From: Alexey Dobriyan <adobriyan@gmail.com>
To: thgarnie@chromium.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 06/11] x86/CPU: Adapt assembly for PIE support
Date: Mon, 8 Jul 2019 22:09:30 +0300 [thread overview]
Message-ID: <20190708190930.GA16215@avx2> (raw)
Thomas Garnier wrote:
> - "pushq $1f\n\t"
> + "movabsq $1f, %q0\n\t"
> + "pushq %q0\n\t"
> "iretq\n\t"
> UNWIND_HINT_RESTORE
> "1:"
Fake PIE. True PIE looks like this:
ffffffff81022d70 <do_sync_core>:
ffffffff81022d70: 8c d0 mov eax,ss
ffffffff81022d72: 50 push rax
ffffffff81022d73: 54 push rsp
ffffffff81022d74: 48 83 04 24 08 add QWORD PTR [rsp],0x8
ffffffff81022d79: 9c pushf
ffffffff81022d7a: 8c c8 mov eax,cs
ffffffff81022d7c: 50 push rax
ffffffff81022d7d: ===> 48 8d 05 03 00 00 00 lea rax,[rip+0x3] # ffffffff81022d87 <do_sync_core+0x17>
ffffffff81022d84: 50 push rax
ffffffff81022d85: 48 cf iretq
ffffffff81022d87: c3 ret
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -710,7 +710,8 @@ static inline void sync_core(void)
"pushfq\n\t"
"mov %%cs, %0\n\t"
"pushq %q0\n\t"
- "pushq $1f\n\t"
+ "leaq 1f(%%rip), %q0\n\t"
+ "pushq %q0\n\t"
"iretq\n\t"
UNWIND_HINT_RESTORE
"1:"
next reply other threads:[~2019-07-08 19:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-08 19:09 Alexey Dobriyan [this message]
2019-07-08 19:35 ` [PATCH v8 06/11] x86/CPU: Adapt assembly for PIE support Thomas Garnier
2019-07-09 18:39 ` Alexey Dobriyan
2019-07-09 18:47 ` Thomas Garnier
-- strict thread matches above, loose matches on Subject: below --
2019-07-08 17:48 [PATCH v8 00/11] x86: PIE support to extend KASLR randomization Thomas Garnier
2019-07-08 17:48 ` [PATCH v8 06/11] x86/CPU: Adapt assembly for PIE support Thomas Garnier
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