[PATCH 03/55] arm/arm64: KVM: Enforce HYP read-only mapping of the kernel's rodata section
From: Marc Zyngier <hidden>
Date: 2016-07-22 17:28:20
Also in:
kvm, kvmarm
Subsystem:
arm port, arm64 port (aarch64 architecture), the rest · Maintainers:
Russell King, Catalin Marinas, Will Deacon, Linus Torvalds
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 <redacted> Signed-off-by: Christoffer Dall <redacted> --- 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 348caab..f332087 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 45dd6df..b308976 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 29fcb33..88db58c 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)
--
2.8.1