From: nicolas.pitre@linaro.org (Nicolas Pitre) 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 12:02:42 -0400 (EDT) [thread overview] Message-ID: <alpine.LFD.2.20.1708141158070.17016@knanqh.ubzr> (raw) In-Reply-To: <20170814125411.22604-21-ard.biesheuvel@linaro.org> 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. > /* This ldmia relies on the memory layout of the mpidr_hash struct */ > ldmia r0, {r1, r6-r8} @ r1 = mpidr mask (r6,r7,r8) = l[0,1,2] shifts > @@ -100,13 +99,13 @@ ENDPROC(cpu_suspend_abort) > .align 5 > .pushsection .idmap.text,"ax" > ENTRY(cpu_resume_mmu) > - ldr r3, =cpu_resume_after_mmu > instr_sync > mcr p15, 0, r0, c1, c0, 0 @ turn on MMU, I-cache, etc > mrc p15, 0, r0, c0, c0, 0 @ read id reg > instr_sync > mov r0, r0 > mov r0, r0 > + ldr r3, =cpu_resume_after_mmu > ret r3 @ jump to virtual address > ENDPROC(cpu_resume_mmu) > .popsection > -- > 2.11.0 > >
WARNING: multiple messages have this Message-ID (diff)
From: Nicolas Pitre <nicolas.pitre@linaro.org> To: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: kernel-hardening@lists.openwall.com, 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 12:02:42 -0400 (EDT) [thread overview] Message-ID: <alpine.LFD.2.20.1708141158070.17016@knanqh.ubzr> (raw) In-Reply-To: <20170814125411.22604-21-ard.biesheuvel@linaro.org> 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. > /* This ldmia relies on the memory layout of the mpidr_hash struct */ > ldmia r0, {r1, r6-r8} @ r1 = mpidr mask (r6,r7,r8) = l[0,1,2] shifts > @@ -100,13 +99,13 @@ ENDPROC(cpu_suspend_abort) > .align 5 > .pushsection .idmap.text,"ax" > ENTRY(cpu_resume_mmu) > - ldr r3, =cpu_resume_after_mmu > instr_sync > mcr p15, 0, r0, c1, c0, 0 @ turn on MMU, I-cache, etc > mrc p15, 0, r0, c0, c0, 0 @ read id reg > instr_sync > mov r0, r0 > mov r0, r0 > + ldr r3, =cpu_resume_after_mmu > ret r3 @ jump to virtual address > ENDPROC(cpu_resume_mmu) > .popsection > -- > 2.11.0 > >
next prev parent reply other threads:[~2017-08-14 16:02 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 [this message] 2017-08-14 16:02 ` [kernel-hardening] " Nicolas Pitre 2017-08-14 18:14 ` Ard Biesheuvel 2017-08-14 18:14 ` [kernel-hardening] " 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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