* [PATCH V7 1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2
@ 2020-09-21 9:12 Huacai Chen
2020-09-21 9:12 ` [PATCH V7 2/3] MIPS: Loongson-3: Enable COP2 usage in kernel Huacai Chen
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Huacai Chen @ 2020-09-21 9:12 UTC (permalink / raw)
To: Thomas Bogendoerfer
Cc: linux-mips, Fuxin Zhang, Huacai Chen, Jiaxun Yang, Huacai Chen
Some processors (such as Loongson-3) need to enable CU2 in kernel mode,
current set/clear method will lose Status.CU2 during context switching,
so use save/restore method instead.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
---
arch/mips/include/asm/switch_to.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/switch_to.h b/arch/mips/include/asm/switch_to.h
index 0b0a93b..a4374b4 100644
--- a/arch/mips/include/asm/switch_to.h
+++ b/arch/mips/include/asm/switch_to.h
@@ -117,6 +117,8 @@ do { \
__restore_dsp(next); \
} \
if (cop2_present) { \
+ u32 status = read_c0_status(); \
+ \
set_c0_status(ST0_CU2); \
if ((KSTK_STATUS(prev) & ST0_CU2)) { \
if (cop2_lazy_restore) \
@@ -127,7 +129,7 @@ do { \
!cop2_lazy_restore) { \
cop2_restore(next); \
} \
- clear_c0_status(ST0_CU2); \
+ write_c0_status(status); \
} \
__clear_r5_hw_ll_bit(); \
__clear_software_ll_bit(); \
--
2.7.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH V7 2/3] MIPS: Loongson-3: Enable COP2 usage in kernel
2020-09-21 9:12 [PATCH V7 1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2 Huacai Chen
@ 2020-09-21 9:12 ` Huacai Chen
2020-09-21 12:15 ` Thomas Bogendoerfer
2020-09-21 9:12 ` [PATCH V7 3/3] MIPS: Loongson-3: Calculate ra properly when unwinding the stack Huacai Chen
2020-09-21 20:24 ` [PATCH V7 1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2 Thomas Bogendoerfer
2 siblings, 1 reply; 7+ messages in thread
From: Huacai Chen @ 2020-09-21 9:12 UTC (permalink / raw)
To: Thomas Bogendoerfer
Cc: linux-mips, Fuxin Zhang, Huacai Chen, Jiaxun Yang, Huacai Chen
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>
---
V3: Stop using ST0_MM and use ST0_CU2 instead (Thank Thomas and Maciej).
V4: Adopt Thomas's suggestion to improve coding style.
V5: Use ST0_KERNEL_CUMASK in all possible places to avoid #ifdefs.
V6: Modify switch_to() and don't touch r4k_switch.S.
V7: For zboot, disable gslq/gssq be generated by toolchain.
arch/mips/boot/compressed/Makefile | 5 +++++
arch/mips/include/asm/mipsregs.h | 7 +++++++
arch/mips/include/asm/stackframe.h | 6 +++---
arch/mips/kernel/head.S | 2 +-
arch/mips/kernel/process.c | 4 ++--
arch/mips/kernel/traps.c | 2 +-
6 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
index 9a9ba77..2c491c1 100644
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -22,6 +22,11 @@ KBUILD_CFLAGS := $(filter-out -pg, $(KBUILD_CFLAGS))
KBUILD_CFLAGS := $(filter-out -fstack-protector, $(KBUILD_CFLAGS))
+# Disable lq/sq in zboot
+ifdef CONFIG_CPU_LOONGSON64
+KBUILD_CFLAGS := $(filter-out -march=loongson3a, $(KBUILD_CFLAGS)) -march=mips64r2
+endif
+
KBUILD_CFLAGS := $(KBUILD_CFLAGS) -D__KERNEL__ -D__DISABLE_EXPORTS \
-DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE) -D"VMLINUX_LOAD_ADDRESS_ULL=$(VMLINUX_LOAD_ADDRESS)ull"
diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index 1a03fdc2..36b8433 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -389,6 +389,13 @@
#define ST0_CU3 0x80000000
#define ST0_XX 0x80000000 /* MIPS IV naming */
+/* in-kernel enabled CUs */
+#ifdef CONFIG_CPU_LOONGSON64
+#define ST0_KERNEL_CUMASK (ST0_CU0 | ST0_CU2)
+#else
+#define ST0_KERNEL_CUMASK ST0_CU0
+#endif
+
/*
* Bitfields and bit numbers in the coprocessor 0 IntCtl register. (MIPSR2)
*/
diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
index 3e8d2aa..aa430a6 100644
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
@@ -450,7 +450,7 @@
*/
.macro CLI
mfc0 t0, CP0_STATUS
- li t1, ST0_CU0 | STATMASK
+ li t1, ST0_KERNEL_CUMASK | STATMASK
or t0, t1
xori t0, STATMASK
mtc0 t0, CP0_STATUS
@@ -463,7 +463,7 @@
*/
.macro STI
mfc0 t0, CP0_STATUS
- li t1, ST0_CU0 | STATMASK
+ li t1, ST0_KERNEL_CUMASK | STATMASK
or t0, t1
xori t0, STATMASK & ~1
mtc0 t0, CP0_STATUS
@@ -477,7 +477,7 @@
*/
.macro KMODE
mfc0 t0, CP0_STATUS
- li t1, ST0_CU0 | (STATMASK & ~1)
+ li t1, ST0_KERNEL_CUMASK | (STATMASK & ~1)
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
andi t2, t0, ST0_IEP
srl t2, 2
diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S
index 7dd234e..61b7358 100644
--- a/arch/mips/kernel/head.S
+++ b/arch/mips/kernel/head.S
@@ -35,7 +35,7 @@
.macro setup_c0_status set clr
.set push
mfc0 t0, CP0_STATUS
- or t0, ST0_CU0|\set|0x1f|\clr
+ or t0, ST0_KERNEL_CUMASK|\set|0x1f|\clr
xor t0, 0x1f|\clr
mtc0 t0, CP0_STATUS
.set noreorder
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index f5dc316..b36297e 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -68,7 +68,7 @@ void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
unsigned long status;
/* New thread loses kernel privileges. */
- status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
+ status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_CU2|ST0_FR|KU_MASK);
status |= KU_USER;
regs->cp0_status = status;
lose_fpu(0);
@@ -133,7 +133,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
childregs = (struct pt_regs *) childksp - 1;
/* Put the stack after the struct pt_regs. */
childksp = (unsigned long) childregs;
- p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
+ p->thread.cp0_status = (read_c0_status() & ~(ST0_CU2|ST0_CU1)) | ST0_KERNEL_CUMASK;
if (unlikely(p->flags & PF_KTHREAD)) {
/* kernel thread */
unsigned long status = p->thread.cp0_status;
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index cf788591..e035295 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -2204,7 +2204,7 @@ static void configure_status(void)
* flag that some firmware may have left set and the TS bit (for
* IP27). Set XX for ISA IV code to work.
*/
- unsigned int status_set = ST0_CU0;
+ unsigned int status_set = ST0_KERNEL_CUMASK;
#ifdef CONFIG_64BIT
status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
#endif
--
2.7.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH V7 3/3] MIPS: Loongson-3: Calculate ra properly when unwinding the stack
2020-09-21 9:12 [PATCH V7 1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2 Huacai Chen
2020-09-21 9:12 ` [PATCH V7 2/3] MIPS: Loongson-3: Enable COP2 usage in kernel Huacai Chen
@ 2020-09-21 9:12 ` Huacai Chen
2020-09-21 20:24 ` [PATCH V7 1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2 Thomas Bogendoerfer
2 siblings, 0 replies; 7+ messages in thread
From: Huacai Chen @ 2020-09-21 9:12 UTC (permalink / raw)
To: Thomas Bogendoerfer
Cc: linux-mips, Fuxin Zhang, Huacai Chen, Jiaxun Yang, Huacai Chen
Loongson-3 has 16-bytes load/store instructions: gslq and gssq. This
patch calculate ra properly when unwinding the stack, if ra is saved
by gssq and restored by gslq.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
---
arch/mips/kernel/process.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index b36297e..37f05c8 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -279,7 +279,21 @@ static inline int is_ra_save_ins(union mips_instruction *ip, int *poff)
*poff = ip->i_format.simmediate / sizeof(ulong);
return 1;
}
-
+#ifdef CONFIG_CPU_LOONGSON64
+ if ((ip->loongson3_lswc2_format.opcode == swc2_op) &&
+ (ip->loongson3_lswc2_format.ls == 1) &&
+ (ip->loongson3_lswc2_format.fr == 0) &&
+ (ip->loongson3_lswc2_format.base == 29)) {
+ if (ip->loongson3_lswc2_format.rt == 31) {
+ *poff = ip->loongson3_lswc2_format.offset << 1;
+ return 1;
+ }
+ if (ip->loongson3_lswc2_format.rq == 31) {
+ *poff = (ip->loongson3_lswc2_format.offset << 1) + 1;
+ return 1;
+ }
+ }
+#endif
return 0;
#endif
}
--
2.7.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH V7 2/3] MIPS: Loongson-3: Enable COP2 usage in kernel
2020-09-21 9:12 ` [PATCH V7 2/3] MIPS: Loongson-3: Enable COP2 usage in kernel Huacai Chen
@ 2020-09-21 12:15 ` Thomas Bogendoerfer
2020-09-23 9:44 ` Jiaxun Yang
0 siblings, 1 reply; 7+ messages in thread
From: Thomas Bogendoerfer @ 2020-09-21 12:15 UTC (permalink / raw)
To: Huacai Chen; +Cc: linux-mips, Fuxin Zhang, Huacai Chen, Jiaxun Yang
On Mon, Sep 21, 2020 at 05:12:27PM +0800, Huacai Chen wrote:
> 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>
> ---
> V3: Stop using ST0_MM and use ST0_CU2 instead (Thank Thomas and Maciej).
> V4: Adopt Thomas's suggestion to improve coding style.
> V5: Use ST0_KERNEL_CUMASK in all possible places to avoid #ifdefs.
> V6: Modify switch_to() and don't touch r4k_switch.S.
> V7: For zboot, disable gslq/gssq be generated by toolchain.
>
> arch/mips/boot/compressed/Makefile | 5 +++++
> arch/mips/include/asm/mipsregs.h | 7 +++++++
> arch/mips/include/asm/stackframe.h | 6 +++---
> arch/mips/kernel/head.S | 2 +-
> arch/mips/kernel/process.c | 4 ++--
> arch/mips/kernel/traps.c | 2 +-
> 6 files changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
> index 9a9ba77..2c491c1 100644
> --- a/arch/mips/boot/compressed/Makefile
> +++ b/arch/mips/boot/compressed/Makefile
> @@ -22,6 +22,11 @@ KBUILD_CFLAGS := $(filter-out -pg, $(KBUILD_CFLAGS))
>
> KBUILD_CFLAGS := $(filter-out -fstack-protector, $(KBUILD_CFLAGS))
>
> +# Disable lq/sq in zboot
> +ifdef CONFIG_CPU_LOONGSON64
> +KBUILD_CFLAGS := $(filter-out -march=loongson3a, $(KBUILD_CFLAGS)) -march=mips64r2
> +endif
> +
thanks for doing this, I'm going to apply this later.
This remind of another question, what about loongson2ef ? I'm getting
kbuild failure because of enabled loongson-mmi mails. Are we are missing
something like cflags-y += $(call cc-option,-mno-loongson-mmi) in Platform
file ? Who is taking care of loongson2ef ?
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH V7 1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2
2020-09-21 9:12 [PATCH V7 1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2 Huacai Chen
2020-09-21 9:12 ` [PATCH V7 2/3] MIPS: Loongson-3: Enable COP2 usage in kernel Huacai Chen
2020-09-21 9:12 ` [PATCH V7 3/3] MIPS: Loongson-3: Calculate ra properly when unwinding the stack Huacai Chen
@ 2020-09-21 20:24 ` Thomas Bogendoerfer
2 siblings, 0 replies; 7+ messages in thread
From: Thomas Bogendoerfer @ 2020-09-21 20:24 UTC (permalink / raw)
To: Huacai Chen; +Cc: linux-mips, Fuxin Zhang, Huacai Chen, Jiaxun Yang
On Mon, Sep 21, 2020 at 05:12:26PM +0800, Huacai Chen wrote:
> Some processors (such as Loongson-3) need to enable CU2 in kernel mode,
> current set/clear method will lose Status.CU2 during context switching,
> so use save/restore method instead.
>
> Signed-off-by: Huacai Chen <chenhc@lemote.com>
> ---
> arch/mips/include/asm/switch_to.h | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
applied patches 1-3 to mips-next.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH V7 2/3] MIPS: Loongson-3: Enable COP2 usage in kernel
2020-09-21 12:15 ` Thomas Bogendoerfer
@ 2020-09-23 9:44 ` Jiaxun Yang
2020-09-24 13:53 ` Thomas Bogendoerfer
0 siblings, 1 reply; 7+ messages in thread
From: Jiaxun Yang @ 2020-09-23 9:44 UTC (permalink / raw)
To: Thomas Bogendoerfer, Huacai Chen; +Cc: linux-mips, Fuxin Zhang, Huacai Chen
于 2020年9月21日 GMT+08:00 下午8:15:54, Thomas Bogendoerfer <tsbogend@alpha.franken.de> 写到:
>On Mon, Sep 21, 2020 at 05:12:27PM +0800, Huacai Chen wrote:
>> 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>
>> ---
>> V3: Stop using ST0_MM and use ST0_CU2 instead (Thank Thomas and Maciej).
>> V4: Adopt Thomas's suggestion to improve coding style.
>> V5: Use ST0_KERNEL_CUMASK in all possible places to avoid #ifdefs.
>> V6: Modify switch_to() and don't touch r4k_switch.S.
>> V7: For zboot, disable gslq/gssq be generated by toolchain.
>>
>> arch/mips/boot/compressed/Makefile | 5 +++++
>> arch/mips/include/asm/mipsregs.h | 7 +++++++
>> arch/mips/include/asm/stackframe.h | 6 +++---
>> arch/mips/kernel/head.S | 2 +-
>> arch/mips/kernel/process.c | 4 ++--
>> arch/mips/kernel/traps.c | 2 +-
>> 6 files changed, 19 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
>> index 9a9ba77..2c491c1 100644
>> --- a/arch/mips/boot/compressed/Makefile
>> +++ b/arch/mips/boot/compressed/Makefile
>> @@ -22,6 +22,11 @@ KBUILD_CFLAGS := $(filter-out -pg, $(KBUILD_CFLAGS))
>>
>> KBUILD_CFLAGS := $(filter-out -fstack-protector, $(KBUILD_CFLAGS))
>>
>> +# Disable lq/sq in zboot
>> +ifdef CONFIG_CPU_LOONGSON64
>> +KBUILD_CFLAGS := $(filter-out -march=loongson3a, $(KBUILD_CFLAGS)) -march=mips64r2
>> +endif
>> +
>
>thanks for doing this, I'm going to apply this later.
>
>This remind of another question, what about loongson2ef ? I'm getting
>kbuild failure because of enabled loongson-mmi mails. Are we are missing
>something like cflags-y += $(call cc-option,-mno-loongson-mmi) in Platform
>file ? Who is taking care of loongson2ef ?
I'll send a patch later. Sorry for the inconvenience.
I'm taking care of it. Just being a little bit busy recently.
Thanks.
- Jiaxun
>
>Thomas.
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH V7 2/3] MIPS: Loongson-3: Enable COP2 usage in kernel
2020-09-23 9:44 ` Jiaxun Yang
@ 2020-09-24 13:53 ` Thomas Bogendoerfer
0 siblings, 0 replies; 7+ messages in thread
From: Thomas Bogendoerfer @ 2020-09-24 13:53 UTC (permalink / raw)
To: Jiaxun Yang; +Cc: Huacai Chen, linux-mips, Fuxin Zhang, Huacai Chen
On Wed, Sep 23, 2020 at 05:44:02PM +0800, Jiaxun Yang wrote:
> 于 2020年9月21日 GMT+08:00 下午8:15:54, Thomas Bogendoerfer <tsbogend@alpha.franken.de> 写到:
> >thanks for doing this, I'm going to apply this later.
> >
> >This remind of another question, what about loongson2ef ? I'm getting
> >kbuild failure because of enabled loongson-mmi mails. Are we are missing
> >something like cflags-y += $(call cc-option,-mno-loongson-mmi) in Platform
> >file ? Who is taking care of loongson2ef ?
>
> I'll send a patch later. Sorry for the inconvenience.
excellent, thank you.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-09-24 13:59 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-21 9:12 [PATCH V7 1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2 Huacai Chen
2020-09-21 9:12 ` [PATCH V7 2/3] MIPS: Loongson-3: Enable COP2 usage in kernel Huacai Chen
2020-09-21 12:15 ` Thomas Bogendoerfer
2020-09-23 9:44 ` Jiaxun Yang
2020-09-24 13:53 ` Thomas Bogendoerfer
2020-09-21 9:12 ` [PATCH V7 3/3] MIPS: Loongson-3: Calculate ra properly when unwinding the stack Huacai Chen
2020-09-21 20:24 ` [PATCH V7 1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2 Thomas Bogendoerfer
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