From: hpa@zytor.com
To: Thomas Garnier <thgarnie@chromium.org>,
kernel-hardening@lists.openwall.com
Cc: kristen@linux.intel.com, Thomas Garnier <thgarnie@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
Nadav Amit <namit@vmware.com>, Jann Horn <jannh@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 03/12] x86: Add macro to get symbol address for PIE support
Date: Mon, 20 May 2019 20:12:55 -0700 [thread overview]
Message-ID: <FF111368-9173-4AC2-9A79-E79A52B104DD@zytor.com> (raw)
In-Reply-To: <20190520231948.49693-4-thgarnie@chromium.org>
On May 20, 2019 4:19:28 PM PDT, Thomas Garnier <thgarnie@chromium.org> wrote:
>From: Thomas Garnier <thgarnie@google.com>
>
>Add a new _ASM_MOVABS macro to fetch a symbol address. It will be used
>to replace "_ASM_MOV $<symbol>, %dst" code construct that are not
>compatible with PIE.
>
>Signed-off-by: Thomas Garnier <thgarnie@google.com>
>---
> arch/x86/include/asm/asm.h | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
>index 3ff577c0b102..3a686057e882 100644
>--- a/arch/x86/include/asm/asm.h
>+++ b/arch/x86/include/asm/asm.h
>@@ -30,6 +30,7 @@
> #define _ASM_ALIGN __ASM_SEL(.balign 4, .balign 8)
>
> #define _ASM_MOV __ASM_SIZE(mov)
>+#define _ASM_MOVABS __ASM_SEL(movl, movabsq)
> #define _ASM_INC __ASM_SIZE(inc)
> #define _ASM_DEC __ASM_SIZE(dec)
> #define _ASM_ADD __ASM_SIZE(add)
This is just about *always* wrong on x86-86. We should be using leaq sym(%rip),%reg. If it isn't reachable by leaq, then it is a non-PIE symbol like percpu. You do have to keep those distinct!
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
next prev parent reply other threads:[~2019-05-21 3:13 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-20 23:19 [PATCH v7 00/12] x86: PIE support to extend KASLR randomization Thomas Garnier
2019-05-20 23:19 ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 01/12] x86/crypto: Adapt assembly for PIE support Thomas Garnier
2019-05-21 4:06 ` Eric Biggers
2019-05-22 20:47 ` Thomas Garnier
2019-05-22 20:55 ` Eric Biggers
2019-05-29 15:48 ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 02/12] x86: Use symbol name in jump table " Thomas Garnier
2019-05-20 23:23 ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 03/12] x86: Add macro to get symbol address " Thomas Garnier
2019-05-21 3:12 ` hpa [this message]
2019-05-22 15:57 ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 04/12] x86: relocate_kernel - Adapt assembly " Thomas Garnier
2019-06-10 21:33 ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 05/12] x86/entry/64: " Thomas Garnier
2019-06-10 21:34 ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 06/12] x86: pm-trace - " Thomas Garnier
2019-06-10 21:34 ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 07/12] x86/CPU: " Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 08/12] x86/acpi: " Thomas Garnier
2019-06-10 23:52 ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 09/12] x86/boot/64: " Thomas Garnier
2019-06-10 22:26 ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 10/12] x86/power/64: " Thomas Garnier
2019-06-10 23:52 ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 11/12] x86/paravirt: " Thomas Garnier
2019-05-20 23:19 ` Thomas Garnier
2019-05-27 5:47 ` Juergen Gross
2019-05-27 5:47 ` Juergen Gross
2019-05-29 15:48 ` Thomas Garnier
2019-05-29 15:48 ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 12/12] x86/alternatives: " Thomas Garnier
2019-06-10 21:32 ` [PATCH v7 00/12] x86: PIE support to extend KASLR randomization Kees Cook
2019-06-10 21:32 ` Kees Cook
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