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MIPS: Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler

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This way it doesn't have to use CONFIG_CPU_HAS_LLSC anymore.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Ralf Baechle
2009-09-17 02:25:05 +02:00
parent f4c6b6bc5a
commit f1e39a4a61
5 changed files with 114 additions and 150 deletions
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112
arch/mips/kernel/syscall.c
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@@ -28,7 +28,9 @@
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/ipc.h>
#include <linux/uaccess.h>
#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/cachectl.h>
#include <asm/cacheflush.h>
@@ -290,12 +292,116 @@ SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
return 0;
}
asmlinkage int _sys_sysmips(long cmd, long arg1, long arg2, long arg3)
static inline int mips_atomic_set(struct pt_regs *regs,
unsigned long addr, unsigned long new)
{
unsigned long old, tmp;
unsigned int err;
if (unlikely(addr & 3))
return -EINVAL;
if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
return -EINVAL;
if (cpu_has_llsc && R10000_LLSC_WAR) {
__asm__ __volatile__ (
" li %[err], 0 \n"
"1: ll %[old], (%[addr]) \n"
" move %[tmp], %[new] \n"
"2: sc %[tmp], (%[addr]) \n"
" beqzl %[tmp], 1b \n"
"3: \n"
" .section .fixup,\"ax\" \n"
"4: li %[err], %[efault] \n"
" j 3b \n"
" .previous \n"
" .section __ex_table,\"a\" \n"
" "STR(PTR)" 1b, 4b \n"
" "STR(PTR)" 2b, 4b \n"
" .previous \n"
: [old] "=&r" (old),
[err] "=&r" (err),
[tmp] "=&r" (tmp)
: [addr] "r" (addr),
[new] "r" (new),
[efault] "i" (-EFAULT)
: "memory");
} else if (cpu_has_llsc) {
__asm__ __volatile__ (
" li %[err], 0 \n"
"1: ll %[old], (%[addr]) \n"
" move %[tmp], %[new] \n"
"2: sc %[tmp], (%[addr]) \n"
" bnez %[tmp], 4f \n"
"3: \n"
" .subsection 2 \n"
"4: b 1b \n"
" .previous \n"
" \n"
" .section .fixup,\"ax\" \n"
"5: li %[err], %[efault] \n"
" j 3b \n"
" .previous \n"
" .section __ex_table,\"a\" \n"
" "STR(PTR)" 1b, 5b \n"
" "STR(PTR)" 2b, 5b \n"
" .previous \n"
: [old] "=&r" (old),
[err] "=&r" (err),
[tmp] "=&r" (tmp)
: [addr] "r" (addr),
[new] "r" (new),
[efault] "i" (-EFAULT)
: "memory");
} else {
do {
preempt_disable();
ll_bit = 1;
ll_task = current;
preempt_enable();
err = __get_user(old, (unsigned int *) addr);
err |= __put_user(new, (unsigned int *) addr);
if (err)
break;
rmb();
} while (!ll_bit);
}
if (unlikely(err))
return err;
regs->regs[2] = old;
regs->regs[7] = 0; /* No error */
/*
* Don't let your children do this ...
*/
__asm__ __volatile__(
" move $29, %0 \n"
" j syscall_exit \n"
: /* no outputs */
: "r" (regs));
/* unreached. Honestly. */
while (1);
}
save_static_function(sys_sysmips);
static int __used noinline
_sys_sysmips(nabi_no_regargs struct pt_regs regs)
{
long cmd, arg1, arg2, arg3;
cmd = regs.regs[4];
arg1 = regs.regs[5];
arg2 = regs.regs[6];
arg3 = regs.regs[7];
switch (cmd) {
case MIPS_ATOMIC_SET:
printk(KERN_CRIT "How did I get here?\n");
return -EINVAL;
return mips_atomic_set(&regs, arg1, arg2);
case MIPS_FIXADE:
if (arg1 & ~3)