[v2,2/3] powerpc/fsl: Add barrier_nospec implementation for NXP PowerPC Book3E

Message ID 1528721608-15443-3-git-send-email-diana.craciun@nxp.com
State Changes Requested
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Series
  • powerpc/fsl: Speculation barrier for NXP PowerPC Book3E
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Commit Message

Diana Madalina Craciun June 11, 2018, 12:53 p.m.
Implement the barrier_nospec as a isync;sync instruction sequence.
The implementation uses the infrastructure built for BOOK3S 64.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
---
 arch/powerpc/include/asm/barrier.h | 10 ++++++++++
 arch/powerpc/include/asm/setup.h   |  2 +-
 arch/powerpc/kernel/Makefile       |  2 +-
 arch/powerpc/kernel/module.c       |  5 +++--
 arch/powerpc/kernel/security.c     | 15 +++++++++++++++
 arch/powerpc/kernel/setup_32.c     |  5 +++++
 arch/powerpc/kernel/setup_64.c     |  6 ++++++
 arch/powerpc/kernel/vmlinux.lds.S  |  4 +++-
 arch/powerpc/lib/feature-fixups.c  | 35 ++++++++++++++++++++++++++++++++++-
 9 files changed, 78 insertions(+), 6 deletions(-)

Comments

Michael Ellerman July 3, 2018, 7:26 a.m. | #1
Hi Diana,

A few comments below ...

Diana Craciun <diana.craciun@nxp.com> writes:
> Implement the barrier_nospec as a isync;sync instruction sequence.
> The implementation uses the infrastructure built for BOOK3S 64.

Do you have any details on why that sequence functions as an effective
barrier on your chips?

In a lot of places we have eg:

 +#if defined(CONFIG_PPC_BOOK3S_64) || defined(CONFIG_PPC_FSL_BOOK3E)

Can you please add a Kconfig symbol to capture that. eg.

config PPC_NOSPEC
	bool
        default y
	depends on PPC_BOOK3S_64 || PPC_FSL_BOOK3E


And then use that everywhere.

> diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
> index f67b3f6..405d572 100644
> --- a/arch/powerpc/include/asm/barrier.h
> +++ b/arch/powerpc/include/asm/barrier.h
> @@ -86,6 +86,16 @@ do {									\
>  // This also acts as a compiler barrier due to the memory clobber.
>  #define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
>  
> +#elif defined(CONFIG_PPC_FSL_BOOK3E)
> +/*
> + * Prevent the execution of subsequent instructions speculatively using a
> + * isync;sync instruction sequence.
> + */
> +#define barrier_nospec_asm NOSPEC_BARRIER_FIXUP_SECTION; nop; nop
> +
> +// This also acts as a compiler barrier due to the memory clobber.
> +#define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
> +
>  #else /* !CONFIG_PPC_BOOK3S_64 */
>  #define barrier_nospec_asm
>  #define barrier_nospec()

If we have CONFIG_PPC_NOSPEC this can be done something like:

#ifdef CONFIG_PPC_BOOK3S_64
#define NOSPEC_BARRIER_SLOT	nop
#elif defined(CONFIG_PPC_FSL_BOOK3E)
#define NOSPEC_BARRIER_SLOT	nop; nop
#endif /* CONFIG_PPC_BOOK3S_64 */

#ifdef CONFIG_PPC_NOSPEC
/*
 * Prevent execution of subsequent instructions until preceding branches have
 * been fully resolved and are no longer executing speculatively.
 */
#define barrier_nospec_asm NOSPEC_BARRIER_FIXUP_SECTION; NOSPEC_BARRIER_SLOT

// This also acts as a compiler barrier due to the memory clobber.
#define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
#else
#define barrier_nospec_asm
#define barrier_nospec()
#endif /* CONFIG_PPC_NOSPEC */


> diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
> index 2b4c40b2..d9dee43 100644
> --- a/arch/powerpc/kernel/Makefile
> +++ b/arch/powerpc/kernel/Makefile
> @@ -76,7 +76,7 @@ endif
>  obj64-$(CONFIG_HIBERNATION)	+= swsusp_asm64.o
>  obj-$(CONFIG_MODULES)		+= module.o module_$(BITS).o
>  obj-$(CONFIG_44x)		+= cpu_setup_44x.o
> -obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o
> +obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o security.o
>  obj-$(CONFIG_PPC_DOORBELL)	+= dbell.o
>  obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o

Can we instead do:

obj-$(CONFIG_PPC_NOSPEC)	+= security.o

> diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
> index c55e102..797c975 100644
> --- a/arch/powerpc/kernel/security.c
> +++ b/arch/powerpc/kernel/security.c
> @@ -13,7 +13,9 @@
>  #include <asm/setup.h>
>  
>  
> +#ifdef CONFIG_PPC_BOOK3S_64
>  unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
> +#endif /* CONFIG_PPC_BOOK3S_64 */

Why are you making that book3s specific?

By doing that you then can't use the existing versions of
setup_barrier_nospec() and cpu_show_spectre_v1/v2().

> @@ -24,6 +26,7 @@ static void enable_barrier_nospec(bool enable)
>  	do_barrier_nospec_fixups(enable);
>  }
>  
> +#ifdef CONFIG_PPC_BOOK3S_64
>  void setup_barrier_nospec(void)
>  {
>  	bool enable;
> @@ -46,6 +49,15 @@ void setup_barrier_nospec(void)
>  	if (!no_nospec)
>  		enable_barrier_nospec(enable);
>  }
> +#endif /* CONFIG_PPC_BOOK3S_64 */
> +
> +#ifdef CONFIG_PPC_FSL_BOOK3E
> +void setup_barrier_nospec(void)
> +{
> +	if (!no_nospec)
> +		enable_barrier_nospec(true);
> +}
> +#endif /* CONFIG_PPC_FSL_BOOK3E */

eg. that is identical to the existing version except for the feature check:

	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
		 security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);


Both those bits are enabled by default, so you shouldn't need to elide
that check.

So basically you should be able to use the existing
setup_barrier_nospec() if you just remove the ifdef around
powerpc_security_features. Or am I missing something?


> diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
> index 7445748..80c1e6e 100644
> --- a/arch/powerpc/kernel/setup_32.c
> +++ b/arch/powerpc/kernel/setup_32.c
> @@ -116,6 +116,11 @@ notrace void __init machine_init(u64 dt_ptr)
>  	/* Do some early initialization based on the flat device tree */
>  	early_init_devtree(__va(dt_ptr));
>  
> +	/* Apply the speculation barrier fixup */
> +#ifdef CONFIG_PPC_FSL_BOOK3E
> +	setup_barrier_nospec();
> +#endif

This ifdef should be handled in a header with an empty version for the
#else case.

> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 7a7ce8a..b2a644a 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -327,6 +327,12 @@ void __init early_setup(unsigned long dt_ptr)
>  
>  	/* Apply all the dynamic patching */
>  	apply_feature_fixups();
> +
> +	/* Apply the speculation barrier fixup */
> +#ifdef CONFIG_PPC_FSL_BOOK3E
> +	setup_barrier_nospec();
> +#endif /* CONFIG_PPC_FSL_BOOK3E */

Can you call it from ppc_md->setup_arch() like the other platforms?

Failing that we could put it in setup_arch() after the call to
ppc_md->setup_arch(), so we can share it with powernv/pseries.

> diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
> index 2b9173d..bea2b87 100644
> --- a/arch/powerpc/lib/feature-fixups.c
> +++ b/arch/powerpc/lib/feature-fixups.c
> @@ -188,7 +188,40 @@ void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_
>  
>  	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
>  }
> +#endif /* CONFIG_PPC_BOOK3S_64 */
> +
> +#ifdef CONFIG_PPC_FSL_BOOK3E
> +void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
> +{
> +	unsigned int instr[2], *dest;
> +	long *start, *end;
> +	int i;
> +
> +	start = fixup_start;
> +	end = fixup_end;
> +
> +	instr[0] = PPC_INST_NOP;
> +	instr[1] = PPC_INST_NOP;
> +
> +	if (enable) {
> +		pr_info("barrier_nospec; using isync; sync as a speculation barrier\n");
> +		instr[0] = PPC_INST_ISYNC;
> +		instr[1] = PPC_INST_SYNC;
> +	}
> +
> +	for (i = 0; start < end; start++, i++) {
> +		dest = (void *)start + *start;
> +		pr_devel("patching dest %lx\n", (unsigned long)dest);
>  
> +		patch_instruction(dest, instr[0]);
> +		patch_instruction(dest + 1, instr[1]);
> +	}
> +
> +	pr_debug("barrier-nospec: patched %d locations\n", i);
> +}
> +#endif /* CONFIG_PPC_FSL_BOOK3E */

It's a bit unfortunate that we end up with two versions of that, which
are 80% the same. But merging them without ugly ifdefs would require a
bit more refactoring. So I guess it's OK for now.

cheers
Diana Madalina Craciun July 5, 2018, 1:21 p.m. | #2
Hi Michael,

Thank you for the review.

On 07/03/2018 10:26 AM, Michael Ellerman wrote:
> Hi Diana,
>
> A few comments below ...
>
> Diana Craciun <diana.craciun@nxp.com> writes:
>> Implement the barrier_nospec as a isync;sync instruction sequence.
>> The implementation uses the infrastructure built for BOOK3S 64.
> Do you have any details on why that sequence functions as an effective
> barrier on your chips?

It was recommended by the hardware team, I do not have details.

>
> In a lot of places we have eg:
>
>  +#if defined(CONFIG_PPC_BOOK3S_64) || defined(CONFIG_PPC_FSL_BOOK3E)
>
> Can you please add a Kconfig symbol to capture that. eg.
>
> config PPC_NOSPEC
> 	bool
>         default y
> 	depends on PPC_BOOK3S_64 || PPC_FSL_BOOK3E
>
>
> And then use that everywhere.

OK.

>
>> diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
>> index f67b3f6..405d572 100644
>> --- a/arch/powerpc/include/asm/barrier.h
>> +++ b/arch/powerpc/include/asm/barrier.h
>> @@ -86,6 +86,16 @@ do {									\
>>  // This also acts as a compiler barrier due to the memory clobber.
>>  #define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
>>  
>> +#elif defined(CONFIG_PPC_FSL_BOOK3E)
>> +/*
>> + * Prevent the execution of subsequent instructions speculatively using a
>> + * isync;sync instruction sequence.
>> + */
>> +#define barrier_nospec_asm NOSPEC_BARRIER_FIXUP_SECTION; nop; nop
>> +
>> +// This also acts as a compiler barrier due to the memory clobber.
>> +#define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
>> +
>>  #else /* !CONFIG_PPC_BOOK3S_64 */
>>  #define barrier_nospec_asm
>>  #define barrier_nospec()
> If we have CONFIG_PPC_NOSPEC this can be done something like:
>
> #ifdef CONFIG_PPC_BOOK3S_64
> #define NOSPEC_BARRIER_SLOT	nop
> #elif defined(CONFIG_PPC_FSL_BOOK3E)
> #define NOSPEC_BARRIER_SLOT	nop; nop
> #endif /* CONFIG_PPC_BOOK3S_64 */
>
> #ifdef CONFIG_PPC_NOSPEC
> /*
>  * Prevent execution of subsequent instructions until preceding branches have
>  * been fully resolved and are no longer executing speculatively.
>  */
> #define barrier_nospec_asm NOSPEC_BARRIER_FIXUP_SECTION; NOSPEC_BARRIER_SLOT
>
> // This also acts as a compiler barrier due to the memory clobber.
> #define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
> #else
> #define barrier_nospec_asm
> #define barrier_nospec()
> #endif /* CONFIG_PPC_NOSPEC */

OK.

>
>
>> diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
>> index 2b4c40b2..d9dee43 100644
>> --- a/arch/powerpc/kernel/Makefile
>> +++ b/arch/powerpc/kernel/Makefile
>> @@ -76,7 +76,7 @@ endif
>>  obj64-$(CONFIG_HIBERNATION)	+= swsusp_asm64.o
>>  obj-$(CONFIG_MODULES)		+= module.o module_$(BITS).o
>>  obj-$(CONFIG_44x)		+= cpu_setup_44x.o
>> -obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o
>> +obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o security.o
>>  obj-$(CONFIG_PPC_DOORBELL)	+= dbell.o
>>  obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
> Can we instead do:
>
> obj-$(CONFIG_PPC_NOSPEC)	+= security.o

OK

>
>> diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
>> index c55e102..797c975 100644
>> --- a/arch/powerpc/kernel/security.c
>> +++ b/arch/powerpc/kernel/security.c
>> @@ -13,7 +13,9 @@
>>  #include <asm/setup.h>
>>  
>>  
>> +#ifdef CONFIG_PPC_BOOK3S_64
>>  unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
>> +#endif /* CONFIG_PPC_BOOK3S_64 */
> Why are you making that book3s specific?
>
> By doing that you then can't use the existing versions of
> setup_barrier_nospec() and cpu_show_spectre_v1/v2().
>
>> @@ -24,6 +26,7 @@ static void enable_barrier_nospec(bool enable)
>>  	do_barrier_nospec_fixups(enable);
>>  }
>>  
>> +#ifdef CONFIG_PPC_BOOK3S_64
>>  void setup_barrier_nospec(void)
>>  {
>>  	bool enable;
>> @@ -46,6 +49,15 @@ void setup_barrier_nospec(void)
>>  	if (!no_nospec)
>>  		enable_barrier_nospec(enable);
>>  }
>> +#endif /* CONFIG_PPC_BOOK3S_64 */
>> +
>> +#ifdef CONFIG_PPC_FSL_BOOK3E
>> +void setup_barrier_nospec(void)
>> +{
>> +	if (!no_nospec)
>> +		enable_barrier_nospec(true);
>> +}
>> +#endif /* CONFIG_PPC_FSL_BOOK3E */
> eg. that is identical to the existing version except for the feature check:
>
> 	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
> 		 security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
>
>
> Both those bits are enabled by default, so you shouldn't need to elide
> that check.
>
> So basically you should be able to use the existing
> setup_barrier_nospec() if you just remove the ifdef around
> powerpc_security_features. Or am I missing something?

OK. I was under the impression that those bits are not enabled by
default. But obviously I was wrong. In this case I will use the existing
function.

>
>
>> diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
>> index 7445748..80c1e6e 100644
>> --- a/arch/powerpc/kernel/setup_32.c
>> +++ b/arch/powerpc/kernel/setup_32.c
>> @@ -116,6 +116,11 @@ notrace void __init machine_init(u64 dt_ptr)
>>  	/* Do some early initialization based on the flat device tree */
>>  	early_init_devtree(__va(dt_ptr));
>>  
>> +	/* Apply the speculation barrier fixup */
>> +#ifdef CONFIG_PPC_FSL_BOOK3E
>> +	setup_barrier_nospec();
>> +#endif
> This ifdef should be handled in a header with an empty version for the
> #else case.

OK

>
>> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
>> index 7a7ce8a..b2a644a 100644
>> --- a/arch/powerpc/kernel/setup_64.c
>> +++ b/arch/powerpc/kernel/setup_64.c
>> @@ -327,6 +327,12 @@ void __init early_setup(unsigned long dt_ptr)
>>  
>>  	/* Apply all the dynamic patching */
>>  	apply_feature_fixups();
>> +
>> +	/* Apply the speculation barrier fixup */
>> +#ifdef CONFIG_PPC_FSL_BOOK3E
>> +	setup_barrier_nospec();
>> +#endif /* CONFIG_PPC_FSL_BOOK3E */
> Can you call it from ppc_md->setup_arch() like the other platforms?
>
> Failing that we could put it in setup_arch() after the call to
> ppc_md->setup_arch(), so we can share it with powernv/pseries.

The reason for which I did not call it from the ppc_md->setup_arch() was
that from my point of view the mitigation is not specific to the
platform code, but rather to the CPU.

>
>> diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
>> index 2b9173d..bea2b87 100644
>> --- a/arch/powerpc/lib/feature-fixups.c
>> +++ b/arch/powerpc/lib/feature-fixups.c
>> @@ -188,7 +188,40 @@ void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_
>>  
>>  	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
>>  }
>> +#endif /* CONFIG_PPC_BOOK3S_64 */
>> +
>> +#ifdef CONFIG_PPC_FSL_BOOK3E
>> +void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
>> +{
>> +	unsigned int instr[2], *dest;
>> +	long *start, *end;
>> +	int i;
>> +
>> +	start = fixup_start;
>> +	end = fixup_end;
>> +
>> +	instr[0] = PPC_INST_NOP;
>> +	instr[1] = PPC_INST_NOP;
>> +
>> +	if (enable) {
>> +		pr_info("barrier_nospec; using isync; sync as a speculation barrier\n");
>> +		instr[0] = PPC_INST_ISYNC;
>> +		instr[1] = PPC_INST_SYNC;
>> +	}
>> +
>> +	for (i = 0; start < end; start++, i++) {
>> +		dest = (void *)start + *start;
>> +		pr_devel("patching dest %lx\n", (unsigned long)dest);
>>  
>> +		patch_instruction(dest, instr[0]);
>> +		patch_instruction(dest + 1, instr[1]);
>> +	}
>> +
>> +	pr_debug("barrier-nospec: patched %d locations\n", i);
>> +}
>> +#endif /* CONFIG_PPC_FSL_BOOK3E */
> It's a bit unfortunate that we end up with two versions of that, which
> are 80% the same. But merging them without ugly ifdefs would require a
> bit more refactoring. So I guess it's OK for now.
>
> cheers
>
Regards,

Diana

Patch

diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
index f67b3f6..405d572 100644
--- a/arch/powerpc/include/asm/barrier.h
+++ b/arch/powerpc/include/asm/barrier.h
@@ -86,6 +86,16 @@  do {									\
 // This also acts as a compiler barrier due to the memory clobber.
 #define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
 
+#elif defined(CONFIG_PPC_FSL_BOOK3E)
+/*
+ * Prevent the execution of subsequent instructions speculatively using a
+ * isync;sync instruction sequence.
+ */
+#define barrier_nospec_asm NOSPEC_BARRIER_FIXUP_SECTION; nop; nop
+
+// This also acts as a compiler barrier due to the memory clobber.
+#define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
+
 #else /* !CONFIG_PPC_BOOK3S_64 */
 #define barrier_nospec_asm
 #define barrier_nospec()
diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index 8721fd0..67a2810 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -56,7 +56,7 @@  void setup_barrier_nospec(void);
 void do_barrier_nospec_fixups(bool enable);
 extern bool barrier_nospec_enabled;
 
-#ifdef CONFIG_PPC_BOOK3S_64
+#if defined(CONFIG_PPC_BOOK3S_64) || defined(CONFIG_PPC_FSL_BOOK3E)
 void do_barrier_nospec_fixups_range(bool enable, void *start, void *end);
 #else
 static inline void do_barrier_nospec_fixups_range(bool enable, void *start, void *end) { };
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 2b4c40b2..d9dee43 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -76,7 +76,7 @@  endif
 obj64-$(CONFIG_HIBERNATION)	+= swsusp_asm64.o
 obj-$(CONFIG_MODULES)		+= module.o module_$(BITS).o
 obj-$(CONFIG_44x)		+= cpu_setup_44x.o
-obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o
+obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o security.o
 obj-$(CONFIG_PPC_DOORBELL)	+= dbell.o
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index 1b3c683..96a9821 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -72,13 +72,14 @@  int module_finalize(const Elf_Ehdr *hdr,
 		do_feature_fixups(powerpc_firmware_features,
 				  (void *)sect->sh_addr,
 				  (void *)sect->sh_addr + sect->sh_size);
-
+#endif /* CONFIG_PPC64 */
+#if defined(CONFIG_PPC64) || defined(CONFIG_PPC_FSL_BOOK3E)
 	sect = find_section(hdr, sechdrs, "__spec_barrier_fixup");
 	if (sect != NULL)
 		do_barrier_nospec_fixups_range(barrier_nospec_enabled,
 				  (void *)sect->sh_addr,
 				  (void *)sect->sh_addr + sect->sh_size);
-#endif
+#endif /* CONFIG_PPC64 || CONFIG_PPC_FSL_BOOK3E */
 
 	sect = find_section(hdr, sechdrs, "__lwsync_fixup");
 	if (sect != NULL)
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index c55e102..797c975 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -13,7 +13,9 @@ 
 #include <asm/setup.h>
 
 
+#ifdef CONFIG_PPC_BOOK3S_64
 unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
+#endif /* CONFIG_PPC_BOOK3S_64 */
 
 bool barrier_nospec_enabled;
 static bool no_nospec;
@@ -24,6 +26,7 @@  static void enable_barrier_nospec(bool enable)
 	do_barrier_nospec_fixups(enable);
 }
 
+#ifdef CONFIG_PPC_BOOK3S_64
 void setup_barrier_nospec(void)
 {
 	bool enable;
@@ -46,6 +49,15 @@  void setup_barrier_nospec(void)
 	if (!no_nospec)
 		enable_barrier_nospec(enable);
 }
+#endif /* CONFIG_PPC_BOOK3S_64 */
+
+#ifdef CONFIG_PPC_FSL_BOOK3E
+void setup_barrier_nospec(void)
+{
+	if (!no_nospec)
+		enable_barrier_nospec(true);
+}
+#endif /* CONFIG_PPC_FSL_BOOK3E */
 
 static int __init handle_nospectre_v1(char *p)
 {
@@ -92,6 +104,7 @@  static __init int barrier_nospec_debugfs_init(void)
 device_initcall(barrier_nospec_debugfs_init);
 #endif /* CONFIG_DEBUG_FS */
 
+#ifdef CONFIG_PPC_BOOK3S_64
 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	bool thread_priv;
@@ -168,3 +181,5 @@  ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, c
 
 	return s.len;
 }
+#endif /* CONFIG_PPC_BOOK3S_64 */
+
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 7445748..80c1e6e 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -116,6 +116,11 @@  notrace void __init machine_init(u64 dt_ptr)
 	/* Do some early initialization based on the flat device tree */
 	early_init_devtree(__va(dt_ptr));
 
+	/* Apply the speculation barrier fixup */
+#ifdef CONFIG_PPC_FSL_BOOK3E
+	setup_barrier_nospec();
+#endif
+
 	early_init_mmu();
 
 	setup_kdump_trampoline();
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 7a7ce8a..b2a644a 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -327,6 +327,12 @@  void __init early_setup(unsigned long dt_ptr)
 
 	/* Apply all the dynamic patching */
 	apply_feature_fixups();
+
+	/* Apply the speculation barrier fixup */
+#ifdef CONFIG_PPC_FSL_BOOK3E
+	setup_barrier_nospec();
+#endif /* CONFIG_PPC_FSL_BOOK3E */
+
 	setup_feature_keys();
 
 	/* Initialize the hash table or TLB handling */
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index ff73f49..af513e6 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -139,14 +139,16 @@  SECTIONS
 		*(__rfi_flush_fixup)
 		__stop___rfi_flush_fixup = .;
 	}
+#endif /* CONFIG_PPC64 */
 
+#if defined(CONFIG_PPC64) || defined(CONFIG_PPC_FSL_BOOK3E)
 	. = ALIGN(8);
 	__spec_barrier_fixup : AT(ADDR(__spec_barrier_fixup) - LOAD_OFFSET) {
 		__start___barrier_nospec_fixup = .;
 		*(__barrier_nospec_fixup)
 		__stop___barrier_nospec_fixup = .;
 	}
-#endif
+#endif /* CONFIG_PPC64 || CONFIG_PPC_FSL_BOOK3E */
 
 	EXCEPTION_TABLE(0)
 
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index 2b9173d..bea2b87 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -188,7 +188,40 @@  void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_
 
 	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
 }
+#endif /* CONFIG_PPC_BOOK3S_64 */
+
+#ifdef CONFIG_PPC_FSL_BOOK3E
+void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
+{
+	unsigned int instr[2], *dest;
+	long *start, *end;
+	int i;
+
+	start = fixup_start;
+	end = fixup_end;
+
+	instr[0] = PPC_INST_NOP;
+	instr[1] = PPC_INST_NOP;
+
+	if (enable) {
+		pr_info("barrier_nospec; using isync; sync as a speculation barrier\n");
+		instr[0] = PPC_INST_ISYNC;
+		instr[1] = PPC_INST_SYNC;
+	}
+
+	for (i = 0; start < end; start++, i++) {
+		dest = (void *)start + *start;
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
 
+		patch_instruction(dest, instr[0]);
+		patch_instruction(dest + 1, instr[1]);
+	}
+
+	pr_debug("barrier-nospec: patched %d locations\n", i);
+}
+#endif /* CONFIG_PPC_FSL_BOOK3E */
+
+#if defined(CONFIG_PPC_BOOK3S_64) || defined(CONFIG_PPC_FSL_BOOK3E)
 void do_barrier_nospec_fixups(bool enable)
 {
 	void *start, *end;
@@ -199,7 +232,7 @@  void do_barrier_nospec_fixups(bool enable)
 	do_barrier_nospec_fixups_range(enable, start, end);
 }
 
-#endif /* CONFIG_PPC_BOOK3S_64 */
+#endif /* CONFIG_PPC_BOOK3S_64 || CONFIG_PPC_FSL_BOOK3E */
 
 void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
 {