From: Pavel Machek <pavel@ucw.cz>
Subject: Re: [PATCH v3 11/27] x86/power/64: Adapt assembly for PIE support
Date: Thu, 24 May 2018 13:03:41 +0200
Message-ID: <20180524110341.GB20225@amd>
References: <20180523195421.180248-1-thgarnie@google.com>
 <20180523195421.180248-12-thgarnie@google.com>
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Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	"David S . Miller" <davem@davemloft.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Philippe Ombredanne <pombredanne@nexb.com>,
	Kate Stewart <kstewart@linuxfoundation.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Yonghong Song <yhs@fb.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Kees Cook <keescook@chromium.org>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Dominik Brodowski <linux@dominikbrodowski.net>,
	Borislav Petkov <bp@alien8.de>, Borislav Petkov <bp@suse.de>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Len Brown <len.brown@intel.com>, Juerge
To: Thomas Garnier <thgarnie@google.com>
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On Wed 2018-05-23 12:54:05, Thomas Garnier wrote:
> Change the assembly code to use only relative references of symbols for t=
he
> kernel to be PIE compatible.
>=20
> Position Independent Executable (PIE) support will allow to extended the
> KASLR randomization range below the -2G memory limit.
>=20
> Signed-off-by: Thomas Garnier <thgarnie@google.com>

Again, was this tested?

> diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate=
_asm_64.S
> index ce8da3a0412c..6fdd7bbc3c33 100644
> --- a/arch/x86/power/hibernate_asm_64.S
> +++ b/arch/x86/power/hibernate_asm_64.S
> @@ -24,7 +24,7 @@
>  #include <asm/frame.h>
> =20
>  ENTRY(swsusp_arch_suspend)
> -	movq	$saved_context, %rax
> +	leaq	saved_context(%rip), %rax
>  	movq	%rsp, pt_regs_sp(%rax)
>  	movq	%rbp, pt_regs_bp(%rax)
>  	movq	%rsi, pt_regs_si(%rax)
> @@ -115,7 +115,7 @@ ENTRY(restore_registers)
>  	movq	%rax, %cr4;  # turn PGE back on
> =20
>  	/* We don't restore %rax, it must be 0 anyway */
> -	movq	$saved_context, %rax
> +	leaq	saved_context(%rip), %rax
>  	movq	pt_regs_sp(%rax), %rsp
>  	movq	pt_regs_bp(%rax), %rbp
>  	movq	pt_regs_si(%rax), %rsi

--=20
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