2021-03-05 04:24:41

by HongJieDeng

[permalink] [raw]
Subject: [PATCH] MIPS: Support large stack.

From: Hongjie Deng <[email protected]>

We need more stack space, xori/ori no longer apply when
_THREAD_MASK exceeds 16 bits

Signed-off-by: Hongjie Deng <[email protected]>
---
arch/mips/include/asm/stackframe.h | 8 ++++++++
arch/mips/kernel/genex.S | 6 ++++++
2 files changed, 14 insertions(+)

diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
index aa430a6..6ebc39f 100644
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
@@ -278,8 +278,16 @@
sll k0, 3 /* extract cu0 bit */
bltz k0, 9f

+#if _THREAD_MASK < (1 << 16 - 1)
ori $28, sp, _THREAD_MASK
xori $28, _THREAD_MASK
+#else
+ li $28, _THREAD_MASK
+ or $28, sp, $28
+ li $24, _THREAD_MASK
+ xor $28, $28, $24
+#endif
+
#ifdef CONFIG_CPU_CAVIUM_OCTEON
.set mips64
pref 0, 0($28) /* Prefetch the current pointer */
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index bcce32a..5ea4fe4 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -662,8 +662,14 @@ isrdhwr:
#endif
MTC0 k0, CP0_EPC
/* I hope three instructions between MTC0 and ERET are enough... */
+#if _THREAD_MASK < (1 << 16 - 1)
ori k1, _THREAD_MASK
xori k1, _THREAD_MASK
+#else
+ li $24 ,_THREAD_MASK
+ or k1, k1, $24
+ xor k1, k1, $24
+#endif
LONG_L v1, TI_TP_VALUE(k1)
.set push
.set arch=r4000
--
1.8.3.1


2021-03-05 07:00:35

by Jiaxun Yang

[permalink] [raw]
Subject: Re: [PATCH] MIPS: Support large stack.



?? 2021/3/5 11:12, HongJieDeng ะด??:
> From: Hongjie Deng <[email protected]>
>
> We need more stack space, xori/ori no longer apply when
> _THREAD_MASK exceeds 16 bits
>
> Signed-off-by: Hongjie Deng <[email protected]>
> ---
> arch/mips/include/asm/stackframe.h | 8 ++++++++
> arch/mips/kernel/genex.S | 6 ++++++
> 2 files changed, 14 insertions(+)
>
> diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
> index aa430a6..6ebc39f 100644
> --- a/arch/mips/include/asm/stackframe.h
> +++ b/arch/mips/include/asm/stackframe.h
> @@ -278,8 +278,16 @@
> sll k0, 3 /* extract cu0 bit */
> bltz k0, 9f
>
> +#if _THREAD_MASK < (1 << 16 - 1)
> ori $28, sp, _THREAD_MASK
> xori $28, _THREAD_MASK
> +#else
> + li $28, _THREAD_MASK
> + or $28, sp, $28
> + li $24, _THREAD_MASK
> + xor $28, $28, $24

Hi Hongjie,

li breaks MIPS64, please try PTR_LI instead.
Also loading immediate cost a lot on MIPS,
you may save a unnecessary li by:

+ PTR_LI v1, _THREAD_MASK
+ or gp, sp, v1
+ xor gp, gp, v1

Also clobber v0/v1 seems much more reasonable than $24 here....

> +#endif
> +
> #ifdef CONFIG_CPU_CAVIUM_OCTEON
> .set mips64
> pref 0, 0($28) /* Prefetch the current pointer */
> diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
> index bcce32a..5ea4fe4 100644
> --- a/arch/mips/kernel/genex.S
> +++ b/arch/mips/kernel/genex.S
> @@ -662,8 +662,14 @@ isrdhwr:
> #endif
> MTC0 k0, CP0_EPC
> /* I hope three instructions between MTC0 and ERET are enough... */
> +#if _THREAD_MASK < (1 << 16 - 1)
> ori k1, _THREAD_MASK
> xori k1, _THREAD_MASK
> +#else
> + li $24 ,_THREAD_MASK
> + or k1, k1, $24
> + xor k1, k1, $24
> +#endif
Ditto.

Actually another possible solution could be `.set at=v1` around it
and let aeembler to decide if it needs a extra register.

Thanks.

- Jiaxun
> LONG_L v1, TI_TP_VALUE(k1)
> .set push
> .set arch=r4000

2021-03-05 08:09:07

by Thomas Bogendoerfer

[permalink] [raw]
Subject: Re: [PATCH] MIPS: Support large stack.

On Fri, Mar 05, 2021 at 11:12:57AM +0800, HongJieDeng wrote:
> From: Hongjie Deng <[email protected]>
>
> We need more stack space, xori/ori no longer apply when
> _THREAD_MASK exceeds 16 bits

who is we and why do need more ?

Thomas.

--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]