This workaround is necessary on certain CPUs when switching from user mode to kernel mode. Move it from its slightly odd location in the middle of get_saved_sp (which it is unrelated to) into the setup_kernel_mode macro. Since the setup_kernel_mode is a new self contained macro, we can ensure that reordering is on and drop the NOP delay slot fillers. Signed-off-by: Matt Redfearn <matt.redfearn@xxxxxxxx> --- arch/mips/include/asm/stackframe.h | 38 +++++++++++++++++++------------------- 1 file changed, 19 insertions(+), 19 deletions(-) diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h index 494fe41f5619..a47a9f5591a3 100644 --- a/arch/mips/include/asm/stackframe.h +++ b/arch/mips/include/asm/stackframe.h @@ -49,6 +49,24 @@ #endif .macro setup_kernel_mode docfi=0 + .set push + .set reorder + +#if !defined(CONFIG_SMP) && defined(CONFIG_CPU_JUMP_WORKAROUNDS) + /* + * Clear BTB (branch target buffer), forbid RAS (return address + * stack) to workaround the Out-of-order Issue in Loongson2F + * via its diagnostic register. + */ + move k0, ra + jal 1f +1: jal 1f +1: jal 1f +1: jal 1f +1: move ra, k0 + li k0, 3 + mtc0 k0, $22 +#endif /* !CONFIG_SMP && CONFIG_CPU_JUMP_WORKAROUNDS */ /* Set thread_info if we're coming from user mode */ ori $28, sp, _THREAD_MASK @@ -59,6 +77,7 @@ pref 0, 0($28) /* Prefetch the current pointer */ .set pop #endif + .set pop .endm .macro SAVE_AT docfi=0 @@ -160,25 +179,6 @@ #else /* !CONFIG_SMP */ /* Uniprocessor variation */ .macro get_saved_sp docfi=0 tosp=0 -#ifdef CONFIG_CPU_JUMP_WORKAROUNDS - /* - * Clear BTB (branch target buffer), forbid RAS (return address - * stack) to workaround the Out-of-order Issue in Loongson2F - * via its diagnostic register. - */ - move k0, ra - jal 1f - nop -1: jal 1f - nop -1: jal 1f - nop -1: jal 1f - nop -1: move ra, k0 - li k0, 3 - mtc0 k0, $22 -#endif /* CONFIG_CPU_JUMP_WORKAROUNDS */ #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) lui k1, %hi(kernelsp) #else -- 2.7.4
