2022-02-24 06:24:25

by Kees Cook

[permalink] [raw]
Subject: [PATCH] riscv: Rename "sp_in_global" to "current_stack_pointer"

To follow the existing per-arch conventions, rename "sp_in_global" to
"current_stack_pointer". This will let it be used in non-arch places
(like HARDENED_USERCOPY).

Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Jisheng Zhang <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Chen Huang <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/current.h | 2 ++
arch/riscv/kernel/stacktrace.c | 4 +---
3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5adcbd9b5e88..b120c32697af 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -16,6 +16,7 @@ config RISCV
select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
select ARCH_HAS_BINFMT_FLAT
+ select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DEBUG_VM_PGTABLE
select ARCH_HAS_DEBUG_VIRTUAL if MMU
select ARCH_HAS_DEBUG_WX
diff --git a/arch/riscv/include/asm/current.h b/arch/riscv/include/asm/current.h
index 1de233d8e8de..21774d868c65 100644
--- a/arch/riscv/include/asm/current.h
+++ b/arch/riscv/include/asm/current.h
@@ -33,6 +33,8 @@ static __always_inline struct task_struct *get_current(void)

#define current get_current()

+register unsigned long current_stack_pointer __asm__("sp");
+
#endif /* __ASSEMBLY__ */

#endif /* _ASM_RISCV_CURRENT_H */
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index 201ee206fb57..278380e2e956 100644
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -14,8 +14,6 @@

#include <asm/stacktrace.h>

-register unsigned long sp_in_global __asm__("sp");
-
#ifdef CONFIG_FRAME_POINTER

void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
@@ -77,7 +75,7 @@ void notrace walk_stackframe(struct task_struct *task,
sp = user_stack_pointer(regs);
pc = instruction_pointer(regs);
} else if (task == NULL || task == current) {
- sp = sp_in_global;
+ sp = current_stack_pointer;
pc = (unsigned long)walk_stackframe;
} else {
/* task blocked in __switch_to */
--
2.30.2


2022-03-23 08:40:43

by Palmer Dabbelt

[permalink] [raw]
Subject: Re: [PATCH] riscv: Rename "sp_in_global" to "current_stack_pointer"

On Wed, 23 Feb 2022 22:04:11 PST (-0800), [email protected] wrote:
> To follow the existing per-arch conventions, rename "sp_in_global" to
> "current_stack_pointer". This will let it be used in non-arch places
> (like HARDENED_USERCOPY).
>
> Cc: Paul Walmsley <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> Cc: Albert Ou <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Jisheng Zhang <[email protected]>
> Cc: Geert Uytterhoeven <[email protected]>
> Cc: Mark Rutland <[email protected]>
> Cc: Chen Huang <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>
> ---
> arch/riscv/Kconfig | 1 +
> arch/riscv/include/asm/current.h | 2 ++
> arch/riscv/kernel/stacktrace.c | 4 +---
> 3 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 5adcbd9b5e88..b120c32697af 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -16,6 +16,7 @@ config RISCV
> select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
> select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
> select ARCH_HAS_BINFMT_FLAT
> + select ARCH_HAS_CURRENT_STACK_POINTER
> select ARCH_HAS_DEBUG_VM_PGTABLE
> select ARCH_HAS_DEBUG_VIRTUAL if MMU
> select ARCH_HAS_DEBUG_WX
> diff --git a/arch/riscv/include/asm/current.h b/arch/riscv/include/asm/current.h
> index 1de233d8e8de..21774d868c65 100644
> --- a/arch/riscv/include/asm/current.h
> +++ b/arch/riscv/include/asm/current.h
> @@ -33,6 +33,8 @@ static __always_inline struct task_struct *get_current(void)
>
> #define current get_current()
>
> +register unsigned long current_stack_pointer __asm__("sp");
> +
> #endif /* __ASSEMBLY__ */
>
> #endif /* _ASM_RISCV_CURRENT_H */
> diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> index 201ee206fb57..278380e2e956 100644
> --- a/arch/riscv/kernel/stacktrace.c
> +++ b/arch/riscv/kernel/stacktrace.c
> @@ -14,8 +14,6 @@
>
> #include <asm/stacktrace.h>
>
> -register unsigned long sp_in_global __asm__("sp");
> -
> #ifdef CONFIG_FRAME_POINTER
>
> void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
> @@ -77,7 +75,7 @@ void notrace walk_stackframe(struct task_struct *task,
> sp = user_stack_pointer(regs);
> pc = instruction_pointer(regs);
> } else if (task == NULL || task == current) {
> - sp = sp_in_global;
> + sp = current_stack_pointer;
> pc = (unsigned long)walk_stackframe;
> } else {
> /* task blocked in __switch_to */

Sorry to be slow on this one. This looks good, but another use of
sp_in_global snuck into fixes and I don't merge fixes into for-next so
that makes this a bit of a headache.

There's a bunch of stuff in flight, so I'm going to hold off on this
until after my first week's merge window PR. I intend on merging the
following, which is at palmer/riscv-sp for now (I'll probably just
cherry-pick that, I usually start basing stuff on Linus' merge of my PR
and just cherry-pick in single patches).

commit 7c4f6bb6fb352cfa6028191c2888356b9157a332
gpg: Signature made Tue 22 Mar 2022 11:12:19 AM PDT
gpg: using RSA key 2B3C3747446843B24A943A7A2E1319F35FBB1889
gpg: issuer "[email protected]"
gpg: Good signature from "Palmer Dabbelt <[email protected]>" [ultimate]
gpg: aka "Palmer Dabbelt <[email protected]>" [ultimate]
Author: Kees Cook <[email protected]>
Date: Wed Feb 23 22:04:11 2022 -0800

riscv: Rename "sp_in_global" to "current_stack_pointer"

To follow the existing per-arch conventions, rename "sp_in_global" to
"current_stack_pointer". This will let it be used in non-arch places
(like HARDENED_USERCOPY).

Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Palmer Dabbelt <[email protected]>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5adcbd9b5e88..b120c32697af 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -16,6 +16,7 @@ config RISCV
select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
select ARCH_HAS_BINFMT_FLAT
+ select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DEBUG_VM_PGTABLE
select ARCH_HAS_DEBUG_VIRTUAL if MMU
select ARCH_HAS_DEBUG_WX
diff --git a/arch/riscv/include/asm/current.h b/arch/riscv/include/asm/current.h
index 1de233d8e8de..21774d868c65 100644
--- a/arch/riscv/include/asm/current.h
+++ b/arch/riscv/include/asm/current.h
@@ -33,6 +33,8 @@ static __always_inline struct task_struct *get_current(void)

#define current get_current()

+register unsigned long current_stack_pointer __asm__("sp");
+
#endif /* __ASSEMBLY__ */

#endif /* _ASM_RISCV_CURRENT_H */
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index 14d2b53ec322..08d11a53f39e 100644
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -14,8 +14,6 @@

#include <asm/stacktrace.h>

-register unsigned long sp_in_global __asm__("sp");
-
#ifdef CONFIG_FRAME_POINTER

void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
@@ -30,7 +28,7 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
pc = instruction_pointer(regs);
} else if (task == NULL || task == current) {
fp = (unsigned long)__builtin_frame_address(0);
- sp = sp_in_global;
+ sp = current_stack_pointer;
pc = (unsigned long)walk_stackframe;
} else {
/* task blocked in __switch_to */
@@ -78,7 +76,7 @@ void notrace walk_stackframe(struct task_struct *task,
sp = user_stack_pointer(regs);
pc = instruction_pointer(regs);
} else if (task == NULL || task == current) {
- sp = sp_in_global;
+ sp = current_stack_pointer;
pc = (unsigned long)walk_stackframe;
} else {
/* task blocked in __switch_to */

Thanks!

2022-03-31 02:44:34

by Palmer Dabbelt

[permalink] [raw]
Subject: Re: [PATCH] riscv: Rename "sp_in_global" to "current_stack_pointer"

On Tue, 22 Mar 2022 19:16:28 PDT (-0700), Palmer Dabbelt wrote:
> On Wed, 23 Feb 2022 22:04:11 PST (-0800), [email protected] wrote:
>> To follow the existing per-arch conventions, rename "sp_in_global" to
>> "current_stack_pointer". This will let it be used in non-arch places
>> (like HARDENED_USERCOPY).
>>
>> Cc: Paul Walmsley <[email protected]>
>> Cc: Palmer Dabbelt <[email protected]>
>> Cc: Albert Ou <[email protected]>
>> Cc: Peter Zijlstra <[email protected]>
>> Cc: Jisheng Zhang <[email protected]>
>> Cc: Geert Uytterhoeven <[email protected]>
>> Cc: Mark Rutland <[email protected]>
>> Cc: Chen Huang <[email protected]>
>> Cc: [email protected]
>> Signed-off-by: Kees Cook <[email protected]>
>> ---
>> arch/riscv/Kconfig | 1 +
>> arch/riscv/include/asm/current.h | 2 ++
>> arch/riscv/kernel/stacktrace.c | 4 +---
>> 3 files changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
>> index 5adcbd9b5e88..b120c32697af 100644
>> --- a/arch/riscv/Kconfig
>> +++ b/arch/riscv/Kconfig
>> @@ -16,6 +16,7 @@ config RISCV
>> select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
>> select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
>> select ARCH_HAS_BINFMT_FLAT
>> + select ARCH_HAS_CURRENT_STACK_POINTER
>> select ARCH_HAS_DEBUG_VM_PGTABLE
>> select ARCH_HAS_DEBUG_VIRTUAL if MMU
>> select ARCH_HAS_DEBUG_WX
>> diff --git a/arch/riscv/include/asm/current.h b/arch/riscv/include/asm/current.h
>> index 1de233d8e8de..21774d868c65 100644
>> --- a/arch/riscv/include/asm/current.h
>> +++ b/arch/riscv/include/asm/current.h
>> @@ -33,6 +33,8 @@ static __always_inline struct task_struct *get_current(void)
>>
>> #define current get_current()
>>
>> +register unsigned long current_stack_pointer __asm__("sp");
>> +
>> #endif /* __ASSEMBLY__ */
>>
>> #endif /* _ASM_RISCV_CURRENT_H */
>> diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
>> index 201ee206fb57..278380e2e956 100644
>> --- a/arch/riscv/kernel/stacktrace.c
>> +++ b/arch/riscv/kernel/stacktrace.c
>> @@ -14,8 +14,6 @@
>>
>> #include <asm/stacktrace.h>
>>
>> -register unsigned long sp_in_global __asm__("sp");
>> -
>> #ifdef CONFIG_FRAME_POINTER
>>
>> void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
>> @@ -77,7 +75,7 @@ void notrace walk_stackframe(struct task_struct *task,
>> sp = user_stack_pointer(regs);
>> pc = instruction_pointer(regs);
>> } else if (task == NULL || task == current) {
>> - sp = sp_in_global;
>> + sp = current_stack_pointer;
>> pc = (unsigned long)walk_stackframe;
>> } else {
>> /* task blocked in __switch_to */
>
> Sorry to be slow on this one. This looks good, but another use of
> sp_in_global snuck into fixes and I don't merge fixes into for-next so
> that makes this a bit of a headache.
>
> There's a bunch of stuff in flight, so I'm going to hold off on this
> until after my first week's merge window PR. I intend on merging the
> following, which is at palmer/riscv-sp for now (I'll probably just
> cherry-pick that, I usually start basing stuff on Linus' merge of my PR
> and just cherry-pick in single patches).
>
> commit 7c4f6bb6fb352cfa6028191c2888356b9157a332
> gpg: Signature made Tue 22 Mar 2022 11:12:19 AM PDT
> gpg: using RSA key 2B3C3747446843B24A943A7A2E1319F35FBB1889
> gpg: issuer "[email protected]"
> gpg: Good signature from "Palmer Dabbelt <[email protected]>" [ultimate]
> gpg: aka "Palmer Dabbelt <[email protected]>" [ultimate]
> Author: Kees Cook <[email protected]>
> Date: Wed Feb 23 22:04:11 2022 -0800
>
> riscv: Rename "sp_in_global" to "current_stack_pointer"
>
> To follow the existing per-arch conventions, rename "sp_in_global" to
> "current_stack_pointer". This will let it be used in non-arch places
> (like HARDENED_USERCOPY).
>
> Signed-off-by: Kees Cook <[email protected]>
> Signed-off-by: Palmer Dabbelt <[email protected]>
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 5adcbd9b5e88..b120c32697af 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -16,6 +16,7 @@ config RISCV
> select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
> select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
> select ARCH_HAS_BINFMT_FLAT
> + select ARCH_HAS_CURRENT_STACK_POINTER
> select ARCH_HAS_DEBUG_VM_PGTABLE
> select ARCH_HAS_DEBUG_VIRTUAL if MMU
> select ARCH_HAS_DEBUG_WX
> diff --git a/arch/riscv/include/asm/current.h b/arch/riscv/include/asm/current.h
> index 1de233d8e8de..21774d868c65 100644
> --- a/arch/riscv/include/asm/current.h
> +++ b/arch/riscv/include/asm/current.h
> @@ -33,6 +33,8 @@ static __always_inline struct task_struct *get_current(void)
>
> #define current get_current()
>
> +register unsigned long current_stack_pointer __asm__("sp");
> +
> #endif /* __ASSEMBLY__ */
>
> #endif /* _ASM_RISCV_CURRENT_H */
> diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> index 14d2b53ec322..08d11a53f39e 100644
> --- a/arch/riscv/kernel/stacktrace.c
> +++ b/arch/riscv/kernel/stacktrace.c
> @@ -14,8 +14,6 @@
>
> #include <asm/stacktrace.h>
>
> -register unsigned long sp_in_global __asm__("sp");
> -
> #ifdef CONFIG_FRAME_POINTER
>
> void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
> @@ -30,7 +28,7 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
> pc = instruction_pointer(regs);
> } else if (task == NULL || task == current) {
> fp = (unsigned long)__builtin_frame_address(0);
> - sp = sp_in_global;
> + sp = current_stack_pointer;
> pc = (unsigned long)walk_stackframe;
> } else {
> /* task blocked in __switch_to */
> @@ -78,7 +76,7 @@ void notrace walk_stackframe(struct task_struct *task,
> sp = user_stack_pointer(regs);
> pc = instruction_pointer(regs);
> } else if (task == NULL || task == current) {
> - sp = sp_in_global;
> + sp = current_stack_pointer;
> pc = (unsigned long)walk_stackframe;
> } else {
> /* task blocked in __switch_to */
>
> Thanks!

Thanks, this is on for-next. I put HARDENED_USERCOPY=y test in for SLAB
and SLUB, not sure if there's anything else that's interesting to test
(we're missing some bits needed for STACKLEAK).

2022-03-31 05:22:23

by Kees Cook

[permalink] [raw]
Subject: Re: [PATCH] riscv: Rename "sp_in_global" to "current_stack_pointer"

On Wed, Mar 30, 2022 at 04:12:18PM -0700, Palmer Dabbelt wrote:
> On Tue, 22 Mar 2022 19:16:28 PDT (-0700), Palmer Dabbelt wrote:
> > On Wed, 23 Feb 2022 22:04:11 PST (-0800), [email protected] wrote:
> >> To follow the existing per-arch conventions, rename "sp_in_global" to
> >> "current_stack_pointer". This will let it be used in non-arch places
> >> (like HARDENED_USERCOPY).
> >>
> >> Cc: Paul Walmsley <[email protected]>
> >> Cc: Palmer Dabbelt <[email protected]>
> >> Cc: Albert Ou <[email protected]>
> >> Cc: Peter Zijlstra <[email protected]>
> >> Cc: Jisheng Zhang <[email protected]>
> >> Cc: Geert Uytterhoeven <[email protected]>
> >> Cc: Mark Rutland <[email protected]>
> >> Cc: Chen Huang <[email protected]>
> >> Cc: [email protected]
> >> Signed-off-by: Kees Cook <[email protected]>
> >> ---
> >> arch/riscv/Kconfig | 1 +
> >> arch/riscv/include/asm/current.h | 2 ++
> >> arch/riscv/kernel/stacktrace.c | 4 +---
> >> 3 files changed, 4 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> >> index 5adcbd9b5e88..b120c32697af 100644
> >> --- a/arch/riscv/Kconfig
> >> +++ b/arch/riscv/Kconfig
> >> @@ -16,6 +16,7 @@ config RISCV
> >> select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
> >> select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
> >> select ARCH_HAS_BINFMT_FLAT
> >> + select ARCH_HAS_CURRENT_STACK_POINTER
> >> select ARCH_HAS_DEBUG_VM_PGTABLE
> >> select ARCH_HAS_DEBUG_VIRTUAL if MMU
> >> select ARCH_HAS_DEBUG_WX
> >> diff --git a/arch/riscv/include/asm/current.h b/arch/riscv/include/asm/current.h
> >> index 1de233d8e8de..21774d868c65 100644
> >> --- a/arch/riscv/include/asm/current.h
> >> +++ b/arch/riscv/include/asm/current.h
> >> @@ -33,6 +33,8 @@ static __always_inline struct task_struct *get_current(void)
> >>
> >> #define current get_current()
> >>
> >> +register unsigned long current_stack_pointer __asm__("sp");
> >> +
> >> #endif /* __ASSEMBLY__ */
> >>
> >> #endif /* _ASM_RISCV_CURRENT_H */
> >> diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> >> index 201ee206fb57..278380e2e956 100644
> >> --- a/arch/riscv/kernel/stacktrace.c
> >> +++ b/arch/riscv/kernel/stacktrace.c
> >> @@ -14,8 +14,6 @@
> >>
> >> #include <asm/stacktrace.h>
> >>
> >> -register unsigned long sp_in_global __asm__("sp");
> >> -
> >> #ifdef CONFIG_FRAME_POINTER
> >>
> >> void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
> >> @@ -77,7 +75,7 @@ void notrace walk_stackframe(struct task_struct *task,
> >> sp = user_stack_pointer(regs);
> >> pc = instruction_pointer(regs);
> >> } else if (task == NULL || task == current) {
> >> - sp = sp_in_global;
> >> + sp = current_stack_pointer;
> >> pc = (unsigned long)walk_stackframe;
> >> } else {
> >> /* task blocked in __switch_to */
> >
> > Sorry to be slow on this one. This looks good, but another use of
> > sp_in_global snuck into fixes and I don't merge fixes into for-next so
> > that makes this a bit of a headache.
> >
> > There's a bunch of stuff in flight, so I'm going to hold off on this
> > until after my first week's merge window PR. I intend on merging the
> > following, which is at palmer/riscv-sp for now (I'll probably just
> > cherry-pick that, I usually start basing stuff on Linus' merge of my PR
> > and just cherry-pick in single patches).
> >
> > commit 7c4f6bb6fb352cfa6028191c2888356b9157a332
> > gpg: Signature made Tue 22 Mar 2022 11:12:19 AM PDT
> > gpg: using RSA key 2B3C3747446843B24A943A7A2E1319F35FBB1889
> > gpg: issuer "[email protected]"
> > gpg: Good signature from "Palmer Dabbelt <[email protected]>" [ultimate]
> > gpg: aka "Palmer Dabbelt <[email protected]>" [ultimate]
> > Author: Kees Cook <[email protected]>
> > Date: Wed Feb 23 22:04:11 2022 -0800
> >
> > riscv: Rename "sp_in_global" to "current_stack_pointer"
> >
> > To follow the existing per-arch conventions, rename "sp_in_global" to
> > "current_stack_pointer". This will let it be used in non-arch places
> > (like HARDENED_USERCOPY).
> >
> > Signed-off-by: Kees Cook <[email protected]>
> > Signed-off-by: Palmer Dabbelt <[email protected]>
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > index 5adcbd9b5e88..b120c32697af 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -16,6 +16,7 @@ config RISCV
> > select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
> > select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
> > select ARCH_HAS_BINFMT_FLAT
> > + select ARCH_HAS_CURRENT_STACK_POINTER
> > select ARCH_HAS_DEBUG_VM_PGTABLE
> > select ARCH_HAS_DEBUG_VIRTUAL if MMU
> > select ARCH_HAS_DEBUG_WX
> > diff --git a/arch/riscv/include/asm/current.h b/arch/riscv/include/asm/current.h
> > index 1de233d8e8de..21774d868c65 100644
> > --- a/arch/riscv/include/asm/current.h
> > +++ b/arch/riscv/include/asm/current.h
> > @@ -33,6 +33,8 @@ static __always_inline struct task_struct *get_current(void)
> >
> > #define current get_current()
> >
> > +register unsigned long current_stack_pointer __asm__("sp");
> > +
> > #endif /* __ASSEMBLY__ */
> >
> > #endif /* _ASM_RISCV_CURRENT_H */
> > diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> > index 14d2b53ec322..08d11a53f39e 100644
> > --- a/arch/riscv/kernel/stacktrace.c
> > +++ b/arch/riscv/kernel/stacktrace.c
> > @@ -14,8 +14,6 @@
> >
> > #include <asm/stacktrace.h>
> >
> > -register unsigned long sp_in_global __asm__("sp");
> > -
> > #ifdef CONFIG_FRAME_POINTER
> >
> > void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
> > @@ -30,7 +28,7 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
> > pc = instruction_pointer(regs);
> > } else if (task == NULL || task == current) {
> > fp = (unsigned long)__builtin_frame_address(0);
> > - sp = sp_in_global;
> > + sp = current_stack_pointer;
> > pc = (unsigned long)walk_stackframe;
> > } else {
> > /* task blocked in __switch_to */
> > @@ -78,7 +76,7 @@ void notrace walk_stackframe(struct task_struct *task,
> > sp = user_stack_pointer(regs);
> > pc = instruction_pointer(regs);
> > } else if (task == NULL || task == current) {
> > - sp = sp_in_global;
> > + sp = current_stack_pointer;
> > pc = (unsigned long)walk_stackframe;
> > } else {
> > /* task blocked in __switch_to */
> >
> > Thanks!
>
> Thanks, this is on for-next. I put HARDENED_USERCOPY=y test in for SLAB
> and SLUB, not sure if there's anything else that's interesting to test
> (we're missing some bits needed for STACKLEAK).

Excellent; thank you!

--
Kees Cook