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authorRalf Baechle <ralf@linux-mips.org>2009-09-17 02:25:05 +0200
committerRalf Baechle <ralf@linux-mips.org>2009-09-17 20:07:49 +0200
commitf1e39a4a616cd9981a9decfd5332fd07a01abb8b (patch)
tree555e0c78611bb30cef2caca1ae1b5043a9999290 /arch/mips/kernel/syscall.c
parentf4c6b6bc5a4fc8d607f2d89369008c85a3a12a8b (diff)
MIPS: Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler
This way it doesn't have to use CONFIG_CPU_HAS_LLSC anymore. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/syscall.c')
-rw-r--r--arch/mips/kernel/syscall.c112
1 files changed, 109 insertions, 3 deletions
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index 8cf384644040..3fe1fcfa2e73 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -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)