From: Peter Zijlstra <peterz@infradead.org>
To: torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com,
julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net,
mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com,
valentin.schneider@arm.com, brgerst@gmail.com,
jpoimboe@redhat.com, luto@kernel.org, bp@alien8.de,
dvlasenk@redhat.com
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
dvyukov@google.com, rostedt@goodmis.org
Subject: [PATCH 11/25] x86/uaccess: Introduce user_access_{save,restore}()
Date: Mon, 18 Mar 2019 16:38:51 +0100 [thread overview]
Message-ID: <20190318155140.910372928@infradead.org> (raw)
In-Reply-To: 20190318153840.906404905@infradead.org
Introduce common helpers for when we need to safely suspend a
uaccess section; for instance to generate a {KA,UB}SAN report.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/include/asm/smap.h | 20 ++++++++++++++++++++
arch/x86/include/asm/uaccess.h | 3 +++
include/linux/uaccess.h | 2 ++
3 files changed, 25 insertions(+)
--- a/arch/x86/include/asm/smap.h
+++ b/arch/x86/include/asm/smap.h
@@ -58,6 +58,23 @@ static __always_inline void stac(void)
alternative("", __stringify(__ASM_STAC), X86_FEATURE_SMAP);
}
+static __always_inline unsigned long smap_save(void)
+{
+ unsigned long flags;
+
+ asm volatile (ALTERNATIVE("", "pushf; pop %0; " __stringify(__ASM_CLAC),
+ X86_FEATURE_SMAP)
+ : "=rm" (flags) : : "memory", "cc");
+
+ return flags;
+}
+
+static __always_inline void smap_restore(unsigned long flags)
+{
+ asm volatile (ALTERNATIVE("", "push %0; popf", X86_FEATURE_SMAP)
+ : : "g" (flags) : "memory", "cc");
+}
+
/* These macros can be used in asm() statements */
#define ASM_CLAC \
ALTERNATIVE("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP)
@@ -69,6 +86,9 @@ static __always_inline void stac(void)
static inline void clac(void) { }
static inline void stac(void) { }
+static inline unsigned long smap_save(void) { return 0; }
+static inline void smap_restore(unsigned long flags) { }
+
#define ASM_CLAC
#define ASM_STAC
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -716,6 +716,9 @@ static __must_check __always_inline bool
#define user_access_begin(a,b) user_access_begin(a,b)
#define user_access_end() __uaccess_end()
+#define user_access_save() smap_save()
+#define user_access_restore(x) smap_restore(x)
+
#define unsafe_put_user(x, ptr, label) \
__put_user_size((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)), label)
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -268,6 +268,8 @@ extern long strncpy_from_unsafe(char *ds
#define user_access_end() do { } while (0)
#define unsafe_get_user(x, ptr, err) do { if (unlikely(__get_user(x, ptr))) goto err; } while (0)
#define unsafe_put_user(x, ptr, err) do { if (unlikely(__put_user(x, ptr))) goto err; } while (0)
+static inline unsigned long user_access_save(void) { return 0UL; }
+static void user_access_restore(unsigned long flags) { }
#endif
#ifdef CONFIG_HARDENED_USERCOPY
next prev parent reply other threads:[~2019-03-18 15:54 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 15:38 [PATCH 00/25] objtool: UACCESS validation v4 Peter Zijlstra
2019-03-18 15:38 ` [PATCH 01/25] x86: Make SMAP 64-bit only Peter Zijlstra
2019-03-18 16:58 ` Linus Torvalds
2019-03-18 17:36 ` Peter Zijlstra
2019-03-18 17:51 ` Peter Zijlstra
2019-03-18 18:10 ` Linus Torvalds
2019-03-21 17:12 ` hpa
2019-03-21 17:25 ` Denys Vlasenko
2019-03-21 18:18 ` hpa
2019-03-21 21:03 ` Peter Zijlstra
2019-03-21 18:21 ` Linus Torvalds
2019-03-19 11:16 ` [PATCH 01/25] sched/x86: Save [ER]FLAGS on context switch Peter Zijlstra
2019-03-18 15:38 ` [PATCH 02/25] tracing: Improve "if" macro code generation Peter Zijlstra
2019-03-18 17:41 ` Steven Rostedt
2019-03-18 23:37 ` Josh Poimboeuf
2019-03-19 10:11 ` Peter Zijlstra
2019-03-20 11:18 ` David Laight
2019-03-20 17:26 ` Linus Torvalds
2019-03-20 17:37 ` David Laight
2019-03-20 17:38 ` Linus Torvalds
2019-03-20 18:18 ` Steven Rostedt
2019-05-09 13:00 ` Steven Rostedt
2019-05-09 16:51 ` Linus Torvalds
2019-05-09 18:29 ` Steven Rostedt
2019-05-09 18:45 ` Josh Poimboeuf
2019-05-09 18:47 ` Josh Poimboeuf
2019-05-09 18:48 ` Randy Dunlap
2019-05-09 18:57 ` Josh Poimboeuf
2019-05-09 19:06 ` Steven Rostedt
2019-05-09 19:28 ` Steven Rostedt
2019-05-09 19:44 ` Linus Torvalds
2019-03-18 15:38 ` [PATCH 03/25] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-03-18 15:38 ` [PATCH 04/25] i915,uaccess: Fix redundant CLAC Peter Zijlstra
2019-03-18 15:38 ` [PATCH 05/25] x86/uaccess: Move copy_user_handle_tail into asm Peter Zijlstra
2019-03-18 15:38 ` [PATCH 06/25] x86/uaccess: Fix up the fixup Peter Zijlstra
2019-03-18 15:38 ` [PATCH 07/25] x86/nospec,objtool: Introduce ANNOTATE_IGNORE_ALTERNATIVE Peter Zijlstra
2019-03-18 15:38 ` [PATCH 08/25] x86/uaccess,xen: Suppress SMAP warnings Peter Zijlstra
2019-03-18 15:38 ` [PATCH 09/25] x86/uaccess: Always inline user_access_begin() Peter Zijlstra
2019-03-18 15:38 ` [PATCH 10/25] x86/uaccess,signal: Fix AC=1 bloat Peter Zijlstra
2019-03-18 15:38 ` Peter Zijlstra [this message]
2019-03-18 15:38 ` [PATCH 12/25] x86/smap: Ditch __stringify() Peter Zijlstra
2019-03-18 15:38 ` [PATCH 13/25] x86/uaccess,kasan: Fix KASAN vs SMAP Peter Zijlstra
2019-03-18 15:38 ` [PATCH 14/25] x86/uaccess,ubsan: Fix UBSAN " Peter Zijlstra
2019-03-18 15:38 ` [PATCH 15/25] x86/uaccess,ftrace: Fix ftrace_likely_update() " Peter Zijlstra
2019-03-18 15:38 ` [PATCH 16/25] x86/uaccess,kcov: Disable stack protector Peter Zijlstra
2019-03-18 15:38 ` [PATCH 17/25] objtool: Set insn->func for alternatives Peter Zijlstra
2019-03-18 15:38 ` [PATCH 18/25] objtool: Handle function aliases Peter Zijlstra
2019-03-18 15:38 ` [PATCH 19/25] objtool: Rewrite add_ignores() Peter Zijlstra
2019-03-18 15:39 ` [PATCH 20/25] objtool: Add --backtrace support Peter Zijlstra
2019-03-18 15:39 ` [PATCH 21/25] objtool: Rewrite alt->skip_orig Peter Zijlstra
2019-03-18 15:39 ` [PATCH 22/25] objtool: Fix sibling call detection Peter Zijlstra
2019-03-18 15:39 ` [PATCH 23/25] objtool: Add UACCESS validation Peter Zijlstra
2019-03-18 23:51 ` Josh Poimboeuf
2019-05-07 11:52 ` Peter Zijlstra
2019-03-18 15:39 ` [PATCH 24/25] objtool: uaccess PUSHF/POPF support Peter Zijlstra
2019-03-18 15:39 ` [PATCH 25/25] objtool: Add Direction Flag validation Peter Zijlstra
2019-03-18 23:57 ` [PATCH 00/25] objtool: UACCESS validation v4 Josh Poimboeuf
2019-03-19 11:20 ` Peter Zijlstra
2019-03-19 11:17 ` [PATCH 26/25] sched/x86_64: Don't save flags on context switch Peter Zijlstra
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