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* [PATCH v3] powerpc/pseries/mce: Avoid instrumentation in realmode
@ 2022-09-26  6:18 Ganesh Goudar
  2022-09-26  9:07 ` Sachin Sant
  2022-09-26  9:39 ` Nicholas Piggin
  0 siblings, 2 replies; 3+ messages in thread
From: Ganesh Goudar @ 2022-09-26  6:18 UTC (permalink / raw)
  To: linuxppc-dev, mpe; +Cc: Ganesh Goudar, npiggin, mahesh, sachinp

Part of machine check error handling is done in realmode,
As of now instrumentation is not possible for any code that
runs in realmode.
When MCE is injected on KASAN enabled kernel, crash is
observed, Hence force inline or mark no instrumentation
for functions which can run in realmode, to avoid KASAN
instrumentation.

Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
---
v2: Force inline few more functions.

v3: Adding noinstr to few functions instead of __always_inline.
---
 arch/powerpc/include/asm/hw_irq.h    | 8 ++++----
 arch/powerpc/include/asm/interrupt.h | 2 +-
 arch/powerpc/include/asm/rtas.h      | 4 ++--
 arch/powerpc/kernel/rtas.c           | 4 ++--
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 983551859891..c4d542b4a623 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -111,7 +111,7 @@ static inline void __hard_RI_enable(void)
 #ifdef CONFIG_PPC64
 #include <asm/paca.h>
 
-static inline notrace unsigned long irq_soft_mask_return(void)
+noinstr static unsigned long irq_soft_mask_return(void)
 {
 	unsigned long flags;
 
@@ -128,7 +128,7 @@ static inline notrace unsigned long irq_soft_mask_return(void)
  * for the critical section and as a clobber because
  * we changed paca->irq_soft_mask
  */
-static inline notrace void irq_soft_mask_set(unsigned long mask)
+noinstr static void irq_soft_mask_set(unsigned long mask)
 {
 	/*
 	 * The irq mask must always include the STD bit if any are set.
@@ -155,7 +155,7 @@ static inline notrace void irq_soft_mask_set(unsigned long mask)
 		: "memory");
 }
 
-static inline notrace unsigned long irq_soft_mask_set_return(unsigned long mask)
+noinstr static unsigned long irq_soft_mask_set_return(unsigned long mask)
 {
 	unsigned long flags;
 
@@ -191,7 +191,7 @@ static inline notrace unsigned long irq_soft_mask_or_return(unsigned long mask)
 	return flags;
 }
 
-static inline unsigned long arch_local_save_flags(void)
+static __always_inline unsigned long arch_local_save_flags(void)
 {
 	return irq_soft_mask_return();
 }
diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
index 8069dbc4b8d1..090895051712 100644
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -92,7 +92,7 @@ static inline bool is_implicit_soft_masked(struct pt_regs *regs)
 	return search_kernel_soft_mask_table(regs->nip);
 }
 
-static inline void srr_regs_clobbered(void)
+static __always_inline void srr_regs_clobbered(void)
 {
 	local_paca->srr_valid = 0;
 	local_paca->hsrr_valid = 0;
diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 00531af17ce0..52d29d664fdf 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -201,13 +201,13 @@ inline uint32_t rtas_ext_event_company_id(struct rtas_ext_event_log_v6 *ext_log)
 #define PSERIES_ELOG_SECT_ID_MCE		(('M' << 8) | 'C')
 
 static
-inline uint16_t pseries_errorlog_id(struct pseries_errorlog *sect)
+__always_inline uint16_t pseries_errorlog_id(struct pseries_errorlog *sect)
 {
 	return be16_to_cpu(sect->id);
 }
 
 static
-inline uint16_t pseries_errorlog_length(struct pseries_errorlog *sect)
+__always_inline uint16_t pseries_errorlog_length(struct pseries_errorlog *sect)
 {
 	return be16_to_cpu(sect->length);
 }
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 693133972294..f9d78245c0e8 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -48,7 +48,7 @@
 /* This is here deliberately so it's only used in this file */
 void enter_rtas(unsigned long);
 
-static inline void do_enter_rtas(unsigned long args)
+static __always_inline void do_enter_rtas(unsigned long args)
 {
 	unsigned long msr;
 
@@ -435,7 +435,7 @@ static char *__fetch_rtas_last_error(char *altbuf)
 #endif
 
 
-static void
+noinstr static void
 va_rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
 		      va_list list)
 {
-- 
2.37.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH v3] powerpc/pseries/mce: Avoid instrumentation in realmode
  2022-09-26  6:18 [PATCH v3] powerpc/pseries/mce: Avoid instrumentation in realmode Ganesh Goudar
@ 2022-09-26  9:07 ` Sachin Sant
  2022-09-26  9:39 ` Nicholas Piggin
  1 sibling, 0 replies; 3+ messages in thread
From: Sachin Sant @ 2022-09-26  9:07 UTC (permalink / raw)
  To: Ganesh Goudar; +Cc: linuxppc-dev, mahesh, npiggin



> On 26-Sep-2022, at 11:48 AM, Ganesh Goudar <ganeshgr@linux.ibm.com> wrote:
> 
> Part of machine check error handling is done in realmode,
> As of now instrumentation is not possible for any code that
> runs in realmode.
> When MCE is injected on KASAN enabled kernel, crash is
> observed, Hence force inline or mark no instrumentation
> for functions which can run in realmode, to avoid KASAN
> instrumentation.
> 
> Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
> ---
> v2: Force inline few more functions.
> 
> v3: Adding noinstr to few functions instead of __always_inline.
> ---

Tested-by: Sachin Sant <sachinp@linux.ibm.com>

- Sachin

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH v3] powerpc/pseries/mce: Avoid instrumentation in realmode
  2022-09-26  6:18 [PATCH v3] powerpc/pseries/mce: Avoid instrumentation in realmode Ganesh Goudar
  2022-09-26  9:07 ` Sachin Sant
@ 2022-09-26  9:39 ` Nicholas Piggin
  1 sibling, 0 replies; 3+ messages in thread
From: Nicholas Piggin @ 2022-09-26  9:39 UTC (permalink / raw)
  To: Ganesh Goudar, linuxppc-dev, mpe; +Cc: mahesh, sachinp

On Mon Sep 26, 2022 at 4:18 PM AEST, Ganesh Goudar wrote:
> Part of machine check error handling is done in realmode,
> As of now instrumentation is not possible for any code that
> runs in realmode.
> When MCE is injected on KASAN enabled kernel, crash is
> observed, Hence force inline or mark no instrumentation
> for functions which can run in realmode, to avoid KASAN
> instrumentation.
>
> Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
> ---
> v2: Force inline few more functions.
>
> v3: Adding noinstr to few functions instead of __always_inline.

I would still like to consider doing a realmode annotation, but
as a minimal fix for the next merge window I suppose this is okay.
There's still no indication for why the annotation exists on the
functions which is a bit annoying, maybe not fundamentally worse
than notrace was, but the scope of reasons why it's there gets
bigger.


> ---
>  arch/powerpc/include/asm/hw_irq.h    | 8 ++++----
>  arch/powerpc/include/asm/interrupt.h | 2 +-
>  arch/powerpc/include/asm/rtas.h      | 4 ++--
>  arch/powerpc/kernel/rtas.c           | 4 ++--
>  4 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
> index 983551859891..c4d542b4a623 100644
> --- a/arch/powerpc/include/asm/hw_irq.h
> +++ b/arch/powerpc/include/asm/hw_irq.h
> @@ -111,7 +111,7 @@ static inline void __hard_RI_enable(void)
>  #ifdef CONFIG_PPC64
>  #include <asm/paca.h>
>  
> -static inline notrace unsigned long irq_soft_mask_return(void)
> +noinstr static unsigned long irq_soft_mask_return(void)
>  {
>  	unsigned long flags;

Don't uninline the ones in headers.

> @@ -128,7 +128,7 @@ static inline notrace unsigned long irq_soft_mask_return(void)
>   * for the critical section and as a clobber because
>   * we changed paca->irq_soft_mask
>   */
> -static inline notrace void irq_soft_mask_set(unsigned long mask)
> +noinstr static void irq_soft_mask_set(unsigned long mask)
>  {
>  	/*
>  	 * The irq mask must always include the STD bit if any are set.
> @@ -155,7 +155,7 @@ static inline notrace void irq_soft_mask_set(unsigned long mask)
>  		: "memory");
>  }
>  
> -static inline notrace unsigned long irq_soft_mask_set_return(unsigned long mask)
> +noinstr static unsigned long irq_soft_mask_set_return(unsigned long mask)
>  {
>  	unsigned long flags;
>  
> @@ -191,7 +191,7 @@ static inline notrace unsigned long irq_soft_mask_or_return(unsigned long mask)
>  	return flags;
>  }
>  
> -static inline unsigned long arch_local_save_flags(void)
> +static __always_inline unsigned long arch_local_save_flags(void)
>  {
>  	return irq_soft_mask_return();
>  }

Can we instead add noinstr to this too, the the other ones that were
changed to always inline?

Thanks,
Nick

> diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
> index 8069dbc4b8d1..090895051712 100644
> --- a/arch/powerpc/include/asm/interrupt.h
> +++ b/arch/powerpc/include/asm/interrupt.h
> @@ -92,7 +92,7 @@ static inline bool is_implicit_soft_masked(struct pt_regs *regs)
>  	return search_kernel_soft_mask_table(regs->nip);
>  }
>  
> -static inline void srr_regs_clobbered(void)
> +static __always_inline void srr_regs_clobbered(void)
>  {
>  	local_paca->srr_valid = 0;
>  	local_paca->hsrr_valid = 0;
> diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
> index 00531af17ce0..52d29d664fdf 100644
> --- a/arch/powerpc/include/asm/rtas.h
> +++ b/arch/powerpc/include/asm/rtas.h
> @@ -201,13 +201,13 @@ inline uint32_t rtas_ext_event_company_id(struct rtas_ext_event_log_v6 *ext_log)
>  #define PSERIES_ELOG_SECT_ID_MCE		(('M' << 8) | 'C')
>  
>  static
> -inline uint16_t pseries_errorlog_id(struct pseries_errorlog *sect)
> +__always_inline uint16_t pseries_errorlog_id(struct pseries_errorlog *sect)
>  {
>  	return be16_to_cpu(sect->id);
>  }
>  
>  static
> -inline uint16_t pseries_errorlog_length(struct pseries_errorlog *sect)
> +__always_inline uint16_t pseries_errorlog_length(struct pseries_errorlog *sect)
>  {
>  	return be16_to_cpu(sect->length);
>  }
> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
> index 693133972294..f9d78245c0e8 100644
> --- a/arch/powerpc/kernel/rtas.c
> +++ b/arch/powerpc/kernel/rtas.c
> @@ -48,7 +48,7 @@
>  /* This is here deliberately so it's only used in this file */
>  void enter_rtas(unsigned long);
>  
> -static inline void do_enter_rtas(unsigned long args)
> +static __always_inline void do_enter_rtas(unsigned long args)
>  {
>  	unsigned long msr;
>  
> @@ -435,7 +435,7 @@ static char *__fetch_rtas_last_error(char *altbuf)
>  #endif
>  
>  
> -static void
> +noinstr static void
>  va_rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
>  		      va_list list)
>  {
> -- 
> 2.37.1


^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-09-26  9:40 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-09-26  6:18 [PATCH v3] powerpc/pseries/mce: Avoid instrumentation in realmode Ganesh Goudar
2022-09-26  9:07 ` Sachin Sant
2022-09-26  9:39 ` Nicholas Piggin

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