diff mbox series

[v3,3/3] xen/riscv: initialize .bss section

Message ID 16fb328e06f6b99d967fa7d186a4c0aaa986050e.1677838213.git.oleksii.kurochko@gmail.com (mailing list archive)
State New, archived
Headers show
Series Do basic initialization things | expand

Commit Message

Oleksii March 3, 2023, 10:24 a.m. UTC
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
---
 xen/arch/riscv/riscv64/head.S | 9 +++++++++
 xen/arch/riscv/setup.c        | 8 ++++++++
 2 files changed, 17 insertions(+)

Comments

Andrew Cooper March 3, 2023, 10:33 a.m. UTC | #1
On 03/03/2023 10:24 am, Oleksii Kurochko wrote:
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

> diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S
> index adf5d6c74a..8887f0cbd4 100644
> --- a/xen/arch/riscv/riscv64/head.S
> +++ b/xen/arch/riscv/riscv64/head.S
> @@ -18,6 +19,14 @@ ENTRY(start)
>          li      t0, SSTATUS_FS
>          csrc    CSR_SSTATUS, t0
>  
> +        /* Clear the BSS */
> +        la      t3, __bss_start
> +        la      t4, __bss_end
> +.L_clear_bss:
> +        REG_S   zero, (t3)
> +        add     t3, t3, __SIZEOF_POINTER__
> +        bltu    t3, t4, .L_clear_bss

Using t3/t4 is fine, but it would also have been fine to use t0/t1.

~Andrew
Oleksii March 3, 2023, 10:42 a.m. UTC | #2
On Fri, 2023-03-03 at 10:33 +0000, Andrew Cooper wrote:
> On 03/03/2023 10:24 am, Oleksii Kurochko wrote:
> > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
> 
> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
> 
> > diff --git a/xen/arch/riscv/riscv64/head.S
> > b/xen/arch/riscv/riscv64/head.S
> > index adf5d6c74a..8887f0cbd4 100644
> > --- a/xen/arch/riscv/riscv64/head.S
> > +++ b/xen/arch/riscv/riscv64/head.S
> > @@ -18,6 +19,14 @@ ENTRY(start)
> >          li      t0, SSTATUS_FS
> >          csrc    CSR_SSTATUS, t0
> >  
> > +        /* Clear the BSS */
> > +        la      t3, __bss_start
> > +        la      t4, __bss_end
> > +.L_clear_bss:
> > +        REG_S   zero, (t3)
> > +        add     t3, t3, __SIZEOF_POINTER__
> > +        bltu    t3, t4, .L_clear_bss
> 
> Using t3/t4 is fine, but it would also have been fine to use t0/t1.
Yeah, I understand that. It was easier to rename and not confuse
something.

Could you please rename them during commit?
Have I to send new patch version?

~ Oleksii
Andrew Cooper March 3, 2023, 10:53 a.m. UTC | #3
On 03/03/2023 10:42 am, Oleksii wrote:
> On Fri, 2023-03-03 at 10:33 +0000, Andrew Cooper wrote:
>> On 03/03/2023 10:24 am, Oleksii Kurochko wrote:
>>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
>> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
>>
>>> diff --git a/xen/arch/riscv/riscv64/head.S
>>> b/xen/arch/riscv/riscv64/head.S
>>> index adf5d6c74a..8887f0cbd4 100644
>>> --- a/xen/arch/riscv/riscv64/head.S
>>> +++ b/xen/arch/riscv/riscv64/head.S
>>> @@ -18,6 +19,14 @@ ENTRY(start)
>>>          li      t0, SSTATUS_FS
>>>          csrc    CSR_SSTATUS, t0
>>>  
>>> +        /* Clear the BSS */
>>> +        la      t3, __bss_start
>>> +        la      t4, __bss_end
>>> +.L_clear_bss:
>>> +        REG_S   zero, (t3)
>>> +        add     t3, t3, __SIZEOF_POINTER__
>>> +        bltu    t3, t4, .L_clear_bss
>> Using t3/t4 is fine, but it would also have been fine to use t0/t1.
> Yeah, I understand that. It was easier to rename and not confuse
> something.
>
> Could you please rename them during commit?
> Have I to send new patch version?

No need to send another patch.  TBH, I wasn't intending to change it at
all - this was just supposed to be a note - but I can if you'd prefer.

~Andrew
Oleksii March 3, 2023, 11:06 a.m. UTC | #4
On Fri, 2023-03-03 at 10:53 +0000, Andrew Cooper wrote:
> On 03/03/2023 10:42 am, Oleksii wrote:
> > On Fri, 2023-03-03 at 10:33 +0000, Andrew Cooper wrote:
> > > On 03/03/2023 10:24 am, Oleksii Kurochko wrote:
> > > > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
> > > Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
> > > 
> > > > diff --git a/xen/arch/riscv/riscv64/head.S
> > > > b/xen/arch/riscv/riscv64/head.S
> > > > index adf5d6c74a..8887f0cbd4 100644
> > > > --- a/xen/arch/riscv/riscv64/head.S
> > > > +++ b/xen/arch/riscv/riscv64/head.S
> > > > @@ -18,6 +19,14 @@ ENTRY(start)
> > > >          li      t0, SSTATUS_FS
> > > >          csrc    CSR_SSTATUS, t0
> > > >  
> > > > +        /* Clear the BSS */
> > > > +        la      t3, __bss_start
> > > > +        la      t4, __bss_end
> > > > +.L_clear_bss:
> > > > +        REG_S   zero, (t3)
> > > > +        add     t3, t3, __SIZEOF_POINTER__
> > > > +        bltu    t3, t4, .L_clear_bss
> > > Using t3/t4 is fine, but it would also have been fine to use
> > > t0/t1.
> > Yeah, I understand that. It was easier to rename and not confuse
> > something.
> > 
> > Could you please rename them during commit?
> > Have I to send new patch version?
> 
> No need to send another patch.  TBH, I wasn't intending to change it
> at
> all - this was just supposed to be a note - but I can if you'd
> prefer.
Feel free to do that.

Thanks.

~ Oleksii
Bobby Eshleman March 9, 2023, 10:48 a.m. UTC | #5
On Fri, Mar 03, 2023 at 12:24:24PM +0200, Oleksii Kurochko wrote:
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
> ---
>  xen/arch/riscv/riscv64/head.S | 9 +++++++++
>  xen/arch/riscv/setup.c        | 8 ++++++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S
> index adf5d6c74a..8887f0cbd4 100644
> --- a/xen/arch/riscv/riscv64/head.S
> +++ b/xen/arch/riscv/riscv64/head.S
> @@ -1,3 +1,4 @@
> +#include <asm/asm.h>
>  #include <asm/riscv_encoding.h>
>  
>          .section .text.header, "ax", %progbits
> @@ -18,6 +19,14 @@ ENTRY(start)
>          li      t0, SSTATUS_FS
>          csrc    CSR_SSTATUS, t0
>  
> +        /* Clear the BSS */
> +        la      t3, __bss_start
> +        la      t4, __bss_end
> +.L_clear_bss:
> +        REG_S   zero, (t3)
> +        add     t3, t3, __SIZEOF_POINTER__
> +        bltu    t3, t4, .L_clear_bss
> +
>          la      sp, cpu0_boot_stack
>          li      t0, STACK_SIZE
>          add     sp, sp, t0
> diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c
> index d9723fe1c0..929565720b 100644
> --- a/xen/arch/riscv/setup.c
> +++ b/xen/arch/riscv/setup.c
> @@ -7,6 +7,14 @@
>  unsigned char __initdata cpu0_boot_stack[STACK_SIZE]
>      __aligned(STACK_SIZE);
>  
> +/*  
> + * To be sure that .bss isn't zero. It will simplify code of
> + * .bss initialization.
> + * TODO:
> + *   To be deleted when the first real .bss user appears
> + */
> +int dummy_bss __attribute__((unused));
> +
>  void __init noreturn start_xen(unsigned long bootcpu_id,
>                                 unsigned long dtb_base)
>  {
> -- 
> 2.39.0
> 
> 

Reviewed-by: Bobby Eshleman <bobbyeshleman@gmail.com>
diff mbox series

Patch

diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S
index adf5d6c74a..8887f0cbd4 100644
--- a/xen/arch/riscv/riscv64/head.S
+++ b/xen/arch/riscv/riscv64/head.S
@@ -1,3 +1,4 @@ 
+#include <asm/asm.h>
 #include <asm/riscv_encoding.h>
 
         .section .text.header, "ax", %progbits
@@ -18,6 +19,14 @@  ENTRY(start)
         li      t0, SSTATUS_FS
         csrc    CSR_SSTATUS, t0
 
+        /* Clear the BSS */
+        la      t3, __bss_start
+        la      t4, __bss_end
+.L_clear_bss:
+        REG_S   zero, (t3)
+        add     t3, t3, __SIZEOF_POINTER__
+        bltu    t3, t4, .L_clear_bss
+
         la      sp, cpu0_boot_stack
         li      t0, STACK_SIZE
         add     sp, sp, t0
diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c
index d9723fe1c0..929565720b 100644
--- a/xen/arch/riscv/setup.c
+++ b/xen/arch/riscv/setup.c
@@ -7,6 +7,14 @@ 
 unsigned char __initdata cpu0_boot_stack[STACK_SIZE]
     __aligned(STACK_SIZE);
 
+/*  
+ * To be sure that .bss isn't zero. It will simplify code of
+ * .bss initialization.
+ * TODO:
+ *   To be deleted when the first real .bss user appears
+ */
+int dummy_bss __attribute__((unused));
+
 void __init noreturn start_xen(unsigned long bootcpu_id,
                                unsigned long dtb_base)
 {