From: Christoph Hellwig <hch@lst.de>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>,
Russell King <rmk@arm.linux.org.uk>,
Alexander Viro <viro@zeniv.linux.org.uk>,
kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linus.walleij@linaro.org,
Russell King <linux@armlinux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Dmitry Safonov <0x7f454c46@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/9] ARM: traps: use get_kernel_nofault instead of set_fs()
Date: Tue, 8 Sep 2020 08:15:28 +0200 [thread overview]
Message-ID: <20200908061528.GB13930@lst.de> (raw)
In-Reply-To: <20200907153701.2981205-3-arnd@arndb.de>
> +static void dump_mem(const char *, const char *, unsigned long, unsigned long, bool kernel_mode);
This adds a pointlessly long line.
And looking at the code I don't see why the argument is even needed.
dump_mem() currently does an unconditional set_fs(KERNEL_DS), so it
should always use get_kernel_nofault.
> +static void dump_instr(const char *lvl, struct pt_regs *regs)
> {
> unsigned long addr = instruction_pointer(regs);
> const int thumb = thumb_mode(regs);
> @@ -173,10 +169,20 @@ static void __dump_instr(const char *lvl, struct pt_regs *regs)
> for (i = -4; i < 1 + !!thumb; i++) {
> unsigned int val, bad;
>
> - if (thumb)
> - bad = get_user(val, &((u16 *)addr)[i]);
> - else
> - bad = get_user(val, &((u32 *)addr)[i]);
> + if (!user_mode(regs)) {
> + if (thumb) {
> + u16 val16;
> + bad = get_kernel_nofault(val16, &((u16 *)addr)[i]);
> + val = val16;
> + } else {
> + bad = get_kernel_nofault(val, &((u32 *)addr)[i]);
> + }
> + } else {
> + if (thumb)
> + bad = get_user(val, &((u16 *)addr)[i]);
> + else
> + bad = get_user(val, &((u32 *)addr)[i]);
> + }
When I looked at this earlier I just added a little helper to make
this a little easier to read. Here is my patch from an old tree:
http://git.infradead.org/users/hch/misc.git/commitdiff/67413030ccb7a64a7eb828e13ff0795f4eadfeb7
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org, Dmitry Safonov <0x7f454c46@gmail.com>,
linus.walleij@linaro.org, kernel@vger.kernel.org,
Russell King <linux@armlinux.org.uk>,
linux-kernel@vger.kernel.org, Russell King <rmk@arm.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
linux-arm-kernel@lists.infradead.org,
Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 2/9] ARM: traps: use get_kernel_nofault instead of set_fs()
Date: Tue, 8 Sep 2020 08:15:28 +0200 [thread overview]
Message-ID: <20200908061528.GB13930@lst.de> (raw)
In-Reply-To: <20200907153701.2981205-3-arnd@arndb.de>
> +static void dump_mem(const char *, const char *, unsigned long, unsigned long, bool kernel_mode);
This adds a pointlessly long line.
And looking at the code I don't see why the argument is even needed.
dump_mem() currently does an unconditional set_fs(KERNEL_DS), so it
should always use get_kernel_nofault.
> +static void dump_instr(const char *lvl, struct pt_regs *regs)
> {
> unsigned long addr = instruction_pointer(regs);
> const int thumb = thumb_mode(regs);
> @@ -173,10 +169,20 @@ static void __dump_instr(const char *lvl, struct pt_regs *regs)
> for (i = -4; i < 1 + !!thumb; i++) {
> unsigned int val, bad;
>
> - if (thumb)
> - bad = get_user(val, &((u16 *)addr)[i]);
> - else
> - bad = get_user(val, &((u32 *)addr)[i]);
> + if (!user_mode(regs)) {
> + if (thumb) {
> + u16 val16;
> + bad = get_kernel_nofault(val16, &((u16 *)addr)[i]);
> + val = val16;
> + } else {
> + bad = get_kernel_nofault(val, &((u32 *)addr)[i]);
> + }
> + } else {
> + if (thumb)
> + bad = get_user(val, &((u16 *)addr)[i]);
> + else
> + bad = get_user(val, &((u32 *)addr)[i]);
> + }
When I looked at this earlier I just added a little helper to make
this a little easier to read. Here is my patch from an old tree:
http://git.infradead.org/users/hch/misc.git/commitdiff/67413030ccb7a64a7eb828e13ff0795f4eadfeb7
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next prev parent reply other threads:[~2020-09-08 6:15 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 15:36 [PATCH 0/9] ARM: remove set_fs callers and implementation Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
2020-09-07 15:36 ` [PATCH 1/9] mm/maccess: fix unaligned copy_{from,to}_kernel_nofault Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
2020-09-08 6:11 ` Christoph Hellwig
2020-09-08 6:11 ` Christoph Hellwig
2020-09-27 9:25 ` Linus Walleij
2020-09-27 9:25 ` [PATCH 1/9] mm/maccess: fix unaligned copy_{from, to}_kernel_nofault Linus Walleij
2020-09-07 15:36 ` [PATCH 2/9] ARM: traps: use get_kernel_nofault instead of set_fs() Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
2020-09-08 6:15 ` Christoph Hellwig [this message]
2020-09-08 6:15 ` Christoph Hellwig
2020-09-17 17:29 ` Arnd Bergmann
2020-09-17 17:29 ` Arnd Bergmann
2020-09-18 7:42 ` Russell King - ARM Linux admin
2020-09-18 7:42 ` Russell King - ARM Linux admin
2020-09-18 12:36 ` Arnd Bergmann
2020-09-18 12:36 ` Arnd Bergmann
2020-09-07 15:36 ` [PATCH 3/9] ARM: oabi-compat: add epoll_pwait handler Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
2020-09-08 6:16 ` Christoph Hellwig
2020-09-08 6:16 ` Christoph Hellwig
2020-09-07 15:36 ` [PATCH 4/9] ARM: syscall: always store thread_info->syscall Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
2020-09-28 9:41 ` Linus Walleij
2020-09-28 9:41 ` Linus Walleij
2020-09-28 12:42 ` Arnd Bergmann
2020-09-28 12:42 ` Arnd Bergmann
2020-09-28 15:08 ` Russell King - ARM Linux admin
2020-09-28 15:08 ` Russell King - ARM Linux admin
2020-09-07 15:36 ` [PATCH 5/9] ARM: oabi-compat: rework epoll_wait/epoll_pwait emulation Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
2020-09-08 6:20 ` Christoph Hellwig
2020-09-08 6:20 ` Christoph Hellwig
2020-09-08 20:56 ` Arnd Bergmann
2020-09-08 20:56 ` Arnd Bergmann
2020-09-07 15:36 ` [PATCH 6/9] ARM: oabi-compat: rework sys_semtimedop emulation Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
2020-09-07 15:36 ` [PATCH 7/9] ARM: oabi-compat: rework fcntl64() emulation Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
2020-09-07 15:36 ` [PATCH 8/9] ARM: uaccess: add __{get,put}_kernel_nofault Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
2020-09-07 15:36 ` [PATCH 9/9] ARM: uaccess: remove set_fs() implementation Arnd Bergmann
2020-09-07 15:36 ` Arnd Bergmann
-- strict thread matches above, loose matches on Subject: below --
2020-10-30 15:45 [PATCH v4 0/9] ARM: remove set_fs callers and implementation Arnd Bergmann
2020-10-30 15:49 ` [PATCH 1/9] mm/maccess: fix unaligned copy_{from,to}_kernel_nofault Arnd Bergmann
2020-10-30 15:49 ` [PATCH 2/9] ARM: traps: use get_kernel_nofault instead of set_fs() Arnd Bergmann
2020-10-30 15:49 ` Arnd Bergmann
2020-11-06 9:02 ` Linus Walleij
2020-11-06 9:02 ` Linus Walleij
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