From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Wed, 17 Aug 2016 17:54:41 +0200 Subject: [PATCH] arm64: kernel: avoid literal load of virtual address with MMU off Message-ID: <1471449281-10367-1-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Literal loads of virtual addresses are subject to runtime relocation when CONFIG_RELOCATABLE=y, and given that the relocation routines run with the MMU and caches enabled, literal loads of relocated values performed with the MMU off are not guaranteed to return the latest value unless the memory covering the literal is cleaned to the PoC explicitly. So defer the literal load until after the MMU has been enabled, just like we do for primary_switch() and secondary_switch() in head.S. Fixes: 1e48ef7fcc37 ("arm64: add support for building vmlinux as a relocatable PIE binary") Signed-off-by: Ard Biesheuvel --- This conflicts with the x25/x26 patch I sent yesterday, but this should probably go into stable, so I based it on v4.8-rc directly. arch/arm64/kernel/sleep.S | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S index 9a3aec97ac09..ccf79d849e0a 100644 --- a/arch/arm64/kernel/sleep.S +++ b/arch/arm64/kernel/sleep.S @@ -101,12 +101,20 @@ ENTRY(cpu_resume) bl el2_setup // if in EL2 drop to EL1 cleanly /* enable the MMU early - so we can access sleep_save_stash by va */ adr_l lr, __enable_mmu /* __cpu_setup will return here */ - ldr x27, =_cpu_resume /* __enable_mmu will branch here */ + adr_l x27, _resume_switched /* __enable_mmu will branch here */ adrp x25, idmap_pg_dir adrp x26, swapper_pg_dir b __cpu_setup ENDPROC(cpu_resume) + .pushsection ".idmap.text", "ax" +_resume_switched: + ldr x8, =_cpu_resume + br x8 +ENDPROC(_resume_switched) + .ltorg + .popsection + ENTRY(_cpu_resume) mrs x1, mpidr_el1 adrp x8, mpidr_hash -- 2.7.4