mirror of https://gitee.com/openkylin/linux.git
MIPS: Loongson-3: Enable COP2 usage in kernel
Loongson-3's COP2 is Multi-Media coprocessor, it is disabled in kernel mode by default. However, gslq/gssq (16-bytes load/store instructions) overrides the instruction format of lwc2/swc2. If we wan't to use gslq/ gssq for optimization in kernel, we should enable COP2 usage in kernel. Please pay attention that in this patch we only enable COP2 in kernel, which means it will lose ST0_CU2 when a process go to user space (try to use COP2 in user space will trigger an exception and then grab COP2, which is similar to FPU). And as a result, we need to modify the context switching code because the new scheduled process doesn't contain ST0_CU2 in its THERAD_STATUS probably. For zboot, we disable gslq/gssq be generated by toolchain. Signed-off-by: Huacai Chen <chenhc@lemote.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
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@ -22,6 +22,11 @@ KBUILD_CFLAGS := $(filter-out -pg, $(KBUILD_CFLAGS))
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KBUILD_CFLAGS := $(filter-out -fstack-protector, $(KBUILD_CFLAGS))
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# Disable lq/sq in zboot
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ifdef CONFIG_CPU_LOONGSON64
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KBUILD_CFLAGS := $(filter-out -march=loongson3a, $(KBUILD_CFLAGS)) -march=mips64r2
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endif
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KBUILD_CFLAGS := $(KBUILD_CFLAGS) -D__KERNEL__ -D__DISABLE_EXPORTS \
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-DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE) -D"VMLINUX_LOAD_ADDRESS_ULL=$(VMLINUX_LOAD_ADDRESS)ull"
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@ -389,6 +389,13 @@
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#define ST0_CU3 0x80000000
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#define ST0_XX 0x80000000 /* MIPS IV naming */
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/* in-kernel enabled CUs */
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#ifdef CONFIG_CPU_LOONGSON64
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#define ST0_KERNEL_CUMASK (ST0_CU0 | ST0_CU2)
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#else
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#define ST0_KERNEL_CUMASK ST0_CU0
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#endif
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/*
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* Bitfields and bit numbers in the coprocessor 0 IntCtl register. (MIPSR2)
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*/
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@ -450,7 +450,7 @@
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*/
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.macro CLI
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mfc0 t0, CP0_STATUS
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li t1, ST0_CU0 | STATMASK
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li t1, ST0_KERNEL_CUMASK | STATMASK
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or t0, t1
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xori t0, STATMASK
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mtc0 t0, CP0_STATUS
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@ -463,7 +463,7 @@
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*/
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.macro STI
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mfc0 t0, CP0_STATUS
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li t1, ST0_CU0 | STATMASK
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li t1, ST0_KERNEL_CUMASK | STATMASK
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or t0, t1
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xori t0, STATMASK & ~1
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mtc0 t0, CP0_STATUS
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@ -477,7 +477,7 @@
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*/
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.macro KMODE
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mfc0 t0, CP0_STATUS
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li t1, ST0_CU0 | (STATMASK & ~1)
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li t1, ST0_KERNEL_CUMASK | (STATMASK & ~1)
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#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
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andi t2, t0, ST0_IEP
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srl t2, 2
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@ -35,7 +35,7 @@
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.macro setup_c0_status set clr
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.set push
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mfc0 t0, CP0_STATUS
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or t0, ST0_CU0|\set|0x1f|\clr
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or t0, ST0_KERNEL_CUMASK|\set|0x1f|\clr
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xor t0, 0x1f|\clr
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mtc0 t0, CP0_STATUS
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.set noreorder
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@ -68,7 +68,7 @@ void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
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unsigned long status;
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/* New thread loses kernel privileges. */
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status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
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status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_CU2|ST0_FR|KU_MASK);
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status |= KU_USER;
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regs->cp0_status = status;
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lose_fpu(0);
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@ -133,7 +133,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
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childregs = (struct pt_regs *) childksp - 1;
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/* Put the stack after the struct pt_regs. */
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childksp = (unsigned long) childregs;
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p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
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p->thread.cp0_status = (read_c0_status() & ~(ST0_CU2|ST0_CU1)) | ST0_KERNEL_CUMASK;
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if (unlikely(p->flags & PF_KTHREAD)) {
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/* kernel thread */
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unsigned long status = p->thread.cp0_status;
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@ -2192,7 +2192,7 @@ static void configure_status(void)
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* flag that some firmware may have left set and the TS bit (for
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* IP27). Set XX for ISA IV code to work.
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*/
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unsigned int status_set = ST0_CU0;
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unsigned int status_set = ST0_KERNEL_CUMASK;
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#ifdef CONFIG_64BIT
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status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
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#endif
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