Re: [PATCH v4 20/23] powerpc/syscall: Do not check unsupported scv vector on PPC32

2021-02-08 Thread Christophe Leroy 




Le 26/01/2021 à 11:16, Nicholas Piggin a écrit :

Excerpts from Christophe Leroy's message of January 26, 2021 12:48 am:

Only PPC64 has scv. No need to check the 0x7ff0 trap on PPC32.

And ignore the scv parameter in syscall_exit_prepare (Save 14 cycles
346 => 332 cycles)

Signed-off-by: Christophe Leroy 
---
  arch/powerpc/kernel/entry_32.S | 1 -
  arch/powerpc/kernel/syscall.c  | 7 +--
  2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 9922a04650f7..6ae9c7bcb06c 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -343,7 +343,6 @@ transfer_to_syscall:
  
  ret_from_syscall:

addir4,r1,STACK_FRAME_OVERHEAD
-   li  r5,0
bl  syscall_exit_prepare
  #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
/* If the process has its own DBCR0 value, load it up.  The internal
diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c
index 476909b11051..30f8a397a522 100644
--- a/arch/powerpc/kernel/syscall.c
+++ b/arch/powerpc/kernel/syscall.c
@@ -86,7 +86,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
local_irq_enable();
  
  	if (unlikely(current_thread_info()->flags & _TIF_SYSCALL_DOTRACE)) {

-   if (unlikely(regs->trap == 0x7ff0)) {
+   if (IS_ENABLED(CONFIG_PPC64) && unlikely(regs->trap == 0x7ff0)) 
{
/* Unsupported scv vector */
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
return regs->gpr[3];
@@ -109,7 +109,7 @@ notrace long system_call_exception(long r3, long r4, long 
r5,
r8 = regs->gpr[8];
  
  	} else if (unlikely(r0 >= NR_syscalls)) {

-   if (unlikely(regs->trap == 0x7ff0)) {
+   if (IS_ENABLED(CONFIG_PPC64) && unlikely(regs->trap == 0x7ff0)) 
{


Perhaps this could be hidden behind a function like trap_is_scv()?

trap_is_unsupported_scv() ?



Ok, I did that in v5

Thanks
Christophe

Re: [PATCH v4 20/23] powerpc/syscall: Do not check unsupported scv vector on PPC32

2021-01-26 Thread Nicholas Piggin 
Excerpts from Christophe Leroy's message of January 26, 2021 12:48 am:
> Only PPC64 has scv. No need to check the 0x7ff0 trap on PPC32.
> 
> And ignore the scv parameter in syscall_exit_prepare (Save 14 cycles
> 346 => 332 cycles)
> 
> Signed-off-by: Christophe Leroy 
> ---
>  arch/powerpc/kernel/entry_32.S | 1 -
>  arch/powerpc/kernel/syscall.c  | 7 +--
>  2 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
> index 9922a04650f7..6ae9c7bcb06c 100644
> --- a/arch/powerpc/kernel/entry_32.S
> +++ b/arch/powerpc/kernel/entry_32.S
> @@ -343,7 +343,6 @@ transfer_to_syscall:
>  
>  ret_from_syscall:
>   addir4,r1,STACK_FRAME_OVERHEAD
> - li  r5,0
>   bl  syscall_exit_prepare
>  #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
>   /* If the process has its own DBCR0 value, load it up.  The internal
> diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c
> index 476909b11051..30f8a397a522 100644
> --- a/arch/powerpc/kernel/syscall.c
> +++ b/arch/powerpc/kernel/syscall.c
> @@ -86,7 +86,7 @@ notrace long system_call_exception(long r3, long r4, long 
> r5,
>   local_irq_enable();
>  
>   if (unlikely(current_thread_info()->flags & _TIF_SYSCALL_DOTRACE)) {
> - if (unlikely(regs->trap == 0x7ff0)) {
> + if (IS_ENABLED(CONFIG_PPC64) && unlikely(regs->trap == 0x7ff0)) 
> {
>   /* Unsupported scv vector */
>   _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
>   return regs->gpr[3];
> @@ -109,7 +109,7 @@ notrace long system_call_exception(long r3, long r4, long 
> r5,
>   r8 = regs->gpr[8];
>  
>   } else if (unlikely(r0 >= NR_syscalls)) {
> - if (unlikely(regs->trap == 0x7ff0)) {
> + if (IS_ENABLED(CONFIG_PPC64) && unlikely(regs->trap == 0x7ff0)) 
> {

Perhaps this could be hidden behind a function like trap_is_scv()?

trap_is_unsupported_scv() ?

Thanks,
Nick

[PATCH v4 20/23] powerpc/syscall: Do not check unsupported scv vector on PPC32

2021-01-25 Thread Christophe Leroy 
Only PPC64 has scv. No need to check the 0x7ff0 trap on PPC32.

And ignore the scv parameter in syscall_exit_prepare (Save 14 cycles
346 => 332 cycles)

Signed-off-by: Christophe Leroy 
---
 arch/powerpc/kernel/entry_32.S | 1 -
 arch/powerpc/kernel/syscall.c  | 7 +--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 9922a04650f7..6ae9c7bcb06c 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -343,7 +343,6 @@ transfer_to_syscall:
 
 ret_from_syscall:
addir4,r1,STACK_FRAME_OVERHEAD
-   li  r5,0
bl  syscall_exit_prepare
 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
/* If the process has its own DBCR0 value, load it up.  The internal
diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c
index 476909b11051..30f8a397a522 100644
--- a/arch/powerpc/kernel/syscall.c
+++ b/arch/powerpc/kernel/syscall.c
@@ -86,7 +86,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
local_irq_enable();
 
if (unlikely(current_thread_info()->flags & _TIF_SYSCALL_DOTRACE)) {
-   if (unlikely(regs->trap == 0x7ff0)) {
+   if (IS_ENABLED(CONFIG_PPC64) && unlikely(regs->trap == 0x7ff0)) 
{
/* Unsupported scv vector */
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
return regs->gpr[3];
@@ -109,7 +109,7 @@ notrace long system_call_exception(long r3, long r4, long 
r5,
r8 = regs->gpr[8];
 
} else if (unlikely(r0 >= NR_syscalls)) {
-   if (unlikely(regs->trap == 0x7ff0)) {
+   if (IS_ENABLED(CONFIG_PPC64) && unlikely(regs->trap == 0x7ff0)) 
{
/* Unsupported scv vector */
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
return regs->gpr[3];
@@ -187,6 +187,9 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
unsigned long ti_flags;
unsigned long ret = 0;
 
+   if (IS_ENABLED(CONFIG_PPC32))
+   scv = 0;
+
CT_WARN_ON(ct_state() == CONTEXT_USER);
 
kuap_check();
-- 
2.25.0