From: Thomas Garnier <thgarnie@chromium.org>
To: kernel-hardening@lists.openwall.com
Cc: kristen@linux.intel.com, keescook@chromium.org,
Thomas Garnier <thgarnie@chromium.org>,
Juergen Gross <jgross@suse.com>,
Thomas Hellstrom <thellstrom@vmware.com>,
"VMware, Inc." <pv-drivers@vmware.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v9 10/11] x86/paravirt: Adapt assembly for PIE support
Date: Tue, 30 Jul 2019 12:12:54 -0700 [thread overview]
Message-ID: <20190730191303.206365-11-thgarnie@chromium.org> (raw)
In-Reply-To: <20190730191303.206365-1-thgarnie@chromium.org>
if PIE is enabled, switch the paravirt assembly constraints to be
compatible. The %c/i constrains generate smaller code so is kept by
default.
Position Independent Executable (PIE) support will allow to extend the
KASLR randomization range below 0xffffffff80000000.
Signed-off-by: Thomas Garnier <thgarnie@chromium.org>
Acked-by: Juergen Gross <jgross@suse.com>
---
arch/x86/include/asm/paravirt_types.h | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 70b654f3ffe5..fd7dc37d0010 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -338,9 +338,25 @@ extern struct paravirt_patch_template pv_ops;
#define PARAVIRT_PATCH(x) \
(offsetof(struct paravirt_patch_template, x) / sizeof(void *))
+#ifdef CONFIG_X86_PIE
+#define paravirt_opptr_call "a"
+#define paravirt_opptr_type "p"
+
+/*
+ * Alternative patching requires a maximum of 7 bytes but the relative call is
+ * only 6 bytes. If PIE is enabled, add an additional nop to the call
+ * instruction to ensure patching is possible.
+ */
+#define PARAVIRT_CALL_POST "nop;"
+#else
+#define paravirt_opptr_call "c"
+#define paravirt_opptr_type "i"
+#define PARAVIRT_CALL_POST ""
+#endif
+
#define paravirt_type(op) \
[paravirt_typenum] "i" (PARAVIRT_PATCH(op)), \
- [paravirt_opptr] "i" (&(pv_ops.op))
+ [paravirt_opptr] paravirt_opptr_type (&(pv_ops.op))
#define paravirt_clobber(clobber) \
[paravirt_clobber] "i" (clobber)
@@ -379,9 +395,10 @@ int paravirt_disable_iospace(void);
* offset into the paravirt_patch_template structure, and can therefore be
* freely converted back into a structure offset.
*/
-#define PARAVIRT_CALL \
- ANNOTATE_RETPOLINE_SAFE \
- "call *%c[paravirt_opptr];"
+#define PARAVIRT_CALL \
+ ANNOTATE_RETPOLINE_SAFE \
+ "call *%" paravirt_opptr_call "[paravirt_opptr];" \
+ PARAVIRT_CALL_POST
/*
* These macros are intended to wrap calls through one of the paravirt
--
2.22.0.770.g0f2c4a37fd-goog
next prev parent reply other threads:[~2019-07-30 19:15 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 19:12 [PATCH v9 00/11] x86: PIE support to extend KASLR randomization Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 01/11] x86/crypto: Adapt assembly for PIE support Thomas Garnier
2019-08-05 16:32 ` Borislav Petkov
2019-08-05 16:54 ` Kees Cook
2019-08-05 17:27 ` Borislav Petkov
2019-08-05 17:53 ` Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 02/11] x86: Add macro to get symbol address " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 03/11] x86: relocate_kernel - Adapt assembly " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 04/11] x86/entry/64: " Thomas Garnier
2019-08-05 17:28 ` Borislav Petkov
2019-08-05 17:50 ` Thomas Garnier
2019-08-06 5:08 ` Borislav Petkov
2019-08-06 8:30 ` Peter Zijlstra
2019-08-06 12:35 ` Borislav Petkov
2019-08-06 13:59 ` Steven Rostedt
2019-08-06 15:35 ` Borislav Petkov
2019-07-30 19:12 ` [PATCH v9 05/11] x86: pm-trace - " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 06/11] x86/CPU: " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 07/11] x86/acpi: " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 08/11] x86/boot/64: " Thomas Garnier
2019-08-09 17:30 ` Borislav Petkov
2019-10-29 21:29 ` Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 09/11] x86/power/64: " Thomas Garnier
2019-07-30 19:12 ` Thomas Garnier [this message]
2019-07-31 12:53 ` [PATCH v9 10/11] x86/paravirt: " Peter Zijlstra
2019-08-12 12:55 ` Borislav Petkov
2019-10-29 21:30 ` Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 11/11] x86/alternatives: " Thomas Garnier
2019-08-12 13:57 ` Borislav Petkov
2019-10-29 21:31 ` Thomas Garnier
2019-08-06 15:43 ` [PATCH v9 00/11] x86: PIE support to extend KASLR randomization Borislav Petkov
2019-08-06 15:50 ` Peter Zijlstra
2019-08-29 19:55 ` Thomas Garnier
2019-09-06 23:22 ` Thomas Garnier
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