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Message-ID: <CACT4Y+Ycgo_uOWrfr33VygtDLXvwPqDwee7OseMOaK6jTZSBjQ@mail.gmail.com>
Date: Wed, 8 Dec 2021 10:48:50 +0100
From: Dmitry Vyukov <dvyukov@...gle.com>
To: Peter Collingbourne <pcc@...gle.com>
Cc: Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>, Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andy Lutomirski <luto@...nel.org>,
Kees Cook <keescook@...omium.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Masahiro Yamada <masahiroy@...nel.org>,
Sami Tolvanen <samitolvanen@...gle.com>,
YiFei Zhu <yifeifz2@...inois.edu>,
Mark Rutland <mark.rutland@....com>,
Frederic Weisbecker <frederic@...nel.org>,
Viresh Kumar <viresh.kumar@...aro.org>,
Andrey Konovalov <andreyknvl@...il.com>,
Gabriel Krisman Bertazi <krisman@...labora.com>,
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Chris Wilson <chris@...is-wilson.co.uk>,
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Alexey Gladkov <legion@...nel.org>,
Ran Xiaokai <ran.xiaokai@....com.cn>,
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Alexander Potapenko <glider@...gle.com>,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Evgenii Stepanov <eugenis@...gle.com>
Subject: Re: [PATCH v3 5/6] arm64: add support for uaccess logging
On Wed, 8 Dec 2021 at 05:48, Peter Collingbourne <pcc@...gle.com> wrote:
>
> arm64 does not use CONFIG_GENERIC_ENTRY, so add the support for
> uaccess logging directly to the architecture.
>
> Link: https://linux-review.googlesource.com/id/I88de539fb9c4a9d27fa8cccbe201a6e4382faf89
> Signed-off-by: Peter Collingbourne <pcc@...gle.com>
> ---
> arch/arm64/Kconfig | 1 +
> arch/arm64/include/asm/thread_info.h | 7 ++++++-
> arch/arm64/kernel/ptrace.c | 7 +++++++
> arch/arm64/kernel/signal.c | 5 +++++
> arch/arm64/kernel/syscall.c | 1 +
> 5 files changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index c4207cf9bb17..6023946abe4a 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -161,6 +161,7 @@ config ARM64
> select HAVE_ARCH_THREAD_STRUCT_WHITELIST
> select HAVE_ARCH_TRACEHOOK
> select HAVE_ARCH_TRANSPARENT_HUGEPAGE
> + select HAVE_ARCH_UACCESS_BUFFER
> select HAVE_ARCH_VMAP_STACK
> select HAVE_ARM_SMCCC
> select HAVE_ASM_MODVERSIONS
> diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
> index e1317b7c4525..0461b36251ea 100644
> --- a/arch/arm64/include/asm/thread_info.h
> +++ b/arch/arm64/include/asm/thread_info.h
> @@ -82,6 +82,8 @@ int arch_dup_task_struct(struct task_struct *dst,
> #define TIF_SVE_VL_INHERIT 24 /* Inherit SVE vl_onexec across exec */
> #define TIF_SSBD 25 /* Wants SSB mitigation */
> #define TIF_TAGGED_ADDR 26 /* Allow tagged user addresses */
> +#define TIF_UACCESS_BUFFER_ENTRY 27 /* thread has non-zero uaccess_desc_addr_addr */
> +#define TIF_UACCESS_BUFFER_EXIT 28 /* thread has non-zero kcur */
>
> #define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
> #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
> @@ -98,6 +100,8 @@ int arch_dup_task_struct(struct task_struct *dst,
> #define _TIF_SVE (1 << TIF_SVE)
> #define _TIF_MTE_ASYNC_FAULT (1 << TIF_MTE_ASYNC_FAULT)
> #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
> +#define _TIF_UACCESS_BUFFER_ENTRY (1 << TIF_UACCESS_BUFFER_ENTRY)
> +#define _TIF_UACCESS_BUFFER_EXIT (1 << TIF_UACCESS_BUFFER_EXIT)
>
> #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
> _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
> @@ -106,7 +110,8 @@ int arch_dup_task_struct(struct task_struct *dst,
>
> #define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
> _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
> - _TIF_SYSCALL_EMU)
> + _TIF_SYSCALL_EMU | _TIF_UACCESS_BUFFER_ENTRY | \
> + _TIF_UACCESS_BUFFER_EXIT)
>
> #ifdef CONFIG_SHADOW_CALL_STACK
> #define INIT_SCS \
> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
> index 88a9034fb9b5..283372eccaeb 100644
> --- a/arch/arm64/kernel/ptrace.c
> +++ b/arch/arm64/kernel/ptrace.c
> @@ -29,6 +29,7 @@
> #include <linux/regset.h>
> #include <linux/tracehook.h>
> #include <linux/elf.h>
> +#include <linux/uaccess-buffer.h>
>
> #include <asm/compat.h>
> #include <asm/cpufeature.h>
> @@ -1854,6 +1855,9 @@ int syscall_trace_enter(struct pt_regs *regs)
> if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
> trace_sys_enter(regs, regs->syscallno);
>
> + if (flags & _TIF_UACCESS_BUFFER_ENTRY)
> + uaccess_buffer_syscall_entry();
> +
> audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
> regs->regs[2], regs->regs[3]);
>
> @@ -1866,6 +1870,9 @@ void syscall_trace_exit(struct pt_regs *regs)
>
> audit_syscall_exit(regs);
>
> + if (flags & _TIF_UACCESS_BUFFER_EXIT)
> + uaccess_buffer_syscall_exit();
> +
> if (flags & _TIF_SYSCALL_TRACEPOINT)
> trace_sys_exit(regs, syscall_get_return_value(current, regs));
>
> diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
> index 8f6372b44b65..5bbd98e5c257 100644
> --- a/arch/arm64/kernel/signal.c
> +++ b/arch/arm64/kernel/signal.c
> @@ -20,6 +20,7 @@
> #include <linux/tracehook.h>
> #include <linux/ratelimit.h>
> #include <linux/syscalls.h>
> +#include <linux/uaccess-buffer.h>
>
> #include <asm/daifflags.h>
> #include <asm/debug-monitors.h>
> @@ -919,6 +920,8 @@ static void do_signal(struct pt_regs *regs)
>
> void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
> {
> + bool uaccess_buffer_pending = uaccess_buffer_pre_exit_loop();
> +
> do {
> if (thread_flags & _TIF_NEED_RESCHED) {
> /* Unmask Debug and SError for the next task */
> @@ -950,6 +953,8 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
> local_daif_mask();
> thread_flags = READ_ONCE(current_thread_info()->flags);
> } while (thread_flags & _TIF_WORK_MASK);
> +
> + uaccess_buffer_post_exit_loop(uaccess_buffer_pending);
> }
>
> unsigned long __ro_after_init signal_minsigstksz;
> diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
> index 50a0f1a38e84..d59022b594f2 100644
> --- a/arch/arm64/kernel/syscall.c
> +++ b/arch/arm64/kernel/syscall.c
> @@ -7,6 +7,7 @@
> #include <linux/ptrace.h>
> #include <linux/randomize_kstack.h>
> #include <linux/syscalls.h>
> +#include <linux/uaccess-buffer.h>
This looks strange... Does some other header miss this include?
>
> #include <asm/daifflags.h>
> #include <asm/debug-monitors.h>
> --
> 2.34.1.173.g76aa8bc2d0-goog
>
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