From 74a6b8885f7026e33f8a4776b7ac17c76b8e5a52 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 13 Jun 2016 15:00:47 +0100 Subject: [PATCH] arm/arm64: KVM: Enforce HYP read-only mapping of the kernel's rodata section In order to be able to use C code in HYP, we're now mapping the kernel's rodata in HYP. It works absolutely fine, except that we're mapping it RWX, which is not what it should be. Add a new HYP_PAGE_RO protection, and pass it as the protection flags when mapping the rodata section. Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm/include/asm/pgtable.h | 1 + arch/arm/kvm/arm.c | 2 +- arch/arm64/include/asm/pgtable-prot.h | 1 + 3 files changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index 348caabb7625..f3320870a90a 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -98,6 +98,7 @@ extern pgprot_t pgprot_s2_device; #define PAGE_KERNEL _MOD_PROT(pgprot_kernel, L_PTE_XN) #define PAGE_KERNEL_EXEC pgprot_kernel #define PAGE_HYP _MOD_PROT(pgprot_kernel, L_PTE_HYP) +#define PAGE_HYP_RO _MOD_PROT(pgprot_kernel, L_PTE_HYP | L_PTE_RDONLY | L_PTE_XN) #define PAGE_HYP_DEVICE _MOD_PROT(pgprot_hyp_device, L_PTE_HYP) #define PAGE_S2 _MOD_PROT(pgprot_s2, L_PTE_S2_RDONLY) #define PAGE_S2_DEVICE _MOD_PROT(pgprot_s2_device, L_PTE_S2_RDONLY) diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 45dd6df70cdf..b30897679e53 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -1300,7 +1300,7 @@ static int init_hyp_mode(void) } err = create_hyp_mappings(kvm_ksym_ref(__start_rodata), - kvm_ksym_ref(__end_rodata), PAGE_HYP); + kvm_ksym_ref(__end_rodata), PAGE_HYP_RO); if (err) { kvm_err("Cannot map rodata section\n"); goto out_err; diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h index 29fcb33ab401..88db58cac587 100644 --- a/arch/arm64/include/asm/pgtable-prot.h +++ b/arch/arm64/include/asm/pgtable-prot.h @@ -56,6 +56,7 @@ #define PAGE_KERNEL_EXEC_CONT __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_CONT) #define PAGE_HYP __pgprot(_PAGE_DEFAULT | PTE_HYP) +#define PAGE_HYP_RO __pgprot(_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY | PTE_HYP_XN) #define PAGE_HYP_DEVICE __pgprot(PROT_DEVICE_nGnRE | PTE_HYP) #define PAGE_S2 __pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY) -- 2.30.2