linux/arch/mips/lib/delay.c
Masahiro Yamada 78bdbbac08 MIPS: do not compile generic functions for CONFIG_CAVIUM_OCTEON_SOC
MIPS provides multiple definitions for the following functions:

  fw_init_cmdline
  __delay
  __udelay
  __ndelay
  memmove
  __rmemcpy
  memcpy
  __copy_user

The generic ones are defined in lib-y objects, which are overridden by
the Octeon ones when CONFIG_CAVIUM_OCTEON_SOC is enabled.

The use of EXPORT_SYMBOL in static libraries potentially causes a
problem for the llvm linker [1]. So, I want to forcibly link lib-y
objects to vmlinux when CONFIG_MODULES=y.

As a groundwork, we must fix multiple definitions that have previously
been hidden by lib-y.

If you look at lib/string.c, arch can define __HAVE_ARCH_* to opt out
the generic implementation.

Similarly, this commit adds CONFIG_HAVE_PLAT_* to allow a platform
to opt out the MIPS generic code.

[1]: https://github.com/ClangBuiltLinux/linux/issues/515

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
2020-03-25 16:07:13 +01:00

70 lines
1.7 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 by Waldorf Electronics
* Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2007, 2014 Maciej W. Rozycki
*/
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/param.h>
#include <linux/smp.h>
#include <linux/stringify.h>
#include <asm/asm.h>
#include <asm/compiler.h>
#include <asm/war.h>
#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
#define GCC_DADDI_IMM_ASM() "I"
#else
#define GCC_DADDI_IMM_ASM() "r"
#endif
#ifndef CONFIG_HAVE_PLAT_DELAY
void __delay(unsigned long loops)
{
__asm__ __volatile__ (
" .set noreorder \n"
" .align 3 \n"
"1: bnez %0, 1b \n"
" " __stringify(LONG_SUBU) " %0, %1 \n"
" .set reorder \n"
: "=r" (loops)
: GCC_DADDI_IMM_ASM() (1), "0" (loops));
}
EXPORT_SYMBOL(__delay);
/*
* Division by multiplication: you don't have to worry about
* loss of precision.
*
* Use only for very small delays ( < 1 msec). Should probably use a
* lookup table, really, as the multiplications take much too long with
* short delays. This is a "reasonable" implementation, though (and the
* first constant multiplications gets optimized away if the delay is
* a constant)
*/
void __udelay(unsigned long us)
{
unsigned int lpj = raw_current_cpu_data.udelay_val;
__delay((us * 0x000010c7ull * HZ * lpj) >> 32);
}
EXPORT_SYMBOL(__udelay);
void __ndelay(unsigned long ns)
{
unsigned int lpj = raw_current_cpu_data.udelay_val;
__delay((ns * 0x00000005ull * HZ * lpj) >> 32);
}
EXPORT_SYMBOL(__ndelay);
#endif