From: Kees Cook <keescook@chromium.org>
To: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
aou@eecs.berkeley.edu, peterz@infradead.org, jszhang@kernel.org,
geert@linux-m68k.org, mark.rutland@arm.com,
chenhuang5@huawei.com, linux-riscv@lists.infradead.org,
wangkefeng.wang@huawei.com, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH] riscv: Rename "sp_in_global" to "current_stack_pointer"
Date: Wed, 30 Mar 2022 21:59:37 -0700 [thread overview]
Message-ID: <202203302159.8FA7A6C@keescook> (raw)
In-Reply-To: <mhng-82a6e73b-c0b7-4625-8a79-ed481f8b2cf1@palmer-ri-x1c9>
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), keescook@chromium.org 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 <paul.walmsley@sifive.com>
> >> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> >> Cc: Albert Ou <aou@eecs.berkeley.edu>
> >> Cc: Peter Zijlstra <peterz@infradead.org>
> >> Cc: Jisheng Zhang <jszhang@kernel.org>
> >> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> >> Cc: Mark Rutland <mark.rutland@arm.com>
> >> Cc: Chen Huang <chenhuang5@huawei.com>
> >> Cc: linux-riscv@lists.infradead.org
> >> Signed-off-by: Kees Cook <keescook@chromium.org>
> >> ---
> >> 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 "palmer@dabbelt.com"
> > gpg: Good signature from "Palmer Dabbelt <palmer@dabbelt.com>" [ultimate]
> > gpg: aka "Palmer Dabbelt <palmer@rivosinc.com>" [ultimate]
> > Author: Kees Cook <keescook@chromium.org>
> > 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 <keescook@chromium.org>
> > Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
> >
> > 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
prev parent reply other threads:[~2022-03-31 4:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-24 6:04 [PATCH] riscv: Rename "sp_in_global" to "current_stack_pointer" Kees Cook
2022-03-23 2:16 ` Palmer Dabbelt
2022-03-30 23:12 ` Palmer Dabbelt
2022-03-31 4:59 ` Kees Cook [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=202203302159.8FA7A6C@keescook \
--to=keescook@chromium.org \
--cc=aou@eecs.berkeley.edu \
--cc=chenhuang5@huawei.com \
--cc=geert@linux-m68k.org \
--cc=jszhang@kernel.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=mark.rutland@arm.com \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.com \
--cc=peterz@infradead.org \
--cc=wangkefeng.wang@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox