[PATCH] provide kernel_execve on all architectures

[mirror_ubuntu-zesty-kernel.git] / arch / mips / kernel / syscall.c

diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index 970e3e96b1d0ccd222b32b845a57108bb75ec0c5..26e1a7e78d13dac0acac8277572c88c74c9a106a 100644 (file)
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -406,3 +406,32 @@ asmlinkage void bad_stack(void)
 {
        do_exit(SIGSEGV);
 }
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+       register unsigned long __a0 asm("$4") = (unsigned long) filename;
+       register unsigned long __a1 asm("$5") = (unsigned long) argv;
+       register unsigned long __a2 asm("$6") = (unsigned long) envp;
+       register unsigned long __a3 asm("$7");
+       unsigned long __v0;
+
+       __asm__ volatile ("                                     \n"
+       "       .set    noreorder                               \n"
+       "       li      $2, %5          # __NR_execve           \n"
+       "       syscall                                         \n"
+       "       move    %0, $2                                  \n"
+       "       .set    reorder                                 \n"
+       : "=&r" (__v0), "=r" (__a3)
+       : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
+       : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
+         "memory");
+
+       if (__a3 == 0)
+               return __v0;
+
+       return -__v0;
+}