
got lost in the conversion to the generic unistd.h file.
It's rather worrying that the code got submitted without a
system call table, which evidently means that it got zero
testing.

Since the system call table has a different layout from the old
one (which was modeled after the mips-o32 one), I also try to
fix the entry.S path to use it. In the modified calling conventions,
all system call arguments are passed as registers r4 through r9,
instead of r4 through r7 plus stack for the fifth and sixth argument.

This matches what other architectures to when they normally pass
arguments on the stack.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann 2009-06-19 11:31:54 +02:00
parent 78229db4c4
commit f673c032ed
4 changed files with 18 additions and 53 deletions
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3
arch/score/kernel/Makefile
View File

@ -5,6 +5,7 @@
extra-y := head.o vmlinux.lds
obj-y += entry.o init_task.o irq.o process.o ptrace.o \
setup.o signal.o sys_score.o time.o traps.o
setup.o signal.o sys_score.o time.o traps.o \
sys_call_table.o
obj-$(CONFIG_MODULES) += module.o

47
arch/score/kernel/entry.S
View File

@ -400,6 +400,8 @@ ENTRY(handle_sys)
sw r4, [r0, PT_ORIG_R4] #for restart syscall
sw r7, [r0, PT_ORIG_R7] #for restart syscall
sw r27, [r0, PT_IS_SYSCALL] # it from syscall
sw r8, [r0, 16] # argument 5 from user r8
sw r9, [r0, 20] # argument 6 from user r9
lw r9, [r0, PT_EPC] # skip syscall on return
addi r9, 4
@ -408,19 +410,14 @@ ENTRY(handle_sys)
cmpi.c r27, __NR_syscalls # check syscall number
bgtu illegal_syscall
slli r8, r27, 3 # get syscall routine
slli r8, r27, 2 # get syscall routine
la r11, sys_call_table
add r11, r11, r8
lw r10, [r11] # get syscall entry
lw r11, [r11, 4] # get number of args
cmpz.c r10
beq illegal_syscall
cmpi.c r11, 4 # more than 4 arguments?
bgtu stackargs
stack_done:
lw r8, [r28, TI_FLAGS]
li r9, _TIF_SYSCALL_TRACE
and.c r8, r8, r9
@ -475,44 +472,6 @@ syscall_trace_entry:
1: sw r4, [r0, PT_R2] # result
j syscall_exit
stackargs:
lw r8, [r0, PT_R0]
andri.c r9, r8, 3 # test whether user sp is align a word
bne bad_stack
subi r11, 5
slli r9, r11, 2
add.c r9, r9, r8
bmi bad_stack
la r9, 3f # calculate branch address
slli r11, r11, 3
sub r9, r9, r11
br r9
2: lw r9, [r8, 20] # argument 6 from usp
sw r9, [r0, 20]
3: lw r9, [r8, 16] # argument 5 from usp
sw r9, [r0, 16]
j stack_done
.section __ex_table,"a"
.word 2b, bad_stack
.word 3b, bad_stack
.previous
/*
* The stackpointer for a call with more than 4 arguments is bad.
* We probably should handle this case a bit more drastic.
*/
bad_stack:
neg r27, r27 # error
sw r27, [r0, PT_ORIG_R4]
sw r27, [r0, PT_R4]
ldi r8, 1 # set error flag
sw r8, [r0, PT_R7]
j syscall_return
illegal_syscall:
ldi r4, -ENOSYS # error
sw r4, [r0, PT_ORIG_R4]

12
arch/score/kernel/sys_call_table.c Normal file
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@ -0,0 +1,12 @@
#include <linux/syscalls.h>
#include <linux/signal.h>
#include <linux/unistd.h>
#include <asm/syscalls.h>
#undef __SYSCALL
#define __SYSCALL(nr, call) [nr] = (call),
void *sys_call_table[__NR_syscalls] = {
#include <asm/unistd.h>
};

9
arch/score/kernel/sys_score.c
View File

@ -75,14 +75,7 @@ int score_clone(struct pt_regs *regs)
if (!newsp)
newsp = regs->regs[0];
parent_tidptr = (int __user *)regs->regs[6];
child_tidptr = NULL;
if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
int __user *__user *usp = (int __user *__user *)regs->regs[0];
if (get_user(child_tidptr, &usp[4]))
return -EFAULT;
}
child_tidptr = (int __user *)regs->regs[8];
return do_fork(clone_flags, newsp, regs, 0,
parent_tidptr, child_tidptr);