From: ard.biesheuvel@linaro.org (Ard Biesheuvel)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 20/30] ARM: kernel: use PC relative symbol references in suspend/resume code
Date: Mon, 14 Aug 2017 19:14:40 +0100 [thread overview]
Message-ID: <CAKv+Gu-k4vUHDz92dsy-d15aBh61-pcGDi3GbX9pmBCbY21SsQ@mail.gmail.com> (raw)
In-Reply-To: <alpine.LFD.2.20.1708141158070.17016@knanqh.ubzr>
On 14 August 2017 at 17:02, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:
> On Mon, 14 Aug 2017, Ard Biesheuvel wrote:
>
>> Replace some unnecessary absolute references with relative ones. Also,
>> to prepare for runtime relocation, which occurs with the caches on,
>> defer taking the absolute address of cpu_resume_after_mmu() until after
>> the MMU is enabled.
>>
>> Cc: Russell King <linux@armlinux.org.uk>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>> arch/arm/kernel/sleep.S | 11 +++++------
>> 1 file changed, 5 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
>> index 3026b119d3ff..9efd1c7d3552 100644
>> --- a/arch/arm/kernel/sleep.S
>> +++ b/arch/arm/kernel/sleep.S
>> @@ -60,18 +60,17 @@
>> ENTRY(__cpu_suspend)
>> stmfd sp!, {r4 - r11, lr}
>> #ifdef MULTI_CPU
>> - ldr r10, =processor
>> - ldr r4, [r10, #CPU_SLEEP_SIZE] @ size of CPU sleep state
>> + ldr_l r4, processor + CPU_SLEEP_SIZE @ size of CPU sleep state
>> #else
>> - ldr r4, =cpu_suspend_size
>> + adr_l r4, cpu_suspend_size
>> #endif
>> mov r5, sp @ current virtual SP
>> add r4, r4, #12 @ Space for pgd, virt sp, phys resume fn
>> sub sp, sp, r4 @ allocate CPU state on stack
>> - ldr r3, =sleep_save_sp
>> + adr_l r3, sleep_save_sp
>> stmfd sp!, {r0, r1} @ save suspend func arg and pointer
>> ldr r3, [r3, #SLEEP_SAVE_SP_VIRT]
>> - ALT_SMP(ldr r0, =mpidr_hash)
>> + ALT_SMP(adr_l r0, mpidr_hash)
>> ALT_UP_B(1f)
>
> The above is dangerous. adr_l expands to more than one instruction which
> is not what ALT_SMP() was designed for. Here it might happen to work
> anyway because it is combined with ALT_UP_B() but with ALT_UP() it
> wouldn't. This is a mistake waiting to happen.
>
OK. I will use the opencoded sequence instead in this case. I.e.,
- ALT_SMP(ldr r0, =mpidr_hash)
+0: ALT_SMP(adr r0, 2f)
ALT_UP_B(1f)
+ ldr r1, [r0]
+ add r0, r0, r1
and
ENDPROC(__cpu_suspend)
+ .align 2
+2: .long mpidr_hash - .
.ltorg
WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Arnd Bergmann <arnd@arndb.de>,
Russell King <linux@armlinux.org.uk>,
Kees Cook <keescook@chromium.org>,
Thomas Garnier <thgarnie@google.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Tony Lindgren <tony@atomide.com>,
Matt Fleming <matt@codeblueprint.co.uk>,
Dave Martin <dave.martin@arm.com>
Subject: [kernel-hardening] Re: [PATCH 20/30] ARM: kernel: use PC relative symbol references in suspend/resume code
Date: Mon, 14 Aug 2017 19:14:40 +0100 [thread overview]
Message-ID: <CAKv+Gu-k4vUHDz92dsy-d15aBh61-pcGDi3GbX9pmBCbY21SsQ@mail.gmail.com> (raw)
In-Reply-To: <alpine.LFD.2.20.1708141158070.17016@knanqh.ubzr>
On 14 August 2017 at 17:02, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:
> On Mon, 14 Aug 2017, Ard Biesheuvel wrote:
>
>> Replace some unnecessary absolute references with relative ones. Also,
>> to prepare for runtime relocation, which occurs with the caches on,
>> defer taking the absolute address of cpu_resume_after_mmu() until after
>> the MMU is enabled.
>>
>> Cc: Russell King <linux@armlinux.org.uk>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>> arch/arm/kernel/sleep.S | 11 +++++------
>> 1 file changed, 5 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
>> index 3026b119d3ff..9efd1c7d3552 100644
>> --- a/arch/arm/kernel/sleep.S
>> +++ b/arch/arm/kernel/sleep.S
>> @@ -60,18 +60,17 @@
>> ENTRY(__cpu_suspend)
>> stmfd sp!, {r4 - r11, lr}
>> #ifdef MULTI_CPU
>> - ldr r10, =processor
>> - ldr r4, [r10, #CPU_SLEEP_SIZE] @ size of CPU sleep state
>> + ldr_l r4, processor + CPU_SLEEP_SIZE @ size of CPU sleep state
>> #else
>> - ldr r4, =cpu_suspend_size
>> + adr_l r4, cpu_suspend_size
>> #endif
>> mov r5, sp @ current virtual SP
>> add r4, r4, #12 @ Space for pgd, virt sp, phys resume fn
>> sub sp, sp, r4 @ allocate CPU state on stack
>> - ldr r3, =sleep_save_sp
>> + adr_l r3, sleep_save_sp
>> stmfd sp!, {r0, r1} @ save suspend func arg and pointer
>> ldr r3, [r3, #SLEEP_SAVE_SP_VIRT]
>> - ALT_SMP(ldr r0, =mpidr_hash)
>> + ALT_SMP(adr_l r0, mpidr_hash)
>> ALT_UP_B(1f)
>
> The above is dangerous. adr_l expands to more than one instruction which
> is not what ALT_SMP() was designed for. Here it might happen to work
> anyway because it is combined with ALT_UP_B() but with ALT_UP() it
> wouldn't. This is a mistake waiting to happen.
>
OK. I will use the opencoded sequence instead in this case. I.e.,
- ALT_SMP(ldr r0, =mpidr_hash)
+0: ALT_SMP(adr r0, 2f)
ALT_UP_B(1f)
+ ldr r1, [r0]
+ add r0, r0, r1
and
ENDPROC(__cpu_suspend)
+ .align 2
+2: .long mpidr_hash - .
.ltorg
next prev parent reply other threads:[~2017-08-14 18:14 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-14 12:53 [PATCH 00/30] implement KASLR for ARM Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 01/30] asm-generic: add .data.rel.ro sections to __ro_after_init Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 14:26 ` Arnd Bergmann
2017-08-14 14:26 ` [kernel-hardening] " Arnd Bergmann
2017-08-14 12:53 ` [PATCH 02/30] ARM: assembler: introduce adr_l, ldr_l and str_l macros Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:29 ` Dave Martin
2017-08-14 15:29 ` [kernel-hardening] " Dave Martin
2017-08-14 15:38 ` Ard Biesheuvel
2017-08-14 15:38 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:50 ` Dave Martin
2017-08-14 15:50 ` [kernel-hardening] " Dave Martin
2017-08-14 16:18 ` Nicolas Pitre
2017-08-14 16:18 ` [kernel-hardening] " Nicolas Pitre
2017-08-14 16:22 ` Ard Biesheuvel
2017-08-14 16:22 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 16:33 ` Nicolas Pitre
2017-08-14 16:33 ` [kernel-hardening] " Nicolas Pitre
2017-08-14 16:42 ` Russell King - ARM Linux
2017-08-14 16:42 ` [kernel-hardening] " Russell King - ARM Linux
2017-08-14 16:56 ` Ard Biesheuvel
2017-08-14 16:56 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:32 ` Dave Martin
2017-08-14 15:32 ` [kernel-hardening] " Dave Martin
2017-08-14 15:40 ` Ard Biesheuvel
2017-08-14 15:40 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:53 ` Dave Martin
2017-08-14 15:53 ` [kernel-hardening] " Dave Martin
2017-08-14 12:53 ` [PATCH 03/30] ARM: head-common.S: use PC-relative insn sequence for __proc_info Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 04/30] ARM: head-common.S: use PC-relative insn sequence for idmap creation Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 05/30] ARM: head.S: use PC-relative insn sequence for secondary_data Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 06/30] ARM: kernel: use relative references for UP/SMP alternatives Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 07/30] ARM: head: use PC-relative insn sequence for __smp_alt Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 08/30] ARM: sleep.S: use PC-relative insn sequence for sleep_save_sp/mpidr_hash Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 09/30] ARM: head.S: use PC-relative insn sequences for __fixup_pv_table Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 10/30] ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 11/30] ARM: kvm: replace open coded VA->PA calculations with adr_l call Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 12/30] arm-soc: exynos: replace open coded VA->PA conversions Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 13/30] arm-soc: mvebu: replace open coded VA->PA conversion Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 14/30] arm-soc: various: replace open coded VA->PA calculation of pen_release Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 15/30] ARM: kernel: switch to relative exception tables Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 16/30] ARM: kernel: use relative phys-to-virt patch tables Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 17/30] arm-soc: tegra: make sleep asm code runtime relocatable Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 14:42 ` Dave Martin
2017-08-14 14:42 ` [kernel-hardening] " Dave Martin
2017-08-14 14:49 ` Ard Biesheuvel
2017-08-14 14:49 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:29 ` Dave Martin
2017-08-14 15:29 ` [kernel-hardening] " Dave Martin
2017-08-14 12:53 ` [PATCH 18/30] ARM: kernel: make vmlinux buildable as a PIE executable Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 19/30] ARM: kernel: use PC-relative symbol references in MMU switch code Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 20/30] ARM: kernel: use PC relative symbol references in suspend/resume code Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 16:02 ` Nicolas Pitre
2017-08-14 16:02 ` [kernel-hardening] " Nicolas Pitre
2017-08-14 18:14 ` Ard Biesheuvel [this message]
2017-08-14 18:14 ` Ard Biesheuvel
2017-08-14 18:37 ` Nicolas Pitre
2017-08-14 18:37 ` [kernel-hardening] " Nicolas Pitre
2017-08-14 12:54 ` [PATCH 21/30] ARM: mm: export default vmalloc base address Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 22/30] ARM: kernel: refer to swapper_pg_dir via its symbol Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 23/30] ARM: kernel: implement randomization of the kernel load address Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 24/30] ARM: decompressor: explicitly map decompressor binary cacheable Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 25/30] ARM: compressed: factor out zImage header and make it extensible Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 26/30] ARM: decompressor: add KASLR support Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 27/30] efi/libstub: add 'max' parameter to efi_random_alloc() Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 28/30] efi/libstub: check for vmalloc= command line argument Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 29/30] efi/libstub: arm: reserve bootloader supplied initrd in memory map Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-18 11:48 ` Ard Biesheuvel
2017-08-18 11:48 ` [kernel-hardening] " Ard Biesheuvel
2017-08-21 10:37 ` Mark Rutland
2017-08-21 10:37 ` [kernel-hardening] " Mark Rutland
2017-08-21 10:39 ` Ard Biesheuvel
2017-08-21 10:39 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 30/30] efi/libstub: arm: implement KASLR Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:30 ` [PATCH 00/30] implement KASLR for ARM Arnd Bergmann
2017-08-14 15:30 ` [kernel-hardening] " Arnd Bergmann
2017-08-14 15:49 ` Ard Biesheuvel
2017-08-14 15:49 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 16:03 ` Arnd Bergmann
2017-08-14 16:03 ` [kernel-hardening] " Arnd Bergmann
2017-08-14 16:28 ` Nicolas Pitre
2017-08-14 16:28 ` [kernel-hardening] " Nicolas Pitre
2017-08-14 17:28 ` Ard Biesheuvel
2017-08-14 17:28 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 18:01 ` Nicolas Pitre
2017-08-14 18:01 ` [kernel-hardening] " Nicolas Pitre
2017-08-14 18:08 ` Ard Biesheuvel
2017-08-14 18:08 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 16:16 ` Nicolas Pitre
2017-08-14 16:16 ` [kernel-hardening] " Nicolas Pitre
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