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From: Mark Brown <broonie@kernel.org>
To: Vincenzo Frascino <Vincenzo.Frascino@arm.com>,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>
Cc: Kees Cook <keescook@chromium.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
	Mark Brown <broonie@kernel.org>,
	Amit Kachhap <amit.kachhap@arm.com>,
	Dave Martin <Dave.Martin@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 11/11] arm64: vdso: Map the vDSO text with guarded pages when built for BTI
Date: Wed,  6 May 2020 20:51:38 +0100	[thread overview]
Message-ID: <20200506195138.22086-12-broonie@kernel.org> (raw)
In-Reply-To: <20200506195138.22086-1-broonie@kernel.org>

The kernel is responsible for mapping the vDSO into userspace processes,
including mapping the text section as executable. Handle the mapping of
the vDSO for BTI similarly, mapping the text section as guarded pages so
the BTI annotations in the vDSO become effective when they are present.

This will mean that we can have BTI active for the vDSO in processes that
do not otherwise support BTI. This should not be an issue for any expected
use of the vDSO.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/kernel/vdso.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 033a48f30dbb..3b0289d5cccb 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -142,6 +142,7 @@ static int __setup_additional_pages(enum arch_vdso_type arch_index,
 				    int uses_interp)
 {
 	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
+	unsigned long gp_flags = 0;
 	void *ret;
 
 	vdso_text_len = vdso_lookup[arch_index].vdso_pages << PAGE_SHIFT;
@@ -160,10 +161,13 @@ static int __setup_additional_pages(enum arch_vdso_type arch_index,
 	if (IS_ERR(ret))
 		goto up_fail;
 
+	if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) && system_supports_bti())
+		gp_flags = VM_ARM64_BTI;
+
 	vdso_base += PAGE_SIZE;
 	mm->context.vdso = (void *)vdso_base;
 	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
-				       VM_READ|VM_EXEC|
+				       VM_READ|VM_EXEC|gp_flags|
 				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
 				       vdso_lookup[arch_index].cm);
 	if (IS_ERR(ret))
-- 
2.20.1


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  parent reply	other threads:[~2020-05-06 19:54 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-06 19:51 [PATCH v3 00/11] arm64: BTI kernel and vDSO support Mark Brown
2020-05-06 19:51 ` [PATCH v3 01/11] arm64: Document why we enable PAC support for leaf functions Mark Brown
2020-05-06 19:51 ` [PATCH v3 02/11] arm64: bti: Support building kernel C code using BTI Mark Brown
2020-05-06 19:51 ` [PATCH v3 03/11] arm64: asm: Override SYM_FUNC_START when building the kernel with BTI Mark Brown
2020-05-06 19:51 ` [PATCH v3 04/11] arm64: Set GP bit in kernel page tables to enable BTI for the kernel Mark Brown
2020-05-06 19:51 ` [PATCH v3 05/11] arm64: bpf: Annotate JITed code for BTI Mark Brown
2020-05-07 20:15   ` Daniel Borkmann
2020-05-07 20:15     ` Daniel Borkmann
2020-05-06 19:51 ` [PATCH v3 06/11] arm64: mm: Mark executable text as guarded pages Mark Brown
2020-05-06 19:51 ` [PATCH v3 07/11] arm64: bti: Provide Kconfig for kernel mode BTI Mark Brown
2020-05-06 19:51 ` [PATCH v3 08/11] arm64: asm: Provide a mechanism for generating ELF note for BTI Mark Brown
2020-05-06 19:51 ` [PATCH v3 09/11] arm64: vdso: Annotate " Mark Brown
2020-05-06 19:51 ` [PATCH v3 10/11] arm64: vdso: Force the vDSO to be linked as BTI when built " Mark Brown
2020-05-06 19:51 ` Mark Brown [this message]
2020-05-07 14:33 ` [PATCH v3 00/11] arm64: BTI kernel and vDSO support Will Deacon
2020-05-07 14:35   ` Will Deacon
2020-05-07 14:59     ` Will Deacon
2020-05-07 15:09       ` Mark Brown
2020-05-07 15:18         ` Will Deacon
2020-05-07 15:48           ` Mark Brown
2020-05-07 15:55             ` Will Deacon
2020-05-07 16:30               ` Mark Brown
2020-05-07 16:36                 ` Will Deacon
2020-05-07 16:47                   ` Mark Brown
2020-05-08 16:53                   ` Mark Brown
2020-05-07 15:07     ` Mark Brown
2020-05-07 15:26       ` Will Deacon
2020-05-07 17:25 ` Will Deacon

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