Re: [PATCH 1/6] arm64: kpti: move check for non-vulnerable CPUs to a function
Hi Julien,
Thanks for looking at this,
On 12/13/2018 03:13 AM, Julien Thierry wrote:
Hi,
On 06/12/2018 23:44, Jeremy Linton wrote:
From: Mian Yousaf Kaukab
Add is_meltdown_safe() which is a whitelist of known safe cores.
Signed-off-by: Mian Yousaf Kaukab
[Moved location of function]
Signed-off-by: Jeremy Linton
---
arch/arm64/kernel/cpufeature.c | 16
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index aec5ecb85737..242898395f68 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -908,8 +908,7 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry,
int scope)
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
-static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
- int scope)
+static bool is_cpu_meltdown_safe(void)
{
/* List of CPUs that are not vulnerable and don't need KPTI */
static const struct midr_range kpti_safe_list[] = {
@@ -917,6 +916,16 @@ static bool unmap_kernel_at_el0(const struct
arm64_cpu_capabilities *entry,
MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
{ /* sentinel */ }
};
+ /* Don't force KPTI for CPUs that are not vulnerable */
This is really a nit, but that comment would make more sense where
is_cpu_meltdown_safe() is called since unmap_kernel_at_el0 is the one
deciding whether to apply KPTI, is_cpu_meltdown_safe() just states
whether the core is safe of not.
That is a good point, thanks.
Otherwise:
Reviewed-by: Julien Thierry
Cheers,
Julien
+ if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ return true;
+
+ return false;
+}
+
+static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
+ int scope)
+{
char const *str = "command line option";
/*
@@ -940,8 +949,7 @@ static bool unmap_kernel_at_el0(const struct
arm64_cpu_capabilities *entry,
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
return true;
- /* Don't force KPTI for CPUs that are not vulnerable */
- if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ if (is_cpu_meltdown_safe())
return false;
/* Defer to CPU feature registers */
Re: [PATCH 1/6] arm64: kpti: move check for non-vulnerable CPUs to a function
Hi,
On 06/12/2018 23:44, Jeremy Linton wrote:
> From: Mian Yousaf Kaukab
>
> Add is_meltdown_safe() which is a whitelist of known safe cores.
>
> Signed-off-by: Mian Yousaf Kaukab
> [Moved location of function]
> Signed-off-by: Jeremy Linton
> ---
> arch/arm64/kernel/cpufeature.c | 16
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index aec5ecb85737..242898395f68 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -908,8 +908,7 @@ has_useable_cnp(const struct arm64_cpu_capabilities
> *entry, int scope)
> #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
> static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
>
> -static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
> - int scope)
> +static bool is_cpu_meltdown_safe(void)
> {
> /* List of CPUs that are not vulnerable and don't need KPTI */
> static const struct midr_range kpti_safe_list[] = {
> @@ -917,6 +916,16 @@ static bool unmap_kernel_at_el0(const struct
> arm64_cpu_capabilities *entry,
> MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
> { /* sentinel */ }
> };
> + /* Don't force KPTI for CPUs that are not vulnerable */
This is really a nit, but that comment would make more sense where
is_cpu_meltdown_safe() is called since unmap_kernel_at_el0 is the one
deciding whether to apply KPTI, is_cpu_meltdown_safe() just states
whether the core is safe of not.
Otherwise:
Reviewed-by: Julien Thierry
Cheers,
Julien
> + if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
> + return true;
> +
> + return false;
> +}
> +
> +static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
> + int scope)
> +{
> char const *str = "command line option";
>
> /*
> @@ -940,8 +949,7 @@ static bool unmap_kernel_at_el0(const struct
> arm64_cpu_capabilities *entry,
> if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
> return true;
>
> - /* Don't force KPTI for CPUs that are not vulnerable */
> - if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
> + if (is_cpu_meltdown_safe())
> return false;
>
> /* Defer to CPU feature registers */
>
--
Julien Thierry
[PATCH 1/6] arm64: kpti: move check for non-vulnerable CPUs to a function
From: Mian Yousaf Kaukab
Add is_meltdown_safe() which is a whitelist of known safe cores.
Signed-off-by: Mian Yousaf Kaukab
[Moved location of function]
Signed-off-by: Jeremy Linton
---
arch/arm64/kernel/cpufeature.c | 16
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index aec5ecb85737..242898395f68 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -908,8 +908,7 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry,
int scope)
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
-static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
- int scope)
+static bool is_cpu_meltdown_safe(void)
{
/* List of CPUs that are not vulnerable and don't need KPTI */
static const struct midr_range kpti_safe_list[] = {
@@ -917,6 +916,16 @@ static bool unmap_kernel_at_el0(const struct
arm64_cpu_capabilities *entry,
MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
{ /* sentinel */ }
};
+ /* Don't force KPTI for CPUs that are not vulnerable */
+ if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ return true;
+
+ return false;
+}
+
+static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
+ int scope)
+{
char const *str = "command line option";
/*
@@ -940,8 +949,7 @@ static bool unmap_kernel_at_el0(const struct
arm64_cpu_capabilities *entry,
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
return true;
- /* Don't force KPTI for CPUs that are not vulnerable */
- if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ if (is_cpu_meltdown_safe())
return false;
/* Defer to CPU feature registers */
--
2.17.2
[PATCH 1/6] arm64: kpti: move check for non-vulnerable CPUs to a function
From: Mian Yousaf Kaukab
Add is_meltdown_safe() which is a whitelist of known safe cores.
Signed-off-by: Mian Yousaf Kaukab
[Moved location of function]
Signed-off-by: Jeremy Linton
---
arch/arm64/kernel/cpufeature.c | 16
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index aec5ecb85737..242898395f68 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -908,8 +908,7 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry,
int scope)
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
-static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
- int scope)
+static bool is_cpu_meltdown_safe(void)
{
/* List of CPUs that are not vulnerable and don't need KPTI */
static const struct midr_range kpti_safe_list[] = {
@@ -917,6 +916,16 @@ static bool unmap_kernel_at_el0(const struct
arm64_cpu_capabilities *entry,
MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
{ /* sentinel */ }
};
+ /* Don't force KPTI for CPUs that are not vulnerable */
+ if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ return true;
+
+ return false;
+}
+
+static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
+ int scope)
+{
char const *str = "command line option";
/*
@@ -940,8 +949,7 @@ static bool unmap_kernel_at_el0(const struct
arm64_cpu_capabilities *entry,
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
return true;
- /* Don't force KPTI for CPUs that are not vulnerable */
- if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ if (is_cpu_meltdown_safe())
return false;
/* Defer to CPU feature registers */
--
2.17.2
[PATCH 1/6] arm64: kpti: move check for non-vulnerable CPUs to a function
Prepare to call it in generic cpu vulnerabilities support.
Signed-off-by: Mian Yousaf Kaukab
---
arch/arm64/include/asm/cpufeature.h | 16
arch/arm64/kernel/cpufeature.c | 9 +
2 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h
b/arch/arm64/include/asm/cpufeature.h
index 1717ba1db35d..0b0b5b3e36ba 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -530,6 +530,22 @@ void arm64_set_ssbd_mitigation(bool state);
static inline void arm64_set_ssbd_mitigation(bool state) {}
#endif
+static inline bool is_cpu_meltdown_safe(void)
+{
+ /* List of CPUs that are not vulnerable and don't need KPTI */
+ static const struct midr_range kpti_safe_list[] = {
+ MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
+ MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
+ { /* sentinel */ }
+ };
+
+ /* Don't force KPTI for CPUs that are not vulnerable */
+ if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ return true;
+
+ return false;
+}
+
#endif /* __ASSEMBLY__ */
#endif
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index e238b7932096..6a94f8bce35a 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -865,12 +865,6 @@ static int __kpti_forced; /* 0: not forced, >0: forced on,
<0: forced off */
static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
int scope)
{
- /* List of CPUs that are not vulnerable and don't need KPTI */
- static const struct midr_range kpti_safe_list[] = {
- MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
- MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
- { /* sentinel */ }
- };
char const *str = "command line option";
/*
@@ -894,8 +888,7 @@ static bool unmap_kernel_at_el0(const struct
arm64_cpu_capabilities *entry,
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
return true;
- /* Don't force KPTI for CPUs that are not vulnerable */
- if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ if (is_cpu_meltdown_safe())
return false;
/* Defer to CPU feature registers */
--
2.11.0
[PATCH 1/6] arm64: kpti: move check for non-vulnerable CPUs to a function
Prepare to call it in generic cpu vulnerabilities support.
Signed-off-by: Mian Yousaf Kaukab
---
arch/arm64/include/asm/cpufeature.h | 16
arch/arm64/kernel/cpufeature.c | 9 +
2 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h
b/arch/arm64/include/asm/cpufeature.h
index 1717ba1db35d..0b0b5b3e36ba 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -530,6 +530,22 @@ void arm64_set_ssbd_mitigation(bool state);
static inline void arm64_set_ssbd_mitigation(bool state) {}
#endif
+static inline bool is_cpu_meltdown_safe(void)
+{
+ /* List of CPUs that are not vulnerable and don't need KPTI */
+ static const struct midr_range kpti_safe_list[] = {
+ MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
+ MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
+ { /* sentinel */ }
+ };
+
+ /* Don't force KPTI for CPUs that are not vulnerable */
+ if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ return true;
+
+ return false;
+}
+
#endif /* __ASSEMBLY__ */
#endif
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index e238b7932096..6a94f8bce35a 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -865,12 +865,6 @@ static int __kpti_forced; /* 0: not forced, >0: forced on,
<0: forced off */
static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
int scope)
{
- /* List of CPUs that are not vulnerable and don't need KPTI */
- static const struct midr_range kpti_safe_list[] = {
- MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
- MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
- { /* sentinel */ }
- };
char const *str = "command line option";
/*
@@ -894,8 +888,7 @@ static bool unmap_kernel_at_el0(const struct
arm64_cpu_capabilities *entry,
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
return true;
- /* Don't force KPTI for CPUs that are not vulnerable */
- if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
+ if (is_cpu_meltdown_safe())
return false;
/* Defer to CPU feature registers */
--
2.11.0
