From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+wqDHfiHPIWEpNLGkWKFirqZnnwL+eqf98yoxhlltiYyUAizUnFiNqRFExtE0yGDigFMkQ ARC-Seal: i=1; a=rsa-sha256; t=1523021698; cv=none; d=google.com; s=arc-20160816; b=DbfzKdPDPXD43P2RQ8f5ZEcULjl5Z2aKWcKaRrXk+YyzAf71g3q2VRs8XmgHbmuS54 /rYLN5f+h0oEvr/UJ2Bmv0RXCTBXER/cL048NSfQZcrqNgcJuF6ZDNs+FiCCX90+QAD5 6eKsO79FYiXTmVrOkUUzMprQk3Ml2MkxDUXf7g9lttcYMSQ6HNkY6SwW+E5gGUDde2Jm 2OaNHEbspMGEjkW8vU1xjEg04A1MAdNj3+SGuGQ3Y9EuM+xtlTLBLFq0CpPpfrQLxJwO 1grZldHhUNmW/b4sT6jlRBMr584VRuwFZ8BrkKN+VMnm32BQaxN/j2avEYFMhBIlhffN G3kA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=+79lN+QtO3s5nak+3TAlcEb+nHykm9AxbCe/hNzrrcU=; b=iXiwjxwk2vk/TD9XUAi87QTlS87uYVW/BG4FOwSgg+DKksMHQcpc5u/prwZG1MhyeH 2cT667+YNRj0PyrPaHkw66Rr/VHd7eictY8cMEd9Xn9XEkKrPN8zCnZ5NTIClAkNVV8Z ik3Cz2KKAwEyckP0Wfmayv7mxv6x+CmQZQ/KrIXcmxB71yGMoj2n+N+lx4tqtxnG4xIo LpE3XzCrmRxQJ5WH6LwQA6BlGPZFvIeBc9I5zY4Acg4KMPdr78yzmJhYKqgFFa/3RfIR MqO1iVq5g/DIcL3+1vo84uMANGAlF9x33Ad/38ph8/CKJBqFygSZr5Bw/dzoDblK30Se 9YGw== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Mark Rutland , Laura Abbott , Shanker Donthineni , Will Deacon , Alex Shi , Greg Hackmann Subject: [PATCH 4.9 058/102] arm64: mm: Map entry trampoline into trampoline and kernel page tables Date: Fri, 6 Apr 2018 15:23:39 +0200 Message-Id: <20180406084339.761446888@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180406084331.507038179@linuxfoundation.org> References: <20180406084331.507038179@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597004000553757821?= X-GMAIL-MSGID: =?utf-8?q?1597004000553757821?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon commit 51a0048beb44 upstream. The exception entry trampoline needs to be mapped at the same virtual address in both the trampoline page table (which maps nothing else) and also the kernel page table, so that we can swizzle TTBR1_EL1 on exceptions from and return to EL0. This patch maps the trampoline at a fixed virtual address in the fixmap area of the kernel virtual address space, which allows the kernel proper to be randomized with respect to the trampoline when KASLR is enabled. Reviewed-by: Mark Rutland Tested-by: Laura Abbott Tested-by: Shanker Donthineni Signed-off-by: Will Deacon Signed-off-by: Alex Shi Signed-off-by: Mark Rutland [v4.9 backport] Tested-by: Will Deacon Tested-by: Greg Hackmann Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/fixmap.h | 5 +++++ arch/arm64/include/asm/pgtable.h | 1 + arch/arm64/kernel/asm-offsets.c | 6 +++++- arch/arm64/mm/mmu.c | 23 +++++++++++++++++++++++ 4 files changed, 34 insertions(+), 1 deletion(-) --- a/arch/arm64/include/asm/fixmap.h +++ b/arch/arm64/include/asm/fixmap.h @@ -51,6 +51,11 @@ enum fixed_addresses { FIX_EARLYCON_MEM_BASE, FIX_TEXT_POKE0, + +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 + FIX_ENTRY_TRAMP_TEXT, +#define TRAMP_VALIAS (__fix_to_virt(FIX_ENTRY_TRAMP_TEXT)) +#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ __end_of_permanent_fixed_addresses, /* --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -692,6 +692,7 @@ static inline void pmdp_set_wrprotect(st extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; extern pgd_t idmap_pg_dir[PTRS_PER_PGD]; +extern pgd_t tramp_pg_dir[PTRS_PER_PGD]; /* * Encode and decode a swap entry: --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -144,11 +145,14 @@ int main(void) DEFINE(ARM_SMCCC_RES_X2_OFFS, offsetof(struct arm_smccc_res, a2)); DEFINE(ARM_SMCCC_QUIRK_ID_OFFS, offsetof(struct arm_smccc_quirk, id)); DEFINE(ARM_SMCCC_QUIRK_STATE_OFFS, offsetof(struct arm_smccc_quirk, state)); - BLANK(); DEFINE(HIBERN_PBE_ORIG, offsetof(struct pbe, orig_address)); DEFINE(HIBERN_PBE_ADDR, offsetof(struct pbe, address)); DEFINE(HIBERN_PBE_NEXT, offsetof(struct pbe, next)); DEFINE(ARM64_FTR_SYSVAL, offsetof(struct arm64_ftr_reg, sys_val)); + BLANK(); +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 + DEFINE(TRAMP_VALIAS, TRAMP_VALIAS); +#endif return 0; } --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -419,6 +419,29 @@ static void __init map_kernel_segment(pg vm_area_add_early(vma); } +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 +static int __init map_entry_trampoline(void) +{ + extern char __entry_tramp_text_start[]; + + pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; + phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); + + /* The trampoline is always mapped and can therefore be global */ + pgprot_val(prot) &= ~PTE_NG; + + /* Map only the text into the trampoline page table */ + memset(tramp_pg_dir, 0, PGD_SIZE); + __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE, + prot, pgd_pgtable_alloc, 0); + + /* ...as well as the kernel page table */ + __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot); + return 0; +} +core_initcall(map_entry_trampoline); +#endif + /* * Create fine-grained mappings for the kernel. */