From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org,
Ard Biesheuvel <ardb@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Kees Cook <keescook@chromium.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: [PATCH 2/2] efi: arm64: Wire up BTI annotation in memory attributes table
Date: Wed, 1 Feb 2023 14:25:40 +0100 [thread overview]
Message-ID: <20230201132540.2196065-3-ardb@kernel.org> (raw)
In-Reply-To: <20230201132540.2196065-1-ardb@kernel.org>
UEFI v2.10 extends the EFI memory attributes table with a flag that
indicates whether or not all RuntimeServicesCode regions were
constructed with BTI landing pads, permitting the OS to map these
regions with BTI restrictions enabled.
So let's take this into account on arm64.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/kernel/efi.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 908499486b00274e..6a61553b64c51dcd 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -97,15 +97,24 @@ int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
return 0;
}
+struct set_perm_data {
+ const efi_memory_desc_t *md;
+ bool has_bti;
+};
+
static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data)
{
- efi_memory_desc_t *md = data;
+ struct set_perm_data *spd = data;
+ const efi_memory_desc_t *md = spd->md;
pte_t pte = READ_ONCE(*ptep);
if (md->attribute & EFI_MEMORY_RO)
pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
if (md->attribute & EFI_MEMORY_XP)
pte = set_pte_bit(pte, __pgprot(PTE_PXN));
+ else if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) &&
+ system_supports_bti() && spd->has_bti)
+ pte = set_pte_bit(pte, __pgprot(PTE_GP));
set_pte(ptep, pte);
return 0;
}
@@ -114,6 +123,8 @@ int __init efi_set_mapping_permissions(struct mm_struct *mm,
efi_memory_desc_t *md,
bool has_bti)
{
+ struct set_perm_data data = { md, has_bti };
+
BUG_ON(md->type != EFI_RUNTIME_SERVICES_CODE &&
md->type != EFI_RUNTIME_SERVICES_DATA);
@@ -129,7 +140,7 @@ int __init efi_set_mapping_permissions(struct mm_struct *mm,
*/
return apply_to_page_range(mm, md->virt_addr,
md->num_pages << EFI_PAGE_SHIFT,
- set_permissions, md);
+ set_permissions, &data);
}
/*
--
2.39.0
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next prev parent reply other threads:[~2023-02-01 13:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-01 13:25 [PATCH 0/2] efi: Enable BTI for EFI runtimes services Ard Biesheuvel
2023-02-01 13:25 ` [PATCH 1/2] efi: Discover BTI support in runtime services regions Ard Biesheuvel
2023-02-01 13:25 ` Ard Biesheuvel [this message]
2023-02-02 17:37 ` [PATCH 0/2] efi: Enable BTI for EFI runtimes services Kees Cook
2023-02-04 8:23 ` Ard Biesheuvel
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